Porosity Controls Spread of Excitation in Tectorial Membrane Traveling Waves
Cochlear frequency selectivity plays a key role in our ability to understand speech, and is widely believed to be associated with cochlear amplification. However, genetic studies targeting the tectorial membrane (TM) have demonstrated both sharper and broader tuning with no obvious changes in hair b...
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| Format: | Article |
| Language: | en_US |
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Elsevier
2014
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| Online Access: | http://hdl.handle.net/1721.1/86142 https://orcid.org/0000-0003-0622-1333 https://orcid.org/0000-0001-6309-0910 https://orcid.org/0000-0003-3369-5067 |
| _version_ | 1811070924253822976 |
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| author | Ghaffari, Roozbeh Farrahi, Shirin Richardson, Guy P. Freeman, Dennis M. Sellon, Jonathan Blake |
| author2 | Whitaker College of Health Sciences and Technology |
| author_facet | Whitaker College of Health Sciences and Technology Ghaffari, Roozbeh Farrahi, Shirin Richardson, Guy P. Freeman, Dennis M. Sellon, Jonathan Blake |
| author_sort | Ghaffari, Roozbeh |
| collection | MIT |
| description | Cochlear frequency selectivity plays a key role in our ability to understand speech, and is widely believed to be associated with cochlear amplification. However, genetic studies targeting the tectorial membrane (TM) have demonstrated both sharper and broader tuning with no obvious changes in hair bundle or somatic motility mechanisms. For example, cochlear tuning of Tectb[superscript –/–] mice is significantly sharper than that of Tecta[superscript Y1870C/+] mice, even though TM stiffnesses are similarly reduced relative to wild-type TMs. Here we show that differences in TM viscosity can account for these differences in tuning. In the basal cochlear turn, nanoscale pores of Tecta[superscript Y1870C/+] TMs are significantly larger than those of Tectb[superscript –/–] TMs. The larger pore size reduces shear viscosity (by ∼70%), thereby reducing traveling wave speed and increasing spread of excitation. These results demonstrate the previously unrecognized importance of TM porosity in cochlear and neural tuning. |
| first_indexed | 2024-09-23T08:43:49Z |
| format | Article |
| id | mit-1721.1/86142 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T08:43:49Z |
| publishDate | 2014 |
| publisher | Elsevier |
| record_format | dspace |
| spelling | mit-1721.1/861422022-09-23T14:07:36Z Porosity Controls Spread of Excitation in Tectorial Membrane Traveling Waves Ghaffari, Roozbeh Farrahi, Shirin Richardson, Guy P. Freeman, Dennis M. Sellon, Jonathan Blake Whitaker College of Health Sciences and Technology Harvard University--MIT Division of Health Sciences and Technology Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology. Research Laboratory of Electronics Sellon, Jonathan Blake Ghaffari, Roozbeh Farrahi, Shirin Freeman, Dennis M. Cochlear frequency selectivity plays a key role in our ability to understand speech, and is widely believed to be associated with cochlear amplification. However, genetic studies targeting the tectorial membrane (TM) have demonstrated both sharper and broader tuning with no obvious changes in hair bundle or somatic motility mechanisms. For example, cochlear tuning of Tectb[superscript –/–] mice is significantly sharper than that of Tecta[superscript Y1870C/+] mice, even though TM stiffnesses are similarly reduced relative to wild-type TMs. Here we show that differences in TM viscosity can account for these differences in tuning. In the basal cochlear turn, nanoscale pores of Tecta[superscript Y1870C/+] TMs are significantly larger than those of Tectb[superscript –/–] TMs. The larger pore size reduces shear viscosity (by ∼70%), thereby reducing traveling wave speed and increasing spread of excitation. These results demonstrate the previously unrecognized importance of TM porosity in cochlear and neural tuning. National Institutes of Health (U.S.) (Grant R01-DC00238) National Science Foundation (U.S.). Graduate Research Fellowship Program (Grant 1122374) National Institutes of Health (U.S.) (Training Grant) 2014-04-14T13:43:33Z 2014-04-14T13:43:33Z 2014-03 2013-09 Article http://purl.org/eprint/type/JournalArticle 00063495 1542-0086 http://hdl.handle.net/1721.1/86142 Sellon, Jonathan B., Roozbeh Ghaffari, Shirin Farrahi, Guy P. Richardson, and Dennis M. Freeman. “Porosity Controls Spread of Excitation in Tectorial Membrane Traveling Waves.” Biophysical Journal 106, no. 6 (March 2014): 1406–1413. https://orcid.org/0000-0003-0622-1333 https://orcid.org/0000-0001-6309-0910 https://orcid.org/0000-0003-3369-5067 en_US http://dx.doi.org/10.1016/j.bpj.2014.02.012 Biophysical Journal Creative Commons Attribution‐NonCommercial License http://creativecommons.org/licenses/by/2.0/uk application/pdf Elsevier Elsevier Open Access |
| spellingShingle | Ghaffari, Roozbeh Farrahi, Shirin Richardson, Guy P. Freeman, Dennis M. Sellon, Jonathan Blake Porosity Controls Spread of Excitation in Tectorial Membrane Traveling Waves |
| title | Porosity Controls Spread of Excitation in Tectorial Membrane Traveling Waves |
| title_full | Porosity Controls Spread of Excitation in Tectorial Membrane Traveling Waves |
| title_fullStr | Porosity Controls Spread of Excitation in Tectorial Membrane Traveling Waves |
| title_full_unstemmed | Porosity Controls Spread of Excitation in Tectorial Membrane Traveling Waves |
| title_short | Porosity Controls Spread of Excitation in Tectorial Membrane Traveling Waves |
| title_sort | porosity controls spread of excitation in tectorial membrane traveling waves |
| url | http://hdl.handle.net/1721.1/86142 https://orcid.org/0000-0003-0622-1333 https://orcid.org/0000-0001-6309-0910 https://orcid.org/0000-0003-3369-5067 |
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