Auditory brainstem response recovery in the dolphin as revealed by double sound pulses of different frequencies.
Recovery of auditory brainstem responses (ABR) in a bottlenose dolphin was studied in conditions of double-pip stimulation when two stimuli in a pair differed in frequency and intensity. When the conditioning and test stimuli were of equal frequencies, the test response was markedly suppressed at short interstimulus intervals; complete recovery appeared at intervals from about 2 ms (when two stimuli were of equal intensity) to 10-20 ms (when the conditioning stimulus exceeded the test by up to 40 dB). When the two stimuli were of different frequencies, the suppression diminished and was almost absent at a half-octave difference even if the conditioning stimulus exceeded the test one by 40 dB. Frequency-dependence curves (ABR amplitude dependence on frequency difference between the two stimuli) had equivalent rectangular bandwidth from +/-0.2 oct at test stimuli of 20 dB above threshold to +/-0.5 oct at test stimuli of 50 dB above threshold.
Popov
V V
VV
Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow.
Supin AYa
Klishin
V O
VO
D000161:Acoustic Stimulation; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology; D001933:Brain Stem / Q000502:physiology; D004289:Dolphins / Q000502:physiology*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D008144:Loudness Perception / Q000502:physiology; D010897:Pitch Discrimination / Q000502:physiology*