Optometry Research Today is a free monthly online journal that collates and summarizes the latest research about Optometry, including details on myopia, optometric practice, therapy.

Temporal dynamics of figure-ground segregation in human vision.

Neri P, Levi DM

Department of Optometry and Visual Science, City University, Northampton Square, London ECIV 0HB, United Kingdom. pn@white.stanford.edu).

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 of 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 studies.

Published 17 January 2007 in J Neurophysiol, 97(1): 951-7.
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