Park Junchol, Phillips James W, Guo Jian-Zhong, Martin Kathleen A, Hantman Adam W, Dudman Joshua T
Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
Sci Adv. 2022 Mar 11;8(10):eabj5167. doi: 10.1126/sciadv.abj5167. Epub 2022 Mar 9.
The interaction of descending neocortical outputs and subcortical premotor circuits is critical for shaping skilled movements. Two broad classes of motor cortical output projection neurons provide input to many subcortical motor areas: pyramidal tract (PT) neurons, which project throughout the neuraxis, and intratelencephalic (IT) neurons, which project within the cortex and subcortical striatum. It is unclear whether these classes are functionally in series or whether each class carries distinct components of descending motor control signals. Here, we combine large-scale neural recordings across all layers of motor cortex with cell type-specific perturbations to study cortically dependent mouse motor behaviors: kinematically variable manipulation of a joystick and a kinematically precise reach-to-grasp. We find that striatum-projecting IT neuron activity preferentially represents amplitude, whereas pons-projecting PT neurons preferentially represent the variable direction of forelimb movements. Thus, separable components of descending motor cortical commands are distributed across motor cortical projection cell classes.
新皮质下行输出与皮质下运动前区回路的相互作用对于塑造熟练运动至关重要。两类广泛的运动皮质输出投射神经元为许多皮质下运动区域提供输入：锥体束（PT）神经元，其投射至整个神经轴；以及脑内（IT）神经元，其投射至皮质和皮质下纹状体。尚不清楚这两类神经元在功能上是串联的，还是每一类都携带下行运动控制信号的不同成分。在此，我们将运动皮质所有层的大规模神经记录与细胞类型特异性扰动相结合，以研究依赖皮质的小鼠运动行为：对操纵杆进行运动学可变的操作以及进行运动学精确的伸手抓握。我们发现，投射至纹状体的IT神经元活动优先代表幅度，而投射至脑桥的PT神经元优先代表前肢运动的可变方向。因此，下行运动皮质指令的可分离成分分布于运动皮质投射细胞类别中。
