The midbrain central gray substance as a highly sensitive neural structure for the production of ultrasonic vocalization in the rat

To test whether there were any functional differences between the central gray substance (PVG) and other neural structures for the production of ultrasonic vocalization in the rat, an electrical stimulation experiment was systematically undertaken in diencephalic and mesencephalic tegmental regions. The sound production sensitivity to electrical stimulation was the highest in PVG. This suggested that the periventricular fiber system of Schu¨tz's bundle might be a possible neural structure underlying sound emission in the rat.