Early functional connectivity in the developing sensorimotor network that is independent of sensory experience

Neonatal sensory experience shapes development of neural pathways carrying sensory information to the cortex. These pathways link to wider functional networks that coordinate activity of separate cortical regions, but it remains unknown when these broader networks emerge or how their maturation is influenced by sensory experience. By imaging activity across the cortex in neonatal mice, we have found unexpectedly early emergence of coordinated activity within a sensorimotor network that includes whisker-related somatosensory cortex and motor cortex. This network is spontaneously active but is not engaged by sensory stimulation, even though whisker deflection reliably drives cortical activity within barrel cortex. Acute silencing of the sensory periphery ablated spontaneous activity that was restricted to barrel cortex but spared this early sensorimotor network coactivity, suggesting that it is driven from elsewhere. Furthermore, perturbing sensory experience by whisker trimming did not impact emergence or early maturation of spontaneous activity in the sensorimotor network. As such, functional sensorimotor cortical networks develop early, in parallel with development of ascending sensory pathways, and their initial maturation is independent of sensory experience.