Regional specialization of movement encoding across the primate sensorimotor cortex

The process by which the cerebral cortex generates movements to achieve different tasks remains poorly understood. Here, we leveraged the rich repertoire of well-controlled primate locomotor behaviors to study how task-specific movements are encoded across the dorsal premotor cortex (PMd), primary motor cortex (M1), and primary somatosensory cortex (S1) under naturalistic conditions. Neural population activity was confined within low-dimensional manifolds and partitioned into task-dependent and task-independent subspaces. However, the prevalence of these subspaces differed between cortical regions. PMd primarily operated within its task-dependent subspace, while S1, and to a lesser extent M1, largely evolved within their task-independent subspaces. The temporal structure of movement was encoded in the task-independent subspaces, which also dominated the PMd-to-M1 communication as the movement plans were translated into motor commands. Our results suggest that the brain utilizes different cortical regions to serialize the motor control by first performing task-specific computations in PMd to then generate task-independent commands in M1.