I am an Associate Professor of Neurology at the University of Pennsylvania and a cognitive neuroscientist. My clinical and research work concerns the organization of the brain for mental operations, in particular visual ability. Using functional MRI, a non-invasive tool for measuring brain activity, I study how neurons are normally arranged to represent and store the appearance of people, places, and things. I use these techniques to understand as well how blindness changes the brain. As a clinician, I treat patients with a variety of disturbances of thinking and memory, with my practice informed by recent insights into the organization of the brain for these functions. I study the methodological development and application of imaging techniques.