Continuous flash suppression reduces negative afterimages

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.