Myelinated afferent nerve fibers from the skin of the rabbit ear

Electrophysiological recordings were made by dissection and microelectrode methods from single myelinated fibers of the great auricular nerve responding to mechanical stimulation of hairs and skin. Two types of hair follicle afferent unit, both rapidly adapting, were observed: type G, conducting at 18 to 54 m/sec, excited by movement of up to six guard hairs, with amplitude thresholds of 8 to 36 μ; and type D, conducting below 18 m/sec, excited by many down hairs and guard hairs with thresholds of 2 to 30 μ. Units responding only to stimulation of the dorsal skin surface comprised a low-threshold group, excited also by movement of ventral hairs, and a high-threshold group, also excited by stimulation of the ventral skin surface. Slowly adapting mechanoreceptive units, touch corpuscles, and type T hair follicle units were not found. The innervation of rabbit car skin thus differs considerably from that of the trunk and limbs.