Function of the vocal folds in the treefrog Leptopelis flavomaculatus
Poster Number
3
Format
Poster Presentation
Faculty Mentor Name
Marcos Gridi-Papp
Faculty Mentor Department
Biological Sciences
Abstract/Artist Statement
Frogs and humans have analogous vocal structures which produce sound through a pair of vocal folds. A key difference, however, is that when air is experimentally passed through a passive frog larynx, it produces sounds at the same frequencies that are found in the frog's natural calls, whereas in mammals and humans one has to artificially position the vocal folds to obtain the frequencies produced in life. The purpose of this study is to discover the feature of the frog larynx that gives it the intrinsic ability of positioning the vocal folds to produce sound. We chose the frog Leptopelis flavomaculatus for this study due its simple call structure and large size. A computer-controlled source of humid air was connected to the larynx of an euthanized frog to produce sound. Laryngeal air pressure, airflow and generated sounds were recorded in an anechoic chamber. Although this project is in its preliminary stages, the initial data show that in a passive frog: 1) the vocal folds are partially open, 2) at low pressures, air flows between the vocal folds without producing sound, 3) at higher pressures the vocal folds close, blocking off the passage of air and 4) at even higher pressures, the vocal folds start to vibrate, allowing the passage of air and producing sound. At the onset of sound, the frog larynx resembles reed-based wind instruments in which increases in pressure reduce airflow, and such valve action has not been described in vertebrate vocal systems.
Location
DeRosa University Center, Ballroom
Start Date
21-4-2011 6:00 PM
End Date
21-4-2011 8:00 PM
Function of the vocal folds in the treefrog Leptopelis flavomaculatus
DeRosa University Center, Ballroom
Frogs and humans have analogous vocal structures which produce sound through a pair of vocal folds. A key difference, however, is that when air is experimentally passed through a passive frog larynx, it produces sounds at the same frequencies that are found in the frog's natural calls, whereas in mammals and humans one has to artificially position the vocal folds to obtain the frequencies produced in life. The purpose of this study is to discover the feature of the frog larynx that gives it the intrinsic ability of positioning the vocal folds to produce sound. We chose the frog Leptopelis flavomaculatus for this study due its simple call structure and large size. A computer-controlled source of humid air was connected to the larynx of an euthanized frog to produce sound. Laryngeal air pressure, airflow and generated sounds were recorded in an anechoic chamber. Although this project is in its preliminary stages, the initial data show that in a passive frog: 1) the vocal folds are partially open, 2) at low pressures, air flows between the vocal folds without producing sound, 3) at higher pressures the vocal folds close, blocking off the passage of air and 4) at even higher pressures, the vocal folds start to vibrate, allowing the passage of air and producing sound. At the onset of sound, the frog larynx resembles reed-based wind instruments in which increases in pressure reduce airflow, and such valve action has not been described in vertebrate vocal systems.