Vibration of the organ of Corti within the cochlear apex in mice

Simon S. Gao, Rosalie Wang, Patrick D. Raphael, Yalda Moayedi, Andrew K. Groves, Jian Zuo, Brian E. Applegate, John S. Oghalai

Research output: Contribution to journalArticlepeer-review


The tonotopic map of the mammalian cochlea is commonly thought to be determined by the passive mechanical properties of the basilar membrane. The other tissues and cells that make up the organ of Corti also have passive mechanical properties; however, their roles are less well understood. In addition, active forces produced by outer hair cells (OHCs) enhance the vibration of the basilar membrane, termed cochlear amplification. Here, we studied how these biomechanical components interact using optical coherence tomography, which permits vibratory measurements within tissue. We measured not only classical basilar membrane tuning curves, but also vibratory responses from the rest of the organ of Corti within the mouse cochlear apex in vivo. As expected, basilar membrane tuning was sharp in live mice and broad in dead mice. Interestingly, the vibratory response of the region lateral to the OHCs, the "lateral compartment," demonstrated frequency-dependent phase differences relative to the basilar membrane. This was sharply tuned in both live and dead mice. We then measured basilar membrane and lateral compartment vibration in transgenic mice with targeted alterations in cochlear mechanics. Prestin499/499, Prestin-/-, and TectaC1509G/C1509G mice demonstrated no cochlear amplification but maintained the lateral compartment phase difference. In contrast, SfswapTg/Tg mice maintained cochlear amplification but did not demonstrate the lateral compartment phase difference. These data indicate that the organ of Corti has complex micromechanical vibratory characteristics, with passive, yet sharply tuned, vibratory characteristics associated with the supporting cells. These characteristics may tune OHC force generation to produce the sharp frequency selectivity of mammalian hearing.

Original languageEnglish (US)
Pages (from-to)1192-1204
Number of pages13
JournalJournal of neurophysiology
Issue number5
StatePublished - Sep 1 2014


  • Biomechanics
  • Cochlea
  • Cochlear amplifier
  • Electromotility
  • Hair cell
  • Hearing
  • Hearing loss

ASJC Scopus subject areas

  • General Neuroscience
  • Physiology


Dive into the research topics of 'Vibration of the organ of Corti within the cochlear apex in mice'. Together they form a unique fingerprint.

Cite this