Disparity Sensitivity and Binocular Integration in Mouse Visual Cortex Areas

Abstract

Binocular disparity, the difference between the two eyes' images, is a powerful cue to generate the three-dimensional depth percept known as stereopsis. In primates, binocular disparity is processed in multiple areas of the visual cortex, with distinct contributions of higher areas to specific aspects of depth perception. Mice, too, can perceive stereoscopic depth, and neurons in primary visual cortex (V1) and higher-order, lateromedial (LM) and rostrolateral (RL) areas were found to be sensitive to binocular disparity. A detailed characterization of disparity tuning properties across mouse visual areas is lacking, however, and acquiring such data might help clarifying the role of higher areas for disparity processing and establishing putative functional correspondences to primate areas. We used two-photon calcium imaging to characterize the disparity tuning properties of neurons in mouse visual areas V1, LM, and RL in response to dichoptically presented binocular gratings, as well as correlated and anticorrelated random dot stereograms (RDS). In all three areas, many neurons were tuned to disparity, showing strong response facilitation or suppression at optimal or null disparity, respectively. This was even the case in neurons classified as monocular by conventional ocular dominance measurements. Spatial clustering of similarly tuned neurons was observed at a scale of about 10 μm. Finally, we probed neurons' sensitivity to true stereo correspondence by comparing responses to correlated and anticorrelated RDS. Area LM, akin to primate ventral visual stream areas, showed higher selectivity for correlated stimuli and reduced anticorrelated responses, indicating higher-level disparity processing in LM compared to V1 and RL.

Visual pursuit behavior in mice maintains the pursued prey on the retinal region with least optic flow

“…This region of the visual field projects onto the temporal retina, which contains both ipsilaterally projecting (uncrossed) RGCs ( Dräger and Olsen, 1980 ; Reese and Cowey, 1986 ) and RGCs which form part of the callosal projection pathway ( Laing et al, 2015 ; Olavarria and Van Sluyters, 1983 ; Ramachandra et al, 2020 ), both of which are considered central to binocular visual processing. In addition, the current study adds to the significance of these previous findings and suggests that the functional focus location is well placed to support stereoscopic depth perception, assuming that this form of visual processing is available to and employed by the mouse ( La Chioma et al, 2019 ; La Chioma et al, 2020 ; Samonds et al, 2019 ; Scholl et al, 2013 ; Scholl et al, 2015 ). Further supportive of the importance and relevance of the region of binocular overlap, another recent study provides strong evidence to suggest that ipsilaterally projecting RGCs in the ventro-temporal retina are important in the final phase of cricket pursuit (mouse to cricket distance less than 6 cm), with selective ablation of these RGCs reducing the probability that coming into close proximity with the cricket resulted in its capture ( Johnson et al, 2021 ).…”

Mouse visual cortex contains a region of enhanced spatial resolution

“…We also observed an increase in CMF within the binocular region of V1, with CMF values being two to three times higher close to the vertical meridian than in the monocular regions of cortex, in agreement with previous studies 3,4,9 . This overrepresentation of binocular regions of space could reflect a requirement for cells representing multiple retinal disparities in this region of space [27][28][29] . The absence of a dependency of CMF on elevation is in line with this view.…”

Sensorimotor Self-organization via Circular-Reactions

“…Take the activated neuron in Figure 2C for example, this neuron in BCM becomes active only when it receives simultaneous stimulation of a UA whose position in the column is indicated by teal color and the UA marked by red. In fact, “binocular-depth neurons” have been found in many species including monkey and mouse (Poggio et al, 1988 ; La Chioma et al, 2020 ).…”