Acoustic features and acoustic change are represented by different central pathways

Cynthia King*, Therese McGee, Edwin W. Rubel, Trent Nicol, Nina Kraus

*Corresponding author for this work

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

The central processing of acoustic stimulus changes can be observed neurophysiologically in the mismatch negativity auditory evoked potential (MMN). Stimuli differing in interaural phase were used to investigate the contributions of the primary and non-primary auditory pathways to the encoding of binaural stimuli and to investigate passively elicited measures of binaural processing in experimental animals. In guinea pigs, the MMN was obtained in response to 1000 Hz tones embedded in white noise (S:N = 2 dB). Using a modified oddball paradigm (that is, two stimuli presented in a series, each with a different probability of occurrence), stimuli were presented binaurally with both the tone and noise in-phase to the two ears (S0N0) as the standard stimulus and the tone 180° out-of-phase (SΠN0) as the deviant stimulus. The MMN, by definition, should occur only in response to a change, or 'mismatch,' between the standard and deviant stimuli. The response to the deviant stimulus in the oddball paradigm was compared to the response to the same stimulus when presented in a series alone. The responsesto S0N0 and SΠN0 collected in a series alone, termed the intrinsic responses, were also compared. Responses were recorded from two surface epidural electrodes - one at the posterior midline and one over the left temporal lobe. AEPs from these locations have been shown to reflect the activity of primary and non-primary thalamo-cortical pathways respectively. A significant MMN was observed at the midline electrode, but no MMN was observed over the temporal lobe. However, there was a significant difference in the intrinsic responses to the two stimuli over the temporal lobe while no difference in the intrinsic responses was seen over the midline. The results suggest that the primary and non-primary auditory pathways appear to provide distinctly different contributions to the encoding of changes in binaural phase. Additionally, the MMN to stimuli differing in interaural phase can be obtained in anesthetized animals and may provide a useful measure of binaural processing.

Original languageEnglish (US)
Pages (from-to)45-52
Number of pages8
JournalHearing research
Volume85
Issue number1-2
DOIs
StatePublished - Jan 1 1995

Keywords

  • Auditory evoked potentials
  • Binaural processing
  • Interaural phase difference
  • Mismatch negativity
  • Primary vs. non-primary pathways

ASJC Scopus subject areas

  • Sensory Systems

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