Description of Research Expertise

My lab studies the neural basis of normative and recovered high-level visual function. Our primary technique is functional magnetic resonance imaging (fMRI), although individual projects also employ behavioral, animal, or patient based research. The projects are complementary, in that they characterize normative neural function for vision and how this can be altered through experience and training, including perturbations that are maximally negative (cortical damage) and positive (restoration of vision in the congenitally blind).

Object perception - Our studies focus upon the representation of face identity, although individual projects also examine more elementary visual processes (such as shape and color). Our work has examined the neural correlates of holistic face perception using manipulation of amodal completion, the neural basis of perceptual similarity of faces and objects, and the neural signature of facial attractiveness. A key methodological approach involves the use of "continuous carry-over designs" for fMRI studies.

Loss and recovery of visual function – We study the effects of cortical damage upon vision and the effects of restoration of visual function. Damage to primary visual cortex produces blindness but occasionally spares some perceptual function (so-called “blindsight”). Our studies characterize the location and properties of these spared neural functions. Conversely, patients with life-long blindness from ophthalmologic disease may soon have visual recovery via retinal prosthetic devices and gene therapy. What are the neural effects of this late recovery of function and how might cortical recovery be optimized? We perform fMRI studies with congenitally blind dogs following gene-therapy reversal of their retinal disease, and with human subjects with congenital blindness.

Perceptual learning studied with perfusion fMRI – Our laboratory has collaborated with Dr. John Detre's group to develop perfusion MRI as a functional imaging modality suitable for the study of the slow changes in neural activity that accompany perceptual learning.

Description of Clinical Expertise

I operate a behavioral neurology speciality clinic. While patients present with a wide variety of cognitive impairments, memory impairments comprise the bulk of my cases.