PSYC 271 Lecture 17: 271 9.1
22 Nov 2016
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Document Summary
Feedback and crosstalk at every level of organization. Synapses on grey matter, which synapses onto motor neurons. Betz cells - synapse to control legs: corticorubrospinal. Contralateral, descend through white matter, synapse on grey and motor neurons. Terminate diffusely on grey matter of multiple spinal segments. Control trunk and proximal limb muscles: cortico-brainstem-spinal tract. Descends and synapses diffusely of multiple segments. Sensorimotor spinal circuits: spinal cord modulates some movement for speed. Stretch re ex: reaction to stretch of muscle spindle, maintains limb stability (patellar tendon test, quick reaction to involuntary stretching preventing muscle damage, allows for re exive corrections, monosynaptic. Withdrawal re ex: reaction to painful stimulus, adaptive, multisynaptic. Walking: mediated cortically and sub-cortically (spinal cord, integration of visual, vestibular, somatosensory information, decorticate and infant organisms can display spinal cord mediated walking re ex without being able to initiate walking on their own.
