Concepts and Challenges in the Biophysics of Hearing: Proceedings of the 10th International Workshop on the Mechanics of Hearing, Keele University, Staffordshire, UK 27 - 31 July 2008

CONTENTS......Page 6
Preface......Page 14
Acknowledgments......Page 16
Workshop Photograph......Page 17
Workshop Delegates......Page 20
SECTION I SOUND TRANSMISSION TO AND FROM THE INNER EAR, AND WAVE PROPAGATION WITHIN IT......Page 30
1 Introduction......Page 32
2.3 Holographic Interferometry Measurement......Page 33
2.6 Analysis of TAHI Images for TM Sensitivity to Sound......Page 34
3 Results and Discussion......Page 35
References......Page 37
1 Introduction......Page 38
2.2 Fiber-Optic Pressure Sensors......Page 39
3.1 Middle Ear Pressure Gain......Page 40
4.1 High Frequency Responses......Page 41
4.3 Comparison with other Chinchilla Studies......Page 42
References......Page 43
2 Methods......Page 44
3 Results......Page 45
4 Discussion......Page 46
References......Page 47
1 Introduction......Page 48
2 Methods......Page 49
3.2 Pressure Gain of the Middle Ear......Page 50
3.4 Effect of Ossicular Discontinuity on Sound Transmission......Page 51
3.5 Cochlear Input Impedance (ZC)......Page 52
References......Page 53
1 Summary......Page 54
References......Page 55
1 Introduction......Page 56
3 Results......Page 57
3.2 Compression pressure is apparent at frequencies well above the cutoff frequency......Page 58
3.3 Transmission of DPs inside the cochlea......Page 59
4 Discussion......Page 60
Acknowledgments......Page 61
Comments & Discussion......Page 62
1 Introduction – ‘hidden waves’......Page 63
2 Classical and non-classical models......Page 64
3 An example: Distortion-Product (DP) waves in a feed-forward model......Page 65
References......Page 67
Comments & Discussion......Page 68
2.1 Surface-Wave Formulas......Page 70
2.2 Cochlear Parameters for Gerbil......Page 71
2.4 Locations of DP Generation......Page 72
3 Results......Page 73
References......Page 75
Comments and Discussion......Page 76
1 Introduction......Page 77
2.2 DPOAE responses of the nonlinear cochlea model......Page 78
3.1 Comparison to experimental data......Page 79
3.2 Distortion product origins......Page 80
4 Discussion......Page 81
References......Page 82
Comments and Discussion......Page 83
1 Introduction – The Allen-Fahey Experiment......Page 84
2.2 Micro-mechanics......Page 85
2.3 Outer hair cell......Page 86
3 Model Results......Page 87
References......Page 89
Comments and Discussion......Page 90
2. Cochlear model......Page 91
3. Wave variables......Page 92
4. Approximate wave variables......Page 94
5. Discussion......Page 95
Comments and Discussion......Page 96
1 Introduction......Page 97
2 Model......Page 98
3 Methods......Page 100
4 Results and Discussion......Page 101
References......Page 102
2 Formulation of the State Space Model......Page 103
3 The Effect of Inhomogeneities in the Linear Cochlea......Page 105
4 Instabilities in the Nonlinear Inhomogeneous Cochlea......Page 106
5 Conclusions......Page 108
Comments and Discussion......Page 109
1 Summary......Page 111
References......Page 112
2. The Model......Page 114
3. Analytic Approximation for the Delay......Page 116
4. Comparison with Experiment......Page 117
5. Summary......Page 118
References......Page 119
SECTION II COCHLEAR AMPLIFICATION: CHARACTERISTICS, MODULATION AND CONTROL......Page 120
1. Introduction......Page 122
2. Key studies......Page 123
2.1.1. Speech-Plosive events......Page 125
2.2. Verification methods......Page 128
3.1. Function of the Inner Ear in speech perception......Page 129
3.2. The dynamic range problem......Page 130
Summary......Page 131
References......Page 132
Comments and Discussion......Page 134
1 Introduction......Page 135
2 Methods......Page 136
3 Results......Page 137
References......Page 139
Comments and Discussion......Page 141
1 Introduction......Page 142
2.3 Measurement of local basilar membrane transfer functions......Page 143
3.1 Conventional basilar membrane transfer functions......Page 144
3.2 Local basilar membrane transfer functions......Page 145
4 Discussion......Page 146
References......Page 147
Comments and Discussion......Page 148
2 Methods......Page 151
3.1 Interferometry......Page 152
4 Discussion......Page 153
Comments and Discussion......Page 154
1 Introduction......Page 157
1.2 Background to resistive (real ) and reactive (imaginary) parts of ZOCC......Page 158
2 Methods......Page 159
3.1 MOCC and SOCC found with BM velocity measurements + model......Page 160
3.2 Direct measurements of resistive and reactive components of ZOCC......Page 161
References......Page 162
Comments and Discussion......Page 163
1 Introduction......Page 164
3.1 OCT images......Page 165
3.2 BM responses at 3 longitudinal positions under RW stimulation......Page 166
4 Discussion......Page 167
References......Page 168
Comments and Discussion......Page 169
2 Methods......Page 170
3.1 BM tuning is sharper in Tectb-/- mice......Page 171
3.2 Neural masking tuning is sharper in Tectb-/- mice......Page 173
4 Discussion......Page 174
References......Page 175
Comments and Discussion......Page 176
1 Introduction......Page 177
3 Results......Page 178
4 Discussion......Page 181
References......Page 182
Comments and Discussion......Page 183
1 Introduction......Page 184
3 Results......Page 185
4 Discussion......Page 187
References......Page 189
Comments and Discussion......Page 190
2 Methods......Page 191
3.2 Auditory nerve fibers......Page 192
3.5 Level independence of BF in further neural pathway......Page 193
4.2 Function of dual tuning......Page 194
References......Page 195
1 Introduction......Page 197
2 Method......Page 198
4 Model......Page 199
References......Page 202
1.1 Previous evidence supporting the notion of homeostatic regulation......Page 204
2 Methods......Page 205
3 Results......Page 206
4 Discussion......Page 208
References......Page 209
1 Summary......Page 210
References......Page 211
1 Introduction......Page 212
3.1 Spectral Fine-Structures......Page 213
3.2 Quasi-static Modulation Patterns......Page 214
3.3 Period Modulation Patterns......Page 215
4 Discussion......Page 216
References......Page 217
Comments and Discussion......Page 218
1 Introduction......Page 219
3.1 Basic effects of contralateral noise on f2-f1 and 2f1-f2......Page 220
3.2 Low frequency biasing induced DPOAE modulation – effect of CAS......Page 221
4 Discussion......Page 223
References......Page 224
1. Introduction......Page 225
3. Results......Page 226
4. Discussion......Page 228
References......Page 230
Comments and Discussion......Page 231
1.1 Extracting Distortion Product Otoacoustic Emissions (DPOAE) components......Page 232
2 Methods......Page 233
3.2 I/O for the Two Major Components as a Function of Primary Ratio......Page 234
4 Discussion......Page 236
References......Page 237
1 Introduction......Page 238
2.2 Method of data analysis......Page 239
3 Results......Page 240
References......Page 243
SECTION III NEW MEASUREMENT TECHNIQUES......Page 244
2 Methods......Page 246
3 Results......Page 247
3.2 The near group......Page 248
3.3 The suppression group......Page 249
3.4 Model attempt......Page 250
References......Page 251
1 Summary......Page 252
References......Page 253
1 Introduction......Page 254
2.2 Data acquisition......Page 255
3 Results......Page 256
References......Page 257
SECTION IV MICROMECHANICS: BM, TM AND SUB-TECTORIAL SPACE......Page 260
2. Methods......Page 262
3. Results......Page 265
4. Discussion......Page 266
References......Page 267
Comments and Discussion......Page 268
1. Introduction......Page 269
3. Results......Page 270
4. Discussion......Page 273
References......Page 274
Comments and Discussion......Page 275
2. Methods......Page 276
3. Measurements and Model......Page 278
4. Discussion......Page 280
Comments and Discussion......Page 281
1 Introduction......Page 284
2 Results and Discussion......Page 285
Acknowledgments......Page 288
Comments and Discussion......Page 289
1.1. A closed-form approximation for TM waves......Page 291
2. Driving TM waves with a cochlear model......Page 292
3.1. TM responses are inconsistent with classical models......Page 293
3.2. Effect of wave parameters on TM tuning......Page 294
4.3. Implications for cochlear tuning......Page 295
Comments and Discussion......Page 296
2 The operation of the vestibule of the labyrinth and the cochlear partition......Page 298
3 The mathematical description and performance of the cochlear partition......Page 300
References......Page 304
1 Introduction......Page 305
2.2 Setup......Page 306
2.4 Data processing......Page 307
3 Results......Page 308
4 Discussion......Page 309
References......Page 310
Comments and Discussion......Page 311
2 Methods......Page 312
3 Results......Page 314
4 Discussion Amplitude [dB]......Page 315
Comments and Discussion......Page 316
1. Introduction......Page 317
2.1. Fluid-Structure-Interaction......Page 318
2.3. Properties......Page 319
3. Results......Page 320
Acknowledgments......Page 321
References......Page 322
SECTION V MODELLING THE COCHLEAR AMPLIFIER AND THE COCHLEA’S DYNAMICS......Page 324
1 Introduction......Page 326
2 Method......Page 327
3 Results......Page 328
4 Discussion......Page 330
References......Page 331
2. OHC Electromotility......Page 332
4.1. Without extracellular resistance......Page 333
5. E.ectiveness of Hair Bundle Motility......Page 334
5.2. Avian ear......Page 336
References......Page 337
1 Introduction......Page 339
2 Methods......Page 340
3 Results......Page 341
3.1 Apex-to-Base Trends......Page 342
4 Discussion and Conclusion......Page 343
References......Page 344
Comments and Discussion......Page 345
2 Mathematical Formulation......Page 348
2.2 Acoustic streaming subproblem......Page 349
Comments and Discussion......Page 350
2 Mathematical Analysis......Page 352
2.2 Slow traveling wave......Page 353
2.4 Computational procedure......Page 354
3 Results......Page 355
Acknowledgments......Page 356
Comments and Discussion......Page 357
2 Method and Results......Page 359
2.1 BM velocity with feed-forward (push) / feed-backward (pull) mechanism......Page 360
2.2 Intracochlear pressure......Page 361
2.3 Cochlear input impedance......Page 362
Acknowledgments......Page 363
Comments and Discussion......Page 364
1 Summary......Page 366
References......Page 368
3 The consequence of Outer Hair Cell (OHC) depolarisation......Page 369
5 The significance of OHC membrane capacitance......Page 370
References......Page 371
1. Introduction......Page 372
2. Methods......Page 373
3. Results......Page 375
Acknowledgments......Page 377
References......Page 378
1 Summary......Page 379
References......Page 380
2. Energy Depot Model with Braking Mechanism......Page 381
3. Results and Discussion......Page 382
References......Page 385
2 The TWAMP......Page 387
4 The conjoined models......Page 388
References......Page 389
SECTION VI HAIR CELLS AND ELECTRO-MECHANICAL TRANSDUCTION......Page 390
1 Introduction......Page 392
2 Methods......Page 393
3.1 Voltage jumps induce time dependent changes in NLC......Page 394
3.3 Temperature jumps induce time dependent changes in NLC......Page 395
4 Discussion......Page 396
References......Page 398
Comments and Discussion......Page 399
2 Methods......Page 400
3 Results and Discussion......Page 401
References......Page 405
1.1. Cochlear amplification in 3-dimensions......Page 406
2.1 Computational techniques......Page 407
3 Results......Page 408
4 Discussion......Page 410
References......Page 411
Comments and Discussion......Page 412
1 Introduction......Page 414
2 Model......Page 415
3 Results and Discussion......Page 416
References......Page 419
1 Summary......Page 420
References......Page 421
1 The outer hair cell lateral wall and its membrane-based motor......Page 422
2.2 Membrane cholesterol effects on prestin-expressing HEK 293 cells are similar to those in OHCs......Page 423
2.3 Effect of cholesterol concentration on peak and magnitude of charge movement......Page 424
2.5 Modulation of cochlear function by cholesterol......Page 425
3.3 Membrane cholesterol and the cochlear amplifier......Page 426
References......Page 427
1 Summary......Page 429
References......Page 431
1 Summary......Page 432
References......Page 433
1 Summary......Page 434
References......Page 435
1 Introduction......Page 436
2 Materials and Methods......Page 437
3 Results......Page 438
4 Discussion......Page 440
References......Page 441
SECTION VII HAIR BUNDLES AND MECHANO-ELECTRICAL TRANSDUCTION......Page 442
1 Introduction......Page 444
2.1 Mechanical stimulation of single hair bundles and Ca2+ iontophoresis......Page 445
2.2 Theoretical description of active hair-bundle mechanics......Page 446
3.1 Three classes of active hair-bundle movements......Page 447
3.2 Ca2+ involvement in active hair-bundle motility......Page 448
4 Discussion......Page 450
References......Page 452
1 Introduction......Page 454
3.1 The fly’s auditory transducers are mechanically gated, spring-operated ion channels......Page 455
3.2 The fly’s auditory transducers are mechanically adapting ion channels......Page 457
4 Discussion......Page 458
References......Page 459
1 Introduction......Page 460
3.1 Transducer-based model of the Drosophila hearing organ......Page 461
3.2 Response to force steps......Page 462
4 Discussion......Page 463
References......Page 464
1 Summary......Page 466
References......Page 467
2 Materials and Methods......Page 468
4 Discussion......Page 470
References......Page 471
1 Introduction......Page 473
3.1 Values for morphological parameters......Page 474
3.2 The morphological factor for upper frequency limit......Page 475
4.1 Are hair-bundle forces likely to be effective in the avian frequency range?......Page 476
References......Page 477
1. Introduction......Page 480
2. Methods......Page 481
3. Results......Page 482
References......Page 483
1. Summary......Page 486
References......Page 487
2 Materials and Methods......Page 488
4 Discussion......Page 489
References......Page 492
SECTION VIII DISCUSSION......Page 494
1. Introduction......Page 496
2. Experimental evidence of power amplification......Page 497
3. Overcoming the outer hair cell’s time constant......Page 505
4. Stimulating inner hair cells......Page 511
5. Differences between the base and apex of the cochlea......Page 515
6. The role of compression waves in forwards transduction......Page 516
7. Robustness of measurement techniques......Page 519
8. Tectorial membrane motion......Page 521
9. Directions for future study......Page 523
Author Index......Page 534