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Understanding the cortical specialization for horizontal disparity

Lookup NU author(s): Professor Jenny ReadORCiD


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Because the eyes are displaced horizontally, binocular vision is inherently anisotropic. Recent experimental work has uncovered evidence of this anisotropy in primary visual cortex (V1): neurons respond over a wider range of horizontal than vertical disparity, regardless of their orientation tuning. This probably reflects the horizontally elongated distribution of two-dimensional disparity experienced by the visual system, but it conflicts with all existing models of disparity selectivity, in which the relative response range to vertical and horizontal disparities is determined by the preferred orientation. Potentially, this discrepancy could require us to abandon the widely held view that processing in V1 neurons is initially linear. Here, we show that these new experimental data can be reconciled with an initial linear stage; we present two physiologically plausible ways of extending existing models to achieve this. First, we allow neurons to receive input from multiple binocular subunits with different position disparities (previous models have assumed all subunits have identical position and phase disparity). Then we incorporate a form of divisive normalization, which has successfully explained many response properties of V1 neurons but has not previously been incorporated into a model of disparity selectivity. We show that either of these mechanisms decouples disparity tuning from orientation tuning and discuss how the models could be tested experimentally. This represents the first explanation of how the cortical specialization for horizontal disparity may be achieved.

Publication metadata

Author(s): Read JC, Cumming BG

Publication type: Article

Publication status: Published

Journal: Neural Computation

Year: 2004

Volume: 16

Issue: 10

Pages: 1983-2020

Print publication date: 01/10/2004

ISSN (print): 0899-7667

ISSN (electronic): 1530-888X

Publisher: M I T Press


DOI: 10.1162/0899766041732440

Notes: Paper uses physiological data recorded by Cumming; I did the data analysis and mathematical modelling.


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