报告题目: |
Measurement of the differential motion inside the organ of Corti in vivo |
报告人: |
Fangyi Chen |
|
PhD
Research Associate/ Engineer
Oregon Health and Science University, USA
|
报告时间: |
2011-09-05 14:00 |
报告地点: |
医学科学楼B321 |
主办单位: |
医学院 |
简介: |
Mechanical process inside the cochlea is the fundamental component of the auditory signal processing. It contributes mostly to the high sensitivity, wide dynamic range and wide frequency range of the hearing. Recent efforts in cochlear mechanics have been focused in understanding the so-called cochlear amplification, which was widely assumed as the mechanism for the cochlea to detect the extremely weak sound (as low as 20 uPa). The outer hair cell, the potential candidate for the cochlear amplifier, is largely believed to cause differential motion inside the organ of Corti. Although tremendous studies have been performed to investigate the differential motion, they are mostly performed in vitro due to the technical difficulties. The extreme vulnerability of the hearing sensitivity requires these results to be testified with in vivo studies. So far, the in vivo study of the organ of Corti motion has been limited to the first surface on the optical access path, which is basilar membrane (BM) at the base and reticular lamina (RL) at the apex of the cochlea. With the recent developed low coherence interferometer, we, for the first time, demonstrated the differential motion of the organ of Corti in vivo. The results showed that vibration of the reticular lamina (RL), the top surface of the organ of Corti, leads that of the basilar membrane (RL), the bottom surface; and RL tuned to a higher frequency. This result contradicts to the previous data from in vitro studies. More importantly, the phase difference between RL and BM is about 90 degrees, rather than 180 degrees, as widely expected. This 90 degree difference suggests that the outer hair cell may contribute to the cochlear amplification in a more complicated manner. |
|
