Partial Inactivation of the Primary Motor Cortex Hand Area: Effects on Individuated Finger Movements

摘要: After large lesions of the primary motor cortex (M1), voluntary movements affected body parts are weak and slow. In addition, relative independence moving one part without others is lost; attempts at individuated a given accompanied by excessive, unintended motion contiguous parts. The effects partial inactivation M1 hand area comparatively unknown, however. If contains somatotopically ordered finger representations implied classic homunculus or simiusculus, then might produce weakness, slowness, loss two adjacent digits affecting other digits. But if control each movement distributed in as many studies suggest, dissociation movement, which fingers impaired be unrelated to location along central sulcus. To investigate motoric deficits resulting from area, we therefore made single intracortical injections muscimol trained monkeys performed visually cued, flexion–extension wrist. We found little any evidence that were after injection was related Unimpaired could flanked on both sides fingers, flexion unaffected even though extension impaired, vice versa. Partial also dissociated weakness slowness versus movement. These findings suggest widely area.