Abstract
Several studies have postulated that psychoacoustic measures of auditory perception are influenced by efferent-induced changes in cochlear responses, but these postulations have generally remained untested. This study measured the effect of stimulus phase curvature and temporal envelope modulation on the medial olivocochlear reflex (MOCR) and on the middle-ear muscle reflex (MEMR). The role of the MOCR was tested by measuring changes in the ear-canal pressure at 6 kHz in the presence and absence of a band-limited harmonic complex tone with various phase curvatures, centered either at (on-frequency) or well below (off-frequency) the 6-kHz probe frequency. The influence of possible MEMR effects was examined by measuring phase-gradient functions for the elicitor effects and by measuring changes in the ear-canal pressure with a continuous suppressor of the 6-kHz probe. Both on- and off-frequency complex tone elicitors produced significant changes in ear canal sound pressure. However, the pattern of results was not consistent with the earlier hypotheses postulating that efferent effects produce the psychoacoustic dependence of forward-masked thresholds on masker phase curvature. The results also reveal unexpectedly long time constants associated with some efferent effects, the source of which remains unknown.
Original language | English (US) |
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Pages (from-to) | 81-99 |
Number of pages | 19 |
Journal | JARO - Journal of the Association for Research in Otolaryngology |
Volume | 16 |
Issue number | 1 |
DOIs | |
State | Published - Jan 30 2015 |
Bibliographical note
Funding Information:The authors thank John J. Guinan, Jr. and Christopher Shera for very helpful discussions on the data in this manuscript. We also thank John J. Guinan and an anonymous reviewer for insightful comments on the earlier version of the manuscript. This work was supported by grant R01 DC 010374 from the National Institutes of Health.
Publisher Copyright:
© 2014, Association for Research in Otolaryngology.
Keywords
- Schroeder-phase complexes
- forward masking
- medial olivocochlear reflex
- middle-ear muscle reflex