KNES 385 Lecture Notes - Lecture 22: Postcentral Gyrus, Rubrospinal Tract, Alpha Motor Neuron

• School: University of Maryland
• Department: Kinesiology
• Course: KNES 385
• Professor: Dr.Gentili

Document Summary

Pathway: dorsal column medulla of brain stem (primary afferent, brainstem thalamus (2nd order neuron, thalamus primary somatosensory cortex (3rd order neuron) Type of information: conscious refined touch, proprioception, vibration. Pathways: primary afferent synapses on 2nd order neuron in spinal cord, crosses midline spinal cord thalamus (2nd order neuron, thalamus primary somatosensory cortex (3rd order neuron) Type of information: conscious crude touch, pain, temperature. Pathway: primary afferent synapses onto 2nd order neuron in spinal cord, second order neuron conveys information to cerebellum (generally on same side as source of information. Type of information: non-conscious proprioception, conscious proprioception generally requires involvement of thalamus and cerebral cortex. Pathway: axons of pyramidal cells in primary motor cortex cross midline and synapse onto motor neurons and interneurons in spinal cord. Role: carry motor commands for voluntary movement: only direct path from cortex to alpha motor neurons, example: fine control of digits of hand. Axons cross midline, descend, and synapse onto spinal neurons at all levels.