MIDDLE-LATENCY RESPONSES OF AWAKE AND ANESTHETIZED JAPANESE MACAQUES

The middle-latency response (MLR) of two Japanese macaques were invest igated. In the awake state, the configuration of the MLR components sh owed two positive peaks: P(a) and P(b). The latency and the configurat ion of P(a) were very similar to those of humans. In the topographic r ecordings, the largest P(a) amplitude was found from the vertex, or R1 , which is 1 cm lateral to the vertex. In the anesthetic state, P(a) a nd P(b) gradually disappeared. This study shows that the MLR in awake Japanese macaques is similar to that in humans, and differs from that in cats. Therefore these awake monkeys are suitable as animal models o f human MLR.