[The nature of an early component of the trigemino-facial (perioral) reflex].

A study was made of an early reflex response of the perioral muscle. The marginal branch of the facial nerve was irritated with electric stimuli in the mode of supramaximal stimulation for the M-response, and the leading of the responses was performed with needle electrodes. After the M-response with the latency of 7.5--15 ms one could record discharges not exceeding, when normal, the amplitude of the M-response, depending, like the M-response, on the position of the stimulating electrode above the branch of the facial nerve. In patients with derangement of the central motoneuron of the facial nerve and in those with the akinetic -rigid syndrome, the amplitude of the discharges did not surpass the M-response. The conclusion is made that these discharges, known in the literature as an early component of trigemino-facial++ (perioral) reflex, present an antidromal response of motoneurons of the facial nerve nucleus.