Non-invasive biophysical measurement of travelling waves in the insect inner ear

Publication Type:Journal Article
Year of Publication:2017
Authors:Sarria-S, FA, Chivers, BD, Soulsbury, CD, Montealegre-Z, F
Journal:Royal Society Open Science
Volume:4
Issue:5
Pagination:170171
Date Published:Jul-18-20172018
Abstrakt:

Frequency analysis in the mammalian cochlea depends on the propagation of frequency information in the form of a travelling wave (TW) across tonotopically arranged auditory sensilla. TWs have been directly observed in the basilar papilla of birds and the ears of bush-crickets (Insecta: Orthoptera) and have also been indirectly inferred in the hearing organs of some reptiles and frogs. Existing experimental approaches to measure TW function in tetrapods and bush-crickets are inherently invasive, compromising the fine-scale mechanics of each system. Located in the forelegs, the bush-cricket ear exhibits outer, middle and inner components; the inner ear containing tonotopically arranged auditory sensilla within a fluid-filled cavity, and externally protected by the leg cuticle. Here, we report bush-crickets with transparent ear cuticles as potential model species for direct, non-invasive measuring of TWs and tonotopy. Using laser Doppler vibrometry and spectroscopy, we show that increased transmittance of light through the ear cuticle allows for effective non-invasive measurements of TWs and frequency mapping. More transparent cuticles allow several properties of TWs to be precisely recovered and measured in vivo from intact specimens. Our approach provides an innovative, non-invasive alternative to measure the natural motion of the sensilla-bearing surface embedded in the intact inner ear fluid.

URL:http://rsos.royalsocietypublishing.org/lookup/doi/10.1098/rsos.170171https://syndication.highwire.org/content/doi/10.1098/rsos.170171
DOI:10.1098/rsos.170171
Short Title:R. Soc. open sci.
Non biological: 
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith