Zijiang J. He

University of Louisville, USA
East China Normal University, China
zjhe@louisville.edu

Abstract

Visual signals carried by the early visual levels are inherently fragmentary and ambiguous.  This is largely due to the retinal images being two-dimensional and the early cortical neurons being limited to coding local orientation edges (features), resulting in a lack of image coherence.  The role of parsing these visual signals into coherent, global surface representations belongs to the intermediate level visual mechanisms.  In this capacity, the intermediate level visual mechanisms essentially play a gating role in that their outputs, surface representations, serve as building blocks for object recognition and space perception.  Not fully understood is how the intermediate level visual mechanisms synthesize the locally represented early feature signals into surface representations.  I will describe a series of psychophysical investigations from my laboratory focused on resolving this issue.  We tested human observers on perceptual tasks of binocular rivalry, motion, visual search, texture spreading-in, surface completion and depth judgments.  Generally, our studies reveal that the intermediate level visual mechanisms construct surface representations using a collection of “perceptual rules” based on real world ecological and 3-D geometric constraints.  In addition, top-down attention and implicit memory also influence the integration of the spatially separated fragments into global surface representations.

Short Bio

Zijiang J. He, Ph.D. is a University Scholar and Professor at the Department of Psychological and Brain Sciences, University of Louisville, USA. He also holds a Chang-jiang visiting scholar position at the East China Normal University. Dr. He’s research focuses on human mid-level vision, perceptual learning, space perception and action. Dr. He received his B.S. in Biophysics (1983) from the University of Science and Technology, China. From 1983 to 1986 he studied Neurobiology at the Shanghai Institute of Physiology, Academia Sinica and obtained an M.S. degree. He subsequently pursued his Ph.D. degree in Physiological Optics & Neuroscience (1990) at the University of Alabama at Birmingham, U.S.A. Dr. He conducted his post-doctoral research on human visual perception and cognition at Harvard University until 1994, when he joined the faculty of the University of Louisville. Dr. He has received several honors and awards including the Sloan Research Fellow, University Scholar at the University of Louisville, Chang-jiang Scholar (Ministry of Education of China), and Distinguished College/University Scientist for 2009 award (Kentucky Academy of Science).