Temporal processing of pitch in the auditory system*

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Abstract
In order to understand our ability to perceive music, we have to understand how our auditory neurons process acoustic signals. It is demonstrated here that temporal processing mechanisms in the auditory brainstem are essential for important aspects of musical perception, like the perception of pitch. Neurophysiological experiments revealed that the temporal feature important for pitch is the periodicity of signal envelopes. The corresponding evidence from neurophysiological, anatomical, and psychophysical experiments will be summarized. The envelope periodicity corresponds to the fundamental frequency of signals and reflects periodic vibrations of sound sources. As a consequence of the cochlear analysis, periodicity is represented not only in the firing patterns of auditory nerve fibers which code the fundamental frequency, but also in those which are involved in the spectral coding of overtones. In the brainstem intrinsic neuronal oscillations, temporal integration, and coincidence detection contribute to the analysis of periodicity information. The result is that periodicity or pitch is represented orthogonal to frequency information in the central auditory system. The implications of these results for musical perception will be discussed.