Feb. 17, 11:45, Wei Ji Ma. Optimality and Probabilistic Computation in Visual Categorization

Stanley A. Klein

Vision Science, UC Berkeley School of Optometry

Connecting psychophysics and appearance to neurophysiology: Towards an understanding of color

In the decades from 1970-1990 there was an optimism that strong connections could be made between psychophysics and the neural interactions found in retina and cortex. That optimism faded for awhile but advances in technology have brought back a glimmer of a new optimism. My talk will be divided into three parts. 1) How a new technology that combines adaptive optics and super precise image stabilization enables one to do careful psychophysics on individual cones and ganglion cells. 2)  Problems in separating early visual processing (thresholds, gain control and multiplicative noise) from decision stage processing will be discussed. I'll argue that abandoning forced choice methods will help resolve some of these problems. 3) How color vision may provide a key for uncovering brain mechanisms will be introduced.  Exploring how individual cones and ganglion cells interact to produce perceptions is likely to produce surprising findings. A number of present and future experiments will be described on stimulating individual ganglion cells. The vision scientists in the audience will be asked to make predictions for the perceptual outcomes.