Temporal resolution of the Florida manatee (Trichechus manatus latirostris) auditory system.
Auditory evoked potential (AEP) measurements of two Florida manatees (Trichechus manatus latirostris) were measured in response to amplitude modulated tones. The AEP measurements showed weak responses to test stimuli from 4 kHz to 40 kHz. The manatee modulation rate transfer function (MRTF) is maximally sensitive to 150 and 600 Hz amplitude modulation (AM) rates. The 600 Hz AM rate is midway between the AM sensitivities of terrestrial mammals (chinchillas, gerbils, and humans) (80-150 Hz) and dolphins (1,000-1,200 Hz). Audiograms estimated from the input-output functions of the EPs greatly underestimate behavioral hearing thresholds measured in two other manatees. This underestimation is probably due to the electrodes being located several centimeters from the brain.
College of Marine Science, University of South Florida, St. Petersburg, 33701, USA. dmann@marine.usf.edu
David A
DA
Mann
Debborah E
DE
Colbert
Joseph C
JC
Gaspard
Brandon M
BM
Casper
Mandy L H
ML
Cook
Roger L
RL
Reep
Gordon B
GB
Bauer
D000161:Acoustic Stimulation; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology; D003216:Conditioning, Operant; D004567:Electrodes, Implanted; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005502:Food; D006309:Hearing / Q000502:physiology*; D008297:Male; D012201:Reward; D013997:Time Factors; D020455:Trichechus / Q000502:physiology*