RT Journal Article
SR Electronic
T1 Circuit organization of the excitatory sensorimotor loop through hand/forelimb S1 and M1
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.01.22.427843
DO 10.1101/2021.01.22.427843
A1 Naoki Yamawaki
A1 Martinna G. Raineri Tapies
A1 Austin M. Stults
A1 Gregory A. Smith
A1 Gordon M. G. Shepherd
YR 2021
UL http://biorxiv.org/content/early/2021/01/24/2021.01.22.427843.abstract
AB Sensory-guided limb control relies on communication across sensorimotor loops. For active touch with the hand, the longest loop is the transcortical continuation of ascending pathways, particularly the lemnisco-cortical and corticocortical pathways carrying tactile signals via the cuneate nucleus, ventral posterior lateral (VPL) thalamus, and primary somatosensory (S1) and motor (M1) cortices to reach corticospinal neurons and influence descending activity. We characterized excitatory connectivity along this pathway in the mouse. In the lemnisco-cortical leg, disynaptic cuneate→VPL→S1 connections excited mainly layer (L) 4 neurons. In the corticocortical leg, S1→M1 connections from L2/3 and L5A neurons mainly excited downstream L2/3 neurons, which excite corticospinal neurons. The findings provide a detailed new wiring diagram for the hand/forelimb-related transcortical circuit, delineating a basic but complex set of cell-type-specific feedforward excitatory connections that selectively and extensively engage diverse intratelencephalic projection neurons, thereby polysynaptically linking subcortical somatosensory input to cortical motor output to spinal cord.Competing Interest StatementThe authors have declared no competing interest.