Effect of efferent activation on binaural frequency selectivity
Jesko L Verhey1, Monika Kordus1, Vit Drga2
1Department of Experimental Audiology, Otto von Guericke University, Leipziger Str. 44, 39120 Magdeburg, Germany.
Hearing Research
|May 12, 2017
Summary
Auditory efferent activation via the medial olivocochlear system widens binaural filters. This suggests efferent activity reduces cochlear gain, impacting binaural frequency selectivity.
Area of Science:
- Auditory Neuroscience
- Psychoacoustics
- Human Auditory System
Background:
- Binaural processing shows reduced frequency selectivity compared to monaural processing.
- The medial olivocochlear (MOC) system is an auditory efferent pathway.
- Understanding MOC's role in binaural hearing is crucial for auditory perception research.
Purpose of the Study:
- To investigate the effect of auditory efferent activation on binaural frequency selectivity.
- To determine if MOC activation influences the effective bandwidth of binaural listening.
Main Methods:
- Listeners detected a 1-kHz signal in a notched-noise masker under diotic and dichotic conditions.
- Auditory efferent system activation was induced using a noise precursor.
- Thresholds were measured with and without the precursor to assess its effect.
Main Results:
- A wider binaural filter was observed in baseline conditions, as expected.
- Precursor presentation, activating the efferent system, resulted in wider binaural filters for both signal phases.
- These findings support the hypothesis of reduced cochlear gain due to efferent activity.
Conclusions:
- Auditory efferent activation broadens binaural frequency-selective filters.
- The medial olivocochlear system's activation appears to reduce cochlear gain, modulating binaural hearing.
- This study provides insights into the efferent control of auditory filtering.
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