Frogs are vertebrates with two distinct auditory organs, rather than the single cochlea of mammals. A great deal is known about frog calling communication behavior, and about the physiology of frog auditory systems. However, unlike the case in mammals, the anatomical details and ultrastructure of how the sensory hair cells are innervated is poorly known. Such details are important in forming hypotheses about mechanisms for the observed frequency selectivity and physiology of frog hearing. This work will use light and electron microscopy to assess how the receptor cells are innervated by the auditory nerve in both these organs, and then to study the detailed architecture of the functional contancts, the synapses, of single nerve fibers in selected regions where function is known. The results will be important not only to comparative aspects of auditory function including physiology and behavior among species, but also to general principles of frequency coding mechanisms which are crucial to auditory neuroscience.
