Feature Of The Week 5/27/11: Researchers Utilize Optical Coherence Tomography to Perform in vivo Investigation into the Process of Hearing
A multidisciplinary research groups spanning several countries (USA, China, Sweden) are using optical coherence tomography (OCT) to investigate minute changes in hair cells within the cochlea - the auditory portion of the inner ear. Below is a summary of their work.
Mammalian hearing is refined by amplification of the sound-evoked vibration of the cochlear partition. This amplification is at least partly due to forces produced by protein motors residing in the cylindrical body of the outer hair cell. To transmit power to the cochlear partition, it is required that the outer hair cells dynamically change their length, in addition to generating force. These length changes, which have not previously been measured in vivo, must be correctly timed with the acoustic stimulus to produce amplification. Using in vivo optical coherence tomography, we demonstrate that outer hair cells in living guinea pigs have length changes with unexpected timing and magnitudes that depend on the stimulus level in the sensitive cochlea. The level-dependent length change is a necessary condition for directly validating that power is expended by the active process presumed to underlie normal hearing.
For more information see recent Article. Courtesy Fangyi Chen and Alfred Nuttall from the Oregon Health & Science University.