Effects of bulbar stimulation and decerebration on visceral afferent responses in the spinal cord

¹ Departments of Anatomy and Medicine, University of California School of Medicine, Los Angeles, and the Veterans Administration Centers, Los Angeles and Sepulveda, California

In a series of adult cats immobilized with Flaxedil, the splanchnic nerve was stimulated and visceral afferent responses were recorded in the cervical spinal cord. Simultaneous stimulation of the ventromedial reticular formation (2 volts, 100/sec., 1 msec.) caused an inhibition of the visceral afferent evoked responses central to the first relay station in the cord. Following decerebration, an extinction of evoked visceral afferent responses recorded in the spinal cord was constantly observed upon successive, single-shock, splanchnic nerve stimuli. This latter phenomenon is probably due to a removal of suprabulbar influences on brain stem reticular systems modulating sensory pathways.