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Cold Spring Harbor Symposia on... 1976
Topics: Animals; Basilar Membrane; Ear; Ear, Inner; Haplorhini; Humans; Models, Neurological; Physical Phenomena; Physics
PubMed: 820509
DOI: 10.1101/sqb.1976.040.01.058 -
Current Opinion in Neurobiology Aug 1992Recent evidence shows that the frequency-specific non-linear properties of auditory nerve and inner hair cell responses to sound, including their sharp frequency tuning,... (Review)
Review
Recent evidence shows that the frequency-specific non-linear properties of auditory nerve and inner hair cell responses to sound, including their sharp frequency tuning, are fully established in the vibration of the basilar membrane. In turn, the sensitivity, frequency selectivity and non-linear properties of basilar membrane responses probably result from an influence of the outer hair cells.
Topics: Acoustic Stimulation; Animals; Basilar Membrane; Humans; Sound
PubMed: 1525542
DOI: 10.1016/0959-4388(92)90179-o -
Acta Oto-laryngologica Apr 2023Numerical simulations can reflect the changes in physiological properties caused by various factors in the cochlea.
BACKGROUND
Numerical simulations can reflect the changes in physiological properties caused by various factors in the cochlea.
AIMS/OBJECTIVE
To analyze the influence of lesions of the basilar membrane (BM) on the dynamic response of the middle ear.
METHOD
Based on healthy human ear CT scan images, use PATRAN software to build a three-dimensional finite element model of the human ear, then apply NASTRAN software to conduct analysis of solid-fluid coupled frequency response. The influence of lesions in the BM on the dynamic response of the middle ear is simulated through the method of numerical simulation.
RESULT
Through comparing experimental data and the frequency-response curve of displacement of BM and stapes, the validity of the model in this paper was verified.
CONCLUSION
Regarding sclerosis in BM, the most obvious decline of displacement and velocity exists in the range of 800-10,000Hz and 800-2000Hz frequency, respectively. The higher degree of sclerosis, the more obvious decline becomes. The maximal decline of hearing can reach from 6.2 dB to 9.1 dB. Regarding added mass in BM, the most obvious decline of displacement exists in the range of 600-1000Hz frequency, and the maximal decline of hearing can reach 4.0 dB. There is no obvious decline in velocity.
Topics: Humans; Basilar Membrane; Sclerosis; Ear, Middle; Cochlea; Stapes; Finite Element Analysis
PubMed: 36939118
DOI: 10.1080/00016489.2023.2187451 -
Scientific Reports Nov 2022The prevailing theory of cochlear function states that outer hair cells amplify sound-induced vibration to improve hearing sensitivity and frequency specificity. Recent...
The prevailing theory of cochlear function states that outer hair cells amplify sound-induced vibration to improve hearing sensitivity and frequency specificity. Recent micromechanical measurements in the basal turn of gerbil cochleae through the round window have demonstrated that the reticular lamina vibration lags the basilar membrane vibration, and it is physiologically vulnerable not only at the best frequency but also at the low frequencies. These results suggest that outer hair cells from a broad cochlear region enhance hearing sensitivity through a global hydromechanical mechanism. However, the time difference between the reticular lamina and basilar membrane vibration has been thought to result from a systematic measurement error caused by the optical axis non-perpendicular to the cochlear partition. To address this concern, we measured the reticular lamina and basilar membrane vibrations in the transverse direction through an opening in the cochlear lateral wall in this study. Present results show that the phase difference between the reticular lamina and basilar membrane vibration decreases with frequency by ~ 180 degrees from low frequencies to the best frequency, consistent with those measured through the round window. Together with the round-window measurement, the low-coherence interferometry through the cochlear lateral wall demonstrates that the time difference between the reticular lamina and basilar membrane vibration results from the cochlear active processing rather than a measurement error.
Topics: Animals; Basilar Membrane; Gerbillinae; Vibration; Cochlea; Hair Cells, Auditory, Outer
PubMed: 36396720
DOI: 10.1038/s41598-022-24394-0 -
European Archives of... Mar 2015Air conduction (AC) is accompanied by displacements of the two cochlear windows, bulk fluid flow between them, a pressure difference across the basilar membrane, leading... (Review)
Review
Air conduction (AC) is accompanied by displacements of the two cochlear windows, bulk fluid flow between them, a pressure difference across the basilar membrane, leading to a passive traveling wave along the membrane, which activates the cochlear amplifier and enhances the displacements. AC interacts with bone conduction (BC) stimulation, so that it has been assumed that BC stimulation also involves a passive traveling wave. However, several clinical conditions and experimental manipulations provide evidence that a passive traveling wave may not be involved in BC stimulation at low intensities. Soft tissue conduction (STC) (also called non-osseous bone conduction) involves applying the bone vibrator to soft tissues on the head, neck and thorax, eliciting auditory sensation. STC stimulation probably does not involve a passive traveling wave. This review presents clinical conditions and experimental manipulations which assess the contributions of AC, BC and STC stimulation to the passive traveling wave. Evidence from the clinic (otosclerosis, round window atresia) and from the laboratory (holes in the wall of the inner ear, immobilization of the ossicular chain and the windows, discontinuity of the chain, measurement of basilar membrane displacements in the absence of the cochlear amplifier) lead to the conclusion that a passive basilar membrane traveling wave may not be involved in stimulation at low sound intensities. It is suggested that at low sound levels, the outer hair cell cochlear amplifier may not be activated by a passive traveling wave, but may be directly activated by the fast cochlear fluid pressures induced by AC, BC and STC stimulation. On the other hand, at high intensities, the cochlea is activated by the slow passive traveling wave.
Topics: Animals; Basilar Membrane; Bone Conduction; Cochlea; Ear Ossicles; Hearing; Humans; Round Window, Ear; Sound
PubMed: 24740735
DOI: 10.1007/s00405-014-3045-z -
Hearing Research Dec 1997Basilar membrane (BM) noise, measured as a velocity signal under the quiet acoustic condition, was investigated in the guinea pig. The cochleas of anesthetized young...
Basilar membrane (BM) noise, measured as a velocity signal under the quiet acoustic condition, was investigated in the guinea pig. The cochleas of anesthetized young healthy guinea pigs were surgically exposed and a hole was made on the lateral wall of the scala tympani of the first cochlear turn for visualization of the BM and measurement of the BM velocity with a laser interferometer. The amplitude and frequency of the BM velocity noise were analyzed by a spectrum analyzer under different conditions. The spectrum of the BM velocity noise was a band limited function with a peak velocity at the topographic best frequency of the measured location on the BM. The peak velocity ranged to about 8 microm/s and depended on the physiological condition of the cochlea. Saline blockage of the external auditory canal or the middle ear did not change the BM noise. BM noise was much smaller, or was not evident, when the cochlear sensitivity decreased. The suppression tuning curve of the BM velocity noise indicates that the maximum suppression caused by an acoustic pure tone occurred at the best frequency location. A low sound level wide band acoustic noise given to the external ear canal produced a spectrum function having the same frequency and amplitude response as the BM noise. Electrical stimulation of the crossed olivocochlear bundle significantly depresses the BM velocity noise. These data demonstrate that the BM noise is a representation of internal rather than external noise. The amplitude and frequency of the BM noise reflect the usual cochlear sensitivity and frequency selectivity. Since the organ of Corti in the sensitive cochlea is a highly sensitive and tuned mechanical system, the internal (to the animal) noise responsible for the BM noise may originate from mechanical vibrations remote from the cochlea and propagated to the ear, or may be caused by Brownian motion of cellular structures in the cochlea.
Topics: Acoustic Stimulation; Animals; Basilar Membrane; Biomechanical Phenomena; Guinea Pigs; Interferometry; Lasers; Noise; Organ of Corti; Scala Tympani
PubMed: 9447916
DOI: 10.1016/s0378-5955(97)00147-0 -
Journal of the Association For Research... Oct 2014The 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...
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.
Topics: Animals; Basilar Membrane; Biomechanical Phenomena; Guinea Pigs; Mice; Mice, Inbred CBA; Tectorial Membrane
PubMed: 24865766
DOI: 10.1007/s10162-014-0463-y -
Scientific Reports 2013To understand how the inner ear-generated sound, i.e., otoacoustic emission, exits the cochlea, we created a sound source electrically in the second turn and measured... (Comparative Study)
Comparative Study
To understand how the inner ear-generated sound, i.e., otoacoustic emission, exits the cochlea, we created a sound source electrically in the second turn and measured basilar membrane vibrations at two longitudinal locations in the first turn in living gerbil cochleae using a laser interferometer. For a given longitudinal location, electrically evoked basilar membrane vibrations showed the same tuning and phase lag as those induced by sounds. For a given frequency, the phase measured at a basal location led that at a more apical location, indicating that either an electrical or an acoustical stimulus evoked a forward travelling wave. Under postmortem conditions, the electrically evoked emissions showed no significant change while the basilar membrane vibration nearly disappeared. The current data indicate that basilar membrane vibration was not involved in the backward propagation of otoacoustic emissions and that sounds exit the cochlea probably through alternative media, such as cochlear fluids.
Topics: Acoustic Stimulation; Animals; Basilar Membrane; Cochlea; Electric Stimulation; Gerbillinae; Otoacoustic Emissions, Spontaneous; Sound; Vibration
PubMed: 23695199
DOI: 10.1038/srep01874 -
The Journal of the Acoustical Society... May 1980In the alligator lizard the entire basilar membrane is accessible for measurements of its velocity by the Mössbauer method. Tests of the method indicate (1) the...
In the alligator lizard the entire basilar membrane is accessible for measurements of its velocity by the Mössbauer method. Tests of the method indicate (1) the Mössbauer source can be placed on the basilar membrane without altering the signal-transmission properties of the cochlea, and (2) the source adheres to the basilar membrane. Isovelocity curves (IVCs) were constructed by plotting (as a function of tone frequency) the sound-pressure level at the tympanic membrane required to produce a specified velocity amplitude. IVCs from 21 lizards for source locations spanning the length of the basilar membrane indicate that basilar-membrane velocity does not vary systematically with longitudinal location as it does in mammalian cochleas. Measurements of velocity waveforms in two lizards do not indicate substantial nonlinearity in the inner-ear mechanical system. The frequency dependence of the basilar-membrane velocity is similar to that of the extrastapes velocity over the range 0.4 to 2 kHz. Thus, the tonotopic organization and frequency selectivity, which have been previously demonstrated in this species in responses of both auditory-nerve fibers and cells of the receptor organ, are apparently not primarily determined by basilar-membrane motion.
Topics: Animals; Basilar Membrane; Cochlear Microphonic Potentials; Cochlear Nerve; Ear, Inner; Lizards; Models, Biological; Stapes; Tympanic Membrane
PubMed: 7372928
DOI: 10.1121/1.384300 -
Hearing Research Sep 2015The basilar membrane velocity of gerbil cochlea showed discrepancy between theoretical model and experimental measurements. We hypothesize that the reasons of such... (Comparative Study)
Comparative Study
The basilar membrane velocity of gerbil cochlea showed discrepancy between theoretical model and experimental measurements. We hypothesize that the reasons of such discrepancies are due to the arch towards the scala tympani and radial tension present in the basilar membrane of the gerbil cochlea. The arch changes the bending stiffness in the basilar membrane, reduces the effective fluid force on the membrane and increases the basilar membrane's inertia. The existence of the radial tension also dampens the acoustic travelling wave. In this paper, the wave number functions along the gerbil basilar membrane are calculated from experimentally measured physical parameters with the theoretical model as well as extracted from experimentally measured basilar membrane velocity with the wave number inversion formula. The two wave number functions are compared and the effects of the tension and membrane arch on the wave number are studied based on various parameters of the model. We found that the bending stiffness across the gerbil basilar membrane varies (1-2 orders along the cochlea in the section 2.2 mm-3 mm from base) more than the calculated value in the flat basilar membrane model and the radial tension increases the damping of the travelling wave in gerbil cochlea significantly (5 times more than that without radial tension). These effects of arch and radial tension in the basilar membrane elucidate the discrepancy between previous theoretical model and experimental measurements in gerbil cochlea.
Topics: Acoustic Stimulation; Animals; Basilar Membrane; Biomechanical Phenomena; Cochlea; Elasticity; Gerbillinae; Hearing; Models, Animal; Models, Biological; Motion; Time Factors
PubMed: 26070425
DOI: 10.1016/j.heares.2015.06.002