Input compensation of dolphin and sea lion auditory brainstem responses using frequency-modulated up-chirps.
J Acoust Soc Am
; 154(2): 739-750, 2023 08 01.
Article
in En
| MEDLINE
| ID: mdl-37556567
ABSTRACT
Frequency-modulated "chirp" stimuli that offset cochlear dispersion (i.e., input compensation) have shown promise for increasing auditory brainstem response (ABR) amplitudes relative to traditional sound stimuli. To enhance ABR methods with marine mammal species known or suspected to have low ABR signal-to-noise ratios, the present study examined the effects of broadband chirp sweep rate and level on ABR amplitude in bottlenose dolphins and California sea lions. "Optimal" chirps were designed based on previous estimates of cochlear traveling wave speeds (using high-pass subtractive masking methods) in these species. Optimal chirps increased ABR peak amplitudes by compensating for cochlear dispersion; however, chirps with similar (or higher) frequency-modulation rates produced comparable results. The optimal chirps generally increased ABR amplitudes relative to noisebursts as threshold was approached, although this was more obvious when sound pressure level was used to equate stimulus levels (as opposed to total energy). Chirps provided progressively less ABR amplitude gain (relative to noisebursts) as stimulus level increased and produced smaller ABRs at the highest levels tested in dolphins. Although it was previously hypothesized that chirps would provide larger gains in sea lions than dolphins-due to the lower traveling wave speed in the former-no such pattern was observed.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Sea Lions
/
Bottle-Nosed Dolphin
Limits:
Animals
Language:
En
Journal:
J Acoust Soc Am
Year:
2023
Document type:
Article
Affiliation country:
United States
Publication country:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA