The Spatial Structure of Neural Encoding in Mouse Posterior Cortex during Navigation.

Navigation engages many cortical areas, including visual, parietal, and retrosplenial cortices. These regions have been mapped anatomically and with sensory stimuli and studied individually during behavior. Here, we investigated how behaviorally driven neural activity is distributed and combined across these regions. We performed dense sampling of single-neuron activity across the mouse posterior cortex and developed unbiased methods to relate neural activity to behavior and anatomical space. Most parts of the posterior cortex encoded most behavior-related features. However, the relative strength with which features were encoded varied across space. Therefore, the posterior cortex could be divided into discriminable areas based solely on behaviorally relevant neural activity, revealing functional structure in association regions. Multimodal representations combining sensory and movement signals were strongest in posterior parietal cortex, where gradients of single-feature representations spatially overlapped. We propose that encoding of behavioral features is not constrained by retinotopic borders and instead varies smoothly over space within association regions.