Steroid-sensitive neuroeffector pathways for sonic and electric communication in fish.

A neuroeffector pathway for communication consists of at least two elements: a peripheral effector organ and a central motor nucleus. Two communication systems are discussed here: the sonic motor and electromotor systems of fish. The electromotor system is used to illustrate species diversity of a peripheral effector, the electric organ. The sonic motor system is discussed in the context of species differences in the organization of a central motor nucleus for communication. Both systems share several anatomical and physiological features related to the generation of a stereotyped communication signal. Moreover, both systems appear to be sensitive to the influences of gonadal steroid hormones in the development of sexually dimorphic communication signals.