Multiple roles for the tectorial membrane in the active cochlea

Lukashkin, Andrei N.; Richardson, Guy P.; Russell, Ian J.

doi:10.1016/j.heares.2009.10.005

Cited by 58 publications

(54 citation statements)

References 103 publications

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“…This change could reflect variations in the volume of the subtectorial space and adjustment of the IHC bundle height for optimization of the fluid flow between the tectorial membrane and the SBs (for review see Lukashkin et al 2010). …”

Section: Tonotopic Variations Of the Zones Of Lamina Reticularis And mentioning

confidence: 99%

Tonotopic Morphometry of the Lamina Reticularis of the Guinea Pig Cochlea with Associated Microstructures and Related Mechanical Implications

Yarin

Lukashkin

Poznyakovskiy

et al. 2013

JARO

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Morphometry of the lamina reticularis of the guinea pig cochlea was performed using scanning electron microscopy. Seventy-four geometrical parameters of the lamina reticularis, the bundles of stereocilia, and individual stereocilia, in all rows of hair cells and within the individual hair cells, were measured at ten equally spaced locations along the longitudinal direction of the cochlea. Variations of the parameters versus the longitudinal coordinate were statistically analyzed and fitted with polynomials (constant, linear, or quadratic). Our data show that a unique set of geometrical parameters of inner and outer hair cells is typical for every frequency-dependent position at the lamina reticularis. Morphology of the outer hair cell structures varies more than respective parameters of the inner hair cells. Mechanical modeling using the obtained geometrical parameters provides a novel glance at the mechanical characteristics with respect to the cochlear tonotopy.

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Section: Tonotopic Variations Of the Zones Of Lamina Reticularis And mentioning

confidence: 99%

Tonotopic Morphometry of the Lamina Reticularis of the Guinea Pig Cochlea with Associated Microstructures and Related Mechanical Implications

Yarin

Lukashkin

Poznyakovskiy

et al. 2013

JARO

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“…Mutations in Tecta are one of the most common causes of autosomal-dominant, nonsyndromic hereditary hearing loss (20), and mouse models for the recessive (21) and dominant (22) forms of deafness arising from mutations in Tecta have been created. Together with data from a Tectb-null mutant mouse (23), these studies have provided evidence that the TM plays multiple roles in hearing (24). Although much is known about the structure of the TM, an ECM that is unique to the cochlea, relatively little is known about how it attaches to the apical surface of the cochlear epithelium.…”

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confidence: 91%

A mouse model for human deafness DFNB22 reveals that hearing impairment is due to a loss of inner hair cell stimulation

Lukashkin

Legan

Weddell

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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The gene causative for the human nonsyndromic recessive form of deafness DFNB22 encodes otoancorin, a 120-kDa inner ear-specific protein that is expressed on the surface of the spiral limbus in the cochlea. Gene targeting in ES cells was used to create an EGFP knock-in, otoancorin KO (Otoa EGFP/EGFP ) mouse. In the Otoa EGFP/EGFP mouse, the tectorial membrane (TM), a ribbon-like strip of ECM that is normally anchored by one edge to the spiral limbus and lies over the organ of Corti, retains its general form, and remains in close proximity to the organ of Corti, but is detached from the limbal surface. Measurements of cochlear microphonic potentials, distortion product otoacoustic emissions, and basilar membrane motion indicate that the TM remains functionally attached to the electromotile, sensorimotor outer hair cells of the organ of Corti, and that the amplification and frequency tuning of the basilar membrane responses to sounds are almost normal. The compound action potential masker tuning curves, a measure of the tuning of the sensory inner hair cells, are also sharply tuned, but the thresholds of the compound action potentials, a measure of inner hair cell sensitivity, are significantly elevated. These results indicate that the hearing loss in patients with Otoa mutations is caused by a defect in inner hair cell stimulation, and reveal the limbal attachment of the TM plays a critical role in this process.T he sensory epithelium of the cochlea, the organ of Corti ( Fig. 1), contains two types of hair cell, the purely sensory inner hair cells (IHCs) and the electromotile, sensorimotor outer hair cells (OHCs). These cells are critically positioned between two strips of ECM, the basilar membrane (BM) and the tectorial membrane (TM). Signal processing in the cochlea is initiated when sound-induced changes in fluid pressure displace the BM in the transverse direction, causing radial shearing displacements between the surface of the organ of Corti (the reticular lamina) and the overlying TM (1). The radial shear is detected by the hair bundles of the IHCs and the OHCs (2), with the stereocilia of the OHC hair bundles forming an elastic link between the organ of Corti and the overlying TM (3). Deflection of the stereocilia gates the hair cell's mechanoelectrical transducer (MET) channels, thereby initiating a MET current (4) that promotes active mechanical force production by the OHCs, which, in turn, influences mechanical interactions between the TM and the BM (5, 6). This nonlinear frequency-dependent enhancement process, which boosts the sensitivity of cochlear responses to lowlevel sounds and compresses them at high levels, is known as the cochlear amplifier (7).Whereas the hair bundles of the OHCs are imbedded into the TM and therefore directly excited by relative displacement of the undersurface of the TM and the reticular lamina, those of the IHCs are not in direct contact with the TM, and the way in which they are driven by motion of the BM remains unclear. Intracellular recordings of the receptor potent...

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“…1A), an extracellular matrix that is anchored medially to the surface of the spiral limbus and laterally to the tallest stereocilia of the outer hair cells (OHCs). Even though the stereocilia of the cochlear inner hair cells (IHCs) appear to be free standing (Lim 1971;Dallos et al 1972), the TM is also thought to facilitate their stimulation (Dallos et al 1972;Richardson et al 2008;Lukashkin et al 2010). The body of the TM contains collagen fibrils embedded in an unusual striated-sheet matrix, the major components of which are alpha and betatectorin (Tecta and Tectb, respectively) and Ceacam16 (Legan et al 1997;Zheng et al 2011;Kammerer et al 2012;Cheatham et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Increased Spontaneous Otoacoustic Emissions in Mice with a Detached Tectorial Membrane

Cheatham¹,

Ahmad²,

Zhou³

et al. 2015

JARO

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Mutations in genes encoding tectorial membrane (TM) proteins are a significant cause of human hereditary hearing loss , and several mouse models have been developed to study the functional significance of this accessory structure in the mammalian cochlea. In this study, we use otoacoustic emissions (OAE), signals obtained from the ear canal that provide a measure of cochlear function, to characterize a mouse in which the TM is detached from the spiral limbus due to an absence of otoancorin (Otoa, Lukashkin et al. 2012). Our results demonstrate that spontaneous emissions (SOAE), sounds produced in the cochlea without stimulation, increase dramatically in mice with detached TMs even though their hearing sensitivity is reduced. This behavior is unusual because wild-type (WT) controls are rarely spontaneous emitters. SOAEs in mice lacking Otoa predominate around 7 kHz, which is much lower than in either WT animals when they generate SOAEs or in mutant mice in which the TM protein Ceacam16 is absent (Cheatham et al. 2014). Although both mutants lack Hensen's stripe, loss of this TM feature is only observed in regions coding frequencies greater than~15 kHz in WT mice so its loss cannot explain the low-frequency, de novo SOAEs observed in mice lacking Otoa. The fact that~80 % of mice lacking Otoa produce SOAEs even when they generate smaller distortion product OAEs suggests that the active process is still functioning in these mutants but the system(s) involved have become less stable due to alterations in TM structure.

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Multiple roles for the tectorial membrane in the active cochlea

Cited by 58 publications

References 103 publications

Tonotopic Morphometry of the Lamina Reticularis of the Guinea Pig Cochlea with Associated Microstructures and Related Mechanical Implications

Tonotopic Morphometry of the Lamina Reticularis of the Guinea Pig Cochlea with Associated Microstructures and Related Mechanical Implications

A mouse model for human deafness DFNB22 reveals that hearing impairment is due to a loss of inner hair cell stimulation

Increased Spontaneous Otoacoustic Emissions in Mice with a Detached Tectorial Membrane

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