Subject: Re: [AUDITORY] Question regarding periodicity in the cochlea From: Andrew Bell <000002410d984f20-dmarc-request@xxxxxxxx> Date: Tue, 14 Nov 2023 21:48:20 +0000--_004_SYYP282MB1615148DD20A500E3AC29442C2B2ASYYP282MB1615AUSP_ Content-Type: multipart/alternative; boundary="_000_SYYP282MB1615148DD20A500E3AC29442C2B2ASYYP282MB1615AUSP_" --_000_SYYP282MB1615148DD20A500E3AC29442C2B2ASYYP282MB1615AUSP_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hello Mathieu: Interesting question. I think the strict spacing of the OHCs is to allow th= e system to be acoustically tuned. Indeed, in my PhD thesis I developed the= idea that the three rows of OHCs is equivalent to a three-finger surface a= coustic wave (SAW) resonator, which seems to come close to what you are wor= king on. The reference is Bell, A. (2005) The underwater piano: A resonance= theory of cochlear mechanics. PhD thesis, Australian National University, = Canberra. https://dx.doi.org/10.25911/5d7a2c6dcff7f A more elaborate and mathematical approach is that of Bryn Davies, who thin= ks the cochlea is a graded metamaterial that acts like an acoustic rainbow = sensor. Have a look at his recent papers listed at https://www.imperial.ac.= uk/people/bryn.davies. He has also recently published a book on the subject= with Habib Ammari: "Metamaterial Analysis and Design: A Mathematical Treat= ment of Cochlea-inspired Sensors" (de Gruyter Applied and Numerical Mathema= tics). Best wishes for your PhD. Andrew. Andrew Bell Eccles Division of Neuroscience John Curtin School of Medical Research The Australian National University Canberra, ACT, Australia From: AUDITORY - Research in Auditory Perception <AUDITORY@xxxxxxxx>= On Behalf Of Mathieu Fran=E7ois Padlewski Sent: Tuesday, November 14, 2023 3:23 AM To: AUDITORY@xxxxxxxx Subject: Question regarding periodicity in the cochlea Dear all, I am a PhD student with a solid-state physics background and am currently w= orking with systems involving periodic structures of active acoustic resona= tors (- a topic completely tangential to this field indeed). Long story short, I coincidentally stumbled upon an electron microscope ima= ge of the cochlea and couldn't help but notice the remarkable periodic stru= cture of the outer hair cells. In solids (and other crystal systems), it tu= rns out that periodicity is key in understanding its conducting and insulat= ing properties. I was wondering if the periodicity of the hair cells been considered to exp= lain phenomena such as tinnitus, tuning curves, nonlinearity, etc... If so,= could anyone provide the relevant literature? Thanks in advance! With kind regards, Mathieu Padlewski [EPFL logo]<https://www.epfl.ch/> Mathieu Padlewski Doctoral Assistant Signal Processing Laboratory - Acoustics EPFL STI IEM LWE ELB 032<https://plan.epfl.ch/?dim_floor=3D0&lang=3Den&dim_lang=3Den&tree_gr= oups=3Dcentres_nevralgiques%2Cacces%2Cmobilite_reduite%2Censeignement%2Ccom= merces_et_services%2Cvehicules%2Cinfrastructure_plan_grp&tree_group_layers_= centres_nevralgiques=3Dinformation_epfl%2Cguichet_etudiants&tree_group_laye= rs_acces=3Dmetro&tree_group_layers_mobilite_reduite=3D&tree_group_layers_en= seignement=3D&tree_group_layers_commerces_et_services=3D&tree_group_layers_= vehicules=3D&tree_group_layers_infrastructure_plan_grp=3Dbatiments_query_pl= an&baselayer_ref=3Dgrp_backgrounds&map_x=3D2532952&map_y=3D1152392&map_zoom= =3D14> (B=E2timent ELB) Station 11 CH-1015 Lausanne Phone: +41 21 693 98 72<tel:+41216939872> Mobile: +41 76 201 06 30<tel:+41762010630> --_000_SYYP282MB1615148DD20A500E3AC29442C2B2ASYYP282MB1615AUSP_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <html> <head> <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Diso-8859-= 1"> <meta name=3D"Generator" content=3D"Microsoft Word 15 (filtered medium)"> <!--[if !mso]><style>v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} </style><![endif]--><style><!-- /* Font Definitions */ @xxxxxxxx {font-family:Helvetica; panose-1:2 11 6 4 2 2 2 2 2 4;} @xxxxxxxx {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4;} @xxxxxxxx {font-family:Calibri; panose-1:2 15 5 2 2 2 4 3 2 4;} @xxxxxxxx {font-family:"Segoe UI"; panose-1:2 11 5 2 4 2 4 2 2 3;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {margin:0cm; font-size:11.0pt; font-family:"Calibri",sans-serif;} a:link, span.MsoHyperlink {mso-style-priority:99; color:#0563C1; text-decoration:underline;} span.EmailStyle20 {mso-style-type:personal-reply; font-family:"Calibri",sans-serif; color:windowtext;} span.EmailStyle21 {mso-style-type:personal; font-family:"Calibri",sans-serif; color:windowtext;} .MsoChpDefault {mso-style-type:export-only; font-size:10.0pt; mso-ligatures:none;} @xxxxxxxx WordSection1 {size:612.0pt 792.0pt; margin:72.0pt 72.0pt 72.0pt 72.0pt;} div.WordSection1 {page:WordSection1;} --></style><!--[if gte mso 9]><xml> <o:shapedefaults v:ext=3D"edit" spidmax=3D"1026" /> </xml><![endif]--><!--[if gte mso 9]><xml> <o:shapelayout v:ext=3D"edit"> <o:idmap v:ext=3D"edit" data=3D"1" /> </o:shapelayout></xml><![endif]--> </head> <body lang=3D"EN-AU" link=3D"#0563C1" vlink=3D"#954F72" style=3D"word-wrap:= break-word"> <div class=3D"WordSection1"> <p class=3D"MsoNormal"><span style=3D"mso-fareast-language:EN-US">Hello Mat= hieu:<o:p></o:p></span></p> <p class=3D"MsoNormal"><span style=3D"mso-fareast-language:EN-US"><o:p>&nbs= p;</o:p></span></p> <p class=3D"MsoNormal"><span style=3D"mso-fareast-language:EN-US">Interesti= ng question. I think the strict spacing of the OHCs is to allow the system = to be acoustically tuned. Indeed, in my PhD thesis I developed the idea tha= t the three rows of OHCs is equivalent to a three-finger surface acoustic wave (SAW) resonator, which seems to co= me close to what you are working on. The reference is </span>Bell, A. (2005) The underwater piano: A resonance theory of cochlear= mechanics. PhD thesis, Australian National University, Canberra. <span style=3D"color:blue"><a href=3D"https://dx.doi.org/10.25911/5d7a2c6dc= ff7f">https://dx.doi.org/10.25911/5d7a2c6dcff7f</a></span><o:p></o:p></p> <p class=3D"MsoNormal"><o:p> </o:p></p> <p class=3D"MsoNormal">A more elaborate and mathematical approach is that o= f Bryn Davies, who thinks the cochlea is a graded metamaterial that acts li= ke an acoustic rainbow sensor. Have a look at his recent papers listed at <a href=3D"https://www.imperial.ac.uk/people/bryn.davies">https://www.imper= ial.ac.uk/people/bryn.davies</a>. He has also recently published a book on = the subject with Habib Ammari: “Metamaterial Analysis and Design: A M= athematical Treatment of Cochlea-inspired Sensors” (de Gruyter Applied and Numerical Mathematics).<o:p></o:p><= /p> <p class=3D"MsoNormal"><o:p> </o:p></p> <p class=3D"MsoNormal">Best wishes for your PhD.<o:p></o:p></p> <p class=3D"MsoNormal"><o:p> </o:p></p> <p class=3D"MsoNormal"><o:p> </o:p></p> <p class=3D"MsoNormal">Andrew.<o:p></o:p></p> <p class=3D"MsoNormal"><o:p> </o:p></p> <p class=3D"MsoNormal"><o:p> </o:p></p> <p class=3D"MsoNormal"><i><span style=3D"color:#4472C4">Andrew Bell<o:p></o= :p></span></i></p> <p class=3D"MsoNormal"><i><span style=3D"color:#4472C4">Eccles Division of = Neuroscience<o:p></o:p></span></i></p> <p class=3D"MsoNormal"><i><span style=3D"color:#4472C4">John Curtin School = of Medical Research<o:p></o:p></span></i></p> <p class=3D"MsoNormal"><i><span style=3D"color:#4472C4">The Australian Nati= onal University<o:p></o:p></span></i></p> <p class=3D"MsoNormal"><i><span style=3D"color:#4472C4">Canberra, ACT, Aust= ralia</span></i><span style=3D"color:#4472C4"><o:p></o:p></span></p> <p class=3D"MsoNormal"><o:p> </o:p></p> <p class=3D"MsoNormal"><span style=3D"mso-fareast-language:EN-US"><o:p>&nbs= p;</o:p></span></p> <p class=3D"MsoNormal"><span style=3D"mso-fareast-language:EN-US"><o:p>&nbs= p;</o:p></span></p> <div> <div style=3D"border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm = 0cm 0cm"> <p class=3D"MsoNormal"><b><span lang=3D"EN-US">From:</span></b><span lang= =3D"EN-US"> AUDITORY - Research in Auditory Perception <AUDITORY@xxxxxxxx= CGILL.CA> <b>On Behalf Of </b>Mathieu Fran=E7ois Padlewski<br> <b>Sent:</b> Tuesday, November 14, 2023 3:23 AM<br> <b>To:</b> AUDITORY@xxxxxxxx<br> <b>Subject:</b> Question regarding periodicity in the cochlea<o:p></o:p></s= pan></p> </div> </div> <p class=3D"MsoNormal"><o:p> </o:p></p> <table class=3D"MsoNormalTable" border=3D"0" cellspacing=3D"0" cellpadding= =3D"0" align=3D"left" width=3D"100%" style=3D"width:100.0%"> <tbody> <tr> <td style=3D"background:#A6A6A6;padding:5.25pt 1.5pt 5.25pt 1.5pt"> <p class=3D"MsoNormal" style=3D"mso-element:frame;mso-element-frame-hspace:= 2.25pt;mso-element-wrap:around;mso-element-anchor-vertical:paragraph;mso-el= ement-anchor-horizontal:column;mso-height-rule:exactly"> <span style=3D"font-size:10.0pt"><o:p> </o:p></span></p> </td> <td width=3D"100%" style=3D"width:100.0%;background:#EAEAEA;padding:5.25pt = 3.75pt 5.25pt 11.25pt"> <div> <p class=3D"MsoNormal" style=3D"mso-element:frame;mso-element-frame-hspace:= 2.25pt;mso-element-wrap:around;mso-element-anchor-vertical:paragraph;mso-el= ement-anchor-horizontal:column;mso-height-rule:exactly"> <span style=3D"font-size:9.0pt;font-family:"Segoe UI",sans-serif;= color:#212121"><o:p> </o:p></span></p> </div> </td> <td width=3D"75" style=3D"width:56.25pt;background:#EAEAEA;padding:5.25pt 3= .75pt 5.25pt 3.75pt;align:left"> </td> </tr> </tbody> </table> <div> <p class=3D"MsoNormal"><span lang=3D"EN-US">Dear all,<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US"> <o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US">I am a PhD student with a solid= -state physics background and am currently working with systems involving p= eriodic structures of active acoustic resonators (- a topic completel= y tangential to this field indeed). <o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US"> <o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US">Long story short, I coincidenta= lly stumbled upon an electron microscope image of the cochlea and couldn't = help but notice the remarkable periodic structure of the outer hair cells. = In solids (and other <i>crystal</i> systems), it turns out that periodicity is key in understand= ing its conducting and insulating properties.<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US"> <o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US">I was wondering if the periodic= ity of the hair cells been considered to explain phenomena such as tinnitus= , tuning curves, nonlinearity, etc… If so, could anyone provide the r= elevant literature?<br> <br> Thanks in advance!<br> <br> With kind regards,<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US">Mathieu Padlewski<o:p></o:p></s= pan></p> <p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-US"><o:p> </o:p></span></p> <table class=3D"MsoNormalTable" border=3D"0" cellspacing=3D"0" cellpadding= =3D"0" width=3D"500" style=3D"width:375.0pt"> <tbody> <tr style=3D"height:15.0pt"> <td width=3D"80" style=3D"width:60.0pt;padding:0cm 0cm 0cm 0cm;height:15.0p= t"> <p class=3D"MsoNormal"><a href=3D"https://www.epfl.ch/"><span style=3D"font= -size:13.5pt;font-family:"Times New Roman",serif;color:red;text-d= ecoration:none"><img border=3D"0" width=3D"100" height=3D"34" style=3D"widt= h:1.0416in;height:.3541in" id=3D"Picture_x0020_1" src=3D"cid:image001.png@xxxxxxxx= 1DA17A0.7BBC11A0" alt=3D"EPFL logo"></span></a><span style=3D"font-size:13.= 5pt;font-family:"Times New Roman",serif;color:black"><o:p></o:p><= /span></p> </td> </tr> <tr style=3D"height:37.5pt"> <td style=3D"padding:0cm 0cm 0cm 0cm;height:37.5pt"> <p class=3D"MsoNormal"><b><span style=3D"font-size:10.0pt;font-family:"= ;Helvetica",sans-serif;color:#707070"><o:p> </o:p></span></b></p> <p class=3D"MsoNormal"><b><span style=3D"font-size:10.0pt;font-family:"= ;Helvetica",sans-serif;color:#707070">Mathieu Padlewski</span></b><spa= n style=3D"font-size:10.0pt;font-family:"Helvetica",sans-serif;co= lor:#707070"><br> <i>Doctoral Assistant<o:p></o:p></i></span></p> <p class=3D"MsoNormal"><i><span style=3D"font-size:10.0pt;font-family:"= ;Helvetica",sans-serif;color:#707070">Signal Processing Laboratory - 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