Meeting Abstract
Females of many species use male courtship displays as a proxy of male fitness to inform decisions of mate choice. Studies of female responses to song have implicated specific auditory cortical regions, such as the caudal mesopallium (CM), in female mate preferences. Here we used an anterograde neural tracer to examine the projections from CM in female Bengalese finches (Lonchura striata). Our results reveal a novel projection from CM to the robust nucleus of the arcopallium (RA) as well as a region we suspect to be the ventral intermediate arcopallium (AIV). These projections may enable CM to influence brain regions implicated in female courtship behaviors. In zebra finches, AIV projects to the ascending auditory stream, which in turn projects to the mediobasal hypothalamus (MBH), a region associated with female copulatory displays. In female Bengalese finches, RA projects to the dorsomedial nucleus of the intercollicular complex (DM), a site necessary for female call production. In addition, DM has recently been shown to project to the cloaca via the respiratory premotor nucleus retroambigualis (RAm). Together, these data reveal pathways through which CM may influence displays and calls in response to preferred song(s). To address the functionality of projections emanating from CM in driving female courtship behaviors, we have begun using an adeno-associated virus encoding the channelrhodopsin protein (ChR2) to selectively and reversibly manipulate CM neurons as female songbirds are engaged in evaluation of song quality. In ongoing experiments, we are testing the prediction that optically induced changes in CM activity while females are listening to song will induce changes in female courtship behaviors.
