The putative propriospinal contribution to feedforward control mechanisms during skilled grasp (360G-Wellcome-207061_Z_17_Z)

The corticospinal pathway is the major direct pathway contributing to hand and motor function, after stroke or spinal cord injury this pathway can become irreversibly damaged. However, other parallel pathways may still function and are accessible to the motor system. The propriospinal network is an interneuronal system that is located at the mid-cervical levels (C3-C4), which transmits and alters descending commands for targeted reaching and grasping. Lesion studies have illuminated the role of this system in the recovery of reach and grasp movements.The aim of this project is to investigate the role of this connection in healthy humans. Specifically, our objective is to show the contribution of this system in feedforward grasping mechanisms. We will employ a motor task that involves grasping an object between the index finger and thumb where the task demands change prior to contact. Paired low-intensity peripheral nerve stimulation (PNS) and transcranial magnetic stimulation (TMS) will be used to probe the propriospinal modulation of corticospinal output during the task. Studying the propriospinal system in healthy humans will show how motor commands are updated at a spinal premotoneuronal level and could provide a novel pathway to target for neurorehabilitation after lesions of the central nervous system.