Dorsal root potentials and ventral root reflexes evoked by nonmyelinated fibers.

Electrical stimulation of C-fibers in the cat superficial peroneal nerve, with the A-fibers either conducting or blocked by cold, evoked dorsal root potentials having the same polarity as those evoked by A-fibers. Ventral root reflexes evoked by A-fibers were facilitated by a pure C-volley in the same or another nerve, but dorsal root potentials evoked by A-fibers were reduced by isolated dorsal root potentials from C-fibers. In the absence of anesthetics, single C-volleys produced brisk and prolonged reflex discharges in ventral roots.