Studies on the flexor reflex.-III. The central effects produced by an antidromic volley

Abstract

In 1822 Magendie demonstrated that no reflex activities were evoked by impulses passing into the spinal cord by a ventral root. This result has been confirmed and extended by other investigators who showed that no action currents can be detected in other nerves when the central end of a cut ventral root is stimulated (Mislawski, 1895; Bernstein, 1898). Attempts have been made to account for the irreversibility of conduction in the reflex arc by postulating a “dynamical polarisation” of the nerve cell so that the conduction would be solely from dendrite to axon, never the reverse (cajal, 1891; van Gehuchten, 1900). The antidromic impulses “back-fired” into a motoneurone might, however, be blocked at the synapse (sherrington, 1900, p. 798). It seems unlikely that the conduction of nerve impulses in the cell body and dendrites of a motoneurone would differ fundamentally from the conduction in peripheral nerve fibres, e. g ., that impulses passing along the dendrites would suffer an irreciprocal decrement. In the present paper it has been assumed that antidromic impulses in motor nerve fibres are blocked at the synapses of the motoneurones.