Grant: Discovery Grants Program - Individual

The proposal concerns rodent vocalization and the code used by animals in vocal communication. Brain mechanisms involved in the production of ultrasonic vocalizations in the rat and the communicative significance, or ""meaning"" of these vocalizations for other rats are studied. Two main types of calls in adult rats are studied: the long alarm calls and the short social calls. The objectives of the proposed research are (1) to provide evidence that each of the vocalization types requires activity of a different brain subsystem, which uses different chemical code. The alarm calls are based on the utilization of the brain chemical known as acetylcholine and the social calls on the chemical known as dopamine. Both of these neurochemicals are released in the brain from terminals of specific neuronal pathways. The project also aims at (2) identifying active brain cells, which produce and release these neurochemicals and are directly involved in production of vocalizations. In addition to that, (3) the proposal includes behavioural studies, which are designed to provide evidence that rats can clearly distinguish different types of their calls and can even recognize calls of individual rats within their group. Finally (4) the proposal contains plans for studies of individual development of vocalizations from infants to adults. The ultimate goal of this proposal is to extend these studies to other species, including man. This research has a potential to reveal brain mechanism of human infant cry and development of vocal expression of human emotions. It will also contribute to our knowledge of the evolutionary development of emotional coloration of speech in humans and non-verbal vocal communication in mammalian species.