The long term objective of this project is to determine the biological significance of the """"""""non-communicative"""""""" function of vocalization and characterize the underlying physiological mechanisms. Although vocalization has traditionally been viewed as a mean of communication, recent evidence from my laboratory strongly indicates that communication also function in an integral physiological capacity. Birdsong, especially in passerine species, has long been a favored research system. The issue of learning in development of song and adaptive significance of acoustic communication are among the problems which have been addressed. The primary question of the mechanism by which the male song may influence the female's endocrine response, culminating in egg- laying, has not been studied. However, this issue has been subject of intensive study of non-songbird system. Recent findings in the study of the female ringdove (Streptopelia risoria) reproductive system has revealed an interesting dimension of vocalization which has received little attention. We have found that a bird's vocalization alters its endocrine state. What neural pathways mediate this endocrine response? Can we demonstrate this basic finding in morphological terms? Are there different circuities involved in endocrine consequence of courtship vs other vocalization such as alarm calls? In this application, I will determine and characterize the chemical features of the neural pathways which mediate the conversion of vocalization into endocrine response. In other words, we intend to demonstrate that an increased luteinizing hormone-releasing hormone (LHRH) release can be traced to neuronal activity in the vocal control nuclei associated with the performance of female nest calls. The proposed studies will add useful information about how acoustic inputs, especially those generated from the individual's own vocalization affect endocrine state and hence the well-being of the individual.
