Coupling Active Hair Bundle Mechanics, Fast Adaptation, and Somatic Motility in a Cochlear Model

Meaud, Julien; Grosh, Karl

doi:10.1016/j.bpj.2011.04.049

Cited by 46 publications

(51 citation statements)

References 53 publications

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“…In agreement with previous calculations [9,12], most of the power gain stems from coupling between somatic motility and the endocochlear potential and outer-hair-cell resting potential. Our analysis clarifies the role of the cochlear active process and offers an explanation for its mechanism.…”

Section: Discussionsupporting

confidence: 91%

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Vibrational modes and damping in the cochlear partition

Maoiléidigh¹,

Hudspeth²

2015

AIP Conference Proceedings

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Abstract. It has been assumed in models of cochlear mechanics that the primary role of the cochlear active process is to counteract the damping of the basilar membrane, the vibration of which is much larger in a living animal than post mortem. Recent measurements of the relative motion between the reticular lamina and basilar membrane imply that this assumption is incorrect. We propose that damping is distributed throughout the cochlear partition rather than being concentrated in the basilar membrane. In the absence of significant damping, the cochlear partition possesses three modes of vibration, each associated with its own locus of Hopf bifurcations. Hair-cell activity can amplify any of these modes if the system's operating point lies near the corresponding bifurcation. The distribution of damping determines which mode of vibration predominates. For physiological levels of damping, only one mode produces a vibration pattern consistent with experimental measurements of relative motion and basilar-membrane motion.

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Section: Discussionsupporting

confidence: 91%

“…Owing to the complexity of cochlear mechanics, detailed physiological models of active and nonlinear cochlear mechanics contain many poorly constrained parameter values; such models might therefore overfit the experimental data [9,10,13]. A second difficulty lies in interpreting such models: their complexity obscures their mechanism.…”

Section: Introductionmentioning

confidence: 99%

Vibrational modes and damping in the cochlear partition

Maoiléidigh¹,

Hudspeth²

2015

AIP Conference Proceedings

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“…Note that even when hair-bundle forcing is included in the model, the coupling is still not symmetric. 29 The group delay from the internal force to the stapes at the $10 kHz best frequency of an active cochlea (100 Hz frequency resolution) is 0.895 ms [computed from a derivative of the phase of the transfer function in the frequency domain (not shown)]. This is less than the 1.12 ms forward group delay from the acoustic stimulation to the BM at 6.5 mm (figure not shown).…”

Section: A Reciprocity and Traveling Timesmentioning

confidence: 95%

“…stiffness of the round window, we use 1.8 Â 10 3 N/m 3 (4 orders less than the value in Wit et al 27 ), which is essentially a pressure release condition. 29 the MET sensitivity is a parameter which is adjusted according to the model predictions' match to experimental data. When the most suitable value (based on experimental data) of the MET sensitivity is determined, the cochlea is labeled as "fully active," corresponding to a healthy cochlea or responses to low level sounds.…”

Section: Model Descriptionmentioning

confidence: 99%

Direction of wave propagation in the cochlea for internally excited basilar membrane

Grosh

2012

The Journal of the Acoustical Society of America

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Otoacoustic emissions are an indicator of a normally functioning cochlea and as such are a useful tool for non-invasive diagnosis as well as for understanding cochlear function. While these emitted waves are hypothesized to arise from active processes and exit through the cochlear fluids, neither the precise mechanism by which these emissions are generated nor the transmission pathway is completely known. With regard to the acoustic pathway, two competing hypotheses exist to explain the dominant mode of emission. One hypothesis, the backward-traveling wave hypothesis, posits that the emitted wave propagates as a coupled fluid-structure wave while the alternate hypothesis implicates a fast, compressional wave in the fluid as the main mechanism of energy transfer. In this paper, we study the acoustic pathway for transmission of energy from the inside of the cochlea to the outside through a physiologically-based theoretical model. Using a well-defined, compact source of internal excitation, we predict that the emission is dominated by a backward traveling fluid-structure wave. However, in an active model of the cochlea, a forward traveling wave basal to the location of the force is possible in a limited region around the best place. Finally, the model does predict the dominance of compressional waves under a different excitation, such as an apical excitation.

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“…The past decade has brought remarkable advances in the understanding of the micromechanics of the auditory system and its components (Barral and Martin 2011;Brownell et al 2011;Cheatham and Dallos 2000;Dong and Olson 2009;Eiber 2008;Elliott et al 2007Elliott et al , 2011Eze and Olson 2011;Fettiplace 2006;Fisher et al 2012;Gao et al 2013;Gavara and Chadwick 2009;Gavara et al 2011;Gu et al 2008;He et al 2008;Hemila et al 2010;Hong and Freeman 2006;Jacob et al 2009;Kapadia and Lutman 2000;Kitani et al 2011;Kolston 2000;Grosh 2011, Meaud andGrosh 2010;Naidu and Mountain 2007;Nam and Fettiplace 2012;Ren and Nuttall 2000;Rhode 2007;Santos-Sacchi 2008;Van Dijk et al 2011;Zhang et al 2007;Zheng et al 2007). Quantitative descriptions of basilar membrane motion patterns are available for the base and the apex of the mammalian cochlea (e.g., Olson et al 2012;Robles and Ruggero 2001).…”

Section: Introductionmentioning

confidence: 99%

Basilar Membrane and Tectorial Membrane Stiffness in the CBA/CaJ Mouse

Teudt

Richter

2014

JARO

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The mouse has become an important animal model in understanding cochlear function. Structures, such as the tectorial membrane or hair cells, have been changed by gene manipulation, and the resulting effect on cochlear function has been studied. To contrast those findings, physical properties of the basilar membrane (BM) and tectorial membrane (TM) in mice without gene mutation are of great importance. Using the hemicochlea of CBA/CaJ mice, we have demonstrated that tectorial membrane (TM) and basilar membrane (BM) revealed a stiffness gradient along the cochlea. While a simple spring mass resonator predicts the change in the characteristic frequency of the BM, the spring mass model does not predict the frequency change along the TM. Plateau stiffness values of the TM were 0.6±0.5, 0.2± 0.1, and 0.09±0.09 N/m for the basal, middle, and upper turns, respectively. The BM plateau stiffness values were 3.7±2.2, 1.2±1.2, and 0.5±0.5 N/m for the basal, middle, and upper turns, respectively. Estimations of the TM Young's modulus (in kPa) revealed 24.3±25.2 for the basal turns, 5.1±4.5 for the middle turns, and 1.9±1.6 for the apical turns. Young's modulus determined at the BM pectinate zone was 76.8±72, 23.9±30.6, and 9.4±6.2 kPa for the basal, middle, and apical turns, respectively. The reported stiffness values of the CBA/CaJ mouse TM and BM provide basic data for the physical properties of its organ of Corti.

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Coupling Active Hair Bundle Mechanics, Fast Adaptation, and Somatic Motility in a Cochlear Model

Cited by 46 publications

References 53 publications

Vibrational modes and damping in the cochlear partition

Vibrational modes and damping in the cochlear partition

Direction of wave propagation in the cochlea for internally excited basilar membrane

Basilar Membrane and Tectorial Membrane Stiffness in the CBA/CaJ Mouse

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