[Differential participation of midbrain structures regulating voice in chicks].

Vocal reactions in chicks are controlled by the same midbrain structures as those in adult hens, namely n. intercollicularis (ICO), n. mesencephalicus lateralis, pars dorsalis (MLD), n. isthmi, pars principalis magnocellularis (IMC), n. mesencephalicus lateralis ventralis (MLV), n. isthmi, pars principalis parvocellularis (IPC). The nuclei ICO, MLO, IPC, IMC control the duration and form of vocal messages, as well as frequency parameters of the spectrum--i.e. the specific components of bioacoustic signals. The reticular formation and MLV are responsible for the amplitude of vocal messages and the interval between the latter.