| Abstract: | Single unit responses elicited through noxious mechanical stimulation of orofacial receptive fields were recorded, with glass micro-electrodes, within the rat ventrobasal complex of the thalamus. The evoked activities were compared before and after de-afferentation of the caudal sub-nucleus by trigeminal tractotomy at the level of the obex. Only units responding to noxious stimulation of oral receptive fields were unaffected by tractotomy. These results provide evidence that the rostral part of the spinal nucleus is involved in trigeminal painful sensation. |
