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Peter M. Narins



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Frog Robotics

Novel Sound Pathways in Amphibians

We are using an electromechanical frog (left) in a field study in French Guiana to understand the cues that evoke aggressive behavior in a dendrobatid frog (right).
Using laser doppler vibrometry (LDV), we have discovered that the lateral body walls over the lungs of a frog vibrate in response to sound. Sound is then transfered from the lungs to the ears through the Eustachian tubes.

Seismic Communication

Ultrasonic Sound Production in Frogs

With behavioral, anatomical and physiological analyses, we are currently exploring the middle ear function in golden moles. Using our scanning LDV, we can map the motion of the middle ear bones in response to vibration.
We discovered that an arboreal frog in Central China produces high level ultrasonic call components. Using a custom-made ultrasonic recorder, we are studying the function of these high-frequency sounds.

Sound Localization

Energy Flow in the Frog Ear

We are making simultaneous sound pressure measurements (1) on both sides of the frog eardrum, (2) of the eardrum velocity using the LDV, and (3) single unit recordings from the auditory nerve to understand the role of the biophysical pressure gradient system in sound localization.

We have shown that low and high frequency sounds preferentially excite different sensing membranes in the inner ear (above).
Frog Chorus Interactions

Cross-Modal Binding

  Vocalizing animals use many methods to avoid interfering with each others' calls. For example, eight species of Puerto Rican frogs divide up the frequency spectrum so that each species uses a nearly "private" channel for its call.    
We have shown that by separating auditory (call) from visual (vocal sac motion) cues with the electromechanical frog, aggression in this dendrobatid frog is attenuated or eliminated, suggesting that cross-modal binding underlies aggressive behavior in this species.

Middle Ear Mechanics

Hair Cell Research

Using the LDV we showed that the once thought "simple frog ear," has several modes of vibration, making it much more mammal-like than had been previously believed.
We are using patch clamp electrodes to explore (1) the channel properties of auditory hair cells, and (2) the subcellular events that occur during transmitter release and uptake.


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