The distribution of cutaneous receptors in the rabbit's hind limb and differential electrical stimulation of their axons.

1. The receptive field properties and conduction velocities of single dorsal root axons, activated from the sural and cutaneous branches of the posterior tibial (medial plantar) nerves, were examined in anaesthetized rabbits.2. The sural nerve sample included all types of units previously recorded from the saphenous nerve (Brown & Iggo, 1967). In particular it was shown that electrical stimulation of the sural nerve at strengths up to 1.3T produced a volley of impulses in a pure population of slowly adapting units (Type I units).3. The medial plantar sample showed an absence of Type I slowly adapting units and Type T hair follicle units. Corresponding to this there were no touch corpuscles or tylotrich hairs in the skin of the hind foot and the fastest medial plantar axons conducted at 60-70 m/sec as opposed to 80-85 m/sec for the sural nerve. Stimulation of the medial plantar nerve at stimulus strengths close to threshold produced a volley of impulses in a nearly pure population of Type G hair follicle units.