Phoneme representation in primary auditory cortex

Authors

  • Shihab Shamma Institute for Systems Research, Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, USA
  • Nima Mesgarani Institute for Systems Research, Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, USA
  • Stephen David Institute for Systems Research, Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, USA
  • Jonathan Fritz Institute for Systems Research, Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, USA

Abstract

We examined the responses of neurons in primary auditory cortex (A1) to phonetically labeled speech stimuli. Sentences were taken from the TIMIT database and chosen to represent a diversity of male and female speakers. We presented these stimuli to awake ferrets while recording the activity of isolated A1 neurons. For analysis, we segmented the continuous speech samples into sequences of phonemes, which represent the smallest signi cant units of speech. We characterized the response properties of each neuron as the peristimulus time histogram (PSTH) response to each phoneme. Across a population of A1 neurons, we observed distinct patterns of phoneme selectivity that may provide a neural basis or low-level phoneme discrimination. We investigated how features of speech are encoded in A1 using a method for reconstructing the speech stimulus from the neural population responses. Stimuli were reconstructed using a linear spectro-temporal model to map the response to the stimulus spectrogram. We compared the accuracy of reconstruction across phonemes. One important factor involved in stimulus reconstruction is the presence of correlations in complex natural stimulus such as speech. Prior knowledge of regularities in the stimulus can bene t reconstruction in noise and when spectro-temporal coverage is limited. We studied the influence of prior knowledge of stimulus correlations, noise and spectro-temporal coverage on reconstruction accuracy in neural data and in simulation.

References

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Additional Files

Published

2007-12-15

How to Cite

Shamma, S., Mesgarani, N., David, S., & Fritz, J. (2007). Phoneme representation in primary auditory cortex. Proceedings of the International Symposium on Auditory and Audiological Research, 1, 187–200. Retrieved from https://proceedings.isaar.eu/index.php/isaarproc/article/view/2007-18

Issue

Vol. 1 (2007): Auditory Signal Processing in Hearing Impaired Listeners

Section

2007/2. Physiological correlates of auditory functions

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