NROC64H3 Lecture : Chapter 14 nroc64.docx
22 Apr 2012
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Document Summary
Axons from brain descend through spinal cord along two major groups of pathways. Lateral pathways: involved in voluntary movement of distal musculature and are under direct cortical control. Ventromedial pathways: involved in control of posture and locomotion and are under brain stem control. Two thirds of the axons in the tract originate in areas 4 and 6 of frontal lobe, aka motor cortex. Most of the remaining axons in the corticospinal tract derive from somatosensory areas of the parietal lobe and serve to regulate the flow of somatosensory information to brain. The right motor cortex directly commands the movement on the left side of the body and vice versa. Originates in the red nucleus of the midbrain. Axons from red nucleus decussate in the pons lateral column of the spinal cord. Major source of input to the red nucleus is the same region that also contributes to the corticospinal tract.
