How does the brain sustain a visual percept?
Perception involves the processing of sensory stimuli and their translation into conscious experience. A novel percept can, once synthesized, be maintained or discarded from awareness. We used event-related functional magnetic resonance imaging to separate the neural responses associated with the maintenance of a percept, produced by single-image, random-dot stereograms, from the response evoked at the onset of the percept. The latter was associated with distributed bilateral activation in the posterior thalamus and regions in the occipito-temporal, parietal and frontal cortices. In contrast, sustained perception was associated with activation of the pre-frontal cortex and hippocampus. This observation suggests that sustaining a visual percept involves neuroanatomical systems which are implicated in memory function and which are distinct from those engaged during perceptual synthesis.
Portas
C M
CM
Wellcome Department of Cognitive Neurology, Institute of Neurology, London, UK. cportas@fil.ion.ucl.ac.uk
Strange
B A
BA
Friston
K J
KJ
Dolan
R J
RJ
Frith
C D
CD
D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D003867:Depth Perception / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology; D008959:Models, Neurological; D010775:Photic Stimulation; D014796:Visual Perception / Q000502:physiology*