Over a century ago, it was discovered that electrical stimulation of the cortex of the precentral gyrus of a dog could elicit movements of the animal’s contralateral limbs. A short time after this observation, neuroscientists learned two related and significant facts from experimen- tal transections of the pyramidal tracts in mammals. First, the neurons that undergo retrograde degeneration after such a lesion are the large pyramidal cells in layer V of the cerebral cortex of the precentral gyrus. Second, the animals exhibit severe movement disorders, mainly involv- ing their extremities. Using more refined electrical stimulation tech- niques, Charles Sherrington later confirmed that movements are elicited with the lowest current intensities from the cortex of the precentral gyrus. Thus the notion was born that the MI cortex is the main arbiter of the complex, discrete movements that characterize much of our voluntary behavior.
KeywordsDopamine Pyramid Xenon Topo Alan
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