The Human Brain

The Cortico-spinal (Pyramidal) Tract

How do we know this?
Electrical stimulation of the motor cortex of anaesthetised animals provided the basic knowledge. A Canadian neurosurgeon, Wilbur Penfield, applied electrical stimuli to the human cortex and elicited movements ot eh contralateral side of the body in the sequence shown in the topographic map.
Injuries to an area of the motor cortex cause a paralysis or weakness of the corresponding muscle groups: fine movements are particularly affected
Modern techniques using magnetic stimuli allow stimulation of areas of motor cortex to be acheived in the conscious subject.

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