[Properties and organization of pyramidal neurons of the rat motor cortex]

Antidromic potential sin cortical neurons elicited by stimulation of pyramids and different segments of the spinal cord were studied with the aid of extracellular recording in rats. Axons of about 2/3 of the cells under study formed the cortico-spinal tract passing through the ventral portion of the dorsal column up to the lumbar segments of the spinal cord. Conduction velocity along the cortico-spinal axons varied from 2.3 to 17.0 m/sec.