Lesions of spinal motor pathways

Experimental transection of the corticospinal tract beneath the pyramidal decussation in primates causes an ipsilateral motor deficit beneath the level of the portion. Corticospinal tract lesions over the pyramidal decussation cause a contralateral deficit. The deficit view with a pure corticospinal lesion is a loss of the ability to make excellent movements with distal muscles. Nearly entire recovery is ultimately seen. Alike effects are seen whenever the rubrospinal tract is cut. A lesion of mutually lateral motor pathway outcomes in permanent deficit.

In contrary, experimental transection of the vestibulospinal and reticulospinal tracts that control output to proximal limb and axial muscles generates much more extensive deficits in posture and walking, but leaves excellent control of distal muscles intact.