The Journal of Neuroscience, August 15, 1999, 19(16):7212-7229
The Subregion Correspondence Model of Binocular Simple Cells
Ed
Erwin1, 4 and
Kenneth
D.
Miller2, 3, 4, 5
Departments of 1 Physiology and
2 Otolaryngology, 3 Neuroscience Graduate
Program, 4 W. M. Keck Center for Integrative Neuroscience,
and 5 Sloan Center for Theoretical Neurobiology, University
of California, San Francisco, California 94143-0444
We explore the hypothesis that binocular simple cells in cat areas
17 and 18 show subregion correspondence, defined as follows: within the region of overlap of the two eye's receptive fields, their
ON subregions lie in corresponding locations, as do their OFF
subregions. This hypothesis is motivated by a developmental model
(Erwin and Miller, 1998) that suggested that simple cells could develop
binocularly matched preferred orientations and spatial frequencies by
developing subregion correspondence.
Binocular organization of simple cell receptive fields is commonly
characterized by two quantities: interocular position shift, the
distance in visual space between the center positions of the two eye's
receptive fields; and interocular phase shift, the difference in the
spatial phases of those receptive fields, each measured relative to its
center position. The subregion correspondence hypothesis implies that
interocular position and phase shifts are linearly related. We compare
this hypothesis with the null hypothesis, assumed by most previous
models of binocular organization, that the two types of shift are uncorrelated.
We demonstrate that the subregion correspondence and null hypotheses
are equally consistent with previous measurements of binocular response
properties of individual simple cells in the cat and other species and
with measurements of the distribution of interocular phase shifts
versus preferred orientations or versus interocular position shifts.
However, the observed tendency of binocular simple cells in the cat to
have "tuned excitatory" disparity tuning curves with preferred
disparities tightly clustered around zero (Fischer and Krüger,
1979; Ferster, 1981; LeVay and Voigt, 1988) follows naturally from the
subregion correspondence hypothesis but is inconsistent with the null hypothesis.
We describe tests that could more conclusively differentiate between
the hypotheses. The most straightforward test requires simultaneous
determination of the receptive fields of groups of three or more
binocular simple cells.
Key words:
binocular cell; simple cell; ON-center; OFF-center; cat
visual cortex; striate cortex; disparity tuning; owl visual Wulst; model
Copyright © 1999 Society for Neuroscience 0270-6474/99/19167212-18$05.00/0