Wednesday, February 13, 2008


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.

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