Jonathan B. Levitt, Associate Professor of Biology at The Graduate Center and City College, is a neuroscientist whose main research focus is the functional organization of the mammalian central visual pathways, and the postnatal refinement of both brain circuitry and physiological function. He is also interested in more general aspects of cerebral cortex organization. Dr. Levitt and his colleagues employ neuroanatomical techniques to characterize the nature and precision of anatomical connections of nerve cells in different areas of the cerebral cortex. They also use electrophysiological techniques to measure the electrical activity of individual brain cells in these areas activated by visual stimuli. The unifying aim of these studies is to determine how anatomical circuitry contributes to the known physiological properties of individual brain cells in different areas of the cerebral cortex, and how this in turn contributes to visual perception. Dr. Levitt has shown that visual stimuli that do not directly evoke responses from brain cells can suppress or enhance the responses of brain cells to other simultaneously presented visual stimuli. His current work aims to reveal the anatomical substrates for such effects. This work is directly relevant to understanding perceptual studies showing that the detectability or appearance of visual stimuli depends critically on the context in which they are situated. Dr. Levitt's work is supported by the National Eye Institute of the National Institutes of Health and the Wellcome Trust (UK).