Binocular disparity, the difference between left and right eye images, is a powerful cue for depth perception. Many neurons in the visual cortex of higher mammals are sensitive to binocular disparity, with distinct disparity tuning properties across primary and higher visual areas. Mouse primary visual cortex (V1) has been shown to contain disparity-tuned neurons, but it is unknown how these signals are processed beyond V1. We find that disparity signals are prominent in higher areas of mouse visual cortex. Preferred disparities markedly differ among visual areas, with area RL encoding visual stimuli very close to the mouse. Moreover, disparity preference is systematically related to visual field elevation, such that neurons with receptive fields in the lower visual field are overall tuned to near disparities, likely reflecting an adaptation to natural image statistics.Our results reveal ecologically relevant areal specializations for binocular disparity processing across mouse visual cortex.Keywords mouse visual cortex, binocular disparity, two-photon calcium imaging, optical imaging, higher visual areas, random dot stereogram, visual depth processing understood. Apart from V1, areas LM and RL contain the largest representation of the binocular visual field (Garrett et al. 2014; Zhuang et al. 2017), making them candidate areas for investigating downstream processing of binocular disparity in mouse visual cortex. In turn, comparison of disparity tuning across different mouse visual areas might help delineating their functional specializations.

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Highlights d Sensitivity for binocular disparity is widespread across areas of mouse visual cortex d Area RL is specialized for disparities corresponding to nearby visual stimuli d Disparity preference is related to visual field elevation d Area RL might contain a visuo-tactile map of near space in front of the mouse

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.