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This article is part of the supplement: Twentieth Annual Computational Neuroscience Meeting: CNS*2011

Open Access Poster presentation

Spatial stereoresolution for depth corrugations may be set in primary visual cortex

Fredrik Allenmark* and Jenny Read

Author Affiliations

Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK

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BMC Neuroscience 2011, 12(Suppl 1):P263  doi:10.1186/1471-2202-12-S1-P263

The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1471-2202/12/S1/P263


Published:18 July 2011

© 2011 Allenmark and Read; licensee BioMed Central Ltd.

This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Poster presentation

Stereo depth perception has recently been modelled based on local cross-correlation between the left and the right eye’s images. This model, which is based on the known physiology of primary visual cortex (V1), has successfully explained many aspects of stereo vision. In particular, it has explained the low spatial stereoresolution for sinusoidal depth corrugations [1,2], suggesting that the limit on stereoresolution may be set in V1. In accordance with the properties of V1 neurons, the disparity detectors used in this model are tuned to locally uniform patches of disparity. Consequently, the model responds better to high amplitude square-wave corrugations than to high amplitude sine-waves, because the square-waves are locally flat while the sinusoidal corrugations are slanted almost everywhere and this slant is particularly large at large amplitudes. The model therefore predicts better performance at detecting square-wave than sine-wave disparity corrugations at high amplitudes. However, in contradiction with this prediction of the model we have recently shown that humans perform no better at detecting square-waves than sine-waves even at high amplitudes [3]. This failure of the model raised the question of whether stereoresolution is not set in V1 but at some later stage of cortical processing, for example involving neurons tuned to slant or curvature or whether a modified version of the model, incorporating more of the known physiology, may explain the new results with square-waves. We have tested a modified version of the local cross-correlation model which, based on psychophysical and physiological evidence that larger disparities are detected by neurons with larger receptive fields (a size-disparity correlation), uses larger windows to detect larger disparities. We show that the performance of this modified model is consistent with the human results, confirming that stereoresolution may indeed be limited by V1 receptive field sizes.

References

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    J Neurosci 2004, 24(9):2077-2089. PubMed Abstract | Publisher Full Text OpenURL

  2. Filippini HR, Banks MS: Limits of stereopsis explained by local cross-correlation.

    J Vis 2009, 9(1):8 1-18. Publisher Full Text OpenURL

  3. Allenmark F, Read JC: Detectability of sine- versus square-wave disparity gratings: A challenge for current models of depth perception.

    Journal of Vision 2010, 10(8):1-16. Publisher Full Text OpenURL