Recurrent Facilitory Pathway of the Pyramidal Tract Cell

Excitatory postsynaptic potentials were recorded intracellulary from the cat pyramidal tract cell by stimulation of the pyramidal tract, either at the rostral pyramid or cerebral peduncle. These potentials occurred in the cells of which conduction velocity between 20 and 168m/see, and were induced by impulses along the pyramidal fibers at 11-16m/sec., i.e., the slowly conducting axons of the pyramidal tract cells. It is suggested that there is recurrent facilitation from the slow to the fast cells which is exerted probably monosynaptically through the axon collaterals of the former.