Fluctuation contrast and speech-on-speech masking: Model midbrain responses to simultaneous speech

Authors

  • Laurel H. Carney Departments of Biomedical Engineering, Neuroscience, and Electrical & Computer Engineering, Del Monte Institute for Neuroscience, University of Rochester, Rochester, NY, USA; Hearing Systems, Department of Electrical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark

Abstract

At the level of the auditory midbrain, low-frequency fluctuations within each frequency channel drive neurons with band-pass modulation transfer functions (MTFs). The amplitude of low-frequency fluctuations in ascending neural signals is affected by stimulus amplitude due to the gradual saturation of the inner hair cells (IHCs) beginning at moderate sound levels. This level dependence of low-frequency fluctuation amplitudes results in contrast cues at the level of the midbrain: Spectral peaks result in lower responses of cells with bandpass-MTFs, whereas spectral valleys result in higher responses. Here, we focus on model population midbrain responses with different best-modulation frequencies (BMFs) to simultaneous speech. Midbrain responses were simulated for single hearing-in-noise (HINT) sentences and for a pair of simultaneous sentences, spoken by a male and a female. Correlations between population responses to individual male (or female) sentences and responses to simultaneous sentences vary with BMF in the range of the male (or female) fundamental frequencies. The pattern of fluctuation contrast across frequency in the midbrain representation provides a framework for studying speech-on-speech masking for listeners with normal hearing and sensorineural hearing loss.

References

Bramsløw, L., Vatti, M., Hietkamp, R.K., and Pontoppidan, N.H. (2014). “Design of a competing voices test,” Poster presented at International Hearing Aid Conference (IHCON).
Bramsløw, L., Vatti, M., Rossing R., and Pontoppidan, N.H. (2017). “An improved competing voices test for test of attention,” Proc. ISAAR, 6, 279-286.

Carney, L.H., Li, T., and McDonough, J.M. (2015). “Speech coding in the brain: representation of vowel formants by midbrain neurons tuned to sound fluctuations,” Eneuro, 2, ENEURO-0004.

Carney, L.H., Kim, D.O., and Kuwada, S. (2016). “Speech coding in the midbrain: Effects of sensorineural hearing loss,” in Physiology, Psychoacoustics and Cognition in Normal and Impaired Hearing (Springer), Adv. Exp. Med. Biol., 894, 427-435. PMID: 27080684

Delgutte, B., and Kiang, N.Y. (1984). “Speech coding in the auditory nerve: I. Vowel-like sounds,” J. Acoust. Soc. Am., 75, 866-878.

Joris, P.X., and Yin, T.C. (1992). “Responses to amplitude-modulated tones in the auditory nerve of the cat,” J. Acoust. Soc. Am., 91, 215-232.

Joris, P.X. (2003). “Interaural time sensitivity dominated by cochlea-induced envelope patterns,” J. Neurosci., 23, 6345-6350.

Joris, P.X., Schreiner, C.E., and Rees, A. (2004). “Neural processing of amplitude-modulated sounds,” Physiol. Rev., 84, 541-577.

Kim, D.O., Zahorik, P., Carney, L.H., Bishop, B.B., and Kuwada, S. (2015). “Auditory distance coding in rabbit midbrain neurons and human perception: monaural amplitude modulation depth as a cue,” J. Neurosci., 35, 5360-5372.

Krishna, B.S., and Semple, M.N. (2000). “Auditory temporal processing: responses to sinusoidally amplitude-modulated tones in the inferior colliculus,” J. Neurophysiol., 84, 255-273.

Langner, G., and Schreiner, C.E. (1988). “Periodicity coding in the inferior colliculus of the cat. I. Neuronal mechanisms,” J. Neurophysiol., 60, 1799-1822.

Mao, J., Vosoughi, A., and Carney, L.H. (2013). “Predictions of diotic tone-in-noise detection based on a nonlinear optimal combination of energy, envelope, and fine-structure cues,” J. Acoust. Soc. Am., 134, 396-406.

Miller, R.L., Schilling, J.R., Franck, K.R., and Young, E.D. (1997). “Effects of acoustic trauma on the representation of the vowel /ε/ in cat auditory nerve fibers,” J. Acoust. Soc. Am., 101, 3602-3616.

Nelson, P.C., and Carney, L. H. (2004). “A phenomenological model of peripheral and central neural responses to amplitude-modulated tones,” J. Acoust. Soc. Am., 116, 2173-2186. PMCID: PMC1379629

Nelson, P.C., and Carney, L.H. (2007). “Neural rate and timing cues for detection and discrimination of amplitude-modulated tones in the awake rabbit inferior colliculus,” J. Neurophysiol., 97, 522-539.

Nielsen, J.B., and Dau, T. (2009). “Development of a Danish speech intelligibility test,” Int. J. Audiol., 48, 729-741.

Nilsson, M., Soli, S.D., and Sullivan, J.A. (1994). “Development of the Hearing in Noise Test for the measurement of speech reception thresholds in quiet and in noise,” J. Acoust. Soc. Am., 95, 1085-1099.

Zilany, M.S.A., Bruce, I.C., and Carney, L.H. (2014). “Updated parameters and expanded simulation options for a model of the auditory periphery,” J. Acoust. Soc. Am., 135, 283-286. PMCID: PMC3985897

Additional Files

Published

2018-01-02

How to Cite

Carney, L. H. (2018). Fluctuation contrast and speech-on-speech masking: Model midbrain responses to simultaneous speech. Proceedings of the International Symposium on Auditory and Audiological Research, 6, 75–82. Retrieved from https://proceedings.isaar.eu/index.php/isaarproc/article/view/2017-10

Issue

Section

2017/2. Neural mechanisms, modeling, and physiological correlates of adaptation