Using individual differences to test the role of temporal and place cues in coding frequency modulation

J Acoust Soc Am. 2015 Nov;138(5):3093-104. doi: 10.1121/1.4935018.

Abstract

The question of how frequency is coded in the peripheral auditory system remains unresolved. Previous research has suggested that slow rates of frequency modulation (FM) of a low carrier frequency may be coded via phase-locked temporal information in the auditory nerve, whereas FM at higher rates and/or high carrier frequencies may be coded via a rate-place (tonotopic) code. This hypothesis was tested in a cohort of 100 young normal-hearing listeners by comparing individual sensitivity to slow-rate (1-Hz) and fast-rate (20-Hz) FM at a carrier frequency of 500 Hz with independent measures of phase-locking (using dynamic interaural time difference, ITD, discrimination), level coding (using amplitude modulation, AM, detection), and frequency selectivity (using forward-masking patterns). All FM and AM thresholds were highly correlated with each other. However, no evidence was obtained for stronger correlations between measures thought to reflect phase-locking (e.g., slow-rate FM and ITD sensitivity), or between measures thought to reflect tonotopic coding (fast-rate FM and forward-masking patterns). The results suggest that either psychoacoustic performance in young normal-hearing listeners is not limited by peripheral coding, or that similar peripheral mechanisms limit both high- and low-rate FM coding.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acoustic Stimulation
  • Adolescent
  • Adult
  • Auditory Perception / physiology*
  • Auditory Threshold
  • Cochlea / physiology*
  • Cochlear Nerve / physiology*
  • Cues*
  • Dichotic Listening Tests
  • Differential Threshold / physiology
  • Female
  • Humans
  • Individuality*
  • Male
  • Models, Neurological*
  • Perceptual Masking
  • Periodicity
  • Pitch Discrimination / physiology
  • Principal Component Analysis
  • Psychoacoustics
  • Time Factors
  • Young Adult