Psychology Review

Tests: Small Samples, Large Consequences

2009-10-16T08:07:00.001-07:00

Dahlstrom, W. G. (1993). Tests: Small Samples, Large Consequences. American Psychologist, 4, 393-399.

Human decision making is a complex process, and one which often has large consequences, both positive and negative. However, this process is not uncommonly fraught with errors of judgment. Psychological tests can serve as a means to offset the impact of these distortions. The article gives several examples of proper and improper use of tests, such as the use of the Stanford-Binet to determine a defendant was not fit to stand trial as an adult, overturning recommendations formerly made by a psychiatrist employing informal ad hoc tests. They define a proper psychological test as meeting six key criteria: using standardized materials and procedures, ensuring optimal motivation in test-takers, recording data immediately, scoring objectively, and establishing test norms. The article is summarized nicely: "The samples of behavior that psychologists collect in the brief time that an hourglass takes to empty have been shown to reveal basic aspects of ability, personality, and temperament that are operative over long spans of an individual's life. Proper gathering of these data by means of well-executed administrations of standardized test instruments can provide gatekeepers with invaluable information to minimize risks of errors of judgment in decisions about their clients and increase the range of predictions that can have large consequences in the lives of those with whom they deal."

Psychiatric Resident Conceptualizations of Mood and Affect within the Mental Status Examination

2009-09-27T19:37:00.001-07:00

Serby, M. (2003). Psychiatric Resident Conceptualizations of Mood and Affect within the Mental Status Examination. American Journal of Psychiatry, 160, 1527-1529.

In the Mental Status Exam (MSE), affect is conceptualized as "external, objective, visible emotional tone. It is also the moment-to-moment measure, while may be labile or constricted, congruent or not with expressed ideas, and may be varied during any interview." Mood, on the other hand, is conceptualized as "an internal, subjective, and sustained emotional state and should be reported as such". However, this study revealed that psychiatric residents do not typically abide strictly to these definitions. They tend to understand that mood is subjective/internal and affect is objective/external, but appear to be less focused on the temporal distinction between the two.

Evidence-Based Assessment of Pediatric Bipolar Disorder

2009-09-27T19:35:00.000-07:00

Youngstrom, E.A. & Duax, J. (2005). Evidence-Based Assessment of Pediatric Bipolar Disorder, Part I: Base Rate and Family History. Journal of American Academic Child and Adolescent Psychiatry, 44, 712-716.

Bipolar disorder is rare in children before puberty, there is controversy about how to diagnose it, and there are few published clinical trials to guide treatment. Additionally, there is evidence that use of stimulants or antidepressants might worsen the course of illness; the compounds most likely to be effective also have the potential for serious side effects and therefore should not be prescribed unless one is confident in the diagnosis and the potential for benefit. On the flip side, there are strong concerns that untreated bipolar disorder will follow a progressive and deteorating course. Therefore, diagnosis of pediatric bipolar disorder (PBD) is both controversial and high-stakes.

This article discusses how one might implement recommendations of Evidenced-Based Practice (EBP) to gather additional information and integrate it in order to obtain greater confidence regarding further testing or treatment. A recent meta-analysis indicates that children with a first-degree relative with bipolar have a 5-fold increase in risk, and children with a second-degree relative with bipolar have a 2.5-fold risk increase. Another recent meta-analysis reveals that no other risk factors besides family history have been sufficiently documented to justify integration into clinical decision-making. Therefore, combining the child's familial information with current diagnostic base rates (which can be obtained from publications reporting rates from similar demographies, clinical settings, and interviewing techniques), and using Bayesian methods can yield probabilities that the specific individual has the diagnosis (or alternately, the frequency with which people showing that test result at that particular clinic would have the condition). If the probability yielded is below the test/no-test threshold, then no further testing may be required. If the number is above the treatment threshold, then treatment may be warranted. (Note: Often the treatment threshold is determined by the clinician in consultation with the family, weighing information about the costs and benefits of treatment.) If the number falls in between these thresholds, then further assessment may be prudent.

The effect of exercise on depression, anxiety, and other mood states

2009-05-01T09:56:00.000-07:00

Byrne, A. & Byrne, D.G. (1993). The effect of exercise on depression, anxiety, and other mood states. Journal of Psychosomatic Research, 37, 565-574.

This review supports the claim that exercise treatments are associated with positive psychological benefits for both clinical and non-clinical populations. Although most of the studies employed aerobic interventions, some studies even showed positive improvements associated with non-aerobic exercise (e.g. weight lifting). However, all of these results need to be interpreted with caution as the result of methodological limitations and indirect evidence. If future studies were to show unequivocally positive psychological gains are caused by exercise interventions, including exercise for people with affective disorders will undoubtedly have a number of advantages since it is time and cost effective by comparison to psychotherapy and pharmacotherapy, comes with few side effects if done correctly, and may even by used to prophylactically prevent the occurrence of future affective episodes.

Repeated stress induces dendritic spine loss in the rat medial prefrontal cortex

2009-04-29T17:57:00.000-07:00

Radley, J.J. et al. (2005). Repeated stress induces dendritic spine loss in the rat medial prefrontal cortex. Cerebral Cortex, 16, 313-320.

The medial prefrontal cortex (mPFC) plays an important role in higher cognitive processes and in the regulation of stress-induced HPA axis activity. This study investigated the effect of stress on dendritic spine density in the mPFC. Rats were restrained for 6 hours daily for 21 days with wire mesh. Following the 21 days of stress, stressed rats weighed less than controls, had a 20% decrease in overall apical dendritic length, a 16% decrease in apical dendritic spine density, and hence an estimated 33% reduction in the total number of axospinous synapses on apical dendrites of pyramidal neurons in the mPFC. These morphological changes may have a significant impact on the functional properties of this region. Clinically, mPFC dysfunction is associated with PTSD and depression. One potential neuroanatomical substrate relevant to these disorders is the mPFC-amygdala circuit. Normally, the mPFC may inhibit amygdala output through its connections on the GABAergic intercalated cells at the border of the lateral and central nuclei of the amygdala. Experimental lesions of the mPFC support this, leading to an enhancement of amygdala-dependent behaviors such as emotionality and fear conditioning. Future studies are needed to investigate the extent to which these morphological changes from chronic stress are reversible.

Comparisons of Stimulus Learning and Response Learning in a Punishment Situation

2009-04-29T11:57:00.001-07:00

Bolles, R.C., Holtz, R., Dunn, T., & Hill, W. (1980). Comparisons of Stimulus Learning and Response Learning in a Punishment Situation. Learning and Motivation, 11, 78-96.

Early on in the study of learning, learning was believed to consist of the attachment of a response to a stimuli (an S-R association). Later, in contrast with the long-held conventional view that all learning was of the S-R form, alternative forms were proposed by Pavlov and others. Examples include stimulus learning (S-S*) and response learning (R-S*). What type of learning underlied punishment, for example? This stimulated debate. In common punishment paradigms, it became obvious that is was unclear whether the animal was learning that shock is correlated there contextually with the bar (stimulus) or whether shock is correlated with its behavior of pressing the bar (response). The purpose of this paper was to attempt to disentangle these different forms of learning experimentally. Four novel experimental paradigms were explored.

Experiment 1 contained one single bar in the chamber which could either be pressed or pulled. Animals had to alternate their behavioral response (press to pull, and back again) in order to be rewarded. Punishment was delivered on every tenth press for half the animals or every tenth pull for the other half. Results showed a rapid initial suppression (fear to environmental stimuli), but later a return to baseline for the unpunishment response and continued suppression for the punished response. This seems to be evidence for both types of learning taking place within one paradigm. Experiment 2 simply adjusted the response contingencies (up and down) to see if results would be sensitive to this type of experimental manipulation. Instead of an FR-10 punishment schedule, rats were shocked on FR-4 or FR-25. FR-4 showed dramatic differences in responding from the outset. FR-25 differences only emerged in the second day of punishment.

Experiment 3 used two bars, each of which could be either pressed or pulled. Thus, four punishment conditions were possible, punishing a left-press, a left-lift, a right-press, or a right-lift. Results showed that when a rat was punished for a left-lift, for example, it quickly stopped lifting AND pressing the left bar. However, it continued to lift AND press the right bar. Thus, learning, in this case, seems to be mostly about stimuli. Experiment 4, like Experiment 2, changed the contingencies. Punishment was shifted from an FR-1 schedule to an FR-10 schedule. Punishment conditions were: press or lift left bar, press or lift right bar, lifting left or right, and pressing left or right. Across the conditions, the general trend that emerged was a rapid emergence of stimulus learning and then a slower but undeniable development of response learning.

Getting comfortable with conversations about race and ethnicity in psychotherapy

2009-04-01T18:55:00.000-07:00

Cardemil, E. V., & Battle, C. L. (2003). Guess who’s coming to therapy? Getting comfortable with conversations about race and ethnicity in psychotherapy. Professional Psychology: Research and Practice, 34, 278-286.

This article urges therapists to engage in open conversations with their clients about race and ethnicity as it applies to the client, the therapist, and the therapeutic alliance. By taking a more active stance and initiating such discussions, especially early in treatment, the therapist may enjoy improved treatment retention, therapeutic alliance, and treatment outcome. After defining race and ethnicity as similar but distinct constructs, the article acknowledges that such conversations will vary in terms of frequency and intensity over different clients and times. It then goes on to provide six recommendations for becoming more comfortable and knowledgeable with having such discussions.

First, it is acknowledged that a client's racial/ethnic background may not be obvious and that it is best to suspend preconceptions about a client and their family members. It is recommended that clients be asked early on in therapy how they identify themselves. Second, it is acknowledged that wide variability exists within racial and ethnic groups and that a client's racial identity development and acculturation process may change over time, thus affecting therapy. Third, it is important to consider how the therapist's own racial/ethnic background may affect the therapeutic process in terms of differences in communication styles and conceptualization of mental health/illness, self, and family/community. Fourth, it is acknowledged that racism, power, and privilege can affect the therapeutic process and that failing to acknowledge such societal issues may invalidate a client's painful personal experiences. Fifth, it is recommended that a client expressing reticence and/or frustration with the topics of race and ethnicity be met with an open and non-defensive explanation that such topics are relevant to many clients, but needn't be pursued if they are found irrelevant or uncomfortable. Lastly, resources for further education/training in race and ethnicity are provided.

Symmetrical effects of amphetamine and alpha-flupenthixol on conditioned punishment and conditioned reinforcement: contrasts with midazolam

2008-12-03T09:15:00.000-08:00

Killcross, A.S., Everitt, B.J., & Robbins, T.W. (1997). Symmetrical effects of amphetamine and alpha-flupenthixol on conditioned punishment and conditioned reinforcement: contrasts with midazolam. Psychopharmacology, 129, 141-152.

There is evidence to suggest that forebrain dopaminergic systems are likely to be involved in both appetitive and aversive motivation. These authors studied the effects of dopamine (DA) agents on conditioned punishment (aversive learning) and conditioned reinforcement (appetitive learning) paradigms using DA agonists and antagonists injected systemically. In conditioned punishment, a Pavlovian CS predicting punishment is added to an instrumental bar-pressing paradigm, but only on one of the bars. Normal animals will adjust their bar-pressing away from this lever. (Note: These authors, however, implemented a punishment procedure by presenting a CS and shock upon bar-press, rather than a conditioned punishment procedure which would only present the CS upon bar-press). In conditioned reinforcement, a CS predicting reward is added to the instrumental bar-pressing paradigm on one of the bars. Animals will naturally come to favor this bar paired with the appetitive CS.

DA agonists increased the effect of a punishing CS, causing the animals to further decrease their bar pressing. DA agonists also enhanced the effect of an appetitive CS, increasing bar pressing. DA antagonists, on the other hand, decreased the effect of a punishing CS. They also reduced the effect of an appetitive CS. Thus, it appears dopaminergic agents modulate the behavioral impact of both appetitively and aversively motivated conditioned stimuli on instrumental performance. Systemic benzodiazepene administration was also explored with results showing a selective impact on aversively-motivated stimuli (i.e. no effect on the appetitive CS).

The Value of Believing in Free Will

2008-11-29T14:13:00.000-08:00

Vohs, K.D. & Schooler, J.W. (2008). The Value of Believing in Free Will. Psychological Science, 19, 1, 49-54.

This study found that weakening people's belief in free-will increased ignoble behaviors, specifically cheating. In the first experiment, a passive cheating paradigm was explored in which a computer "glitch" allowed the correct answer to a question to be flashed onto the screen unless the participant explicitly suppressed it. The experimental group was read a statement encouraging a belief in determinism, while the control condition was read an unrelated statement. Those in the experimental group showed weaker free will beliefs and more frequent cheating.

In the second experiment, an active cheating paradigm was explored. After reading either a pro-free-will statement or an anti-free-will statement, participants were left in the room on the "honor system" and told to reward themselves for their number of correct responses. In this experiment, as in the previous one, participants were under the impression that their anonymity was preserved. Results were similar with the determinism condition showing weaker free will beliefs and higher than average cheating. Thus, people's beliefs regarding their sense of control and self-agency may have social implications.

Different lateral amygdala outputs mediate reactions and actions elicited by a fear-arousing stimulus

2008-11-22T19:26:00.001-08:00

Amorapanth, P., LeDoux, J.E., & Nader, K. (2000). Different lateral amygdala outputs mediate reactions and actions elicited by a fear-arousing stimulus. Nature Neuroscience, 3, 1, 74-79.

One common reaction to threat is elicitation of unlearned species-typical defense reactions. Another is the ability to take novel actions in threatening situations, which may also prove advantageous. In escape-from-fear (EFF) tasks, animals come to learn that an arbitrary response (e.g. stepping into the adjoining chamber) terminates a CS which predicts shock. Authors placed lesions throughout the fear circuit to see try to elucidate function. Lateral amygdala (LA) is believed to be the sensory interface where CS information enters the amygdala; lesions here block acquisition of both conditioned freezing responses, as expected, but also block acquisition of the CS's reinforcement of a new response in the EFF task. Central nucleus (CE) lesions block expression of hard-wired motoric output (i.e. freezing itself), but not the EFF. Basal nucleus (B) lesions had no effect on conditioned freezing, but did block the EFF. By way of interactions between the B and striatal circuits, reinforcement in the amygdala may come to reinforce novel motor responses. Thus, it may be that activation of LA by a CS triggers a reactive response output system via the CE and an active output system via the B.

Nonconscious mimicry as an automatic behavioral response to social exclusion

2008-10-23T11:38:00.000-07:00

Lakin, J.L., Chartrand, T.L., & Arkin, R.M. (2008). I am too just like you: Nonconscious mimicry as an automatic behavioral response to social exclusion. Psychological Science, 19, 8, 816-822.

First, this study showed that following exclusion by a group, participants increased their nonconscious behavioral mimicry of a brand-new interaction partner, reinforcing the expectation that people should be motivated to engage in affiliative behaviors after exclusion. Second, the study attempted to see if this automatic behavior is carried out bluntly, or whether it is sensitive to other factors. Researchers found that individuals excluded by an in-group mimicked the behaviors of a subsequent interaction partner only if the partner was an in-group member (as opposed to an out-group member). Therefore, it appears that people are selective with their use of automatic mimicry, increasing employment of it with people who can potentially restore their status with the in-group. In this way, belongingness was seen as related to mimicry. (Other factors, such as mood, self-esteem, meaningful existence, and control did not appear to be as related.)

Ethanol-conditioned flavor preferences compared with sugar- and fat-conditioned preferences in rats

2008-10-09T13:17:00.000-07:00

Ackroff, K., Rozental, D., Scalfani, A. (2004). Ethanol-conditioned flavor preferences compared with sugar- and fat-conditioned preferences in rats. Physiology & Behavior, 81, 699-713.

Past studies in rats have suggested that the postingestive effects of various nutrients can condition strong flavor preferences. Research has been conducted on ethanol using oral conditioning (where the ethanol is mixed in with the flavoring, thus adding its own flavor to the mixture) and intragastic conditioning (where the ethanol is injected into the rat’s stomach after it ingests the flavoring, thus eliminating the ethanol’s flavor as a conditioning factor). However, the findings of these studies have been somewhat contradictory. Mehiel and Bolles (1988) found that rats equally preferred a flavor paired with ethanol and a flavor paired with sucrose, while Sherman et al. (1983) found that rats preferred a flavor paired with glucose to a flavor paired with ethanol. These studies different in terms of design, route of administration, and sugar used, but it is unclear which of these factors are responsible for the confliction. The present study examined this question in a series of four related experiments.

In the first experiment, sucrose and ethanol were compared to each other as well as to a control of water. These nutrients were each paired with a different flavor and administered through intragastric infusion. Unlimited access to alternating flavor/nutrient combinations was provided during a training period and then the amount of each combination consumed was measuring during a test in which the rats could choose between different combinations. The results were that (1) the rats preferred both sucrose- and ethanol-paired flavors to the water-paired flavor, (2) the rats strongly preferred the sucrose-paired flavor to the ethanol-paired flavor, and (3) the rats ingested more sucrose mixture than ethanol mixture during the training period.

The second experiment attempts to control for finding (3) in experiment one by adding the additional constraint that sucrose mixture consumption was limited to the previous day’s ethanol mixture consumption. Findings (1) and (2) did not change as a result.

In the third experiment, the oral conditioning method was used in place of intragastric infusion for nutrient administration. Once again, the findings did not change.

Finally, in the fourth experiment, ethanol was compared to fructose and corn oil using the intragastic infusions. Similar to the sucrose findings, the rats preferred these new sugars to ethanol, while still preferring ethanol to water.

This study supports the findings of Sherman et al. (1983) and eliminates training intakes, route of administration, and specific sugar/fat as explanations of Mehiel and Bolles’ (1988) contradictory findings. Something other than energy concentration affects the efficacy of ethanol as a reinforcer, making it less powerful than other sugars/fats.

Evidence for episodic memory in a Pavlovian conditioning procedure in rats

2008-10-06T00:24:00.000-07:00

O'Brien, Jamus; Sutherland, Robert J. Evidence for episodic memory in a Pavlovian conditioning procedure in rats. Hippocampus. Vol 17(12) 2007, 1149-1152.

Several requirements have been proposed for establishing episodic memory in nonlinguistic species. Clayton et al. (2003) suggest that episodic memory competence requires integrated representations of “what", "where", and "when” content that can be flexibly updated as more information is gathered. Tests of episodic memory should be novel and unexpected, exceed the capacity of short-term memory (Dere et al., 2006), be unsolvable by familiarity judgments (Gallistel, 1990), and involve memories formed in unique one-trial learning episodes (Morris, 2001). In this article, O’Brien and Sutherland design and run an experiment that attempts to meet these requirements while testing for the flexible and integrated representations required for episodic memory.

In this experiment, twenty-two male Long-Evans rats were run through three experimental phases. In Phase 1, rats were given time to explore two different “contexts” (boxes A and B). These boxes were Plexiglas modular test chambers with steel grid floors. Box A had black colored walls and was scented with Quatzyl-D-Plus, while box B was white and scented with Clinicide. Each rat visited Box A on three successive mornings and Box B on three successive evenings. In Phase 2, rats were exposed to a single immediate shock in a “chimerical” box that was half black, half white, and unscented. For half the rats, this occurred in the morning and for the other half, it occurred in the evening; this is the study’s independent variable. In Phase 3, during mid-day, rats were placed in one of the contexts from Phase 1 (either Box A or Box B). Fear responses (this study’s dependent variable) were then measured by timing conditioned “freezing” behavior.

A repeated measure ANOVA was conducted on the percent of time spent freezing during Phase 3, and it was predicted that rats placed in the context congruent to the time of day of their shock would exhibit more freezing than rats placed in the incongruent context. (For example, if a rat was in Box A in the morning and Box B in the evening during Phase 1 and received its shock in the morning during Phase 2, then the congruent context would be Box A and the incongruent context would be Box B.) The results were a significant relationship in the direction predicted (F_(1,20) = 45.0, P < 0.001).

These findings support the idea that rats acquire memories laden with temporal context (or “when” content), such as the time of day, which is an important requirement of establishing episodic memory competence. Further studies could continue this line of research by establishing evidence for rats generating “what” and “where” content, and by exploring the nature of rats’ temporal cues – possibly endogenous circadian oscillators (Gallistel, 1990) or the age of granule cells in the dentate gyrus of the hippocampus (Aimone et al., 2006).

Modifying shyness-related behavior through symptom misattribution

2008-09-19T13:31:00.000-07:00

Brodt, S.E. & Zimbardo, P.G. (1981). Modifying shyness-related behavior through symptom misattribution. Journal of Personality and Social Psychology, 41, 437-449.

In response to anxiety-evoking stimuli, people develop a complex constellation of reactions. Over time, a general categorical label may come to link these components together and serve as a central explanation. For some people, this label may undergo further transformation from its original situational attribution to a broader usage that includes the person's disposition (personal causality). For example, a person may immediately invoke the label "I am afraid of men" which in turn may kick off a response chain and impose constraints upon it, creating self-fulfilling prophecies. The authors of this study wanted to weaken the 3-part link between perceived symptoms of arousal, the corresponding dispositional label, and resultant behaviors by intervening with symptom misattribution.

In this experiment with 46 college women, the dispositional label studied was shyness -- an excessive self-focus in which potential rejection by other people and social anxiety are salient cognitions. Seeking to redirect the arousal from an anxiety-laden source (being alone with a member of the opposite sex) to a nonpsychological source, the researchers exposed all the groups to intense noise and led the "shy misattribution" group to believe that common side effects of noise bombardment was heart-pounding and increased pulse, symptoms normally associated with their social anxiety. Another group, the "shy comparison" group were led to believe the noise only caused dry mouth. Another "non-shy" group, unlike the other groups did not score high on shyness ratings, were given the same story as the "shy misattribution group". Results showed that shy women, when given an alternative explanation for their social anxiety, were able to overcome normal limitations of their shyness, talking significantly more, acting more assertive, and showing a stronger affiliative preference than the comparison group. Thus, misattribution demonstrates the power of social cognitions in controlling behavior.

Hippocampal involvement in contextual modulaton of fear extinction

2008-09-15T12:59:00.001-07:00

Ji, J. & Maren, S. (2007). Hippocampal involvement in contextual modulaton of fear extinction. Hippocampus, 17, 749-758.

Responding to an extinguished CS is susceptible to many recovery effects. The first is renewal, in which changing the context favors recall of extinguished fear memory. Examination of its several forms (ABA, AAB, ABC) led researchers to postulate that following extinction the meaning of the CS becomes ambiguous and requires context to disambiguate; inhibitory association is "gated" so that its activation requires the simultaneous presence of the CS and the extinction context. The second is spontaneous recovery, or the return of conditional responding with the passage of time. Studies suggest that renewal and spontaneous recovery appear to result from a similar control mechanism, rather than simply erasure of the original fear memory. Therefore, some see SR as another renewal effect that occurs outside of the "temporal extinction context". Third is reinstatement, in which the extinguished response returns after extinction if the animal is merely exposed to the US alone in a distinct context. This, likewise, appears to be a context-dependent process.

These all suggest that extinction involves new learning, and that this learning is especially sensitive to context. The hippocampus, mPFC, and amygdala have been implicated in this learning. One model holds that when the animal is tested within the extinction context, hippocampus drives mPFC inhibition of LA. When animals are presented with an extinguished CS outside of the extinction context, the hippocampus may inhibit mPFC activation and thus promote excitation in the LA to renew extinguished fear under these conditions. Another model posits direct projection from hippocampus to LA subserving contextual modulation of extinction.

Switching on and off fear by distinct neuronal circuits

2008-09-09T10:57:00.000-07:00

Herry, C. et al. (2008). Switching on and off fear by distinct neuronal circuits. Nature, 454, 600-605.

Whereas firing of amygdala neurons is necessary for retrieval of conditioned fear memories, extinction of these fear memories is thought to be controlled by constraining this neural activity by local inhibitory circuitry (under the influence of mPFC). However, fear extinction is known to be a fragile behavioral state, readily influenced by context, i.e. changing context can result in spontaneous recovery. This raises the question of whether there are specialized circuits driving behavioral transitions in opposite directions, namely fear-on and fear-off. This paper showed that neurons in the BA could be divided into distinct functional classes: those exhibiting selective increases in CS+ evoked spike firing during and after fear conditioning (fear neurons) and those exhibiting selective increases in CS+ evoked spike firing during extinction (extinction neurons). Further, close analysis revealed that these two groups were not only functionally different but also differentially connected, with (1) fear neurons selectively receiving input from the hippocampus, and (2) extinction neurons being reciprocally connected to the mPFC while fear neurons only projected unidirectionally to the mPFC. This would indicate that co-localized within the same nucleus, two discrete neuronal circuits exist, intermingled in a salt-and-pepper-like manner. Their close anatomical proximity may serve to facilitate local interactions, although these mechanisms remain unexplored. Taken together with evidence showing emotional perseveration (persistent lack of state change) concomitant with inactivation of the BA, results suggest that the BA is unlikely to be associated with the storage, retrieval, or expression of conditioned fear and extinction memories, but is more likely to mediate context-dependent behavioral transitions between low and high fear states.

mPFC neurons signal memory for fear extinction

2008-09-08T13:25:00.001-07:00

Milad, M.R. & Quirk, G.J. (7 November 2002). Neurons in the medial prefrontal cortex signal memory for fear extinction. Nature, 420, 70-74.

Extinction is a process thought to form a new memory that inhibits the once-learned conditioned response. This paper suggests that consolidation of extinction learning potentiates activity in the infralimbic cortex (IL) of the mPFC which inhibits fear during subsequent encounters with fear stimuli. Electrophysiological recording showed that IL activity remained unresponsive during the conditioning phase and also during extinction training on Day 1. However, by Day 2, activity in the IL in response to tone was present from the start of the extinction phase. Further, stimulation of the IL paired with tone presentation resulted in less freezing behavior and also accelerated extinction learning. Therefore, enhanced extinction learning could be mediated directly by the stimulation or indirectly by the behavioral feedback of decrease freezing. Since the BLA sends excitatory projections to IL, it is possible that these inputs serve to potentiate IL neurons during the consolidation of extinction. The IL is then likely to inhibit expression of fear behavior via its projections to intercalated (ITC) cells in the CE, dampening the output of the amygdala. Pairing reminder stimuli with activation of the ventral mPFC through transcranial magnetic stimulation (TMS) might help strengthen extinction of fear in clinical settings.

Neural mechanisms of extinction

2008-09-08T09:33:00.000-07:00

Quirk, G.J. & Mueller, D. (2007). Neural mechanisms of extinction learning and retrieval. Neuropsychopharmacology Reviews, 1-17.

The simplest form of emotional regulation is extinction, is which conditioned responding to a stimulus decreases when the reinforcer is omitted. Exinction, like any learning process, occurs in 3 phases: acquisition, consolidation, and retrieval. Cannabinoid and opioid receptors appear to be implicated in the acquisition of extinction since anandamide and opioid antagonists impair within-session extinction of fear. Consolidation appears to depend on protein synthesis within the BLA, frequency bursting of the infralimbic region (IL) of the vmPFC shortly after extinction, and general involvement of the hippocampus, especially in tasks such as inhibitory avoidance and contextual fear. Retrieval of extinction memories involves the expression of inhibitory circuitry and is highly context-specific. Inhibition circuitry within the amygdala includes local inhibitory neurons within the BLA and CE, as well as islands of GABAergic neurons between these two sites known as the intercalated (ITC) cells. ITC cells could serve as a site of extinction memory since they inhibit CE output neurons and BLA neurons, acting as an off-switch for the amygdala. ITC cells receive strong projection from the IL mPFC, and IL activity is correlated with the extent of extinction retrieval. In fact, electrical stimulation of IL reduces conditioned fear and strengthens extinction memory. The prelimbic (PL) mPFC, on the other hand, excites fear expression and can augment fear expression via projections to the basal nucleus of the amygdala. Thus, the PFC can fully control overall fear expression. Individuals with PTSD show reduced vmPFC and hippocampal volume and activity, as well as increased amygdala activity. Stress may also impair extinction, since chronic stress is shown to decrease dendritic branching and spine count in hippocampus and mPFC, but increase it in BLA, which could be expected to increase conditioning and impair extinction. Pharmacological adjuncts to current extinction-based exposure therapies may accelerate and strengthen extinction. Among them D-cycloserine, yohimbine, sulpiride, and methylene blue show promise. Administration of glucocorticoids such as cortisol before exposure therapy may also help.

Dopamine gates LTP in lateral amygdala

2008-09-07T19:42:00.000-07:00

Bissiere, S., Humeau, Y., & Luthi, A. (June 2003). Dopamine gates LTP induction in lateral amygdala by suppressing feedforward inhibition. Nature Neuroscience, 6, 6, 587-591.

It has been known that both long-term potentiation (LTP) and concomitant activation of dopaminergic nerves to the amygdala underlie the acquisition of fear conditioning. In fact, dopamine is known to be released in the amygdala during stress and intra-amygdala injection of dopamine receptor antagonists prevents fear conditioning. This study investigated the mechanisms supporting this and showed how dopamine could modulate fear conditioning by modulating inhibitory synaptic transmission within the amygdala. Specifically, D2 dopamine receptors could enable the induction of LTP by suppressing feedforward inhibition from local inhibitory interneurons.

Neuronal Signalling of Fear Memory

2008-09-05T15:28:00.000-07:00

Maren, S. & Quirk, G.J. (November 2004). Neuronal Signalling of Fear Memory. Nature Reviews Neuroscience, 5, 844-850.

Plasticity within the CNS is necessary for the representation of new information, and can range from synthesis and insertion of synaptic proteins to whole-brain synchronization of neuronal activity. Pavlovian fear conditioning is an especially interesting phenomenon since such fear memories are acquired rapidly and are long-lasting. Research first noticed conditioning-induced changes in the midbrain, thalamus, and cortex; however, it was unclear whether or not these were primary sites of plasticity or were simply downstream from other plastic sites. Eventually the lateral nucleus of the amygdala (LA), receiving direct projections from the auditory thalamus, was posited to be vital for auditory fear conditioning. The dorsal subdivision of the nucleus (LAd) seems to be the first site in the auditory pathway to show associative plasticity that is not fed forward passively from upstream sites, is not dependent on downstream sites, and is crucial for conditioned behavior. And LA neurons appear to drive plasticity at both thalamic and cortical levels.

Fear memories are useful to anticipate and respond to dangers within the environment. However, when signals for aversive events no longer predict those events, fear to those signals subsides. This is an inhibitory learning process known as extinction. It appears that although fear subsides after extinction, the fear memory is not erased. Extinction seems to be highly context dependent and sometimes short-lived. Fear responses can be spontaneously recovered over time. It seems biology has deemed it better to fear than not to fear. It is more likely that additional memories which interfere with pre-existing excitatory responses are learned in the extinction process. Again the amygdala seems to be essentially involved here. Further, the mPFC, which has an inhibitory influence on both the LA and the CE (the main output regions of the amygdala) through a rich network of inhibitory interneurons embedded in the amygdala, appears to be a major participant, and is perhaps modulated by context via hippocampus.

Emotion Circuits in the Brain

2008-09-05T12:01:00.001-07:00

LeDoux, J.E. (2000). Emotion Circuits in the Brain. Annual Reviews in Neuroscience, 23, 155-184.

Emotion research was largely lost for some time in the wake of the cognitive revolution. However, people soon realized a purely cognitive view of the brain -- leaving out emotions, motivations, and the like -- is likely to paint an unrealistic view of real minds. Unfortunately, attempts to dig into emotions once again were hamstrung by the limbic system concept, a flawed and inadequate theory of the emotional brain: cognition does not only reside in the neocortex and emotions do not only reside within the limbic system (a moving target itself).

Emotion research began its official resurgence with a bottoms-up examination of fear conditioning, with a bulk of the work focused on the auditory modality. Research soon named amygdala as centrally important, a site where transmission of information about the CS and US converged and output projections controlled fear reactions. On the input side, CS sensory inputs terminate in the lateral amygdala (LA), coming from both the auditory thalamus and the auditory cortex, although plasticity seems to occur initially through the thalamic pathway. US information also seems to converge in the amygdala, receiving inputs from the spino-thalamic tract, cortical areas that process somatosensory stimuli including nociceptive stimuli, the parabrachial area, and the spinal cord. On the outbound side, the central nucleus of the amygdala (CE) projects to autonomic (hypothalamus) and defensive motoric (periaqueductal gray) centers. Methodologies used have largely been single unit recordings, long-term potentiation (LTP) studies, and pharmacological experiments which block LTP. Studies have focused on two types of fear learning: simple fear conditioning (a benign tone comes to evoke a fear response) and contextual fear conditioning (fear responsivity to environmental cues). Research agrees that the amygdala seems to be required for Pavlovian fear conditioning to occur, although the site of long-term fear memory storage is still unknown: it may very well exist in the amygdala, but it may also be distributed across multiple structures or transferred off to cortical areas over time. However, plasticity within the amygdala is probably not required for learning cognitive aspects of fear.

Human studies have echoed many of the results from animal literature. Additionally, they have found perceptual deficits of the emotional meaning of faces in patients with amygdalar damage. The amygdala also appears activated more strongly in the presence of fearful and angry faces than of happy ones. Further, when the activity of the amygdala during fear conditioning is cross-correlated with other regions of the brain, the strongest relations are seen in subcortical areas, emphasizing the importance of the direct thalamo-amygdala pathway in the human brain. Although a fear conditioning approach cannot account for all aspects of human fear and anxiety disorders, it may be especially elucidating for PTSD, panic disorders, and phobias. Difficulty in extinguishing fear memories witnessed in human disorders may also involve the medial prefrontal cortex circuitry.

Future research needs to integrate both cognition and emotion. How fear processing in the amygdala can influence perceptual, attentional, and memory functions of the cortex, and vice versa, is begging for additional research, although it is known that the amygdala does receive input from cortical sensory processing regions and projects back to these both directly and indirectly. How conscious emotional feelings are manifest is also relatively unexplored, although the models posit that feelings may arise from interactions between the amygdala and prefrontal working memory areas, sensory processing areas in cortex, long-term memory systems in the temportal lobe, and arousal systems which maintain global projections.

Our 100th Post!

2008-08-19T18:20:00.001-07:00

Congratulations to all those who posted, i.e. Jeff and I. Maybe we can recruit some more people to join in! Stay tuned.

An Illustration of DBT

2008-08-13T23:25:00.000-07:00

Linehan, M.M. (1998). An Illustration of Dialectical Behavior Therapy. In Session: Psychotherapy in Practice, 4, 2, 21-44.

In addition to providing illustrative transcripts from dialectical behavior therapy (DBT) sessions, the bulk of the read, this paper also summarizes DBT's theoretical perspective, its various treatment stages and targets, as well as treatment strategies. DBT was developed to treat clients meeting criteria for borderline personality disorder (BPD) whose behavioral patterns are commonly problematic and stressful for clients and therapists alike, not the least of which is suicidality. DBT theorizes that BPD individuals lack interpersonal, self-regulation, and distress-tolerance skills, and what skills they do possess are often undermined by behaviors which block the use of the capabilities the client does have. As such, outcomes are typically unpredictable, even for patients who resist the tempting urge to quit and remain in treatment.

DBT recommends splitting up therapy into different stages, each with unique goals. In Stage I, treatment tries to achieve self-control, with control over one's suicidal behaviors being most important. In Stage II, clients try to experience emotions without resistance and to form and maintain connections to people, places, and activities, even if they are somehow associated with past trauma. Stage III focuses on reducing residual problematic patterns that interfere with clients achieving other important goals. When successful, Stage IV achieves a lasting sense of completeness and the capacity for sustained joy.

DBT's treatment strategies include: (1) dialectical strategies which combine acceptance with change, synthesize opposites, and move the client from "either-or" thinking to "both-and" thinking; (2) core strategies of client validation and problem-solving; (3) communication strategies which balance warm responsiveness to the client's wishes with irreverence; and (4) case management strategies which help the therapist tackle the difficult problems of suicidality with team support and aim to ultimately teach the client how to effectively interact with their world, rather than teaching the environment how to interact with them.

Functional analytic psychotherapy

2008-08-12T20:57:00.000-07:00

Kohlenberg, R.J. & Tsai, Mavis. Functional analytic psychotherapy. Journal of Psychotherapy Integration, 4, 175-201.

Functional analytic psychotherapy (FAP) is a radical behaviorist approach to psychotherapy. As such, it views everything we do as behavior and believes these behaviors are the result of contingencies of reinforcement we have experienced in past relationships. The therapy emphasizes the importance of the client-therapist relationship since it creates a functionally similar environment [to the "real world"] which can evoke problematic behavior (deemed CRB1's) that can then be observed and responded to with reinforcement, shaping, and interpretations. Improvements witnessed in-session (deemed CRB2's) can be praised and reinforced immediately, and the clinician's reinforcement can be assessed for effectiveness. Further, its emphasis on contextualism leads therapists to develop a comprehensive understanding of the meaning of a client's behaviors and forces practitioners to remain open-minded about an intervention's potential effectiveness given the context. As such, FAP commonly embraces and enhances concepts and techniques from different therapies, such as psychoanalysis and cognitive therapy. Practitioners of FAP are encouraged to tailor their use of therapeutic techniques depending on: what will evoke the client's problems in the session, whether the client's problems are rule-governed or contingency-shaped, and what will be naturally reinforcing of the client's target behaviors.

Acceptance and commitment therapy

2008-07-29T15:22:00.000-07:00

Harris, R. (August 2006). Embracing your demons: an overview of acceptance and commitment therapy. Psychotherapy in Australia, 12, 4, 2-8.

Acceptance and Commitment Therapy (ACT) is one of the "third-wave" behavioral therapies which emphasizes mindfulness and is intended to be used with a broad range of clinical conditions. The goal of ACT is to create a rich and meaningful life, while accepting the pain that inevitably goes with it. Western psychology has typically operated under the "healthy normality" assumption which states that by their nature, humans are psychologically healthy. That is, they will naturally be happy and content, and suffering is seen as abnormal. However, research shows that psychiatric disorders are exceedingly commonplace, as is nonclinical psyshological suffering, despite our high standards of living. ACT assumes, rather, that psychological processes of a normal human mind are often destructive. They posit that there is a dark side of language and cognition which sits at the root of this suffering. We often struggle with our thoughts and feelings, hoping to change them, avoid them, ameliorate them, and get rid of suffering. In doing so, ACT points at that some of these tactics often create extra suffering for ourselves. These "emotional control strategies" commonly become costly, life-distorting, or harmful. In ACT, there is no attempt to reduce, change, avoid, suppress, or control these private experiences. Instead, mindfulness is encouraged.

ACT commonly employs six techniques: (1) Cognitive Defusion: Learning to perceive thoughts, images, emotions, and memories as what they are, not what they appear to be. (2) Acceptance: Allowing them to come and go without struggling with them. (3) Contact with the present moment: Awareness to the here and now experience with openness, interest, and receptiveness. (4) Observing the self: Accessing a transcendent sense of self, a continuity of consciousness which is changing. (5) Values: Discovering what is most important to one's true self. (6) Committed Action: Setting goals according to values and carrying them out responsibly.

Relapse Prevention for Alcohol and Drug Problems

2008-07-27T17:52:00.000-07:00

Witkiewitz, K. & Marlatt, G.A. (2004). Relapse Prevention for Alcohol and Drug Problems. American Psychologist, 59, 4, 224-235.

Relapse prevention (RP) is a cognitive-behavioral approach with the goal of identifying and preventing high-risk situations such as substance abuse, obsessive-compulsive behavior, sexual offending, obesity, and depression. Relapse is seen as both an outcome and as a transgression in the process of behavior change. An initial setback (lapse) may either translate into a return to the previous problematic behavior (relapse) or into the individual turning again towards positive change (prolapse). That individuals commonly experience lapses, and even relapses, is not contested. However, an understanding of this phenomenon continues to evolve.

Relapse is thought to be multi-determined, especially by self-efficacy, outcome expectancies, craving, motivation, coping, emotional states, and interpersonal factors. High self-efficacy, negative outcome expectancies, potent availability of coping skills following treatment, positive affect, and functional social support are expected to predict positive outcome. Craving has not historically been shown to serve as a strong predictor.

The article proposes a new reconceptualization of relapse as a multidimensional, complex system. Such a nonlinear dynamical system is believed to be able to best predict the data witnessed, which commonly includes cases where small changes introduced into the equation seem to have large effects. The model also introduces concepts of self-organization, feedback loops, timing/context effects, and interplay between tonic and phasic processes. The effectiveness and efficacy of RP for various goals is also discussed in the article.

(I, Doug Girard, am the author of this article, Relapse Prevention, and I release its content under the terms of the GNU Free Documentation License, Version 1.2 and later.)

Theory-based research for understanding dynamic psychotherapy

2008-07-10T20:53:00.001-07:00

Luborsky, L., Barber, J.P., & Crits-Christoph, P. (1990). Theory-based research for understanding the process of dynamic psychotherapy. Journal of Consulting and Clinical Psychology, 58, 3, 281-287.

This article reviews empirical support for 6 basic theoretical assumptions central to psychodynamic psychotherapy. (1) A therapeutic alliance must develop. The strength of therapeutic alliance (the collaborative and affective bond between therapist and client) is shown to predictive of positive outcomes. (2) Patients display transference. Trends from existing studies show central relationship patterns exist which are largely consistent over time and may be projected onto the therapist. (3) Accurate interpretations of transference by the clinician lead to increased benefits for the client. Findings are inconsistent on this point, specifically on the relation between increased number of transference interpretations and outcomes. Mediators may exist, such as how the patient responds to the interpretation. (4) The patient will benefit more from more accurate interpretations. Accurate interpretations correlate with "better" sessions. Accuracy of interpersonal aspects of interpretation predicted outcomes best. (5) Increased insight about themselves and their relationships with others leads to better outcomes. Gaining an understanding about the therapist and others is associated with outcomes. An understanding of self and parents does not seem to be as well correlated. (6) Improved patients show greater change in their transference patterns. Results are consistent with the theory that transference still exists but is under better control and mastery. Patients' expectations of how others will respond becomes less negative and their mental health improves.

Prolonged Exposure Treatment for PTSD following 9/11

2008-07-10T19:54:00.001-07:00

Kazi, A., Freund, B., & Ironson, G. (2008). Prolonged Exposure Treatment for Posttraumatic Stress Disorder following the 9/11 attack with a person who escaped from the Twin Towers. Clinical Case Studies, 7, 100-116.

This article chronicles the progress of one 9/11 survivor through the cognitive-behavioral therapy intervention of prolonged exposure (PE) therapy to address her PTSD and depressive symptomatology. This treatment consists of (1) imaginal exposure, and (2) in vivo exposure. It is designed to elicit emotional processing until the detrimental traumatic memories and avoidances have habituated (desensitized). After 15 sessions this client improved 75% as measured by a composite index. However, there was residual symptomatology 6 months after therapy ended but measures remained sub-clinical. Progress through treatment can be seen as waxing and waning, but trending towards improvement. Still, in this type of therapy clients must be stressed before they are to feel better. With the prevalence of PTSD at 8% in the US population, clinicians are calling more and more for effective treatment regimes. PE may be a promising candidate.

Statistical Functions

2008-06-18T15:24:00.000-07:00

Zimmerman, D. W., & Zumbo, B. D. (1992). Parametric alternatives to the student t test under violation of normality and homogeneity of variance. Perceptual and Motor Skills, 74, 835-844.
*Rank order tests are effective only under violations of normality; modified t-tests are far better under conditions of violated homogeneity of variance

Clinch, J. J. & Keselman, H. J. (1982). Parametric alternatives to the analysis of variance. Journal of Educational Statistics, 7, 215-231.
*Different tests were compared under various assumption violations via Monte Carlo methods; the ANOVA F test did worst, while the Brown/Forsyth method did best overall

Tomarken, A. J. & Serlin, R. C. (1986). Comparison of ANOVA alternatives under variance heterogeneity and specific noncentrality structures. Psychological Bulletin, 99, 90-99.
*ANOVA F test alternatives were compared on Type I error rates and power under variance heterogeneity; the Welch test did best in all cases except when extreme means were paired with high variances, where the Brown/Forsyth method did better

Wilcox, R. R. (1998). How many discoveries have been lost by ignoring modern statistical methods? American Psychologist, 53, 300-314.
*Many nonsignificant research results could have been significant if modern statistical methods had been used; new methods also create more accurate confidence intervals

Alternatives to Null Hypothesis Significance Testing

2008-06-18T15:23:00.000-07:00

Abelson, R. P. (1985). A Variance Explanation Paradox: When a Little Is a Lot. Psychological Bulletin. 97 (1), 129-34.
*Using percent variance to explain the influence of situational factors is misleading

Prentice, D. A., & Miller, D. T. (1992). When small effects are impressive. Psychological Bulletin, 112, 160-164.
*Interpretation of effect size requires careful consideration of the topic being researched

Bem, D. J., & Honorton, C. (1994). Does Psi Exist? Replicable Evidence for an Anomalous Process of Information Transfer. PSYCHOLOGICAL BULLETIN. 115 (1), 4.
*An example of meta-analysis in action, arguing that psi exists (and is replicable)

Kirsch, I. & Sapirstein, G. (1998). Listening to Prozac but hearing placebo: A meta-analysis of antidepressant medication. Prevention & Treatment, 1
*An example of meta-analysis in action, arguing that SSRI’s work through placebo effect

Krueger, J. (2001). Null Hypothesis Significance Testing: On the Survival of a Flawed Method. AMERICAN PSYCHOLOGIST. 56, 16-26.
*Critics and defenders of NHST use Bayesian ideas; the real issue at stake is replicability

Seaman, M. A., & Serlin, R. C. (1998). Equivalence Confidence Intervals for Two-Group Comparisons of Means. PSYCHOLOGICAL METHODS. 3 (4), 403-411.
*Equivalence confidence intervals can and should replace NHST for determining if two group means are practically equivalent

Duckworth, W.M. and Stephenson, W.R. Resampling methods: Not just for statisticians anymore. Invited paper presented at JSM 2003, San Francisco, CA.
*Explores how to teach resampling methods (jackknife and bootstrap) to psychologists

Controversy in Null Hypothesis Significance Testing

2008-06-18T15:20:00.000-07:00

Macdonald, R. R. (1997). On statistical testing in psychology. BRITISH JOURNAL OF PSYCHOLOGY. 88 (2), 333-348.
*Criticisms of NHST apply to Neyman-Pearson approach, but not the Fisherian approach

Huberty, C. J. (1993). Historical Origins of Statistical Testing Practices. Journal of Experimental Education. 61 (4), 317-33.
*Textbooks in psychology confuse the use and interpretation of p-values and alpha-levels

Gigerenzer, G. (1993). The superego, the ego, and the id in statistical reasoning. In G. Keren & C. Lewis (Eds.), A handbook for data analysis in the behavioral sciences: Methodological issues (pp. 311-339). Hillsdale, NJ: Lawrence Erlbaum Associates.
*Textbooks present an incoherent “hybrid logic,” mixing Neyman-Pearson and Fisher

Kaiser, H. (1960). Directional statistical decisions. Psychological Review. 67, 160-167.
*When using two-sided tests, it makes no sense to use a non-directional test

Greenwald, A. G. (1975). Consequences of prejudice against the null hypothesis. Psychological Bulletin, 82, 1-20.
*The false ideas that null results are useless or more likely to be due to incompetence prevents (or at least slows) scientific progress

Rosenthal, R. (1979). The “File Drawer Problem” and tolerance for null results. Psychological Bulletin, 86, 638-641.
*Research that results in null results are rarely published, making a field of research look more “significant” than it might actually be

Rozeboom, W. W. (1960). The fallacy of the null-hypothesis significance test. Psychological Bulletin. 57, 416-28.
*Using statistical tests to make “decisions” is naïve and rejection criteria are arbitrary, calling for a use of confidence intervals and (if possible) Bayesian statistics

Bakan D. (1966). The test of significance in psychological research. Psychological Bulletin. 66 (6), 423-37.
*Statistical results are often misinterpreted, calling for Bayesian methods

Hunter, J. E. (1997). Needed: A Ban on the Significance Test. PSYCHOLOGICAL SCIENCE -CAMBRIDGE-. 8 (1), 3-7.
*NHST breaks down when H0 is false and most studies purposely use H0's they know to be false, causing the error rate (Type I and II) of NHST to be around 60%

Cohen, J. (1994). The Earth Is Round (p <.05). AMERICAN PSYCHOLOGIST. 49 (12), 997.
*The logic of NHST is flawed and backwards; we need to better understand our data

Cohen, J. (1990). Things I Have Learned (So Far). American Psychologist. 45 (12), 1304-12.
*Informed judgment from the researcher is indispensable; power analysis can help

Loftus, G. R. (1996). Psychology Will Be a Much Better Science When We Change the Way We Analyze Data. CURRENT DIRECTIONS IN PSYCHOLOGICAL SCIENCE. 5 (6), 161-170.
*Null hypotheses are rarely possible, making “significance” useless; power is under-attended and the dichotomy of effects/non-effects is artificial

Harris, R. J. (1997). Reforming significance testing via three-valued logic. In Harlow, L.L., Mulaik, S.A., & Steiger, J.H. (Eds.) What if there were no significance tests? Hillsdale, NJ: Erlbaum.
*Three-valued logic can establish directionality and address Type III error

Wilkinson, L. (1999). Statistical Methods in Psychology Journals: Guidelines and Explanations. AMERICAN PSYCHOLOGIST. 54 (8), 594-604.
*APA decided not to ban NHST, instead urging researchers to distinguish between statistical and theoretical significance, and also use modern statistical graphics

Abelson, R. P. (1997). On the Surprising Longevity of Flogged Horses: Why There Is a Case for the Significance Test. PSYCHOLOGICAL SCIENCE -CAMBRIDGE-. 8 (1), 12-15.
*NHST can be used effectively in combination with other methods; enforcing a complete ban on it would be throwing away a tool that can be useful in a number of situations

Greenwald, A. G., Gonzalez, R., Harris, R. J., & Guthrie, D. (1996). Effect Sizes and p Values: What Should Be Reported and What Should Be Replicated? PSYCHOPHYSIOLOGY. 33 (2), 175-183.
*The interpretation of p-values in terms of replicability is widely mistaken

Harris, R. J. (1997). Significance Tests Have Their Place. PSYCHOLOGICAL SCIENCE -CAMBRIDGE-. 8 (1), 8-11.
*Three-valued logic can help NHST; using confidence intervals as an alternative runs into the same problems as NHST, while providing less information than a p-value would

Jones, L. V., & Tukey, J. W. (2000). A Sensible Formulation of the Significance Test. PSYCHOLOGICAL METHODS. 5, 411-414.
*Yet another iteration of the virtues of three-valued logic applied to NHST

Balancing work and family

2008-06-05T13:35:00.001-07:00

Pleck, J.H. (1999). Balancing work and family. Scientific American Presents: Men's Health.

With women's move into the workplace over the last few decades, men's roles have changed as well. Men spend much less of their lives working than they did in the past. Father's are not only becoming more available, but more engaged in the family as well. However, these effects are countered by an increase in divorce rates and an increase in the number of unmarried fathers. The family is far more psychologically central to men than work, as is the case for women. Fathers tend to carry their emotions home with them from work, whereas mothers keep their family experiences insulated from the workplace. There also still exist gross gender differences in the nature of behavioral interaction with children. However, despite changing roles, companies have not caught up in their sympathy for their male employees' work-family problems, so social change is still lagging.

Child care quality matters

2008-05-25T16:12:00.000-07:00

Love et al. (August 2003). Child care quality matters: how conclusions may vary with context. Child Development, 74, 4, 1021-1033.

A report from the NICHD concluded that more time spent in a variety of nonmaternal care arrangements leads to more externalizing behavior problems, regardless of child care quality. Authors were skeptical and tested the generalizability of these findings with 3 other studies. These new findings suggest that quality of child care is an important factor influencing children's development, and that quality may be an important moderator of the amount of time in care.

Cultural variation in infant's sleeping arrangements

2008-05-09T14:53:00.000-07:00

Morelli, G.A., Rogoff, B., Oppenheim, D., & Goldsmith, D. (1992). Cultural variation in infant's sleeping arrangements: Questions of Independence. Developmental Psychology, Vol. 28, No. 4, 604-613.

Cultural practices differentiate infant sleep arrangements. In the middle-class US population, a common goal is to have infants sleep in their own rooms as soon as possible, consonant with the culture's importance on independence. In the Mayan population, it is not uncommon for children to sleep with their parents or other siblings well on into childhood, reflecting their culture's value on interpersonal relations. Changes are not prescribed by the authors; instead, broader cultural perspective is offered for American readers.

Seasonal changes of hippocampus volume in parasitic cowbirds

2008-05-07T15:20:00.000-07:00

Clayton, N.S., Reboreda, J.C., & Kacelnik, A. (1997). Seasonal changes of hippocampus volume in parasitic cowbirds. Behavioral Processes, 41, 237-243.

This study compared a set of phylogenetically closely related species with striking differences in natural behavior, offering the opportunity for seeking neural differences in association with these behavioral changes. Notable differences exist in these South American cowbirds of the genus Molothrus related to parasitic nesting. In one species, the birds are especially active during the breeding season, searching and locating potential hosts' nests. In another two species, only females are active during the breeding season in locating potential hosts' nests (sexual dimorphism). A fourth species is non-parasitic and no sexual differences are known with respect to spatial memory use in either season. Results show that the first species shows significantly larger relative hippocampal volume in the breeding season. The sexual dimorphic species show significantly larger relative hippocampal volume in the breeding season, but only in females. The evidence suggests seasonal variation in neuroanatomy associated with specific changes in behavior, namely spatial memory demands, as opposed to purely seasonal fluctuations per se.

Continuous flash suppression reduces negative afterimages

2008-05-07T14:09:00.000-07:00

Tsuchiya, N. & Koch, C. (August 2005). Continuous flash suppression reduces negative afterimages. Nature Neuroscience, Vol. 8, No. 8, 1096-1101.

Continuous flash suppression (CFS) is a tool that can be used to reliably suppress vivid images from conscious awareness for long periods of time. Here, different patterned images ("Mondrians") are flashed rapidly into one eye while input to the corresponding location in the other eye remains fixed, the latter typically remaining unseen often for durations greater than ten times what can be achieved with binocular rivalry or other masking methods, even though the image remains present on the retina for several minutes. Interestingly, researchers discovered that negative afterimages or "photogenes", effects lingering in view after termination of the visual stimulus, also seem to be diminished with exposure to CFS. Though it is widely believed that afterimages originate among retinal neurons, this evidence supports the conclusion that the weakened afterimage must be due to interference from sites at or beyond binocular convergence, such as the lateral geniculate nucleus (LGN) or cortex. Specifically, it must be an area which receives input from both eyes but does not correspond directly to the neuronal correlates of perceptual awareness. The results hint at differences between concepts of attention and awareness.

Sign Language in the Brain

2008-05-06T11:01:00.000-07:00

Hickok, G., Bellugi, U. & Klima, E.S. (June 2001). Sign Language in the Brain. Scientific American.

Because sign language relies heavily upon visual-spatial contrast, one might expect sign language to be supported by systems in the right hemisphere rather than the traditional left hemisphere language systems. However, this does not appear to be the case. A deaf signer with damage to Wernicke's area is likely to have comprehension difficulties and one with damage to Broca's area may have difficulty producing signs, just like normal speakers. And signers with right hemisphere damage continued to be fluent and accurate in their production of signs, used normal grammar, and comprehended signs with ease. One exception of the left hemisphere's monopoly on language production is creation of a coherent discourse, where right hemisphere damage may lead to rambling as it tends to be involved in more global-level processes. Generally speaking, sign language abilities of lifelong signers appear to be independent of their nonlinguistic spatial skills. Thus, it is likely that signers maintain unique early stages of processing compared to regular speakers, but thereafter neural organization is quite similar, being translated into a format optimized for linguistic processing and being routed to central linguistic systems.

Marijuana use as a coping response

2008-05-05T17:49:00.001-07:00

Preston, P. (2006). Marijuana use as a coping response to psychological strain: racial, ethnic, and gender differences among young adults. Deviant Behavior, 27, 397-420.

Besides tobacco and alcohol, marijuana is the most frequently used and abused substance. This study used data taken from the National Household Survey of Drug Abuse (from all 50 states), and examined 4601 subjects between the ages of 18-25 who used marijuana within the past year. Their dependent variable was marijuana use frequency, defined as either recreational or chronic, with chronic being greater than 12 times per month. Independent variables measured included strain, economic strain, norms favorable to drug use, number of friends who use drugs, and attitudes towards risky behavior. Results were also examined through the lenses of gender, ethnicity, marital status, employment status, and education.

Results indicate that social learning factors have the strongest effect on chronic marijuana use, operationalized as the number of friends who use drugs and a personal approval of drug use. Strain (operationalized as social nervousness) had the next strongest effect. Self control had a weak effect overall. High school dropouts and the unmarried were found to be particularly at risk for becoming chronic users. Strain appeared to have a stronger effect on minority groups, possibly suggesting fewer alternative coping strategies in this population. Minority women experience a "double-whammy", more likely than their nonminority counterparts to be chronic users and also more likely to be affected by social learning and self control variables.

Love in Infant Monkeys

2008-05-05T10:31:00.000-07:00

Harlow, H.F. (June 1959). "Love in Infant Monkeys", Scientific American.

Harlow used baby rhesus monkeys to yield insights into the origin of the infant's love for its mother and concluded that bodily contact comfort is a decisive variable in this relationship. For example, newborn monkeys preferred a surrogate "cloth" mother to a "wire" mother, and sought out the cloth mother in times of emotional stress. Other variables were also explored. A mother's rocking motion appeared to enhance affection, but less so than simple contact. Heat of the mother did not appear to be an important variable. Other visual, auditory, and olfactory stimulation may also play a role. Additionally, a critical period to attachment formation seems to be evident.

Neuronal activity related to faces and matching

2008-04-25T10:28:00.001-07:00

Ojemann, J.G., Ojemann, G.A., & Lettich, E. (1992). Neuronal activity related to faces and matching in human right nondominant temporal cortex. Brain, 115, 1-13.

Using microelectrode recording, this group set out to look at changes in neuronal activity in response to faces, previously described in monkey cortex but not well established in humans. Recording was restricted to areas of right anterior temporal cortex that would be later resected in an epileptic lobectomy, areas that showed the least epileptic activity on electrocorticography. Seven neuronal populations related to face perception were identified. In addition, three other populations, only in middle temporal gyrus, increased activity with the labelling of the emotional expression of a face. The ease with which a given task can elicit specific, temporally-coupled changes in neuronal activity suggest that human association cortex is compartmentalized into behaviorally specific systems.

Addressing Psychosocial Problems at Work

2008-04-18T10:12:00.000-07:00

Probst, T.M. et al. (2008). A preliminary evaluation of SOLVE: Addressing Psychosocial Problems at Work. Journal of Occupational Health Psychology, Vol. 13, No. 1, 32-42.

SOLVE is a workplace intervention program implemented by many companies worldwide which aims to address the interrelated issues of job stress, workplace violence, tobacco use, drug and alcohol abuse, and HIV/AIDS. Psychosocial issues tend to coexist, e.g. stress leads to workplace hostility which spills over into home life and often results in poor coping strategies. SOLVE is based on cognitive behavioral therapy (CBT) models, which believe that behavior is influenced by cognitions, knowledge is necessary for behavioral change, and both are broadly influenced by dynamic interactions between numerous forces. Therefore, SOLVE attempts to make individuals aware of threats and their consequences, make them aware of benefits of the touted strategies, and provide specific information for tackling the health-related issues, while being both person- and organization-directed. Although SOLVE is used widely, its efficacy has not been evaluated. Current studies demonstrate improvements in knowledge among participants across locale which is encouraging. However, they do not assess attitudinal or behavioral changes, or bottom-line benefits to the organization.

The Visual Cliff

2008-04-17T22:27:00.000-07:00

Gibson, E.J. & Walk, R.D. (April 1960). The "Visual Cliff". Scientific American.

To investigate depth perception in human and animal species, these authors created the "visual cliff" which allowed them to experimentally adjust the optical and tactical stimuli associated with a simulated cliff while protecting the subjects from injury. They discovered that all species can perceive and avoid a sharp drop by the time they take up independent locomotion, be it at Day 1 in chicks, 4 weeks in rats, or 6 months in humans. Most rely on visual cues for depth perception. The rat, however, relies predominantly on tactual cues (being nocturnal) but will fall back on sound vision when needed. Next, the experimenters wanted to find out which visual cues played the decisive role in depth perception. Using dark-reared animals, they concluded motion parallax is an innate cue for depth discrimination, whereas responses to differential pattern-density may be learned later.

(I, Doug G, am the author of this article, The Visual Cliff, and I release its content under the terms of the GNU Free Documentation License, Version 1.2 and later.)

Web-based Methods in Terrorism and Disaster Research

2008-04-17T21:27:00.000-07:00

Schlenger, W.E. & Silver, R.C. (April 2006). Web-based Methods in Terrorism and Disaster Research. Journal of Traumatic Stress, Vol. 26, No. 2, 185-193.

Gaining access to a traumatized population in the aftermath of a disaster can be challenging. The need for rapid response and appropriate probability sampling along with the observational nature of the studies (i.e. no random assignment) and post-only design can be problematic for the generalizability of the results. Recently, web-based methods have helped to address some of these age-old issues. (1) The literature indicates that people respond more honestly to sensitive questions in self-report than in interview-based assessments. (2) The use of e-mail also assists greatly with retention rates in longitudinal studies. (3) Respondents can answer surveys within the privacy of their home at a time that is convenient to them. (4) Question delivery can be standardized. (5) Time-consuming and error-prone steps of data coding and entry are eliminated. (6) And most importantly, recent companies such as Knowledge Networks Inc. have recruited nationally representative probability samples for just such uses. Panels can even be created in advance of disasters, enabling premeasure to be linked to postevent responses. However, these new technologies are not without their issues, e.g. populations may suffer infrastructure disruptions due to disaster that render data collection impossible such as in Hurricane Katrina.

The Early Origins of Autism

2008-04-17T16:41:00.000-07:00

Rodier, P.M. (February 2000). The Early Origins of Autism. Scientific American.

Miller and Stromland made a surprising observation that 5% of thalidomide victims had autism, a rate about 30 times higher than the rate among the general population. This suggested that autism originates in the early weeks of pregnancy when the nervous system is just beginning to develop. Examining these victims' specific malformations indicated that their development had been impacted about 20-24 days into gestation, before many pregnant women even know they are pregnant. This was way earlier than investigators would have guessed, since very few neurons are even formed by the 4th week. However, most are the motor nerves of the cranial nerves in the brain stem. And indeed, many subjects with autism exhibit abnormalities of eye movement and lack of facial expression, consistent with this observation.

However, it is more likely that these early brain injuries affect more than just the function of the cranial nerve, and may interfere with proper development or wiring of other brain regions in turn. People with autism consistently show a reduction in the number of neurons in the cerebellum of the brainstem, a structure typically thought to involved in fine motor control but also seen activated during certain tasks requiring high-level cognitive processing. Some people with autism also display marked decreases in the facial nucleus (controls muscles of facial expression) and superior olive (a relay station for auditory information). Interestingly, "knock-out" mice engineered to lack the expression of the gene known as Hoxa1 (active when brainstem neurons are forming), show all of these symptoms. While variant alleles of Hoxa1 have been identified, these are only one of many genes involved in the spectrum of autism disorder. Other genes must be found which also increase the risk (or decrease the risk) of developing the disorder.

Coping with stress in different phases of romantic development

2008-04-16T11:34:00.000-07:00

Nieder, T. & Seiffge-Krenke, I. (2001). Coping with stress in different phases of romantic development. Journal of Adolescence, 24, 297-311.

This study followed adolescents longitudinally between ages 14 and 17, annually measuring their quality of relationships, their stress levels, and their coping styles. The results taken together provide support for a developmental sequence in romantic development. The percent of participants in a relationship increased over this time period, and the durations of these relationships increased with time. With this came increases in depth -- intimacy, affection, and extent of sexual activity. Romantic stress was highest in earlier years stemming from diverse sources, later decreasing and stabilizing with age. And active coping with romantic stress was lowest initially and significantly increased at 15, remaining high. As romantic relationships develop, stress is more and more related to conflicts between the romantic partners; yet such conflicts are increasingly resolved by dyadic communication as a coping strategy. Surprisingly, the development of a more active coping style over time was not associated with the decrease in amount of romantic stress. Instead, intimacy and affection is consistently associated with reduced stress, suggesting that as the relationship matures over time romantic stress decreases.

HPA Axis, neuroendocrine factors, and stress

2008-04-07T17:39:00.000-07:00

Tsigos, C. & Chrousos, G.P. (2002). Hypothalamic-pituitary-adrenal axis, neuroendocrine factors, and stress. Journal of Psychosomatic Research, 53, 865-871.

Psychology is concerned with the transactions and interactions we have with the world. Stress research examines how we respond to transactions that are stressful. This paper does a great job to illustrate the complexity of our physiological responses to stressors.

CRH/AVP. The paper begins with our physiological response following detection of a stressor. CRH and AVP are secreted into a special portal system and activate neurons of the paraventricular nuclei (PVN) of the hypothalamus, which primarily kicks off activation of the greater hypothalamic-pituitary-adrenal (HPA) axis.

LC/NE system. The locus ceruleus and other noradrenergic cell groups of the medulla and pons, collectively known as the LC/NE system, serve as a global alarm system, using brain epinephrine to execute autonomic and neuroendocrine responses.

The autonomic axis. The ANS provides rapid response to stress, engaging the SNS and withdrawing the PSNS, and enacting cardiovascular, respiratory, gastrointestinal, renal, and endocrine changes.

The HPA Axis. CRH and AVP normally follow certain circadian rhythms, with increasing pulses seen in the early morning hours and decreasing throughout the day. During acute stress, pulsations in this portal system markedly increase, resulting in release of ACTH from the pituitary into the general bloodstream, which finally results in secretion of cortisol and other glucocorticoids from the adrenal cortex. These corticoids involve the whole body in the organism's response to stress and ultimately contribute to the termination of the response via inhibitory feedback.

Other changes. Concomitant with the aforementioned changes, the sympathetic-adrenomedullary system (SAM) influences the body organs, and vagal and sacral parasympathetic responses are also instantiated mediating our gut responses to stress.

The paper also goes into advanced topics including interactions that exist between the HPA axis and the immune system, interactions between the HPA and the gonadal and growth axes, and interactions between the HPA and metabolism. It also discusses pathologies related to the HPA axis. A spectrum of conditions may be associated with increased and prolonged activation of the HPA axis, including melancholic depression, anorexia nervosa, OCD, panic anxiety, excessive exercising, and childhood sexual abuse. Another group of conditions may be associated with hypoactivation of the stress system, including atypical depression, seasonal depression, and chronic fatigue syndrome. Antalarmin, a CRH-R1 antagonist, was also mentioned as being a potentially important drug to combat HPA axis disorders characterized by HPA and LC/NE hyperactivity in the future.

Language Interpretation and the Immediacy Assumption

2008-04-04T12:34:00.000-07:00

Hagoort, P. & von Berkum, J. (April 3, 2007). Beyond the sentence given. Philosophical Transactions of the Royal Society, 362, 801-811.

The view that language interpretation takes place in a two-step process has predominated, with the meaning of the sentence being computed first and the sentence meaning then being integrated with other sources of information (e.g. context, world knowledge). However, event-related brain potentials (ERPs) appear to be inconsistent with this model, finding strong empirical evidence that linguistic and extra-linguistic information are integrated in the same time-frame during sentence interpretation. Similar latencies and amplitudes of the N400 effect witnessed for all types of semantic mismatches support the immediacy assumption, that disparate information is brought to bear on language interpretation as soon as it becomes available. Neuroimaging studies suggest that the left inferior frontal cortex, including Broca's area, is an important node in the semantic unification network, and that this area is not language specific but acts as a single integration space.

Depression and cortisol responses to psychological stress

2008-03-31T23:10:00.000-07:00

Burke, H.M., Davis, M.C., Otte, C., & Mohr, D.C. (2005). Depression and cortisol responses to psychological stress: a meta-analysis. Psychoneuroendocrinology, 30, 846-856.

This meta-analysis pulled data from seven studies (196 participants with an average age of 40), each of which examined responses to psychological (non-pharmacological) stressors. Specifically, it examined the relationship between major depressive disorder (MDD) and levels of the stress hormone cortisol during three stages of experimentally-induced stress: (1) unstimulated 'baseline', (2) 'stress reactivity' in which cortisol increases from baseline, and (3) 'stress recovery' in which cortisol returns to baseline levels.

They concluded that at baseline MDD patients have lower cortisol levels than their non-depressed (ND) counterparts in morning studies and higher baseline cortisol levels than control groups in afternoon studies. This reveals somewhat opposite patterns of normal daily cortisol fluctuation (although some have described this as simply flattened diurnal activity). Therefore, it was critical to control for these baseline effects seen in the MDD group. After adjusting for these baseline effects, MDD individuals showed blunted stress reactivity and impaired stress recovery by comparison to controls.

Put simply, normal subjects show specific baseline patterns of cortisol release throughout the day and exhibit boosted cortisol levels and rapid recovery to baseline in response to stressors. These healthy cortisol activity curves are dynamic and responsive. MDD subjects, in contrast, show abnormal baseline patterns during the day and exhibit relatively flat and unresponsive patterns of cortisol secretion during and following stress. These effects were found to be most pronounced in older and more severely depressed patients. This altered hypothalamic-pituitary-adrenal (HPA) axis functioning appears somehow linked to depression.

Aversive learning enhances perceptual and cortical discrimination

2008-03-31T16:46:00.000-07:00

Li, W, Howard, J.D., Parrish, T.B., & Gottfried, J.A. (March 28, 2008). Aversive learning enhances perceptual and cortical discrimination of indiscriminable odor cues. Science, Vol. 319, 1842-1844.

With this study, the authors explored the impact of aversive conditioning on olfactory discrimination. While most conditioning studies examine the acquisition of new behavioral responses (CR) to formerly benign stimuli presentations, this examined how associative learning can actually alter the perceptual processing of the conditioned stimulus (CS) itself. Following a conditioning regimen, behavioral accuracy for distinguishing by smell between a previously indistinguishable pair of molecules (CS+) rose by more than a factor of 2, exceeding both chance and preconditioning performance. Interestingly, following conditioning, no improvement in distinguishing between the unconditioned control pair (CS-) was witnessed, indicating that these effects are specific to the CS+. After conditioning, reorganization of neural coding was also observed in the posterior piriform cortex, where neural representations of odor identity are maintained. This may shed new light on anxiety disorders which are characterized by exaggerated sensory sensitivity and hypervigilance, potentially self-reinforcing patterns.

Prolongation of brainstem auditory-evoked responses in Autistic probands and their unaffected relatives

2008-03-18T18:05:00.000-07:00

Maziade, M. et al. (2000). Prolongation of brainstem auditory-evoked responses in Autistic probands and their unaffected relatives. Arch Gen Psychiatry, 57, 1077-1083.

Genetic factors play a major role in autism, with heritability greater than 90%. As the search for biological markers of autism continues, electrophysiological markers have been considered more and more. Early EEG studies comparing autistic subjects to control subjects revealed differences in early brain auditory-evoked responses (BAER). Prolonged BAERs indicate a slowing in nerve conduction within the early auditory system. This study confirmed slow latencies between consecutive sequential waves in autistic individuals, and went further to show that first degree relatives also show significantly longer interpeak latencies (IPLs) than matched controls. Although no significant prolongation was found in second and third degree relatives, resemblance of the IPL trait was found within families. While autism is a complex disorder, perhaps a combination of many neurophysiological deficits, IPL prolongation could be a marker of one of these deficits.

Anterior prefrontal function

2008-03-11T20:54:00.000-07:00

Koechlin, E. & Hyafil, A. (October 26, 2007). Anterior prefrontal function and the limits of human decision making. Science, Vol. 318, 594-598.

Based on recent empirical findings and predictions from a neurocomputational model, the authors of this review propose a role for the not-yet-well-understood frontopolar cortex (FPC), also known as the anterior prefrontal cortex or Brodmann's area 10. They argue that processing of 'cognitive branching' is the core function of the FPC. Cognitive branching enables a previously running task to be maintained in a pending state for subsequent retrieval and execution upon completion of the ongoing one. Many of our complex behaviors and mental activities require simultaneous engagement of multiple tasks, and the FPC may perform a domain-general function in these scheduling operations.

Empowering Techniques of Play Therapy

2008-03-11T20:16:00.000-07:00

Griffith, M. (1997). Empowering Techniques of Play Therapy: A Method for Working with Sexually Abused Children. Journal of Mental Health Counseling. 19 (2), 130-42.

This article, like many others, begins with a brief survey of play therapy theory. It is remarked that play is the natural medium of expression for children and that sexual abuse seems to block many basic developmental needs. Treatment goals are outlined and plotted along a pattern which the process of therapy follows. A case study is provided to articulate these points and exemplify the "five stages" of play therapy. These stages are the establishment of the therapeutic relationship, the later exploratory stage (in which regressive and repetitive behaviors often appear), the limit-setting stage (in which the child tests the boundaries and safety of the therapeutic setting), the growth stage (see below), and the termination stage. Treatment goals in the growth stage involve confronting the "four characteristics of sexual trauma" which are sexual traumatization, stigmatization, betrayal, and powerlessness. Sexual traumatization can lead to confusion between sexuality and affection, confusion about sexual norms, age-inappropriate sexual knowledge, and sexual behavior. It is believed that through the use of empowering techniques of play therapy (expressive/imaginative play and non-direction), the emotional distress of sexual abuse can be relieved and normal psychological development can resume.

The gateway hypothesis of rostral prefrontal cortex function

2008-03-11T18:19:00.000-07:00

Burgess, P.W., Dumontheil, I., & Gilbert, S.J. (2007). The gateway hypothesis of rostral prefrontal cortex (area 10) function. Trends in Cognitive Science, Vol. 11, No. 7.

The rostral prefrontal cortex, area 10, is a particularly large brain region in humans, but its function is still poorly understood, to which this paper provides a nascent hypothesis. Their 'gateway hypothesis' suggests that the rostral PFC serves as a gateway between the internal mental life that exists in the absence of sensory influence (i.e. pure, imaginative cognition) and stimulus-oriented cognition. They maintain that lateral and medial subregions are differentially sensitive to changes in demands for stimulus-oriented or stimulus-independent attending, and together their coordination enables us to attend to either environmental stimuli or to self-generated representations. They highlight initial supporting evidence and discuss goals for future experimentation.

(A more general role is proffered by Koechlin & Hyafil.)

Neural substrates of musical creativity

2008-03-11T14:45:00.001-07:00

Limb, C.J. & Braun, A.R. (February 2008). Neural substrates of spontaneous musical performance: an fMRI study of jazz improvisation. Public Library of Science ONE, 3, 2, e1679.

This study imaged jazz musicians with fMRI during low and high complexity improvisational sessions to look for correlations in brain activation/deactivation patterns. They found widespread deactivation in the dorsolateral prefrontal cortex (dlPFC), where goal-directed behaviors are thought to be consciously monitored, evaluated, and corrected. Deactivation was also observed in limbic structures. They also found consistent activation in sensorimotor areas, as expected, as well as focal activation in the medial prefrontal cortex (MPFC), a currently poorly understood structure. An emerging view sees this region, Brodmann Area 10, as playing an important role in "the neural instantiation of the self, organizing internally motivated, self-generated, and stimulus-independent behaviors".

Play therapy with sexually abused children

2008-03-10T20:20:00.000-07:00

Hill, A. (2006). Play therapy with sexually abused children: Including parents in therapeutic play. CHILD AND FAMILY SOCIAL WORK. 11 (4), 316-324.

According to this article, situations in which sexual abuse has increased a child's separation anxiety can often be improved by including parents in play therapy. This allows the child to feel more secure in his/her primary attachment relationships, while presenting the often confused and uncomfortable parents with a positive model of interaction to emulate. It may also be beneficial for the therapist to witness and interact in the parent-child relationship which, if strained, can often exacerbate the trauma. It is noted that parents benefit from participating in the therapy by eliminating feelings of exclusion and jealousy they may have developed in response to the new therapist-child relationship, by countering feelings of guilt and failure in the role of parent/protector common to situations of child abuse, and by rebuilding confidence in their parenting abilities.

Possible complications of introducing parents into child therapy are discussed. Issues of the child's privacy and confidentiality are naturally raised, as well as the possibility that some parents might be unwilling to participate or counter-productive in the process. Suggestions or interventions by the therapist may be viewed as criticism by the parent.

Two case studies are provided to exemplify these points and to illustrate the situation of a child expressing anger towards his/her parents in response to sexual abuse (by someone else). While this is a common occurrence in play therapy, it becomes complicated when that parent is present. Lastly, it is noted that including parents in play therapy can counteract the "dynamic of secrecy" often imposed on the sexually abused child by the abuser.

Plasticity underlying fear conditioning occurs in the BLA

2008-03-10T12:34:00.000-07:00

Fanselow, M.S. & LeDoux, J.E. (June 1999). Why we think plasticity underlying Pavlovian fear conditioning occurs in the basolateral amygdala. Neuron, Vol. 23, 229-232.

A debate over the role of the neural plasticity in the amygdala has been ongoing. The 'encoding view' believes that neural plasticity in the basolateral complex of the amygdala (BLA) encodes the emotional component of memories formed during fear conditioning. The 'modulatory view' sees the amygdala as modulating memories stored in other brain regions, not unlike current theories of the hippocampus. This paper believes that the two views are not mutually exclusive, and argues for a synthesized model in which the amygdala is both the site of fear memory encoding and storage and a modulator of memory functions in other structures.

Play Therapy with Sexually Traumatized Children

2008-03-07T17:36:00.000-08:00

Kelly, M. M. (1995). Play Therapy with Sexually Traumatized Children: Factors That Promote Healing. Journal of Child Sexual Abuse. 4 (3), 1-11.

This article begins with a survey of play therapy theory, with special attention given to various writer's takes on the merits of directive vs. non-directive approaches. It is argued that the treatment of sexually abused children often involves a series of "resolution cycles" characterized by the alternation of active work and periods of respite. Each of these cycles comprises three phases: testing the therapeutic relationship, readdressing the trauma, and protective distancing and denial. Another cycle will then be initiated only if there is trust and respect between the child and the therapist. Cycles can take as long as four or more sessions to complete, or may play out in the course of a single session (as is common in the beginning stages of therapy).

Two case studies (one with a 7 year old girl and another with an 8 year old boy) are provided to illustrate the progression of such cycles and to show that the denial phase usually occurs when the child's personal resources are exhausted. It is argued that a clear understanding of these cycles can furnish a therapist with more realistic expectations when working with sexually abused children.

A case study using child-centered play therapy approach to treat enuresis and encopresis

2008-03-07T17:13:00.001-08:00

Cuddy-Casey, M. (1997). A case study using child-centered play therapy approach to treat enuresis and encopresis. ELEMENTARY SCHOOL GUIDANCE AND COUNSELLING. 31 (3), 220-225.

Enuresis (bedwetting) and encopresis (bed-defecation) may come from one or more of the following causes: medical-genetic disorders, emotional disturbances, and failure to learn. Depending on the main cause, different treatments are used. Physicians are usually called to deal with the organic problems underlying medical-genetic disorders, while behavioral techniques are used to treat problems stemming from a failure to learn. However, problems rooted in emotional disturbances are commonly lumped into the "failure to learn" category and treated thusly. This article argues for an alternative treatment (i.e. non-directive play therapy) to be used in response enuresis and encopresis rooted in emotional disturbances.

A case example is provided in which an 8-year old male with enuresis and encopresis is treated with play therapy after medical-genetic disorders and failure-to-learn are ruled out. In these sessions, the child began to exhibit aggressive behavior and admitted to wanting to destroy the playroom's pictures and wall clock, which he believed to have cameras hidden behind them. After this admission was received with the permissiveness and acceptance that are the hallmarks of non-directive therapy, the child also admitted that he did not use public restrooms because of this fear of hidden cameras. He spent the next few sessions searching the playroom for cameras and, upon not finding any, began to have less and less problems with enuresis/encopresis.

Parallel incentive processing: an integrated view of amygdala function

2008-03-06T16:16:00.001-08:00

Balleine, B.W. & Killcross, S. (May 2006). Parallel incentive processing: an integrated view of amygdala function. Trends in Neuroscience, Vol. 29, 272-279.

Although the amygdala has been long studied for its involvement in emotional learning and memory, the exact nature of its involvement is still disputed. Historically, a serial model has predominated, with the lateral nucleus detecting threatening stimuli and the central nucleus initiating expression of defensive behaviors and other bodily responses associated with fear reactivity. However, in this paper Balleine and Killcross opine perhaps it's time to consider alternative models, and propose a model which, based on appetitive conditioning studies, has the basolateral and central nuclei operating independently and in parallel to mediate incentive processes in both appetitive and aversive situations. They suggest the basolateral nucleus encodes emotional events with reference to their particular sensory features, while the central nucleus provides affective significance to processing, motivating or inciting responses and actions.

Jungian Play Therapy in Elementary Schools

2008-03-05T15:30:00.000-08:00

Allan, J., & Brown, K. (1993). Jungian Play Therapy in Elementary Schools. Elementary School Guidance and Counseling. 28 (1), 30-41.

This article discusses the Jungian approach to play therapy and provides a case study to exemplify its methods. As a (or perhaps the) proto-humanistic psychologist, Jung believed that growth and transformation are the main drives in the psyche. Thus, counseling involves mainly providing a safe and protective setting in which these internal processes can propel a child into change. This so-called self-healing archetype requires a healthy connection between the child's conscious and unconscious worlds. Therapy is thus also aimed at creating such a connection.

Jungian play therapy identifies three major themes or stages through which a child's play evolves: chaos, struggle, and resolution. It is through the progression of this resolution that the ego develops a sense of control and mastery as it learns to mediate the "struggle of opposites." Towards the end of therapy, common themes become construction, reparation, and healing.

Jungian play therapy is directive in its counseling style and makes use of interpretation interventions to "deepen affective expression." This is received much more positively by the child if it is initiated after a strong therapeutic relationship of rapport is established. This point and others are illustrated in the case study of a third grader with aggressive behavior problems. His sand play had a recurrent theme of "good guys" struggling against "bad guys." When, later in therapy, this theme was interpreted as analogous to his own feelings of isolation and confliction, he accepted it and showed remarkable change in the next session. In the next sand world he made, there was a fenced off area where kids could go and nothing could happen to them. It is argued that this opportunity to release his feelings allowed the child's positive, integrating mechanisms to guide him to growth, and that the direct interpretations expedited this process.

The Masterson Approach with Play Therapy

2008-03-05T01:16:00.000-08:00

Mulherin, M. A. (2001). The Masterson Approach with Play Therapy: A Parallel Process between Mother and Child. AMERICAN JOURNAL OF PSYCHOTHERAPY. 55, 251-272.

This article illustrates the principles of the Masterson Approach with a long-term case study involving a child and his mother in adjunct therapy. The Masterson Approach (with which I am not very familiar) is a psychodynamic developmental self and object relations approach. It involves providing opportunities for diagnostic assessment, developing a working relationship within therapy, assisting in the breakdown of defenses, facilitating verbalization, providing cathartic release, and preparing the child for future life events. As will be seen, the diagnosis has a large effect on which treatment strategies are deemed appropriate.

The initial diagnosis for both the mother and son was distancing borderline disorder. As a result, the technique of confrontation was used as intervention. However, as confrontation led to increased anxiety in both patients, the diagnosis was changed to schizoid disorder of the self and interpretation of the schizoid dilemma became the primary therapeutic technique. This seemed to have drastic effect, as both patients responded positively. The new diagnosis was thus confirmed.

An interesting aspect of this case study was the enmeshment, or parallel progression of the mother and son. Often the son would act out (in his sand trays) the very same conflicts his mother struggled with in her verbal therapy. They both exhibited signs of the splitting defense mechanism, with the son accepting his mother while rejecting his father, and the mother having panic attacks as she fantasized about reuniting with her separated husband.

Two interesting events in the play therapy are also worth noting. First was when the son explicitly acknowledged the symbolic nature of his play by remarking (after destroying one of his sand worlds) that he was glad those "bad feelings [were] gone". And second was when the creation of a loss/death-themed sand world in his fifth year of treatment seemed to usher in a much more integrated child. After this cathartic experience, his regressive defenses completely disappeared.

Play therapy; the troubled child's self-encounter

2008-03-04T22:36:00.000-08:00

Hyde ND. (1971). Play therapy; the troubled child's self-encounter. The American Journal of Nursing. 71 (7), 1366-70.

A general overview with anecdotal examples of non-directive play therapy from a psychiatric nurse. The article quotes largely and effectively from the major players (Axline, Moustakas, etc.). There is not much here that you can't get from the primary texts themselves, but it is not bad either. It outlines the theoretical framework of non-direction, permissiveness, and attentiveness on the part of the therapist. It also acknowledges the projection, darkness, and struggle for integration evident in children's play.

An experiment with play therapy

2008-03-04T22:28:00.000-08:00

Smith LF. (1977). An experiment with play therapy. The American Journal of Nursing. 77 (12), 1963-5.

A summarized and anecdotal account of an amateur play therapist (nursing student) working with a withdrawn child. Only very limited dialogue is provided, more often utilizing descriptions of what actions and conversations took place. This article is another case study to read, but without dialogue and given the inexperience of the therapist, it leaves much to be desired as a learning tool. The child in this case study expressed his anxiety in an obsession with cleanliness, spending much of the time cleaning the windows and walls of the playroom. He also played extensively with a customizable doll house, deconstructing and reconstructing it, and had the therapist act out his own daily routines.

Using play therapy in outpatient settings

2008-03-04T22:21:00.000-08:00

Meer PA. (1985). Using play therapy in outpatient settings. MCN. The American Journal of Maternal Child Nursing. 10 (6).

This article demonstrates the ambiguity existing in terms such as "play therapy" in research contemporary to it. What is described here is toys being used by nurses in calming children and preparing them for medical procedures, which is very different from the play therapies used by professional therapists in building permissive and accepting relationships with "troubled" children.

Aside from this rather frustrating catachresis, the article describes the interesting application of play-related concepts to children in health care settings. Specifically, puppets and dolls can be used to familiarize children with the equipment and procedures they will later be exposed to. Allowing children to participate in this play-acting can make them feel more control over the situation, assuaging some of their anxiety and leading to an overall feeling of independence.

Play Therapy With Abused Children: A Review of the Literature

2008-03-04T22:08:00.000-08:00

White, J., & Allers, C. T. (1994). Play Therapy With Abused Children: A Review of the Literature. JOURNAL OF COUNSELING AND DEVELOPMENT. 72 (4), 390.

This article gives an overview of play therapy, identifies and explores seven characteristic behaviors exhibited by abused children, identifies and explores two general themes of play in abused children, and critiques play therapy research. The characteristic behaviors are developmental immaturity, opposition and aggression, withdrawal and passivity, self-deprecating and self-destructive behavior, hypervigilance, sexual behavior, and dissociation. The recurrent themes of play behavior are unimaginative/literal play and repetition/compulsion. Each of these behaviors and themes are elaborated on and special attention is paid to the differences between the behaviors exhibited by sexually abused, physically abused, and neglected children. Lastly, contemporary research is critiqued for its inconsistent definitions, nonstandardized methodologies, and flawed statistical designs.

Use of the telephone in child play therapy

2008-03-04T21:52:00.000-08:00

Spero MH. (1980). Use of the telephone in child play therapy. Social Work. 25 (1), 57-60.

A brief exposition of the use and benefits of supplying a toy telephone in child play therapy settings. Spero begins by remarking that a toy is only as useful in a therapeutic context as the child's willingness to play with it. Thus, despite the potential goldmine of communication in a toy telephone, this is wasted unless the child decides to use it. Having said this, he continues on to highlight the potential uses the toy telephone might be to. A child may hold a conversation with an imaginary party, fantasize a connection with the deceased or unavailable, or even exercise projection by assuming the role of both parties. Four brief case studies are provided to illustrate these potential uses. It is remarked that children will often pretend to phone their therapist (early in therapy) in an attempt to form a connection with them, and that the act of forcibly hanging-up can be a powerful way for reserved children to learn to express their desires and frustrations.

Play therapy: the children's views

2008-03-04T21:29:00.000-08:00

Carroll, J. (2002). Play therapy: the children's views. CHILD AND FAMILY SOCIAL WORK. 7, 177-188.

A qualitative study on children's reactions to non-directive play therapy. Interview questions pertained to how the children felt about their introduction to play therapy, their relationship with the therapist, the therapeutic processes, their likes and dislikes in therapy, and the termination of their therapy. Children's responses varied greatly, but several basic themes emerged. Notably, while children universally enjoyed their relationship with the therapist greatly, they were largely unable to pinpoint what aspects of the therapist's behavior were most helpful. The children appreciated the provisions of food at the beginning of therapy and described their sessions as being importantly "fun". Many seemed to dislike explicit "talking about their feelings". This is a truly fascinating project, but unfortunately only a small sample size was acquired. More research on this is needed.

Classical fear conditioning in functional neuroimaging

2008-03-04T20:15:00.001-08:00

Buchel, C. & Dolan, R.J. (2000). Classical fear conditioning in functional neuroimaging. Current Opinion in Neurobiology, 10, 219-223.

A brief overview of the brief history of the examination of classical conditioning with functional neuroimaging. Early PET studies showed a striking absence of expected amygdala activation, but later demonstrated the expected amygdala involvement. More recently, 'backward masking' designs indicate a hemispheric difference when the CS+ was presented out of awareness, with greater activation observed in the right amygdala. fMRI studies showed amygdala participation during initial acquisition and early phases of extinction, and also demonstrated the characteristic decreases in amygdala activation over time. Interestingly, blocked fMRI designs revealed that social phobics do not show the 'physiological' decrease of amygdala activation over time. Finally, the paper points out the controversy about the role of the amygdala. One camp regards the amygdala as a rapid subcortical information processing unit that is continuously involved in the processing of CSs in aversive classical conditioning, producing deliberately high "false alarm" rates and being kept under the supervision of cortical controllers. The other camp sees the amygdala as enabling or permitting associative plasticity that encodes acquired sensory contingencies which are later expressed at a cortical level; once the association has been learned, the systems mediating the modulation of plasticity disengage and hence we see the decline in amygdala activation. More on this debate here.

Neural mechanisms of extinction learning and retrieval

2008-03-04T12:54:00.000-08:00

Quirk, G.J. & Mueller, D. (2008). Neural mechanisms of extinction learning and retrieval. Neuropsychopharmacology, 33, 56-72.

Early in the study of classical conditioning, Pavlov observed spontaneous recovery of responding to an extinguished conditioned stimulus. This witnessed 'uncovering phenomena', brought on by a change in context or stimulus presentation, led to the belief that extinction is not erasure of a previous fear memory but rather the learning of an additional inhibitory memory. This paper reviews what has been learned about extinction learning ever since. Like other types of learning, extinction occurs in three phases: acquisition, consolidation, and retrieval. Acquisition seems to depend on the basolateral amygdala (BLA) and the ventrolateral periaqueductal gray (vlPAG) structures. Consolidation seems to be most dependent on the BLA, where the learning of new memories (requiring protein synthesis) appears to take place. It also seems to rely on the involvement of the prefrontal cortex and the hippocampus. Retrieval requires expression of an inhibitory memory, and as such, during retrieval we see activation of inhibitory networks in the amygdala, cortical control of amygdala inhibition by the IL mPFC, and contextual regulation provided by the hippocampus and mPFC. Thus, like classical conditioning, extinction seems to be distributed across a network of structures, rather than centered in any one particular area.

The paper also raises many fascinating special issues. One challenges the Pavlovian idea that extinction is purely an additional inhibitory memory: recent evidence seems to indicate that extinction leads to reversal of conditioning-induced phosphorylation of CREB, indicating some erasure of the original BLA fear memory!

It also discusses anxiety disorders and PTSD which may be caused by a failure to retrieve an extinction memory generated in extinction-based treatment. Subjects with PTSD show reduced volume and activity in the vmPFC and hippocampus areas, along with increased activity in the amygdala, suggesting inhibitory control and contextual modulation of extinction may be compromised. It also mentions that chronic stress can impede extinction-based therapies, decreasing dendritic branching and spine count in the vmPFC and hippocampus, and increasing dendritic branching and spine count in the BLA, thereby enhancing conditioning effects and impairing extinction. Recently, deficits in fear extinction observed in these human disorders have been combated with pharmacological agents, facilitating extinction of the fear memory with the help of D-cycloserine and impairing fear memory reconsolidation with the B-adrenergic receptor blocker propranolol.

Human amygdala activation during conditioned fear acquisition and extinction

2008-03-03T13:37:00.001-08:00

LaBar, K.S., Gatenby, J.C., Gore, J.C., LeDoux, J.E., & Phelps, E.A. (May 1998). Human amygdala activation during conditioned fear acquisition and extinction: a mixed-trial fMRI study. Neuron, Vol. 20, 937-945.

The amygdala is believed to be a key component in a network mediating survival functions by coordinating behavioral plans of action based on the integration of exteroceptive and interoceptive information. The amygdala, in particular, has been thought to be the structure responsible for detecting and reacting to potentially threatening environmental stimuli through classical conditioning learning.

However, attempts to investigate amygdala function in humans has produced inconsistent results, with failures to notice increased amygdala blood flow in PET being most surprising. Difficulties may stem from the small size and troublesome subcortical placement of the structure, and that amygdalar responses are relatively transient to discrete cues, have low spontaneous neuronal firing rates, and exhibit marked habituation (gradual signal intensity reduction). This study attempted to overcome these difficulties by using a mixed-trial fMRI design. This time, results successfully showed amygdala/periamygdaloid cortex involvement during both conditioned fear acquisition and extinction, biased towards the right hemisphere in both cases.

Previous lesion studies have shown the integrity of the amygdala is required for expression of learned conditioned fear associations. However, the temporal pattern of amygdala activity (greatest during early acquisition and early extinction, and degrading over time) suggests that this activity may only partially underlie expression. The paper offers a hypothesis that the observed activation may be related to encoding the emotional meaning of the conditioned stimulus. This is consistent with with the amygdala activity witnessed during the initial stages of learning (when stimulus is novel) and during early extinction (when the meaning of the stimulus has changed).

The Emotionally Engaged Analyst

2008-03-02T01:41:00.000-08:00

Miller, M.L. (2008). The Emotionally Engaged Analyst: Theories of affect and their influence on therapeutic action. Psychoanalytic Psychology, Vol. 25, No. 1, 3-25.

The article provides a review of affect theories and how they relate to therapy. As Dahl mentions, "the absence of a coherent psychoanalytic theory of emotions is truly remarkable, given clinician's nearly universal belief in the centrality of emotions in every patient's life and treatment".

Two broad categories have predominated thus far. One is the cognitive appraisal theory of emotion which holds that emotions are the conscious or unconscious cognitive appraisal of an arousing stimulus. These cognitive evaluations are formed by assimilating the current event into a stored schema that represents earlier experiences in similar circumstances. Schemas may be processed in subsymbolic, nonverbal symbolic, and verbal symbolic modes. If we are to represent and understand emotional experiences, subsymbolic processes must be integrated with symbolic processes. This idea forms the basis for therapy: enable the patient to metabolize unformulated subsymbolic experiences of emotion into meaningful feelings.

The second category encompasses so-called functional and discrete theories of emotion. These theories hold that the brain is more an emotional organ than a cognitive one, and emotions are seen as a hierarchy of embedded regulatory functions necessary for the automatic adaptive survival of the organism. Emotions are orchestrated in response to significant changes perceived in the internal or external milieu, and responses are executed subcortically. Cortical involvement occurs after subcortical emotional processes have begun; this may later influence the execution of the underlying emotional processes by providing the informational context of the body, the self, and the environment. Feelings, the mental representations of ongoing regulatory processes, do not initiate these emotional processes but are instead the product of them. These theories view the essence of change in psychoanalytic treatment as the remodeling of the nonconscious procedures through which the person adapts to his or her environment.

The dynamic systems theory of emotion, a recent theoretical addition, can be viewed as a combination of the cognitive appraisal schema of emotion and the discrete/functional models of emotion with an emphasis on social interaction. In this model, emotions should be seen not as discrete states of being or constructed interpretive programs but as ongoing, continuous processes influencing and being influenced by the complex context in which they occur. Emotions emerge as three critical component systems (the subcortical arousal system, the cortical interpretive system, and the motor system) dance together. In so doing, emotions, meanings, and actions are continuously modified and negotiated. Viewed in the context of social interaction, another three-way interaction can be seen to take place between each person's own emotional processes, those of the person he or she in interacting with, and the emotional character of the interaction itself. Although all of these components within the individual and without can interact with one another in an infinite number of ways, they have a tendency to self-organize into a finite number of stable patterns which tend to repeat under particular conditions and ultimately define the different emotional states and state transitions a system can take. The goal of therapy is then to engender systemic change, to perturb the system appropriately into allowing transformations in the emotional experience of the client. In a truly interactive system, with multiple internal and external factors contributing to the individual's emotional experience, as one component within the system changes, all other components adjust to that change. As such, the analyst's emotional participation is viewed as an essential component.

Brain systems mediating aversive conditioning

2008-02-29T13:09:00.000-08:00

Buchel, C., Morris, J., Dolan, R.J., & Friston, K.J. (May 1998). Brain systems mediating aversive conditioning: an event-related fMRI study. Neuron, Vol. 20, 947-957.

Classical conditioning refers to a type of associative learning whereby a previously neutral stimulus (CS) comes to elicit a behavioral response by being paired with an aversive unconditioned stimulus (US). This study implemented a human classical conditioning paradigm in which images of faces (CS) were paired with an aversive tone (US). To assess which areas of the brain were related to conditioning, event-related fMRI responses were compared between presentation of conditioned stimuli (CS+) and unconditioned stimuli (CS-) after skin conductance indicated the conditioning regimen was completed successfully. To be more accurate, CS- was compared to the occasional trials of CS+ which were not followed by a tone.

Unequivocal differential responses were found in two cortical areas: the anterior cingulate cortex (ACC) and the anterior insula. These structures receive input from the amygdala, which also shows interesting activation patterns during this paradigm. The lateral amygdala in particular shows time-dependent neural responses, with higher than baseline responses at first but habituating over time. A possible explanation is a negative feedback loop, an analgesia kicked off by the amygdala and mediated by endogenous opioids which leads to reduced conditioning over time. Finally, differential activation was also witnessed in the red nucleus together with premotor structures, characteristic of response expression.

Happy 50th post!!! And happy bissextile day!!!

Conflict Monitoring and the ACC

2008-02-27T12:21:00.000-08:00

Botvinick, M.M., Cohen, J.D., & Carter, C.S. (December 2004). Conflict monitoring and anterior cingulate cortex: An update. Trends in Cognitive Sciences, Vol. 8, No. 12, 539-546.

Activity in the dorsal anterior cingulate cortex (ACC) shows up in a variety of tasks. For example, a transient potential (known as the error-related negativity, or ERN) is elicited from the posterior ACC in response to error commission. And a similar evoked potential, the feedback-related negativity (FRN), occurs in response to error feedback and may derive from the same portion of the cingulate that generates the ERN. These activity patterns during commission of errors led researchers to suggest an 'error detection' function for the ACC.

However, tasks which require overriding of habitual responses and tasks which require selecting among a set of equally permissible responses also yield ACC activation. This led researchers to put forth a 'conflict detection' theory of ACC function, with the structure being especially responsible for selecting between competing motor responses.

However, recent studies have proposed other unifying theories to explain the role of the ACC beyond just error detection and conflict monitoring. Some suggest the ACC serves to evaluate action outcomes, performing cost-benefit analyses on possible outcomes and using reward-related information to guide action selection. This 'action-outcome evaluation' view is particularly consonant with other research connecting the mesencephalic dopamine system with the ACC in reinforcement learning.

Pain and emotion interactions in subregions of the cingulate gyrus

2008-02-27T09:42:00.000-08:00

Vogt, B.A. (July 2005). Pain and emotion interactions in subregions of the cingulate gyrus. Nature Neuroscience Reviews, Volume 6, 533-544.

Beyond Brodmann's simplistic account of the cingulate gyrus with two divisions, recent cytoarchitectural studies favor a four-region model based on connections and function. This includes the ACC, the MCC, the PCC, and the RSC. This new theoretical construct, in conjunction with new neuroimaging data, is shedding light on the cingulate's role in pain and emotion processing.

Regarding emotion, it seems that the cingulate cortex processes emotion differentially.

ACC - Activity during sadness is greatest in the sACC, believed to be important for storage of negatively valenced memories, and which has projections to subcortical autonomic centers. Happiness tends to elicit activity in the pACC, but this is not an autonomic integration center.
MCC - Fear is associated with activity in the aMCC, the only cingulate structure to receive input from amygdala.
PCC - The vPCC also shows activity during happiness, but is believed to be characterized by the assessing the self-relevance of emotional events (an emotional pre-processor).
RSC - The RSC is still poorly understood but is believed to play a role in memory access of valenced information.

Regarding pain processing, we also see evidence for differential processing, but we also see overlap in processing pain and emotion.

MCC - It appears the aMCC could be related to fear-avoidance behaviors (as alluded to above). More posteriorly, activations in the pMCC evoke skeletomotor body orientations but without affective (autonomic) or emotional (valenced) content.
PCC - The dPCC, likewise, seems to be involved in orienting the body in response to noxious sensory stimuli.

In quick summary, authors hypothesize that the midline and intralaminar thalamic nuclei (MITN) provide the primary source of nociceptive information to the cingulate; as such, the cingulate is likely to have access to nearly full body receptive fields for cutaneous, muscle, and visceral noxious stimuli. However, each subregion of the cingulate differs in the density of these inputs, how they use the information for pain processing, and how they projection to other structures. The cingulate gyrus is likely to mediate three main aspects of pain processing: unpleasantness or 'suffering' in the pACC, fear-avoidance in the aMCC, and body orientation in response to noxious stimuli in the pMCC and dPCC.

Deep brain stimulation for treatment-resistant depression

2008-02-26T20:51:00.000-08:00

Mayberg et al. (March 3, 2005). Deep brain stimulation for treatment-resistant depression. Neuron, Vol. 45, 651-660.

This experiment exposed a small sample of six people with treatment-resistant depression to deep brain stimulation (DBS) in the subgenual cingulate region (BA25), known to be a critical region for modulating negative mood states, and showing elevated activity in these refractory patients.

Acute effects of stimulation included sudden mood change (reduced negative and increased positive scores), as well as improvements in interest and activity level. Upon continued use, sleep patterns were among the first of the normalized symptoms, followed by increased energy, interest and pleasure in social activity, decreased apathy and anhedonia, and improved planning abilities. Upon discontinuation of chronic treatment, mood improvements tended to persist, whereas cognitive aspects of depression (e.g. poor concentration, apathy) did not, perhaps indicating differential effects on different connected systems.

These results, showing a sustained remission of depression in four out of six patients who previously failed to respond to medications, psychotherapy, and ECT, still warrant further investigation (for starters, a larger sample size) but do favor a positive interpretation of the efficacy of DBS for people with refractory depression. With its connections to brainstem, hypothalamus, and insula (read: sleep, appetite, libido, and neuroendocrine effects) and reciprocal pathways to the orbitofrontal/medial prefrontal cortices and the anterior and posterior cingulate cortices (read: influences on learning, memory, reward, and motivation), this study also sheds light on the subgenual cingulate region as a critical node of a distributed mood-regulatory network involved in major depression.

dlPFC promotes LTM formation via WM organization

2008-02-26T18:35:00.000-08:00

Blumenfeld, R.S. & Ranganath, C. (January 18, 2006). Dorsolateral prefrontal cortex promotes long-term memory formation through its role in working memory organization. The Journal of Neuroscience, 26, 3, 916-925.

This paper speculates that the different regions of the prefrontal cortex contribute differentially to working memory (WM). Specifically, they argue that the dorsolateral prefrontal cortex (dlPFC) is recruited during tasks requiring organization of items active in WM, while the ventrolateral prefrontal areas (vlPFC) are involved in WM maintenance, or simply holding items in short-term memory.

The study begins behaviorally by showing that overall memory is increased during tasks which require organization by re-ordering (in comparison to tasks which are merely rehearsals). Single items encoded on re-ordering trials were significantly more likely to be judged as "remembered" than from rehearsal trials. And organization of items during re-ordering trials resulted in much higher recollection together, suggesting the strengthening of associative links between items in these organization trials. Then the paper shifts to the fMRI data to attempt to implicate the dlPFC specifically. Their evidence: the dlPFC showed increased activation during the delay (encoding) period of re-ordering trials relative to rehearse trials.

However, one very possible alternative explanation is the effect of nonspecific factors correlated with task difficulty. Reorder and rehearse trials differ in a number of ways, difficulty being the most significant. Perhaps the increased attention required in the re-ordering trials led to changes in behavioral results and a general increase in activation in the dlPFC (and elsewhere). This raises concerns that the activity in the dlPFC could be attributed to processes other than organization.

Changes in Hippocampi of Taxi Drivers

2008-02-26T17:17:00.000-08:00

Maguire et al. (April 11, 2000). Navigation-related structural change in the hippocampi of taxi drivers. PNAS, Vol. 97, No. 8, 4398-4403.

This correlational study showed taxi drivers had a significantly greater volume in the posterior hippocampus, whereas control subjects showed greater volume in the anterior hippocampus. Authors interpret the results as evidence for the relative redistribution of gray matter in the hippocampus in response to the occupational need to store increasingly detailed spatial representations. The amount of time spent as a taxi driver was found to be correlated with the amount of volume in the right posterior hippocampus, suggesting that while mental spatial maps are likely to be stored in the posterior hippocampus and necessitate progressive structural changes over time, the left hippocampus may participate in spatial navigation and memory differently from the right.

Neural fate of ignored stimuli

2008-02-20T21:47:00.000-08:00

Yi, D. et al. (September 2004). Neural fate of ignored stimuli: dissociable effects of perceptual and working memory load. Nature Neuroscience, Volume 7, Number 9, 992-996.

After some debate over whether attention acts a filter early in the processing hierarchy ("early selection") or whether it blocks awareness of perceptually encoded stimuli at a late stage of processing ("late selection"), the field has accepted both accounts to some degree. When task difficulty is low, late selection may be more likely, whereas aggressive early selection may be more common when task difficulty is high. However, task difficulty can be defined in several ways and this paper predicted and confirmed that increasing perceptual demands properly constitutes task difficulty and leads to this early selection behavior, whereas increasing working memory loads does not.

Experimentally, subjects were shown faces foveally, surrounded by background images depicting scenes. They were told to fixate on the faces and ignore the background images. Faces were cycled, but so were the background images. In the EASY block, subjects were asked to play a "one-back" game, discriminating between the current face image and face presented prior. Subject performance was high. However, in addition to this primary task, the parahippocampal place area (PPA) showed activity that indicated it was indeed processing the background image changes successfully as well. But as the perceptual load was adjusted, with the HARD block requiring more difficult facial discriminations, it was clear that the PPA was not processing the background scenes to the same extent as in the low perceptual load condition. By comparison, the MEMORY block, in which "two-back" rules required subjects to maintain more information in working memory for longer, did not demonstrate these attenuation effects on background processing, i.e. the PPA was still successfully detecting background changes. This indicated, as hypothesized, that perceptual demands and working memory load result in differential attentional effects.

Molecular Mechanisms of Memory Storage

2008-02-19T23:51:00.000-08:00

Hawkins, R.D., Kandel, E.R., & Bailey, C.H. (June 2006). Molecular Mechanisms of Memory Storage in Aplysia. Biological Bulletin, 210, 174-191.

This article reviews what molecular biology currently knows about the underlying nervous system mechanisms for memory. Memory comes in several forms. The short-term form, kicked off by brief and well-spaced stimulation pulses, lasts minutes and involves alterations in the effectiveness of existing synaptic connections. This can be accomplished via covalent modifications of pre-existing proteins by a variety of kinases, enhanced neurotransmitter release, and other means of short-term sensitization which increase the excitability of the neuron pair. The intermediate form, created by repeated and more prolonged exposure to stimulation, lasts hours and often requires translation-but-not-transcription-dependent processes. The final and most stable phase of long-term memory storage is characterized by the modulation of both function and structure of specific synaptic connections. This form, lasting days, weeks, or longer, requires full gene expression for synaptic remodeling and the growth of new synaptic connections. The mechanisms, though varied, together create a continuum between short- and long-term memory storage. (Other changes, such as increases in spine size, increases in the size and number of synaptic vesicles, or the clustering of such vesicles, can be seen along this spectrum.)

The paper also mentions the significance of synaptic tagging mechanisms discovered only recently. Given that many of these methods of potentiation kick off cell-wide processes, being able to identify the specific synapse whose activation originally triggered these processes is extremely important. (More here)

Finally, the article talks about potential memory longevity concerns. Since biological molecules have a short half-life (hours to days) compared to the duration of memory (up to years), researchers hoped to better understand the self-sustaining properties of memory. CPEB, which is a prion-like protein and is known to take two different conformational states, has an active state which has the ability to "awaken" dormant mRNAs to initiate translation at the local activated synapse. CPEB, in addition to being proposed as a synaptic marker, also seems to be a good candidate for sustained synapse-specific potentiation since it is also known to self-perpetuate once active. CPEB-3 has been found in mammal hippocampus and is induced by dopamine.

Control of goal-directed and stimulus-driven attention

2008-02-17T21:05:00.000-08:00

Corbetta, M. & Shulam, G.L. (March 2002). Control of goal-directed and stimulus-driven attention in the brain. Nature Reviews Neuroscience, Volume 3, 201 - 215.

This paper proposes that visual attention (orienting) is controlled by two interacting networks. One system which is centered on the dorsal posterior parietal and frontal cortex, is involved in the cognitive, top-down, goal-directed selection of sensory information and responses. The second system, largely lateralized to the right hemisphere, is centered on the temporoparietal and ventral frontal cortex and is specialized for the detection of behaviorally-relevant stimuli, particularly when they are salient or unexpected. The second network reflects stimulus-driven, bottom-up control of attention, and can be seen as a 'circuit-breaker' of the first network, interrupting ongoing cognitive activity and directing attention to stimuli outside the focus of current processing when necessary.

Direct and indirect activation effects on reconsolidation in amygdala

2008-02-16T23:36:00.000-08:00

Debiec, J., Doyere, V., Nader, K., LeDoux, J.E. (February 28, 2006). Directly reactivated, but not indirectly reactivated, memories undergo reconsolidation in the amygdala. PNAS, Volume 103, Number 9, 3428-3433.

The first experiment of the paper used second-order fear conditioning (SOFC) to create an associative memory network in rat brain. To do this, a conditioned stimulus (CS1) is paired with an unconditioned stimulus (US), which naturally elicits a response. After pairing, now CS1 elicits the response (such as freezing in fear). This is the first-order conditioning. Now, a second conditioned stimulus (CS2) is paired with CS1, and by association elicits the response transitively. When extinction of CS1 responding does not affect the responding of CS2, CS2 is considered independent of the first-order fear memory. But if CS2 responding decreases with CS1 extinction, then we have an associative chain (CS2 --> CS1 --> US).

The second experiment, building on such a conditioning chain, discovered that extinction of freezing responses to the first-order stimulus (CS1) leads to responding impairments in CS2. Extinction of the second-order stimulus (CS2), does not have any effect on CS1. This builds a case for a hierarchical, uni-directional chain.

The last experiment examined the effect of activation (memory retrieval) on such an associative chain. (In another paper, Nader and LeDoux showed that reactivation of a memory places it in a labile state -- that is, susceptible to disruption -- until again reconsolidated.) Results demonstrated that protein synthesis inhibition after exposure to a single CS1 impairs responses to both CS1 and CS2. But protein synthesis inhibition after exposure to a single CS2, only disrupts CS2 and leaves CS1 freezing intact. Therefore, it is believed that when the first-order association is directly activated, it is placed into a labile state, which may have an impact on dependent associations. However, when the first-order association is only indirectly activated (through an associative chain), it appears that there is not sufficient stimulation to kick off cellular processes which would place it in a labile state, so it remains fixed.

Clinical applications of such research may be in the areas of PTSD, where victims suffer not only from fearful memories, but also from everyday stimuli somehow associated with the initial trauma. This study shows that disrupting associated reactions will only alleviate the sufferer from these quirky stress reactions, while breaking associative chains at the root cause may provide cascading relief.

Visual Attention

2008-02-16T17:03:00.000-08:00

Kanwisher, N. & Wojciulik, E. (November 2000). Visual Attention: Insights from Brain Imaging. Nature Reviews: Neuroscience, Volume 1, 91-98.

This review discusses four major questions related to attention's role in visual processing. First, where in the visual pathway does attention act? Second, what is able to be selected by attention? Third, how does attention affect neural responses? And fourth, where do attentional signals comes from?

Where in the visual pathway does attention act? It has been known for some time that substantial effects of attention can be found in the extrastriate cortex. However, it was not until recently that attentional modulation was discovered in earlier stages of the visual processing pathway (e.g. primary visual cortex). This may be more common when the processing load is considered high.

What gets selected by attention? Under different conditions, attention can select spatial locations, feature dimensions, whole visual objects, or even a combination thereof. However, these may not always be deployed with perfect control.

How does attention affect neural responses? Evidence exists which supports attention influence as being characterized as multiplicative (gain modulations) and/or additive (baseline shifts). And some postulate that increasing baseline activity in a neural population may bring these cells into a dynamic range where the same stimulus input will produce larger responses.

What is the source of attentional signals? Researchers have implicated the fronto-parietal network in providing top-down biasing signals to visual regions, and speculate that this system supports a very heterogeneous set of attention tasks.

Subcortical Face Processing

2008-02-15T19:20:00.000-08:00

Johnson, M.H. (October 2005). Subcortical Face Processing. Nature Neuroscience Reviews, Volume 6, 766-774.

The most well-known visual pathway uses parvocellular channels from the retina to the LGN and on to the primary visual cortex, where very complicated fine-grained image processing is carried out. However, evidence supports multiple visual pathways, and last I checked, 12 different visual pathways have been identified in the brain so far. This review paper discusses a specific subcortical face-detection system which involves the superior colliculus, pulvinar, and amygdala.

Researchers hypothesize that this pathway is more rapid than cortical routes, relies on rather low-fidelity (low-spatial-frequency) visual information, and can critically modulate cortical processing. One characterization is that this pathway is important for directing emotional attention, providing an emotional flavoring to higher-order visual processing. As this pathway is thought to bias the cortical processing of visual input -- detecting the prescence of faces, orienting us towards them, and activating dependent cortical regions -- this may a particularly important pathway during development when cortical structures (such as the fusiform face area, orbitofrontal cortices, and other cortical regions involved in the social brain network) are still being molded. Atypical processing of socially salient stimuli, seen in such disorders as autism, Turner syndrome, and Williams syndrome, may be associated with a failures in this subcortical pathways, leading to improper development and specialization of dependent cortical circuits.

Differential processing of objects under various viewing conditions in the human LOC

2008-02-13T21:28:00.000-08:00

Grill-Spector, K. et al. (September 1999). Differential processing of objects under various viewing conditions in the human lateral occipital complex. Neuron, Vol. 24, 187-203.

This study used fMRIa techniques to investigate the brain's object-selective regions (namely the lateral occipital complex). fMRIa assumes that a group of neurons will respond to repeated presentations of a stimulus with attenuated responses. This signal reduction is presumably the result of neural fatigue from repeated exposure. Thus, "adaptation" data can be used to identify which types of stimulus are effectively treated identically by a certain region of the brain. This is especially interesting in structures further up the processing hierarchy where lower-level transformations have likely given way to more abstract, general representations of the stimuli. Researchers can then explore what properties of objects are preserved and which are transformed to a canonical representation by the time signals converge on a specific region.

First, the study sought to understand how long adaptation effects last. Time durations as long as 8 sec between matched stimuli still elicited amplitude reductions, establishing that adaptation has a fairly long-lasting effect.

Secondly, the study set out to examine which object properties were invariant within the LOC. The results indicate that the LOC is less sensitive to changes in size and position, compared to changes induced by illumination and viewpoint (rotation). In other words, it seems the LOC receives visual input which has been normalized for size and position.

fMRIa

2008-02-13T18:33:00.001-08:00

Krekelberg, B, Boynton, G.M., & van Wezel, R.J.A. (2006). Adaptation: from single cells to BOLD signals. Trends in Neuroscience.

Functional magnetic resonance imaging adaptation (fMRIa) is an increasingly popular method which takes advantage of the brain changes which occur in response to long exposure to some evocative stimulus. If Stimulus 1 (S1) excites a certain neuronal population, repeated exposure to S1 will result in subsequently attenuated responses. This may be due to neural fatigue (i.e. the more a neuron fires, the more its subsequent responses will be reduced) or may be due to coupled hemodynamic processes. However, when S1 is followed by a unique stimulus, S2, the response amplitudes should not be attenuated as a fresh sub-population of neurons is excited. Using this technique can allow researchers to determine if the same or unique neuronal groups are involved in processing two stimuli. This paper goes on to describe the utility of the technique in examination of the visual system, particularly orientation, motion, and face detection. It also stresses the importance of adaptation timescale in experimental design.

Neuronal CPEB Stabilizes Synapse-Specific LTF

2008-02-12T13:18:00.000-08:00

Si, K. et al. (December 26, 2003). A neuronal isoform of CPEB Regulates local protein synthesis and stabilizes synapse-specific long-term facilitation in Aplysia. Cell, Vol. 115, 893-904.

Synaptic plasticity has been offered as one answer to questions regarding the neurobiological mechanisms of memory. The gist of plasticity is that the synapses are effectively "strengthened", forming a stronger connection between neighboring neurons. Plasticity has at least two forms: one a short-term form lasting minutes, and the other a long-term form lasting days or weeks. How does each work? And how are specific, individual synapses strengthened when most cellular mechanisms (e.g. gene expression) are thought to act cell-wide?

Short-term changes are characterized by covalent modifications of preexisting proteins and the strengthening of preexisting connections. However, specific mechanisms for this are not offered by the authors. This paper takes aim instead at long-term plasticity, characterized by creation and projection of of new synaptic connections and growth of new synaptic terminals, requiring both structural changes in the shape, size, and morphology of the synapse as well as regulatory controls that determine where and when to grow.

The article shows that neural stimulation can: (1) send a signal from the synapse to the nucleus that kicks off the gene expression process necessary for long-term facilitation, and (2) "mark" the specific activated synapse so that translation can occur (proper materials can be synthesized) at the specifically marked synapse. CPEB, which resembles a prion (a protein that can switch between two functionally distinct morphological states), seems to act as the needed "marker". ApCPEB appears necessary for the long-term stabilization of facilitation, but not for short-term facilitation. Its ability to polyadenylate (elongate) the mRNA that reaches the marked synapse stabilizes this mRNA molecule, allowing it to resist catalyzation longer thereby increasing its output of building-block proteins. Interestingly, this process can be kicked off by as little as one, single stimulation event.

For a more holistic review of memory mechanisms, see Molecular Mechanisms for Storage.

Retinotopy and Functional Subdivision of Human Areas MT and MST

2008-02-10T15:16:00.000-08:00

Huk, A.C. et al. (August 15, 2002). Retinotopy and Functional Subdivision of Human Areas MT and MST. The Journal of Neuroscience, Volume 22, Number 16, 7195-7205.

Much research in neuroscience has begun with animal studies (and invasive techniques) and only later been continued with human subjects (with predominantly non-invasive methodologies). This paper discusses the attempts to reconcile the areas of visual cortex responsible for detecting visual motion in the macaque and the human. In particular, two sub-divisions of the dorsal superior temporal sulcus (STS) are well-studied in the macaque: the middle temporal (MT) and the medial superior temporal (MST) visual areas. The MT is characterized by a distinguishable retinotopic map and a coarse-grained small receptive field, whereas the MST is just the opposite. This experiment was designed to recognize areas displaying these characteristics in the human MT+ or V5 area, thought to be homologous to the macaque STS, using fMRI. Subregions of the human MT+ were tentatively identified, bridging the gap between animal and human research.

New images from human visual cortex

2008-02-10T14:48:00.000-08:00

R.B.h. Tootell et al. (1996). New images from human visual cortex. Trends in Neuroscience, Vol. 19, No. 11, 481-489.

This article takes aim at broadly reviewing animal and human studies of the human visual cortex. There has been a long and successful tradition of studying the visual cortex in our Old World monkey relatives, the macaques. Although there are significant differences, there are also striking similarities and key learnings that can be generalized from examination of macaque cortex. The article discusses the attempts to converge the research in these two different disciplines of human and animal studies on the basis of functional properties, retinotopy, histology, and connectivity. Among others, it covers the principles of disproportionate cortical mapping, cortical flattening (or unfolding) techniques common to animal studies, and the 'where' vs. 'what' pathways of the visual system. Although these two distinct pathways are well understood in the monkey, they are defined with more uncertainty in the human. The article discusses motion processing and spatial organization in the dorsal 'where' pathway, and color processing, form recognition, and object identification in the ventral 'what' pathway.

A flexible fusiform area for subordinate-level visual processing automatized by expertise

2008-02-06T21:19:00.000-08:00

Tarr, M.J. & Gauthier, I. (August 2000). FFA: A flexible fusiform area for subordinate-level visual processing automatized by expertise. Nature Neuroscience, Volume 3, Number 8, 764-769.

The article explores the controversy over face perception in the fusiform gyrus. Is face perception carried out by domain-specific mechanisms specialized for processing faces in particular, or are faces handled by domain-general mechanisms? This article argues for the latter alternative. Specifically, it emphasizes categorization and expertise in a given object domain (e.g. faces, cars) affect the response of the fusiform area independent of stimulus geometry. Counter-evidence and rebuttals are too complicated to get into in such a summary. However, the heatedness of the debate leaves this issue far from closed.

Domain specificity in face perception

2008-02-06T21:07:00.000-08:00

Kanwisher, N. (August 2000). Domain specificity in face perception. Nature Neuroscience, Volume 3, Number 8, 759-763.

The article explores the controversy over face perception in the fusiform gyrus. Is face perception carried out by domain-specific mechanisms specialized for processing faces in particular, or are faces handled by domain-general mechanisms? This article argues for the former alternative. It uses inversion, holistic recognition advantages, and a double-dissociation between face and object recognition found in the neuropsychological record (prosopagnosia patients who cannot recognize faces but who can recognize objects and C.K. who is impaired in reading and object recognition but whose facial recognition is preserved) as primary pieces of evidence. Counter-evidence and rebuttals are too complicated to get into in such a summary. However, the case seems far from closed.

Serotonin and Hallucinogens

2008-02-04T12:28:00.000-08:00

Aghajanian, G.K. & Marek, G.J. (1999). Serotonin and Hallucinogens. Neuropsychopharamcology, Vol. 21, No. 2S.

Many possibilities are offered as to how LSD and other hallucinogens create their unusual psychoactive effects. The article gets very specific with different serotonin sub-types in different brain regions being implicated. I find the article and the facts confusing enough to assume that the complicated effect enacted in the use of such psychedelics will be only be fully understood after considerably more research.

Psychedelic Medicine

2008-02-03T13:56:00.000-08:00

Horgan, J. (February 26, 2005). Psychedelic Medicine: Mind bending, health giving. New Scientist.

A typical overview of the tumultuous history of the use of psychedelics in medicine and therapy by science writer John Horgan. I found the 'Psychedelic Healing' more interesting and informative; I would recommend reading this instead.

Autonomic Correlates of ADHD and ODD in Preschool Children

2008-02-01T14:54:00.000-08:00

Cromwell, S.E., Beauchaine, T.P., Gatzke-Kopp, L., Sylvers, P., Mead, H., & Chipman-Chacon, J. (2006). Autonomic Correlates of Attention-Defecit/Hyperactivity Disorder and Oppositional Defiant Disorder in Preschool Children. Journal of Abnormal Psychology, Volume 115, Number 1, 174-178.

Conduct disorder in adolescence and antisocial behavior in adults has been shown to be marked by autonomic underarousal. This study attempted to see if much younger, at-risk pre-schoolers are autonomically similar to older externalizing children and adults. Firstly, the study found that pre-school children with ADHD and ODD showed attenuated EDR, a measure of sympathetic nervous system (SNS). Decreased SNS activity is thought to be a marker of disinhibition. Secondly, the study found ADHD and ODD pre-schoolers have attenuated SNS-linked cardiac activity, which serves as a marker of reward sensitivity. Children with underactive reward systems may engage in reward-seeking behavior to compensate for a chronically suppressed dopaminergic subsystem. Finally, as compared with controls, the paper showed no substantial differences in these ADHD/ODD groups in RSA, a marker of parasympathetic nervous system (PNS) activity, and more generally, emotional regulation. The results support the hypothesis that even very young ADHD and ODD children are similar in autonomic biology to older antisocial groups. However, these preschool years may represent a critical period during which noradrenergic, serotonergic, and dopaminergic systems that govern behavioral control are most vulnerable to long-term changes, and importantly, emotional dysregulation, a hallmark of most psychological disorders, may be positively affected through early detection and intervention during this timeframe.

Psychedelic Healing?

2008-01-30T11:37:00.000-08:00

Brown, D.J. (January 2008). Psychedelic Healing? Scientific American Mind, 66-71.

Between 1897 and 1972, many studies were conducted on the therapeutic effects of psychotropic drugs; however, there were virtually no such studies conducted between 1972 and 1990 largely due to political reasons. Since then, research has begun anew, specifically into tryptamines (e.g. LSD, psilocybin) and phenethylamines (e.g. mescaline, MDMA). Tryptamine hallucinogens are thought to bind to serotonin-2A receptors in the cortex, effectively interfering with the processing of sensory information. The beneficial effects observed, such as positive changes in mood, reduction of anxiety, and raising of the pain threshold, may arise from subsequent 5HT-2A receptor downregulation. Phenethylamines are believed to mimic the effects of the dopamine neurotransmitter, but may also bind to the same serotonin receptors activated by the tryptamines. As psychedelics are known to elicit behavioral processes that are useful in the therapeutic context, such as enhanced symbolism and imagery, increased suggestibility, increased contact between emotions and ideations, and controlled regression, with the proper set and setting drug-assisted psychotherapy may show the potential to relieve patients who suffer with treatment-resistant psychiatric disorders.

Facilitation of Extinction of Conditioned Fear by D-Cycloserine

2008-01-30T10:07:00.000-08:00

Davis, M., Myers, K.M., Ressler, K.J. Rothbaum, B.O. (2005). Facilitation of Extinction of Conditioned Fear by D-Cycloserine. American Psychological Association, Volume 14, Number 4, 214-219.

Conditioned fear can be suppressed through a process known as extinction, in which repeated exposure to a fearful stimuli minus any aversive effects leads to a gradual reduction in the fear response. Extinction is not thought to be an "unlearning" process, but rather the addition of a supplementary learning process which actively inhibits or suppresses fear responses that are no longer adaptive. Although not much is known about the neural underpinnings of extinction, it is known that the process depends on NMDA receptors within the amygdala which help to consolidate extinction. The compound D-cycloserine binds to the NMDA receptor and improves its efficiency, and administration of D-cycloserine in rats was shown to dose-dependently enhance extinction.

Taking this laboratory research to the clinic, researchers were curious to see if similar effects would be witnessed in human subjects. This article showed that D-cycloserine used alongside exposure therapy for acrophobics (people suffering from a fear of heights) resulted in significantly larger reductions in phobic symptoms and faster improvement as compared with placebo-controlled subjects. While this paints an optimistic picture for the use of D-cycloserine with phobias, it remains to be seen whether the compound will show equally impressive results in improving cognitive behavioral therapies for more complex anxiety disorders such as PTSD.

Prediction of immediate and future rewards differentially recruits cortico-basal ganglia loops

2008-01-29T19:55:00.001-08:00

Tanaka, S.C. et al. (August 2004). Prediction of immediate and future rewards differentially recruits cortico-basal ganglia loops. Nature Neuroscience, Volume 7, Number 8, 887-893.

Curiously, lesions in the nucleus accumbens in rats result in a tendency to choose small immediate rewards over larger future rewards. And low activity in the central serotonergic system is also associated with impulsive behavior in humans. This article argues that the lateral orbit-frontal cortex (OFC) takes on the role of predicting immediate rewards, while the dorsolateral prefrontal cortex (dlPFC), dorsal pre-motor cortex (dMC), and inferior parietal cortex (IPC) are involved in prediction of future outcomes. Therefore, different sub-loops of the cortico-basal ganglia network are specialized for reward prediction at different time scales. The last piece of the puzzle, the dorsal raphe nucleus, is thought to use serotonin influence to control the effective time scale of reward prediction, allowing flexible selection of a relevant time-scale appropriate for the task at the time of decision-making.

Using human brain lesions to infer function

2008-01-27T19:42:00.000-08:00

Rorden, C. & Karnath, H. (October 2004). Using human brain lesions to infer function: a relic from a past era in the fMRI age? Nature Reviews, Vol. 5, 813-819.

Patients with brain lesions have historically provided neuroscience with momentous insights into brain function. However, with the advent of non-invasive in vivo imaging techniques such as CT, MRI, fMRI, DTI, and the like, researchers are questioning the role of lesion methods going forward. This article argues that lesions studies will continue to fill a unique niche in the future, especially in combination with new imaging protocols: "The power of cognitive neuroscience comes from using convergent tools to investigate the same theoretical question."

Looking into the Functional Architecture of the Brain with Diffusion MRI

2008-01-26T23:50:00.000-08:00

Le Bihan, D. (June 2003). Looking into the Functional Architecture of the Brain with Diffusion MRI. Nature Reviews, Vol 4, 469-480.

Diffusion Magnetic Resonance Imaging (dMRI) is an exciting new addition to non-invasive neuroscience imaging, providing a view of anatomical connectivity in the brain based on the principle of molecular diffusion. Diffusion of water molecules in the direction of axonal myelinated fibres is about three to six times faster than in the perpendicular direction. In applying this maxim to detailed MRI measures of water displacement, it is possible to map the orientation in space of the white matter tracks in the brain. Utilizing the diffusion tensor imaging (DTI) technique provides even more exquisite detail on tissue microstructure. Information about the structural and dynamic wiring that determines how brain areas are networked has particular applicability to the study neurological and psychiatric disorders in which connectivity dysfunction is thought to be part of the underlying etiology.

CBT vs. Pharmacotherapy for Chronic Primary Insomnia

2008-01-25T19:28:00.000-08:00

Sivertsen, B. et al. (June 2006). Cognitive Behavioral Therapy vs. Zopiclone for Treatment of Chronic Primary Insomnia in Older Adults. The Journal of the American Medical Association, Vol 295, No. 24, 2851-2858.

This study compared the effects of cognitive behavioral therapy (CBT) against sleep medication (Lunesta) and placebo intervention for chronic insomnia in older adults. The results showed that CBT resulted in improved short-term and long-term outcomes compared with pharmacotherapy on 3 out of 4 measures. Interestingly, for most outcomes Lunesta did not differ significantly from placebo.

Behavioral control, the medial prefrontal cortex, and resilience

2008-01-23T16:29:00.000-08:00

Maier, S.F., Amat, J., Baratta, M.V., Paul, E., & Watkins, L.R. (2006). Behavioral control, the medial prefrontal cortex, and resilience. Dialogues in Clinical Neuroscience, Vol. 8, No. 4, 397-406.

In a previous article reviewed, "Stressor controllability and learned helplessness: The roles of the dorsal raphe nucleus, serotonin, and corticotrophin-releasing factor", Maier et al showed that the degree of control an organism has over a stressor modulates the impact of this stressor. But how, exactly, controllability enters the equation neurobiologically was undiscussed. This article tackles that issue with some interesting conclusions drawn.

Although the dorsal raphe nucleus (DRN) plays a critical role in learned helplessness, it is unlikely that it is the brain structure responsible for detecting whether or not a stressor is under behavioral control or not. It has neither the processing power nor the appropriate inputs to make such an assessment. However, the ventral medial pre-frontal cortex (vmPFC) is thought to be that structure. Electrical stimulation of this area leads to inhibition of serotonin neurons in the DRN. And inactivating this region eliminates the differential effects of controllability -- that is, both inescapable and escapable shocks produce the same behavioral outcomes. Further, directly activating the vmPFC during inescapable and escapable shocks produces responses in the both groups equivalent to an escapable shock, eluding learned helplessness.

So-called 'immunization effects' are also interesting. Initial experiences with controllable shock appears to attenuate the typical behavioral response to a later exposure to uncontrollable shock. The article shows how the vmPFC becomes associated with the stressor during controllable shock trials and later becomes re-activating again during subsequent uncontrollable trials, thereby inhibiting the DRN.

Furthermore, this 'trained' vmPFC projects to other structures besides the DRN. One of particular importance is the amygdala which is known to play a critical role in classical fear conditioning. The article shows how the pathway from the vmPFC to the central nucleus of the amygdala (CE) can be used to inhibit CE function, thereby retarding fear conditioning. As has been shown, inescapable shock prior to fear conditioning exaggerates fear conditioning. But escapable shock, a stressful event in itself, before fear conditioning is actually shown to reduce the phenomena of fear (in comparison with never-before-shocked animals). The authors remarked, "We know of no other position that would predict, or even explain, how exposure to a highly stressful event could retard the later development of fear." In other words, repeated exposure to aversive stimuli hyper-sensitize the animal to fear. But, repeated exposure to aversive stimuli which the animal can exercise some control over actually helps to desensitize the animal to fear by involving the vmPFC. Still more encouraging, this mechanism of resilience may generalize broadly to quite different situations and circumstances.