Circuit organization of the excitatory sensorimotor loop through hand/forelimb S1 and M1

eLife

Gregory A Smith¹  Austin Stults¹  Naoki Yamawaki²  Gordon MG Shepherd²  Martinna G Raineri Tapies² 

[1] Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, United States;Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States;

关键词: neocortex;    motor;    somatosensory;    sensorimotor;    corticospinal;    thalamus;    Mouse;   

DOI  :  10.7554/eLife.66836

来源: eLife Sciences Publications, Ltd

【 摘 要 】

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.

【 授权许可】

CC BY