Synaptic actions of cutaneous A delta fibers on primate motoneurons.

Postsynaptic potentials were recorded from flexor and extensor motoneurons in the lumbosacral enlargement of alpha-chloralose- and sodium pentobarbital-anesthetized monkeys spinalized at a lower thoracic level, in response to volleys in A delta fibers in a cutaneous peripheral nerve (sural nerve). These potentials could be recorded and analyzed in most primate motoneurons with greater ease than in the cat. They correlated well with the third negative wave of the cord dorsum potential (N3 wave) which is also characteristically more distinct in the monkey than in the cat.