Characterization of Torque-Related Activity in Primary Motor Cortex During a Multijoint Postural Task

摘要: The present study examined neural activity in the shoulder/elbow region of primary motor cortex (M1) during a whole-limb postural task. By selectively imposing torques at shoulder, elbow, or both joints we addressed how neurons represent changes torque single joint, multiple joints, and their interrelation. We observed that similar proportions reflected these were highly intermingled across cortical surface. Most torque-related reciprocally excited inhibited (relative to unloaded baseline activity) by opposing flexor extensor joint. Although coexcitation/coinhibition was occasionally it rarely joints. A second analysis assessed relationship between single-joint multijoint activity. In contrast our previous observations, found neither linear nor vector summation activities could capture breadth responses torques. Finally, studied neurons' directional tuning all conditions, i.e., joint-torque space. Our population M1 exhibited strong bimodal distribution preferred-torque directions (PTDs) biased toward shoulder-extensor/elbow-flexor (whole-limb flexor) shoulder-flexor/elbow-extensor extensor) Notably, recently PTDs sample proximal arm muscles. This observation illustrates intimate periphery.