BIOLOGY 2C03 Lecture Notes - Spinal Cord, Supplementary Motor Area, Premotor Cortex
Document Summary
Motor system iv motor cortex: functions and properties of premotor cortex, motor cortex, and supplementary motor area. The premotor cortex codes object position with respect to arm, independent of fixation point and hand configuration. Primary motor cortex is sensitive to forces needed to perform a reaching movement. Like the somatosensory cortex, the motor cortex has a somatotopic map. The motor map can change after amputation, a result of loss of strength of inhibitory interneurons connecting two areas in the motor cortex. Following amputation, the size of the motor region bordering amputated region enlarges; phantom limb pain may be a result of size imbalance between the two hemispheres. Following a lesion of a motor region, forced use of damaged region (constrained motion rehabilitation) helps restore some motor function. Some primary motor cortex neurons respond to direction of muscle forces, thus primary motor cortex is responsible for determining required muscle activity to generate desired movement.