Meeting Abstract

19.1  Sunday, Jan. 4  Noradrenaline, Receiver Error and the Cocktail Party Effect LYNCH, Kathleen S.*; BALL, Gregory F.; Johns Hopkins University lynchks@jhu.edu

In humans, the ability to attend to important signals while simultaneously rejecting intrusion from other sources is termed the ‘cocktail party effect’. This task is relevant to the study of animal communication because animals often communicate within a cacophonous background of noise, which may result in signal detection errors. We examined the role of the noradrenergic (NA) system during signal reception. The NA system simultaneously regulates selective attention and sensory processing thus, it is possible that it is involved in signal detection. We degraded the noradrenergic system in female canaries (Serinus canaria) by administering N-(2-chloroethyl)-N-2-bromobenzyl-amine hydrochloride (DSP-4), a noradrenergic-specific neurotoxin. We measured auditory responses to conspecific and heterospecific songs using ZENK protein expression within the caudomedial nidopallium (NCM) and the mesopallium caudomedial (CMM). ZENK expression in these regions is typically higher in birds exposed to conspecific songs as compared to heterospecific songs. We found that that this differential ZENK induction is abolished specifically within dNCM and CMM in female canaries treated with DSP-4. Furthermore, in DSP-4 treated birds, conspecific song-induced ZENK expression is significantly reduced as compared to saline treated birds. This suggests that the noradrenergic system modifies auditory processing by enhancing neuronal responses to conspecific songs rather than inhibiting neuronal responses to signals that are less relevant, such as heterospecific songs. Together, our results reveal that noradrenaline regulates auditory processing in such a way that facilitates the females ability to assess communication signals.