HVC lesions modify immediate early gene expression in auditory forebrain regions of female songbirds.

It is well established that auditory forebrain regions of oscine birds are essential for the encoding of species-typical songs and are, therefore, vital for recognition of song during sociosexual interactions. Regions such as the caudal medial nidopallium (NCM) and the caudal medial mesopallium (CMM) are involved in perceptual processing of song and the formation of auditory memories. There is an additional telencephalic nucleus, however, that has also been implicated in species recognition. This nucleus is HVC, a prominent nucleus that sits at the apex of the song system, and is well known for its critical role in song learning and song production in male songbirds. Here, we explore the functional relationship between auditory forebrain regions (i.e., NCM and CMM) and HVC in female canaries (Serinus canaria). We lesion HVC and examine immediate early gene responses to conspecific song presentation within CMM and NCM to explore whether HVC can modulate auditory responses within these forebrain regions. Our results reveal robust deficits in ZENK-ir in CMM and NCM of HVC-lesioned females when compared with control- and sham-lesioned females, indicating that functional connections exists between HVC and NCM/CMM. Although these connected regions have been implicated in song learning and production in males, they likely serve distinct functions in female songbirds that face the task of song recognition rather than song production. Identifying functional connections between HVC and auditory regions involved in song perception is an essential step toward developing a comprehensive understanding of the neural basis of song recognition.

Dopamine release in the medial preoptic area is related to hormonal action and sexual motivation.

To help elucidate how general the role of dopamine (DA) release in the medial preoptic area (mPOA) is for the activation of male sexual behavior in vertebrates, we recently developed an in vivo microdialysis procedure in the mPOA of Japanese quail. Using these techniques in the present experiment, the temporal pattern of DA release in relation to the precopulatory exposure to a female and to the expression of both appetitive and consummatory aspects of male sexual behavior was investigated. Extracellular samples from the mPOA of adult sexually experienced male quail were collected every 6 min before, while viewing, while in physical contact with, and after exposure to a female. In the absence of a precopulatory rise in DA, males failed to copulate when the barrier separating them from the female was removed. In contrast, males that showed a substantial increase in mPOA DA during precopulatory interactions behind the barrier, copulated with females after its removal. However, there was no difference in DA during periods when the quail were copulating as compared to when the female was present but the males were not copulating. In addition, we show that precopulatory DA predicts future DA levels and copulatory behavior frequency. Furthermore, the size of the cloacal gland, an accurate indicator of testosterone action, is positively correlated with precopulatory DA. Taken together, these results provide further support for the hypothesis that DA action in the mPOA is specifically linked to sexual motivation as compared to copulatory behavior per se.