Computation and Neural Systems Seminar

We have a remarkable ability to recognize the behavioral significance, or category membership of a wide range of visual stimuli. While much is known about how simple visual features (such as color, orientation and direction of motion) are processed in early stages of the visual system, much less is known about how the brain learns and recognizes categorical information that gives meaning to incoming stimuli. This talk will review a series of neurophysiological and behavioral experiments aimed at understanding the neuronal representations underlying visual categorization and decision making with a focus on parietal and prefrontal cortices. We have found that the activity of individual neurons in both the posterior parietal and lateral prefrontal cortices can reflect the learned category membership of visual stimuli, and that these two areas play distinct roles in category-based decision making. The relationship between non-spatial cognitive signals and spatial signals (related to attention and eye movements) in parietal cortex will also be discussed.