PSL300H1 Lecture Notes - Lecture 31: Rubrospinal Tract, Reticular Formation, Premotor Cortex
Document Summary
Purpose: motor output that is planned & refined by motor cortex, basal ganglia, Cortical motor areas: red nucleus, synergy, motor cortex, motor field, premotor area, sma, cma. Rubrospinal cells: activate localized synergies (not widespread synergies, esp. distal limbs & in the face, gripping & twisting hand movements. Definition: groups of muscles contracting together, for specific purpose. Organized by reticulospinal tract: widespread (cover half of the body, generate support postures. Organized by rubrospinal tract: highly localized, specific hand & face movements. Located at the precentral gyrus (immediately anterior to central sulcus) Somatotropic organization (penfield"s motor homunculus: does not correspond with the size of the body parts, but to the amount of innervations of each body part. Direct corticospinal axons motoneuron synapses: distal limbs, speech-motor nuclei. Most corticospinal tracts (axons from motor cortex spinal cord) go to interneurons. More common pathway: motor cortex midbrain (mesencephalon) medulla . Cross to contralateral medullary pyramid descends: lateral corticospinal tract.
