The visual cortex first represents information in terms of local image features such as pieces of contour and patches of color. But many tasks in vision (search, recognition, control of grasping) require selection of information about a specific object. Our laboratory focuses on the transformation from image to object representation. Many perceptual phenomena suggest such a transformation. For example, Rubin's well known vase/face figure demonstrates the perceptual tendency to assign contrast borders to objects. We have recently discovered that neurons in monkey visual cortex, specifically areas V2 and V4, represent such "border ownership". We are now studying the question of how border ownership coding relates to attentional selection. We also study the neural mechanisms of 3-D shape perception. The question here is whether the system differentiates between contrast borders arising from reflectance borders, occluding contours, and 3-D edges.
The laboratory is in the Zanvyl Krieger Mind/Brain Institute, located on the beautiful Homewood Campus of the Johns Hopkins University. The growing Mind/Brain Institute, which was initiated by Steven Muller, then president, and Vernon Mountcastle in the mid-1980s, is a leader in systems neurophysiology with an exceptional concentration of research in perceptual systems. The Institute was first directed by Guy McKhann, former Hopkins chief of Neurology, and currently by Kenneth Johnson, former director of highly regarded Philip Bard Laboratories. The Institute now includes 5 behaving monkey laboratories focusing on vision and touch, and laboratories for neuroanatomy, study of plasticity in brain slices, and computational neuroscience. Cooperative projects exist with Biomedical Engineering and Psychology Departments.