ROLE OF SPINOCERVICAL TRACT IN PRODUCTION OF PRIMARY CORTICAL RESPONSE EVOKED BY FOREPAW STIMULATION

The dorsal column and the dorsolateral part of the lateral column on one side of the spinal cord of the cat were individually isolated and stimulated at a level between the third and fourth spinal roots. The gross potentials evoked by such stimulation, and by forepaw stimulation, were recorded at three different sites in the contralateral cerebral hemisphere; they differed in configuration according to the pathway stimulated. When recorded from the forepaw focus, dorsal column stimulation produced potentials similar to those evoked by forepaw stimulation, whereas dorsolateral column stimulation yielded small, mainly negative deflections of relatively long latency and small applitude. Transection of the spinocervical route in three different places had no measurable effect on the peripherally evoked primary cortical response, whereas transection of the dorsal column pathway all but eliminated the peripherally evoked response. Prior stimulation of the dorsal column had a profound effect on the peripherally evoked primary response, whereas prior stimulation of the dorsolateral column had a negligible effect. It is concluded that the spinocervical pathway plays a negligible role in production of the forepaw-evoked primary cortical response, in both somatosensory area I and II. © 1969.