Widespread motor-correlated activity in the primary somatosensory and motor cortices

Neuronal activation throughout the cortex correlates strongly with the animal’s movement. Movement-related cortical activity in the sensory areas is thought to function as corollary discharge and to modulate sensory processing during self-generated motor activity. However, the exact role, neuronal circuits, and cortical computations associated with the cortex-wide motor signals are not fully elucidated. Here, we investigated the active neuronal properties during spontaneous movement episodes in the primary somatosensory (S1) and the primary motor (M1) cortices of awake mice. Whole-cell patch-clamp recordings were performed from layer 2/3 (L2/3) and layer 5 (L5) pyramidal neurons. Movement-correlated neuronal responses were observed in both S1 and M1 cortices. Notably, the neural activity in S1 was more coordinated than in M1. Furthermore, neurons in S1 exhibited a larger change in membrane potential depolarization during movement than the neurons in M1. The activity patterns of L5 and L2/3 neurons were distinct during movement episodes, as evidenced by differences in action potential firing, membrane potential variability, and onset of movement-related activity. Ultimately, we demonstrate that there is widespread self-generated motor activity in neurons across cortical layers and regions.