Mammalian auditory epithelium (the organ of Corti) stands out among different inner-ear epithelia in that it has large extracellular fluid spaces such as the tunnel of Corti, Nuel’s space, outer tunnel, and spacing between outer hair cells. We tested the hypothesis that advective flow facilitates mass transport in the cochlear fluids, using computational simulations of cochlear fluid dynamics and ex vivo experiments to investigate mass transport in extracellular fluid spaces of the cochlea. Three model simulations were performed in series—cochlear mechanics, nonlinear fluid dynamics, and mass transport. In nonlinear fluid dynamics, we incorporated convection terms for more accurate computation of drift flow. For mass transport, both diffusion and advection were considered. For experiments, we measured vibrations of excised cochlear turns using optical coherence tomography. The excised OoC was subjected to acoustic and electrical stimulations.
REFERENCES
1.
Zidanic
, M.
and W.E.
Brownell
, Fine structure of the intracochlear potential field. I. The silent current
. Biophys J
, 1990
. 57
(6
): p. 1253
–68
.2.
Johnstone
, B.M.
, R.
Patuzzi
, J.
Syka
, and E.
Sykova
, Stimulus-related potassium changes in the organ of Corti of guinea-pig
. J Physiol
, 1989
. 408
: p. 77
–92
.3.
Brownell
, W.E.
, C.R.
Bader
, D.
Bertrand
, and Y.
de Ribaupierre
, Evoked mechanical responses of isolated cochlear outer hair cells
. Science
, 1985
. 227
(4683
): p. 194
–6
.4.
Zheng
, J.
, W.
Shen
, D.Z.
He
, K.B.
Long
, L.D.
Madison
, and P.
Dallos
, Prestin is the motor protein of cochlear outer hair cells
. Nature
, 2000
. 405
(6783
): p. 149
–55
.5.
Ashmore
, J.
, Cochlear outer hair cell motility
. Physiol Rev
, 2008
. 88
(1
): p. 173
–210
.6.
Fettiplace
, R.
and K.X.
Kim
, The physiology of mechanoelectrical transduction channels in hearing
. Physiol Rev
, 2014
. 94
(3
): p. 951
–86
.7.
Chen
, F.
, D.
Zha
, A.
Fridberger
, J.
Zheng
, N.
Choudhury
, S.L.
Jacques
, R.K.
Wang
, X.
Shi
, and A.L.
Nuttall
, A differentially amplified motion in the ear for near-threshold sound detection
. Nat Neurosci
, 2011
. 14
(6
): p. 770
–4
.8.
Ren
, T.
, W.
He
, Y.
Li
, K.
Grosh
, and A.
Fridberger
, Light-induced vibration in the hearing organ
. Sci Rep
, 2014
. 4
: p. 5941
.9.
Ren
, T.
, W.
He
, and P.G.
Barr-Gillespie
, Reverse transduction measured in the living cochlea by low-coherence heterodyne interferometry
. Nat Commun
, 2016
. 7
: p. 10282
.10.
Lee
, H.Y.
, P.D.
Raphael
, J.
Park
, A.K.
Ellerbee
, B.E.
Applegate
, and J.S.
Oghalai
, Noninvasive in vivo imaging reveals differences between tectorial membrane and basilar membrane traveling waves in the mouse cochlea
. Proc Natl Acad Sci U S A
, 2015
. 112
(10
): p. 3128
–33
.11.
Lee
, H.Y.
, P.D.
Raphael
, A.
Xia
, J.
Kim
, N.
Grillet
, B.E.
Applegate
, A.K. Ellerbee
Bowden
, and J.S.
Oghalai
, Two-Dimensional Cochlear Micromechanics Measured In Vivo Demonstrate Radial Tuning within the Mouse Organ of Corti
. J Neurosci
, 2016
. 36
(31
): p. 8160
–73
.12.
Dong
, W.
and E.S.
Olson
, Detection of cochlear amplification and its activation
. Biophys J
, 2013
. 105
(4
): p. 1067
–78
.13.
Vavakou
, A.
, N.P.
Cooper
, and M.
van der Heijden
, The frequency limit of outer hair cell motility measured in vivo
. Elife
, 2019
. 8
.14.
Meaud
, J.
and K.
Grosh
, The effect of tectorial membrane and basilar membrane longitudinal coupling in cochlear mechanics
. J Acoust Soc Am
, 2010
. 127
(3
): p. 1411
–21
.15.
Meaud
, J.
and K.
Grosh
, Effect of the attachment of the tectorial membrane on cochlear micromechanics and two-tone suppression
. Biophys J
, 2014
. 106
(6
): p. 1398
–405
.16.
Yoon
, Y.J.
, C.R.
Steele
, and S.
Puria
, Feed-forward and feed-backward amplification model from cochlear cytoarchitecture: an interspecies comparison
. Biophys J
, 2011
. 100
(1
): p. 1
–10
.17.
Wang
, Y.
, C.R.
Steele
, and S.
Puria
, Cochlear Outer-Hair-Cell Power Generation and Viscous Fluid Loss
. Scientific reports
, 2016
. 6
: p. 19475
.18.
Liu
, Y.W.
and S.T.
Neely
, Outer hair cell electromechanical properties in a nonlinear piezoelectric model
. J Acoust Soc Am
, 2009
. 126
(2
): p. 751
–61
.19.
Liu
, Y.W.
and S.T.
Neely
, Suppression tuning of distortion-product otoacoustic emissions: results from cochlear mechanics simulation
. J Acoust Soc Am
, 2013
. 133
(2
): p. 951
–61
.20.
Nam
, J.H.
and R.
Fettiplace
, Optimal electrical properties of outer hair cells ensure cochlear amplification
. PLoS One
, 2012
. 7
(11
): p. e50572
.21.
Nam
, J.H.
, Microstructures in the organ of Corti help outer hair cells form traveling waves along the cochlear coil
. Biophys J
, 2014
. 106
(11
): p. 2426
–33
.22.
Liu
, Y.
, S.M.
Gracewski
, and J.H.
Nam
, Consequences of Location-Dependent Organ of Corti Micro-Mechanics
. PLoS One
, 2015
. 10
(8
): p. e0133284
.23.
Cormack
, J.
, Y.
Liu
, J.H.
Nam
, and S.M.
Gracewski
, Two-compartment passive frequency domain cochlea model allowing independent fluid coupling to the tectorial and basilar membranes
. The Journal of the Acoustical Society of America
, 2015
(To appear).24.
Prodanovic
, S.
, S.M.
Gracewski
, and J.H.
Nam
, Power Dissipation in the Cochlea Can Enhance Frequency Selectivity
. Biophys J
, 2019
. 116
(7
): p. 1362
–1375
.25.
Ren
, T.
, W.
He
, and D.
Kemp
, Reticular lamina and basilar membrane vibrations in living mouse cochleae
. Proc Natl Acad Sci U S A
, 2016
.26.
He
, W.
, D.
Kemp
, and T.
Ren
, Timing of the reticular lamina and basilar membrane vibration in living gerbil cochleae
. Elife
, 2018
. 7
.27.
Cooper
, N.P.
, A.
Vavakou
, and M.
van der Heijden
, Vibration hotspots reveal longitudinal funneling of sound-evoked motion in the mammalian cochlea
. Nat Commun
, 2018
. 9
(1
): p. 3054
.28.
Dewey
, J.B.
, B.E.
Applegate
, and J.S.
Oghalai
, Amplification and Suppression of Traveling Waves along the Mouse Organ of Corti: Evidence for Spatial Variation in the Longitudinal Coupling of Outer Hair Cell-Generated Forces
. J Neurosci
, 2019
. 39
(10
): p. 1805
–1816
.29.
Strimbu
, C.E.
, Y.
Wang
, and E.S.
Olson
, Manipulation of the Endocochlear Potential Reveals Two Distinct Types of Cochlear Nonlinearity
. Biophys J
, 2020
. 119
(10
): p. 2087
–2101
.30.
van der Heijden
, M.
and A.
Vavakou
, Rectifying and sluggish: Outer hair cells as regulators rather than amplifiers
. Hear Res
, 2021
: p. 108367
.31.
Shokrian
, M.
, C.
Knox
, D.H.
Kelley
, and J.H.
Nam
, Mechanically facilitated micro-fluid mixing in the organ of Corti
. Sci Rep
, 2020
. 10
(1
): p. 14847
.32.
Karavitaki
, K.D.
and D.C.
Mountain
, Evidence for outer hair cell driven oscillatory fluid flow in the tunnel of corti
. Biophys J
, 2007
. 92
(9
): p. 3284
–93
.33.
Zagadou
, B.F.
and D.C.
Mountain
, Analysis of the cochlear amplifier fluid pump hypothesis
. J Assoc Res Otolaryngol
, 2012
. 13
(2
): p. 185
–97
.34.
van der Heijden
, M.
, Frequency selectivity without resonance in a fluid waveguide
. Proc Natl Acad Sci U S A
, 2014
.35.
Salt
, A.N.
and K.
Hirose
, Communication pathways to and from the inner ear and their contributions to drug delivery
. Hear Res
, 2018
. 362
: p. 25
–37
.36.
Liu
, Y.
, S.M.
Gracewski
, and J.H.
Nam
, Two passive mechanical conditions modulate power generation by the outer hair cells
. PLoS Comput Biol
, 2017
. 13
(9
): p. e1005701
.37.
Johnson
, D.L.
, J.
Koplik
, and R.
Dashen
, Theory of dynamic permeability and tortuosity in fluid-saturated porous media
. Journal of fluid mechanics
, 1987
. 176
: p. 379
–402
.38.
Jabeen
, T.
, J.C.
Holt
, J.
Becker
, and J.H.
Nam
, Interactions between passive and active vibrations in the organ of Corti In vitro
. Biophysical Journal
, 2020
. 119
(2
): p. 314
–325
.39.
Ohyama
, K.
, A.N.
Salt
, and R.
Thalmann
, Volume flow rate of perilymph in the guinea-pig cochlea
. Hear Res
, 1988
. 35
(2-3
): p. 119
–29
.40.
Juhn
, S.K.
, L.P.
Rybak
, and S.
Prado
, Nature of blood-labyrinth barrier in experimental conditions
. Ann Otol Rhinol Laryngol
, 1981
. 90
(2 Pt 1): p. 135
–41
.41.
Lighthill
, J.
, Acoustic Streaming in the Ear Itself
. Journal of Fluid Mechanics
, 1992
. 239
: p. 551
–606
.42.
Edom
, E.
, D.
Obrist
, and L.
Kleiser
, Steady streaming in a two-dimensional box model of a passive cochlea
. Journal of Fluid Mechanics
, 2014
. 753
: p. 254
–278
.43.
Sumner
, L.
, J.
Mestel
, and T.
Reichenbach
, Steady streaming as a method for drug delivery to the inner ear
. Sci Rep
, 2021
. 11
(1
): p. 57
.
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