SPATIAL-DISTRIBUTION OF CORTICOSPINAL POTENTIALS FOLLOWING TRANSCRANIAL ELECTRIC AND MAGNETIC STIMULATION IN HUMAN SPINAL-CORD

To investigate the spatial distribution of the human corticospinal tra ct in the spinal cord, evoked spinal cord potentials (ESCPs) following transcranial electrical and magnetic stimulation were recorded simult aneously from both the anterior and posterior epidural space in five a nesthetized patients. One ESCP component following transcranial electr ical stimulation (D-wave) and at least two ESCP components (initially D-wave and later I-wave) following transcranial magnetic stimulation w ere recorded in all subjects. The negative peak latency of all the pot entials recorded from the posterior epidural space was the same as tha t recorded anteriorly. The amplitude ratio of the ESCP following elect rical stimulation (posterior/anterior) was 1.10+/-0.12, while that of ESCPs following magnetic stimulation was 1.08+/-0.12 (N1) and 1.15+/-0 .16 (N2). These results suggest that lateral corticospinal tract desce nding dorsolateral fasciculus in the spinal cord is main corticospinal pathway and spatial distribution of D and I-waves are similar in the human cervical cord. (C) 1997 Elsevier Science B.V.