The Disconnect Between the Tuning of the Eardrum and the Brain in the Treefrog Litoria caerulea
Poster Number
32
Format
Poster Presentation
Faculty Mentor Name
Marcos Gridi-Papp
Faculty Mentor Department
Biological Sciences
Abstract/Artist Statement
Frogs rely on acoustic communication for mating but they tend to hear within a narrow frequency range. The tuning of their hearing matches that of their vocal folds, allowing for the reception of conspecific signals. Similarly, vibrations at the ear drum are maximal within the same frequencies as neurological data recorded from the midbrain. We measured the hearing performance of 10 male Indonesian White's treefrogs (Litoria caerulea) at both ends of the auditory pathway (eardrums and brain). Using laser vibrometry, we quantified the tympanic membrane response to sound. We compared these data with neural responses recorded by a tungsten electrode in the torus semicircularis, within the optic lobe. We found that the eardrum’s peak response occurs around twice the frequency of the peak brain sensitivity, which is a closer match to the main frequency in the species’ call. These results were obtained with the same protocol that recently revealed a very close match in the tuning of calls, eardrums and brain of gray treefrogs (Hyla versicolor). We hypothesize that: 1) The larger females have their ears tuned to the male calls, but males remain out of tune for having both small body size and ears; 2) This species might produce an undocumented behavioral adjustment of tuning, which did not occur under anesthesia in our measurements.
Location
DeRosa University Center, Ballroom
Start Date
20-4-2013 1:00 PM
End Date
20-4-2013 3:00 PM
The Disconnect Between the Tuning of the Eardrum and the Brain in the Treefrog Litoria caerulea
DeRosa University Center, Ballroom
Frogs rely on acoustic communication for mating but they tend to hear within a narrow frequency range. The tuning of their hearing matches that of their vocal folds, allowing for the reception of conspecific signals. Similarly, vibrations at the ear drum are maximal within the same frequencies as neurological data recorded from the midbrain. We measured the hearing performance of 10 male Indonesian White's treefrogs (Litoria caerulea) at both ends of the auditory pathway (eardrums and brain). Using laser vibrometry, we quantified the tympanic membrane response to sound. We compared these data with neural responses recorded by a tungsten electrode in the torus semicircularis, within the optic lobe. We found that the eardrum’s peak response occurs around twice the frequency of the peak brain sensitivity, which is a closer match to the main frequency in the species’ call. These results were obtained with the same protocol that recently revealed a very close match in the tuning of calls, eardrums and brain of gray treefrogs (Hyla versicolor). We hypothesize that: 1) The larger females have their ears tuned to the male calls, but males remain out of tune for having both small body size and ears; 2) This species might produce an undocumented behavioral adjustment of tuning, which did not occur under anesthesia in our measurements.