[Electrophysiological study of the blinking reflex of Macacus cynomolgus]

An electromyographic study of the blink reflex has been undertaken in the monkey Macacus cynomolgus. Reflex responses were evoked by stimulating trigeminal or facial afferent pathways and their modifications studied when a conditioning stimulus was applied to other afferences. The response may have two components (R1 = short latency, R2 = long latency) but R1 was only present after stimulating the ipsilateral supra-orbital nerve, whereas R2 alone occurred when either facial or contralateral supra-orbital nerves were stimulated. Previous stimulations of facial or contralateral supra-orbital nerves resulted in a facilitation of the reflex followed by some inhibition of R1 and R2 which became complete when the time interval was sufficient. The responses were depressed from 5 c/s (R1) or 2 c/s (R2).