High-frequency ultrasonic vocalization induced by intracerebral glutamate in rats.


Direct injection of glutamate, a neuroexcitatory agent, into the anterior hypothalamic-preoptic area of the rat brain induced ultrasonic vocalization. This vocalization was characterized by short-duration calls (below 60 ms) of high sound frequency (pitch), mostly above 40 kHz, and was similar to the known 50-kHz vocalization observed in natural situations… (More)