Layer-specific integration of locomotion and concurrent wall touching in mouse barrel cortex

During navigation rodents continually sample the environment with their whiskers. How locomotion modulates neuronal activity in somatosensory cortex and how self-motion is integrated with whisker touch remains unclear. Here, we used calcium imaging in mice running in a tactile virtual reality to investigate modulation of neurons in layer 2/3 (L2/3) and L5 of barrel cortex. About a third of neurons in both layers increased activity during running and concomitant whisking, in the absence of touch. Fewer neurons were modulated by whisking alone (<10%). Whereas L5 neurons responded transiently to wall-touching during running, L2/3 neurons showed sustained activity after touch onset. Consistently, neurons encoding running-with-touch were more abundant in L2/3 compared to L5. Few neurons across layers were also sensitive to abrupt perturbations of tactile flow. We propose that L5 neurons mainly report changes in touch conditions whereas L2/3 neurons continually monitor ongoing tactile stimuli during running.