A Model for Periodicity Coding in the Auditory System
The processing of complex sounds is thought to require the analysis of both spectral and temporal features. The initial processing of temporal features is believed to take place in a monaural pathway or pathways from the cochlea to the inferior colliculus (IC). We hypothesize that temporal processing begins with enhancement of temporal features by the cochlea and by cells in the cochlear nucleus and ends with a coincidence detection mechanism in the IC.
Amplitude modulated (AM) stimuli were used in all model simulations for comparison with data from physiological experiments. The peripheral model consists of a basilar membrane, inner-hair cell, and auditory nerve fiber models. The cochlear model output, was compared to auditory nerve experimental data taken by Joris and Yin (1992) with respect to modulation gain. The cochlear nucleus model, likewise, was compared to data collected by Rhode and Greenberg (1994). The IC model was compared to the findings of Langner and Schreiner (1988).
The result from each stage of the model showed good agreement with the physiological data. At the cochlear level, the model was able to reproduce physiological responses to AM over the same stimulus intensity range as well as frequency range. The cochlear nucleus model also performed well duplicating levels of modulation gain and temporal enhancement seen in the physiological experiments. The IC model was able to process the temporal features passed through the first two model stages and produced modulation transfer functions (MTFs) similar to those seen by Langner and Schreiner. The complete model output can be thought of as a cellular matrix whose activity maps the temporal content of spectral components within an acoustic stimulus.
KeywordsHair Cell Auditory Nerve Inferior Colliculus Basilar Membrane Cochlear Nucleus
Unable to display preview. Download preview PDF.
- Casseday, J.H., Ehrlich, D. and Covey. E. Neural Tuning for Sound Duration: Role of Inhibitory Mechanisms in the Inferior Colliculus. Science 264: 847 850, 1994.Google Scholar
- Cassedy, J.H. and Covey, E. Mechanisms for Analysis of Auditory Temporal Patterns in The Brainstem of Echoloeating Bats. In: Neural Representations of Temporal Patterns H.L. Hawkins, T.A. McMullen, R.R. Popper. and R.R. Fay, eds.. Springer Verlag, New York, 1996.Google Scholar
- Grinell, A.D. The Neurophysiology of Audition in Bats: Intensity and Frequency Parameters. J. Physiol 16738–67, 1963 (a).Google Scholar
- Langner, G. and Schreiner, C.E. Periodicity Coding in the Inferior Colliculus of the Cat. I. Neuronal Mechanisms. J. Neuro-Physiol. 60: 1799–1822, 1988.Google Scholar
- Patterson, R.D., Nimmo-Smith, I. Holdsworth, J., and Rice, P. Spiral vos final report, part A: The auditory filter-bank. Cambridge Electronic Design. Contract Rep. (APU 2341 ), 1988.Google Scholar
- Rhode, W.S. and Greenberg, S. Encoding of Amplitude Modulation in the Cochlear Nucleus of the Cat. Journal of Neurophysiologv. 71: 1797–1825, 1994.Google Scholar
- Singh, S. and Mountain, D.C. A Model for Duration Coding in the Inferior Colliculus. Computational Neuroscience ‘86. Google Scholar