Sound-induced brain activity depends on stimulus subjective salience in female zebra finches.

A key point in the study of acoustic perception is whether brain responsiveness to sounds depends on sound acoustic structure or sound perceptive salience. Songbirds provide some evidence that higher auditory regions are sensitive to the subjective importance of the stimulus for the subject. In the present paper, we compare brain activation elicited by mate versus non-mate calls in female zebra finches Taeniopygia guttata. Using playback, we examined the responsiveness of the caudal telencephalon by measuring the evoked expression of the immediate early gene ZENK. Our results show that mate calls elicit a significantly higher ZENK expression than the calls of another male in hippocampus, but not in auditory areas. Using a hierarchical ascending classification, we show that this difference in brain activation is not explained by call acoustic structure, but relies on call identity. Thus, these results give evidence for a genomic response to calls in hippocampus that differentiate between call identity, and not between call structure. Our study gives further insight into the implication of the hippocampus in sound recognition in female songbirds.