NEURAL MECHANISMS OF VISUAL PERCEPTION

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DESCRIPTION: To comprehend the neural basis of visual perception, it is necessary to determine how information in sensory regions of the brain comes to influence motor and premotor circuitry governing behavior. For all but the most reflexive visual responses, the link between sensory and motor processes must encompass a perceptual decision. The decision may be regarded as a tractable element of visual perception, within the grasp of modern visual neuroscience. The past 30 years has furnished an abundance of knowledge about the representation of visual data in cortex and nearly as much about cortical areas governing oculomotor function. The next objective of this research program is to unite these ends of the sensorimotor continuum. Analogous to a court of law, the visual cortex contain the evidence, while the motor cortex reflects the judge's sentence. The present inquiry is directed at the jury's deliberations toward a verdict: how does the brain interpret its sensory maps to activate the appropriate motor circuitry? The primary goal of the proposed research is (1) to characterize the neurophysiological correlates of a visual perceptual decision in the dorsolateral prefrontal cortex of the rhesus monkey. (2) to establish the nature of computations that underlie the neural response within this brain region, and (3) to delineate the role of attention and contextual cues on the sensorimotor transformation. These investigations represent new territory for visual neuroscience, amalgamating several fields: visual psychophysics, computational neuroscience, oculomotor physiology and the neurobiology of memory. Processes that convert evidence in sensory maps to categorical decisions are likely generic to many aspects of cognition. The neural correlate of a visual decision thus serves as a model for other higher cortical functions. By elucidating its neurobiological basis these studies are likely to found new approaches for intervening in diseases affecting visual cognition and intellectual function.