Complex cells in the early visual cortex have multiple disparity detectors in the 3D binocular RFs

Abstract

Event Abstract Back to Event Complex cells in the early visual cortex have multiple disparity detectors in the 3D binocular RFs The slight differences of the two retinal images provide the stereoscopic cue for the perception of the 3D space. These differences are called binocular disparity, and modulate the firing rate of many neurons in the early visual cortex. Disparity selectivity of visual neurons is described most comprehensively by the binocular receptive fields (RFs), which represent how inputs from the two eyes interact to elicit neuronal responses. To date, binocular RF profiles have been investigated for neurons in the early visual cortex in the 2D plane. However, binocular RFs are inherently a 3D entity in space. Here we examined binocular interaction in the 3D space to elucidate mechanisms to detect binocular disparity signals and further pooling of these detectors to comprise the whole binocular RFs in single neurons in the early visual cortex. We recorded from neurons in the early visual cortex of anaesthetized and paralyzed cats while they are stimulated by uncorrelated dichoptic 2D dynamic noise stimuli. We used a spike-triggered analysis to examine structure of the 3D binocular RFs. Spike-triggered stimuli for both eyes were picked up, and were taken apart into thin strips tilted along the X axes (orthogonal to optimal orientation) at Y positions (parallel to optimal orientation). They were multiplied to yield interaction terms between the stimulus strips. The interaction terms were summed for all spike-triggered stimuli to obtain a binocular interaction map in the X dimensions between the pair of the Y positions. This computation was applied for all pairs of Y positions between the left- and right-eye stimuli. For a subset of complex cells, we found no binocular interaction in the RFs between the distant pairs of Y positions between the two eyes even though the both positions were well within the RFs. This means that the detectors for binocular disparity cover a limited portion in the RF and that they are pooled in space to construct the whole RF. Sixteen out of 34 complex cells showed extensive spatial pooling of disparity detectors (RF size / detector size > 1.5). Simple cells generally showed hardly any pooling of the underlying detectors (comparison of the degree of spatial pooling between the populations of simple and complex cells; Wilcoxon rank sum test, p < 0.0001). The degree of spatial pooling was also related to binocularity of cells; neurons with balanced inputs from the two eyes tended to show a large degree of spatial pooling (Wilcoxon rank sum test, p < 0.0005). However, the degree of spatial pooling was not related to optimal orientation, spatial frequency, and the size of detectors. For those complex cells showed extensive pooling of detectors for binocular disparity, tuning curves to binocular disparity were invariant along the Y axis. These results indicate that a substantial proportion of complex cells detect constant binocular disparities in the RFs by collecting inputs only from many antecedent neurons that prefer identical disparities at different positions. This work was supported by Grant-in-Aid for Scientific Research 18020017, 13308048, CREST Yoshioka Project, and Global COE. Conference: Computational and systems neuroscience 2009, Salt Lake City, UT, United States, 26 Feb - 3 Mar, 2009. Presentation Type: Poster Presentation Topic: Poster Presentations Citation: (2009). Complex cells in the early visual cortex have multiple disparity detectors in the 3D binocular RFs. Front. Syst. Neurosci. Conference Abstract: Computational and systems neuroscience 2009. doi: 10.3389/conf.neuro.06.2009.03.167 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 03 Feb 2009; Published Online: 03 Feb 2009. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Google Google Scholar PubMed Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.