ABSTRACT
Experimental transection of the corticospinal tract below the pyramidal decussation in primates causes an ipsilateral motor deficit below the level of the section. Corticospinal tract lesions above the pyramidal decussation cause a contralateral deficit. The deficit seen with a pure corticospinal lesion is a loss of the ability to make fine movements with distal muscles. Almost complete recovery is eventually seen. Similar effects are seen if the rubro-spinal tract is cut. A lesion of both lateral motor pathways results in permanent deficits.
