Rodriguez-Moreno Paola, Loza-Vaqueiro Juliana, Olivares-Moreno Rafael, Rojas-Piloni Gerardo
Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus UNAM-Juriquilla, Querétaro, Mexico.
Sci Rep. 2025 Aug 30;15(1):31998. doi: 10.1038/s41598-025-17047-5.
The sensorimotor cortex is crucial for learning and executing new movements with precision. It selectively modulates sensory information flow and represents motor information in a spatially organized manner. The pyramidal system is made up of layer 5 pyramidal tract neurons (PTNs), which are organized into populations with distinct morphological, genetic and functional properties. These subpopulations project to different subcortical structures in a segregated manner. To understand whether PTNs projecting to different structures play distinct functional roles in motor control, we characterized two types of layer 5 neurons in the motor cortex: corticorubral (CR) neurons, which project to the red nucleus, and corticospinal (CS) neurons, which project to the spinal cord. To analyze movement performance in rats, we compared the selective optogenetic inhibition of motor cortex CS or CR neurons during lever movement execution in response to a light stimulus. As the animals progressed through the training sessions, the variability of lever trajectories decreased, and the movements became more stereotyped. Photoinhibition of CS or CR neurons increased the performance variability of learned movements but differentially affected kinematic parameters. CR neuron inhibition affected amplitude, duration, reaction times, speed, and acceleration of the movement. In contrast, the inhibition of CS neurons mainly altered the duration and acceleration of the movement. The results indicate that the same motor order would be expected to have different causal effects when sent to different brain regions.
感觉运动皮层对于精确学习和执行新动作至关重要。它选择性地调节感觉信息流,并以空间组织的方式表征运动信息。锥体系统由第5层锥体束神经元(PTN)组成,这些神经元被组织成具有不同形态、遗传和功能特性的群体。这些亚群以分离的方式投射到不同的皮层下结构。为了了解投射到不同结构的PTN在运动控制中是否发挥不同的功能作用,我们对运动皮层中的两种第5层神经元进行了表征:投射到红核的皮质红核(CR)神经元和投射到脊髓的皮质脊髓(CS)神经元。为了分析大鼠的运动表现,我们比较了在杠杆运动执行过程中,响应光刺激对运动皮层CS或CR神经元进行选择性光遗传学抑制的情况。随着动物在训练过程中的进展,杠杆轨迹的变异性降低,运动变得更加刻板。对CS或CR神经元的光抑制增加了学习运动的表现变异性,但对运动学参数有不同的影响。CR神经元抑制影响运动的幅度、持续时间、反应时间、速度和加速度。相比之下,CS神经元的抑制主要改变运动的持续时间和加速度。结果表明,当相同的运动指令发送到不同的脑区时,预期会产生不同的因果效应。