Title: Temporal Dynamics of Figure-ground Segregation in Human Vision

The segregation of figure from ground is arguably one of the most fundamental operations in human vision. Neural signals reflecting this operation appear in cortex as early as 50 ms and as late as 300 ms after presentation of a visual stimulus, but it is not known when these signals are used by the brain to construct the percepts of figure and ground. We used psychophysical reverse correlation to identify the temporal window for figure-ground signals in human perception, and found it to lie within the range 100-160 ms. Figure enhancement within this narrow temporal window was transient, rather than sustained as may be expected from measurements in single neurons. These psychophysical results prompt and guide further electrophysiological investigations. Page 1 of 24 Articles in PresS. J Neurophysiol (September 27, 2006). doi:10.1152/jn.00753.2006 Copyright © 2006 by the American Physiological Society.