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. H ere we demonstrate neuronal masking release in amplitude-modulated backgrou nd noise on the level of the European starling's auditory forebrain, an are a that is the analogue of the mammalian primary auditory cortex. Tone-evoke d responses in the presence of modulated and unmodulated maskers were recor ded in unrestrained birds via radiotelemetry. Based on a rate code, the ave rage amount of neuronal masking release was similar to that observed in a p sychoacoustic study on the starling with stimuli confined to a single audit ory tilter. The results suggest that the neurons exploited predominantly te mporal features of the acoustic background to improve signal detection. Neu roReport 12:1825-1829 (C) 2001 Lippincott Williams & Wilkins.