Behavioral decomposition reveals rich encoding structure employed across neocortex in rats

Active movement drives neural activity throughout cortex, but it is unclear how different cortical systems might use such signals. Here, the authors shed light on this by mapping how sensory and motor cortical areas encode naturalistic 3D behavior. The cortical population code is pervaded by activity patterns evoked by movement, but it remains largely unknown how such signals relate to natural behavior or how they might support processing in sensory cortices where they have been observed. To address this we compared high-density neural recordings across four cortical regions (visual, auditory, somatosensory, motor) in relation to sensory modulation, posture, movement, and ethograms of freely foraging male rats. Momentary actions, such as rearing or turning, were represented ubiquitously and could be decoded from all sampled structures. However, more elementary and continuous features, such as pose and movement, followed region-specific organization, with neurons in visual and auditory cortices preferentially encoding mutually distinct head-orienting features in world-referenced coordinates, and somatosensory and motor cortices principally encoding the trunk and head in egocentric coordinates. The tuning properties of synaptically coupled cells also exhibited connection patterns suggestive of area-specific uses of pose and movement signals, particularly in visual and auditory regions. Together, our results indicate that ongoing behavior is encoded at multiple levels throughout the dorsal cortex, and that low-level features are differentially utilized by different regions to serve locally relevant computations.

Automated summary

This study investigates how different cortical systems encode naturalistic 3D behavior by mapping sensory and motor cortical areas. The results show that the cortical population code is influenced by movement but the relationship between these signals and natural behavior in sensory cortices is still unknown. By comparing high-density neural recordings across four cortical regions in rats, the researchers find that momentary actions can be decoded universally, while more elementary and continuous features follow region-specific organization. The findings suggest that ongoing behavior is encoded at multiple levels throughout the dorsal cortex, with different regions utilizing low-level features for locally relevant computations.