Seminars in Hearing Research at Purdue (SHRP)

Date: Thursday, September 16, 2021

Time: 10:30 – 11:20 am

Location: LYLE 1150

Title: The effect of broadband elicitor duration on transient-evoked otoacoustic emissions and a behavioral measure of gain reduction

Speaker: William Salloom, PhD candidate, PULSe program (Strickland lab)

Abstract: Humans are able to encode sound over a wide range of intensities despite the fact that neurons in the auditory periphery have much smaller dynamic ranges. There is a feedback system that originates at the level of the brainstem that may help solve the dynamic range problem. This system is the medial olivocochlear reflex (MOCR), which is a bilateral sound-activated system which decreases amplification of sound by the outer hair cells in the cochlea. Much of the previous research on the MOCR in animals and humans has been physiologically based, and has used long broadband noise elicitors. However, the effect of the duration of broadband noise elicitors on similar behavioral tasks is unknown. Additionally, MOCR effects measured using otoacoustic emissions (OAEs), have not consistently shown a positive correlation with behavioral gain reduction tasks. This may be due to different methodologies being utilized for the OAE and behavioral tasks, and/or due to the analysis techniques not being optimized to observe a relationship. In the current study, we explored the effects of ipsilateral broadband noise elicitor duration both physiologically and behaviorally in the same subjects. Both measures used similar stimuli in a forward-masking paradigm. We tested two research questions: 1) Are the time constants of the physiological and behavioral measures similar to one another (thus reflecting the same mechanism) 2) Can the changes in physiological responses by the elicitor predict the changes in behavioral responses in the same subjects, as a function of elicitor duration. By keeping our stimuli and subjects consistent throughout the study, as well as using various methods analyze our OAE data, we have optimized the conditions to determine the relationship between physiological and behavioral measures of gain reduction. The findings for both of these questions will be discussed. Understanding these effects is not only of fundamental importance to how the auditory system adapts to sound over time, but is also of practical importance in laboratory settings that use broadband noise to elicit the MOCR.

Zoom Info:

https://purdue-edu.zoom.us/j/93108158900?pwd=RDdTQ0Z4UE9Rb0JUenhjMG1SMkp2QT09

Meeting ID: 931 0815 8900

Passcode: 11501150

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The working schedule for this academic is here:

https://purdue.edu/TPAN/hearing/shrp_schedule

The titles and abstracts of the talks will be added here:

https://purdue.edu/TPAN/hearing/shrp_abstracts