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Sci Rep. 2014 Aug 4;4:5941. doi: 10.1038/srep05941.

Light-induced vibration in the hearing organ.

Author information

1
Oregon Hearing Research Center, Department of Otolaryngology, Oregon Health &Science University, Portland, Oregon 97239, USA.
2
Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.
3
1] Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA [2] Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.
4
1] Department of Clinical and Experimental Medicine, Linköping University, 581 85 Linköping, Sweden [2] Center for Hearing and Communication Research, Department of Clinical Science, Intervention, and Technology, Karolinska Institutet, Stockholm, Sweden.

Abstract

The exceptional sensitivity of mammalian hearing organs is attributed to an active process, where force produced by sensory cells boost sound-induced vibrations, making soft sounds audible. This process is thought to be local, with each section of the hearing organ capable of amplifying sound-evoked movement, and nearly instantaneous, since amplification can work for sounds at frequencies up to 100 kHz in some species. To test these fundamental precepts, we developed a method for focally stimulating the living hearing organ with light. Light pulses caused intense and highly damped mechanical responses followed by traveling waves that developed with considerable delay. The delayed response was identical to movements evoked by click-like sounds. This shows that the active process is neither local nor instantaneous, but requires mechanical waves traveling from the cochlear base toward its apex. A physiologically-based mathematical model shows that such waves engage the active process, enhancing hearing sensitivity.

PMID:
25087606
PMCID:
PMC4120310
DOI:
10.1038/srep05941
[Indexed for MEDLINE]
Free PMC Article

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