TY - JOUR
T1 - Probing cochlear tuning and tonotopy in the tiger using otoacoustic emissions
AU - Bergevin, Christopher
AU - Walsh, Edward J.
AU - McGee, JoAnn
AU - Shera, Christopher A.
N1 - Funding Information:
Acknowledgments The support, advice, and assistance of the veterinarians and staff of the Henry Doorly Zoo were invaluable to the completion of this study. All procedures were approved by the Institutional Animal Care and Use Committee. We thank Sebastiaan Meenderink and John Rosowski for helpful comments on the manuscript. The work was supported by the National Science Foundation (grants 0823417 and 0602173), the Howard Hughes Medical Institute (grant 52003749), and the National Institutes of Health (grants R01 DC003687 and P30 DC05209).
PY - 2012/8
Y1 - 2012/8
N2 - Otoacoustic emissions (sound emitted from the ear) allow cochlear function to be probed noninvasively. The emissions evoked by pure tones, known as stimulus-frequency emissions (SFOAEs), have been shown to provide reliable estimates of peripheral frequency tuning in a variety of mammalian and non-mammalian species. Here, we apply the same methodology to explore peripheral auditory function in the largest member of the cat family, the tiger (Panthera tigris). We measured SFOAEs in 9 unique ears of 5 anesthetized tigers. The tigers, housed at the Henry Doorly Zoo (Omaha, NE), were of both sexes and ranged in age from 3 to 10 years. SFOAE phase-gradient delays are significantly longer in tigers-by approximately a factor of two above 2 kHz and even more at lower frequencies-than in domestic cats (Felis catus), a species commonly used in auditory studies. Based on correlations between tuning and delay established in other species, our results imply that cochlear tuning in the tiger is significantly sharper than in domestic cat and appears comparable to that of humans. Furthermore, the SFOAE data indicate that tigers have a larger tonotopic mapping constant (mm/octave) than domestic cats. A larger mapping constant in tiger is consistent both with auditory brainstem response thresholds (that suggest a lower upper frequency limit of hearing for the tiger than domestic cat) and with measurements of basilar-membrane length (about 1. 5 times longer in the tiger than domestic cat).
AB - Otoacoustic emissions (sound emitted from the ear) allow cochlear function to be probed noninvasively. The emissions evoked by pure tones, known as stimulus-frequency emissions (SFOAEs), have been shown to provide reliable estimates of peripheral frequency tuning in a variety of mammalian and non-mammalian species. Here, we apply the same methodology to explore peripheral auditory function in the largest member of the cat family, the tiger (Panthera tigris). We measured SFOAEs in 9 unique ears of 5 anesthetized tigers. The tigers, housed at the Henry Doorly Zoo (Omaha, NE), were of both sexes and ranged in age from 3 to 10 years. SFOAE phase-gradient delays are significantly longer in tigers-by approximately a factor of two above 2 kHz and even more at lower frequencies-than in domestic cats (Felis catus), a species commonly used in auditory studies. Based on correlations between tuning and delay established in other species, our results imply that cochlear tuning in the tiger is significantly sharper than in domestic cat and appears comparable to that of humans. Furthermore, the SFOAE data indicate that tigers have a larger tonotopic mapping constant (mm/octave) than domestic cats. A larger mapping constant in tiger is consistent both with auditory brainstem response thresholds (that suggest a lower upper frequency limit of hearing for the tiger than domestic cat) and with measurements of basilar-membrane length (about 1. 5 times longer in the tiger than domestic cat).
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U2 - 10.1007/s00359-012-0734-1
DO - 10.1007/s00359-012-0734-1
M3 - Article
C2 - 22645048
AN - SCOPUS:84864912827
VL - 198
SP - 617
EP - 624
JO - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
JF - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
SN - 0340-7594
IS - 8
ER -