The organ of the inner ear which detects sound is the cochlea, and the auditory nerve carries information from the receptors to several clusters of cells forming the cochlear nuclei in the brainstem. Although most tests of auditory coding have used tone bursts to elicit nerve responses, adaptation is common in receptor organs, so that the neural responses may change during the stimulus. Also, natural sounds have a dynamic rather than constant character. Since intensity variations are basic components of natural auditory stimuli, dynamic response properties can play an important role in the detection, identification, and masking of such stimuli. This project will involve recording activity of single neurons and of compound neural responses from the whole auditory nerve. Changes in adaptation and in sensitivity will be studied as they are affected by the intensity, frequency, or modulation frequency of the sound. A newly discovered residual potential in the cochlea will be investigated to determine its neural basis, along with exploration of the interactions in one ear produced by stimulation of the brain or by the opposite ear. This fundamental work will have impact on auditory neuroscience, and the aspects of coding will be important to other sensory systems and to information processing paradigms.
