Activation of L2/3 neurons in the primary somatosensory cortex during motor output

Rodents rely heavily on somatosensation to explore their environment. The primary somatosensory cortex (S1) contributes to the encoding and perception of tactile stimuli. Although S1 neurons also receive non-tactile inputs, it is unclear whether S1 similarly encodes non-tactile sensory-based behaviour. Whole-cell patch clamp recordings were used to investigate the voltage response of layer 2/3 (L2/3) pyramidal neurons in S1 during performance in either a tactile-based or auditory-based association task in mice. A robust and sustained voltage response was evoked in L2/3 pyramidal neurons during correct responses in both tasks, indicating that the response was not dependent on the delivery of the tactile stimuli. Furthermore, L2/3 pyramidal neurons were active during spontaneous motor bouts, with voltage responses preceding the motor output. Notably, optogenetic suppression of the primary motor cortex did not affect this motor-correlated activity in the L2/3 neurons of S1. In conclusion, L2/3 pyramidal neurons in S1 are active during motor output, and the activation primarily originates from brain areas other than the motor cortex.