Long-term unit recording from somatosensory neurons in the spinal ganglia of the freely walking cat.

A new technique has been developed for stable, long-term recording from groups of individual primary afferent neurons in the freely walking cat. A number of fine, flexible wires are inserted into dorsal root ganglia via a small laminotomy in the lumbar spine. The cut end of each wire can record stable and separable action potentials from one to three dorsal root ganglion neurons; each unit has typically held for 1 to 4 days. A broad range of myelinated somatosensory afferent (conduction velocities of 30 to 120 meters per second) have been studies during locomotion. Most cutaneous and proprioceptive afferent studied have been sensitive monitors of complex combinations of step-cycle components, and their firing patterns would often have been difficult to predict from existing information.