Evolution has given the primate a unique, direct pathway from the motor areas of the cerebral cortex to arm muscle motoneurons. This pathway conveys enormous control capability and has endowed the primate with a wide, flexible repertoire of movement. There are other, less direct, corticospinal pathways that contribute to this behavioral repertoire. Motor cortical areas have dense terminations in interneuronal fields throughout the cervical cord. What is the function of these projections? One descending pathway relays cortical signals disynaptically to motoneurons through short, premotor, propriospinal neurons in the C3-C4 segments. In the cat, this pathway exerts significant control over forelimb reaching movements, and recent evidence suggests that it is also important in primates. We are recording the activity of interneurons in the C3-C4 segments of monkeys performing trained hand, arm, and neck movements to help elucidate the functional role of this propriospinal pathway in the primate. Our data provide insights into the organization of cortical control of movement and have implications for potential mechanisms of motor recovery following spinal cord injury.

Perlmutter博士は上部頚髄ニュー ロンの随意運動制御における役割について研究しておられます。