[MARMAM] Paper on CT imaging and hearing of pygmy killer whales

Eric Montie emontie at uscb.edu
Mon Feb 28 20:03:38 PST 2011


Dear Colleagues,

I would like to bring to your attention the following paper, "Live CT
imaging of sound reception anatomy and hearing measurements in the pygmy
killer whale, Feresa attenuata", published in the Journal of Experimental
Biology 214, 945-955.  The "Inside JEB" synopsis and the research article
can be found at the following website:
http://jeb.biologists.org/current.dtl. 

 

Summary

In June 2008, two pygmy killer whales (Feresa attenuata) were stranded alive
near Boca Grande, FL, USA, and were taken into rehabilitation. We used this
opportunity to learn about the peripheral anatomy of the auditory system and
hearing sensitivity of these rare toothed whales. Three-dimensional (3-D)
reconstructions of head structures from X-ray computed tomography (CT)
images revealed mandibles that were hollow, lacked a bony lamina medial to
the pan bone and contained mandibular fat bodies that extended caudally and
abutted the tympanoperiotic complex. Using auditory evoked potential (AEP)
procedures, the modulation rate transfer function was determined. Maximum
evoked potential responses occurred at modulation frequencies of 500 and
1000 Hz. The AEP-derived audiograms were U-shaped. The lowest hearing
thresholds occurred between 20 and 60 kHz, with the best hearing sensitivity
at 40 kHz. The auditory brainstem response (ABR) was composed of seven waves
and resembled the ABR of the bottlenose and common dolphins. By changing
electrode locations, creating 3-D reconstructions of the brain from CT
images and measuring the amplitude of the ABR waves, we provided evidence
that the neuroanatomical sources of ABR waves I, IV and VI were the auditory
nerve, inferior colliculus and the medial geniculate body, respectively. The
combination of AEP testing and CT imaging provided a new synthesis of
methods for studying the auditory system of cetaceans.

 

If you have any questions, feel free to contact me.

 

Cheers,

Eric

 

Eric W. Montie

Assistant Professor of Biology

Department of Science and Mathematics

University of South Carolina Beaufort

One Univeristy Boulevard

Bluffton, SC  29909

 

Office Phone: (843) 208-8107

Fax: (843) 208-8294

Email: emontie at uscb.edu

 

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