Lateral suppression of rhythmic evoked responses in the dolphin's auditory system.
In the auditory system of bottlenose dolphins (Tursiops truncatus), a brain-evoked response to rhythmic sound amplitude modulations (the envelope-following response) was markedly suppressed by addition of another sound with a frequency 5-20 kHz higher and an intensity down to 40 dB lower than that of the amplitude-modulated signal. This effect was called paradoxical lateral suppression. This phenomenon was primarily observed when the amplitude-modulated stimulus had a carrier frequency above 30 kHz and modulation rates above 500 Hz. Only the sustained rhythmic response was suppressed, while the transient on-response was not. This indicates that the suppression influenced the ability of evoked potentials to follow rapid amplitude modulations. This prevents weak sounds from being masked by stronger ones.
Popov
V V
VV
Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow.
Supin AYa
Klishin
V O
VO
D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D001306:Auditory Pathways / Q000502:physiology*; D001933:Brain Stem / Q000502:physiology; D004289:Dolphins / Q000502:physiology*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D008297:Male; D009433:Neural Inhibition / Q000502:physiology*; D010507:Periodicity; D013997:Time Factors