paper available: Modeling V1 Disparity Tuning to Time-varying Stimuli

[Ning Qian]

Dear Colleagues.

The following paper on "Modeling V1 Disparity Tuning to Time-varying
Stimuli" is available at:

http://brahms.cpmc.columbia.edu/publications/v1time.ps.gz

Best regards,

Ning


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Modeling V1 Disparity Tuning to Time-varying Stimuli

Yuzhi Chen, Yunjiu Wang, and Ning Qian, J. Neurophysiol. (in press). 

Abstract

Most models of disparity selectivity consider only the spatial
properties of binocular cells. However, the temporal response is an
integral component of real neurons' activities, and time-varying
stimuli are often used in the experiments of disparity tuning. To
understand the temporal dimension of V1 disparity representation, we
incorporate a specific temporal response function into the disparity
energy model, and demonstrate that the binocular interaction of
complex cells is separable into a Gabor disparity function and a
positive time function. We then investigate how the model simple and
complex cells respond to widely used time-varying stimuli, including
motion-in-depth patterns, drifting gratings, moving bars, moving
random dot stereograms, and dynamic random dot stereograms. It is
found that both model simple and complex cells show more reliable
disparity tuning to time-varying stimuli than to static stimuli, but
similarities in the disparity tuning between simple and complex cells
depend on the stimulus. Specifically, the disparity tuning curves of
the two cell types are similar to each other for either drifting
sinusoidal gratings or moving bars. In contrast, when the stimuli are
dynamic random dot stereograms, the disparity tuning of simple cells
is highly variable, whereas the tuning of complex cells remains
reliable. Moreover, cells with similar motion preferences in the two
eyes cannot be truly tuned to motion in depth, regardless of the
stimulus types. These simulation results are consistent with a large
body of extant physiological data, and provide some specific, testable
predictions.