RT Journal Article
SR Electronic
T1 Developmental “awakening” of primary motor cortex to the sensory consequences of movement
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 331983
DO 10.1101/331983
A1 James C. Dooley
A1 Mark S. Blumberg
YR 2018
UL http://biorxiv.org/content/early/2018/09/20/331983.abstract
AB Before primary motor cortex (M1) develops its motor functions, it functions like a somatosensory area. Here, by recording from neurons in the forelimb representation of M1 in postnatal day (P) 8-12 rats, we demonstrate a rapid shift in its sensory responses. At P8-10, M1 neurons respond overwhelmingly to feedback from sleep-related twitches of the forelimb, but the same neurons do not respond to wake-related movements. By P12, M1 neurons suddenly respond to wake movements, a transition that results from opening the sensory gate in the external cuneate nucleus. Also at P12, few M1 neurons respond to twitches, but the full complement of twitch-related feedback observed at P8 can be unmasked through local disinhibition. Finally, through P12, M1 sensory responses originate in the deep thalamorecipient layers, not primary somatosensory cortex. These findings demonstrate that M1 initially establishes a sensory framework upon which its later-emerging role in motor control is built.