Release from masking in fluctuating background noise in a songbird's auditory forebrain.
Fluctuations in the ubiquitous masking background noise can be exploited by the vertebrate auditory system to considerably improve signal detection. Here we demonstrate neuronal masking release in amplitude-modulated background noise on the level of the European starling's auditory forebrain, an area that is the analogue of the mammalian primary auditory cortex. Tone-evoked responses in the presence of modulated and unmodulated maskers were recorded in unrestrained birds via radiotelemetry. Based on a rate code, the average amount of neuronal masking release was similar to that observed in a psychoacoustic study on the starling with stimuli confined to a single auditory filter. The results suggest that the neurons exploited predominantly temporal features of the acoustic background to improve signal detection.
Klump
G M
GM
Institut für Zoologie, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany.
Nieder
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D000161:Acoustic Stimulation; D000818:Animals; D001306:Auditory Pathways / Q000502:physiology*; D001309:Auditory Threshold / Q000502:physiology*; D005260:Female; D008297:Male; D009474:Neurons / Q000502:physiology*; D016548:Prosencephalon / Q000502:physiology*; D017603:Signal Detection, Psychological / Q000502:physiology*; D020308:Songbirds / Q000502:physiology*; D014828:Vocalization, Animal / Q000502:physiology