Sympathetic Skin Nerve Activity and Skin Temperature Changes in Man

Abstract

Abstract Simultaneous recordings of skin temperature and efferent sympathetic impulse activity in cutaneous nerve fascicles were made in two healthy subjects and in one patient with paraplegia due to a transverse lesion of the spinal cord at the level of the first lumbar segment. In the patient the recordings were made below the level of the lesion in a skin area deprived of sensibility but with preserved temperature responses to indirect heating and cooling. The sympathetic nerve activity showed the same characteristics both in the paraplegic patient and in the healthy subjects. Evoked changes in sympathetic nerve activity were followed by changes in skin temperature of the same type in all three subjects. The demonstration of concomitant changes in evoked sympathetic nerve activity in a peripheral nerve and in skin temperature in the corresponding skin area strongly supports the concept that the cutaneous thermoregulatory vasomotor response (CTVR), is a consequence of changes in efferent sympathetic nerve activity. The results demonstrate that loss of somatic sensation and voluntary motor function can be combined with a functionally intact efferent sympathetic pathway below the level of a “complete” lesion of the spinal cord.