Reflex responses evoked from cats' coccygeal ventral roots by electrical stimulation of the tail nerves.

In the terminal cone of the cat spinal cord, the coccygeal segments give rise to the ventrolateral and dorsomedial nerves of the tail. Extracellular recording was made from the ventral root of the coccygeal segments after stimulation of each or both ventrolateral and dorsomedial nerves. Stimulation of either nerve caused a polysynaptic response of 5- or 10-ms latency. A monosynaptic response was not seen unless posttetanic potentiation was carried out, or both nerves were stimulated simultaneously. It is suggested that the ventrolateral and dorsomedial nerves are linked by a common pathway, allowing spatial summation to take place, thus facilitating the elicitation of a monosynaptic response. The neural organization underlying the muscle movements of the cat's tail is discussed.