An evoked potential study of spinal pathways projecting to the cerebral somatosensory areas in the dog

Summary Evoked potentials from stimulation of the hindlimbs were recorded in the cerebral somatosensory areas of dogs using Nembutal anaesthesia. Various transections of the low thoracic spinal cord were made in order to determine the pathways projecting to these areas. The shortest latency cortical activation was obtained via two pathways: the dorsal column pathway and the spinocervical tract which is located in the dorsomedial part of the lateral funiculus (DLF). Cortical activation after longer latency was obtained via ventral pathways in both the contralateral and ipsilateral spinal halves. The cortical potentials elicited by adequate (hair) stimuli depended mainly on transmission via the dorsal column and DLF pathways.