Distributed and Retinotopically Asymmetric Processingn of Coherent Motion in Mouse Visual Cortex

Abstract

Perception of visual motion is important for a range of ethological behaviors in mammals. In primates, specific higher visual cortical regions are specialized for processing of coherent visual motion. However, the distribution of motion processing among visual cortical areas in mice is unclear, despite the powerful genetic tools available for measuring population neural activity. Here, we used widefield and 2-photon calcium imaging of transgenic mice expressing a calcium indicator in excitatory neurons to measure mesoscale and cellular responses to coherent motion across the visual cortex. Imaging of primary visual cortex (V1) and several higher visual areas (HVAs) during presentation of natural movies and random dot kinematograms (RDKs) revealed heterogeneous responses to coherent motion. Although coherent motion responses were observed throughout visual cortex, particular HVAs in the putative dorsal stream (PM, AL, AM) exhibited stronger responses than ventral stream areas (LM and LI). Moreover, beyond the differences between visual areas, there was considerable heterogeneity within each visual area. Individual visual areas exhibited an asymmetry across the vertical retinotopic axis (visual elevation), such that neurons representing the inferior visual field exhibited greater responses to coherent motion. These results indicate that processing of visual motion in mouse cortex is distributed unevenly across visual areas and exhibits a spatial bias within areas, potentially to support processing of optic flow during spatial navigation.