Archives—October 2010

Keat Ghee Ong Receives 3M Nontenured Faculty Award

Keat Ghee Ong, an assistant professor in the Department of Biomedical Engineering, has received 3M Nontenured Faculty Awards in 2009 and 2010 to support his research on wireless implantable sensor technologies. The award, which is nominated by 3M researchers working on research topics that are of interest to 3M, is currently sponsored by Jim Vanous of SEMS Electronics Applications group.

First in vivo Measurement of Differential Motion in the Guinea Cochlea

Monday, October 4
211 Chemical Sciences Building
3:00 pm

Presenter: Niloy Choudhury, Ph.D., Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon

Abstract: Auditory response in mammals depends upon an amplifying mechanism which hypothetically uses forces from outer hair cell (OHC) motility to enhance sound-induced vibration of the organ of Corti in the cochlea. Differential motion among key structures in this organ and proper timing of OHC force generation are essential to this hypothesis.  An optical coherence tomography (OCT) system was designed and built to image the microstructures and measure mechanical vibrations at different cellular structures in the guinea pig cochlea.  The traditional OCT system was modified to  allow measure of nanometer scale vibration motion.  The new scheme  allows quantitative values for phase and amplitude vibration in the presence of bulk animal motion.  The engineering of the system as well as the first ever  in vivo measurements of differential motion of two functionally important structures in the organ of Corti, the basilar membrane and reticular lamina, will be presented.  Results show that the reticular lamina vibrates at a greater magnitude than the basilar membrane and has a significant phase lead.  Similar phase relation between OHC receptor potentials and basilar membrane motion were observed. These results demonstrate that a powerful enhancement of vibration occurs at the apical surface of sensory hair cells and that  OHC force generation is optimally timed for counteracting viscosity-related energy loss.