NSCI 201 Chapter Notes - Chapter 17: Upper Motor Neuron, Alpha Motor Neuron, Premotor Cortex

• School: McGill University
• Department: Neuroscience
• Course: NSCI 201
• Professor: Kevin Francis Casey

Document Summary

This lecture: motor cortex/ brainstem, top-down decision making. Refer to 14. 16 for organization of neural structures. Recall: local circuit neurons in spinal cord gray matter! Medial circuits are bilateral, extend along larger segments of spinal cord to control posture and balance. Lateral circuits are ipsilateral, cover less segments, shorter rostral-caudal distances to control limbs and distal structures. Projections from brain are contralateral; crossover happens in medulla (brainstem)! Information from brain sent through lateral and medial white matter tracts. Lateral: from motor cortex to distal motor neurons, ne motor control. Medial: from brainstem to proximal motor neurons, much more unconscious control. Unlike gray matter, white matter tracts innervating motor neurons are not continuous can have damage to one segment and only lose function there. Primary motor cortex and premotor areas in cerebral cortex! Primary motor cortex: just anterior of primary somatosensory, dorsal to central sulcus, produces movement and motor generation. More direct connections to spinal cord (70%), lower stimulation threshold.