Brain and Cognitive Sciences

The Neural Control of Vision

The central focus of this work is to determine how visual information is processed in the brain. Using behavioral methods, brain imaging and single-cell recordings, we assess what the relative contributions are of various brain areas in the processing of color, brightness, motion, depth, texture and shape. A portion of this work examines how various brain regions involved in vision interact by relying on feed-back circuits from higher to lower areas, such as from areas V2 to V1. In our recent work we are also examining the feasibility of creating a prosthetic device for the blind based on electrical microstimulation of primary visual cortex.

The Neural Control of Visually Guided Eye movements

Our ability to process visual information relies critically on eye movements. The retina is highly specialized as it has only a small region, the fovea, which can provide high-acuity vision by virtue of a high density of photoreceptors. Therefore, to be able to see fine detail in the visual scene, we need to repeatedly shift our gaze with saccadic eye movements. When objects move about, such as a bird flying in the sky, we need to keep tracking it for fine-detail analysis; this is accomplished by smooth pursuit eye movements. Numerous brain areas contribute to our ability to make these saccadic and smooth pursuit eye movements. We study these areas in monkeys with single-cell recordings, microstimulation, and the infusion of pharmacological agents to assess the nature of the excitatory and inhibitory circuits involved. The areas we study include the superior colliculus, the visual cortex, the frontal eye fields and the medial eye fields.