My major research
interests are the functional organization of the primate visual system
and the neural basis of perception in health and disease. Recently, I have focused on how information from the two eyes is normally integrated to produce depth perception or binocular rivalry. In addition,
I study binocular vision and the neurological characterization
of adults and children with amblyopia (lazy eye). I also have longstanding interests in aspects of shape perception.
I approach these topics with studies of normal behavior, the behavioral effects of focal lesions, and physiological measurement of brain activity. I currently use functional magnetic resonance imaging (fMRI) techniques or magnetoencephalography (MEG) to measure local physiological signals in brain tissue while human subjects view visual stimuli. I take much of my inspiration from the relatively well-understood monkey visual system, which is similar to the human system. Using fMRI and appropriate visual stimulation provides clear, non-invasive localization of the boundaries of the multiple areas in human visual cortex, areas known previously only from monkeys. An important methodological advantage is the use of tools that enable visualization of brain activation data as a 2-D pattern on the flattened brain, and facilitate the build-up of increasingly detailed maps of the visual areas in single subjects.