UI  - 98267703
AU  - Versnel H
AU  - Shamma SA
TI  - Spectral-ripple representation of steady-state vowels in primary
      auditory cortex [In Process Citation]
LA  - Eng
DA  - 19980529
DP  - 1998 May
IS  - 0001-4966
TA  - J Acoust Soc Am
PG  - 2502-14
SB  - M
CY  - UNITED STATES
IP  - 5 Pt 1
VI  - 103
JC  - H3K
AA  - AUTHOR
AB  - Responses to various steady-state vowels were recorded in single units
      in the primary auditory cortex (AI) of the barbiturate-anaesthetized
      ferret. Six vowels were presented (/a/, /epsilon/, 2 different /i/'s,
      and 2 different /u/'s) in a natural voiced and a synthetic unvoiced
      mode. In addition, the responses to broadband stimuli with a
      sinusoidally shaped spectral envelope (called ripple stimuli) were
      recorded in each cell, and the response field (RF), which consists of
      both excitatory and inhibitory regions, was derived from the ripple
      transfer function. We examined whether the vowel responses could be
      predicted using a linear ripple analysis method [Shamma et al.,
      Auditory Neurosci. 1, 233-254 (1995)], i.e., by cross correlating the
      RF of the single unit, and the smoothed spectral envelope of the vowel.
      We found that for most AI cells (71%) the relative responses to natural
      vowels could be predicted on the basis of this method. Responses and
      prediction results for unvoiced and voiced vowels were very similar,
      suggesting that the spectral fine structure may not play a significant
      role in the neuron's response to the vowels. Predictions on the basis
      of the entire RF were significantly better than based solely on best
      frequency (BF) (or "place"). These findings confirm the ripple analysis
      method as a valid method to characterize AI responses to broadband
      sounds as we proposed in a previous paper using synthesized spectra
      [Shamma and Versnel, Auditory Neurosci. 1, 255-270 (1995)].
AD  - Institute for Systems Research and Electrical Engineering Department,
      University of Maryland, College Park 20742, USA. hv@physiol.ox.ac.uk
RO  - O:099
PMID- 0009604344
SO  - J Acoust Soc Am 1998 May;103(5 Pt 1):2502-14

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