[Responses of auditory neurons of the medulla oblongata of the frog to presentation of tones with sinusoidal amplitude modulation].

The responses of single units in the medullary auditory regions of the frog Rana ridibunda to sinusoidally amplitude-modulated tones of characteristic frequencies were studied. The reproduction of the sound modulation in the discharge frequency of the units was determined from cycle histograms of the discharges locked to the modulation period. In dorsal nucleus units the amplitude modulation was preserved in the discharge modulation over a wide modulation frequency and sound intensity ranges. In many superior olivary neurons an enhancement of small amplitude changes within the range of modulation frequencies 70-150 Hz was observed. The reaction phase was linear-dependent on the modulation frequency. The best enhancement of amplitude changes took place for small modulation indices.