Vocal communication in vertebrate animals is one behavior that displays sexually dimorphic characteristics (i.e., males and females are different). Dr. Bass has chosen to study teleost fishes as a model system of this type of behavior. In the species to be studied males generate vocalizations in order to attract females to the nest, but no such behavior is seen in the females. In previous studies it has been shown that the behavioral sex differences in vocalizations are correlated with anatomical and physiological traits of the muscles and neurons that comprise the sonic motor pathway. The proposed research will study the underlying basis of these differences. The electrophysiological properties of the nerve cells involved in these responses will be analysed. The morphological features and the chemical nature of specific nerve cells in this system will be identified. Changes induced by testosterone, a reproductively active steroid hormone, will be measured both physiologically and anatomically. These studies will contribute to fundamental knowledge about the role of steroid hormones in the regulation of nerve cell function and sexually differentiated behaviors in vertebrates.
