Sound durations longer than 25 ms recruit efferent feedback that reduces measured suppression

Evidence

It is possible that previous psychoacoustic studies of suppression underestimated the amount of suppression by using maskers that were long enough to elicit the medial olivocochlear reflex (MOCR). The MOCR is a sound-elicited efferent feedback loop that reduces OHC amplification or gain (Cooper and Guinan 2006 ). Gain starts to be affected approximately 25 ms after elicitor onset. Evidence from physiological studies in animals suggests that elicitation of the MOCR may decrease or modify suppression (Winslow and Sachs 1987 ; Kawase et al. 1993 ). Previous studies of aging effects on suppression used masker and suppressor durations of 200–500 ms (Dubno and Ahlstrom 2001a , b ; Gifford and Bacon 2005 ; Sommers and Gehr 1998 , 2010 ). These durations were long enough to elicit MOCR-induced gain reductions and possibly reduce suppression estimates. — Dijk, Pim van, Physiology, Psychoacoustics and…, 925

Categorization

• DEFINE: Defines the medial olivocochlear reflex (MOCR), an efferent feedback loop reducing OHC gain, with its ~25 ms onset latency.
• XREF: The idea that a measurement paradigm itself alters the measured mechanism is a classic reflexivity problem paralleling hearing-aid and adaptation research.
• SHARE: Send to anyone in auditory neuroscience: behavioral suppression studies with 200-500 ms maskers may have systematically underestimated suppression because the elicitor activates MOCR gain reduction.