Auditory and Vestibular Efferents

1. Auflage 2010
ISBN: 978-1-4419-7070-1
Verlag: Springer-Verlag
Format: PDF
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, 359 Seiten

Efferent sensory systems have emerged as major components of processing by the central nervous system. Whereas the afferent sensory systems bring environmental information into the brain, efferent systems function to monitor, sharpen, and attend selectively to certain stimuli while ignoring others. This ability of the brain to implement these functions enables the organism to make fine discriminations and to respond appropriately to environmental conditions so that survival is enhanced. Our focus will be on auditory and vestibular efferents, topics linked together by the inner ear connection.

The biological utility of the efferent system is striking. How it functions is less well understood, and with each new discovery, more questions arise. The book that is proposed here reflects our vision to share what is known on the topic by authors who actually have made the observations.

Autoren/Hrsg.

Inhaltsverzeichnis

1;Series Preface;8
2;Volume Preface;10
3;Contents;12
4;Contributors;14
5;Chapter 1: Introduction to Efferent Systems;18
5.1;1.1 Introduction and Overview;18
5.2;1.2 Overview of the Volume;22
5.3;1.3 Comparison with Other Sensory Systems;27
5.4;1.4 Summary;28
5.5;References;29
6;Chapter 2: Anatomy of Olivocochlear Neurons;33
6.1;2.1 Introduction;33
6.2;2.2 OC Neurons in the Brain Stem;33
6.2.1;2.2.1 Distributions of Lateral vs. Medial Olivocochlear Neurons;33
6.2.2;2.2.2 Numbers of Neurons;36
6.2.3;2.2.3 Axonal Characteristics;37
6.3;2.3 Peripheral Projections;37
6.3.1;2.3.1 Separate Terminations of LOC and MOC Neurons;37
6.3.2;2.3.2 Terminations of LOC Fibers;38
6.3.3;2.3.3 Terminations of MOC Fibers;39
6.4;2.4 Central Branches to the Cochlear and Vestibular Nuclei;41
6.5;2.5 Neurochemistry;43
6.6;2.6 Ultrastructure of Synaptic Inputs to OC Neurons;43
6.7;2.7 Neural Pathway of the Medial Olivocochlear Reflex;45
6.7.1;2.7.1 Direct Reflex Pathway;45
6.7.2;2.7.2 Modulatory Pathways;48
6.8;2.8 Summary;48
6.9;References;49
7;Chapter 3: Physiology of the Medial and Lateral Olivocochlear Systems;54
7.1;3.1 Introduction;54
7.2;3.2 MOC Effects in the Cochlea: Overview;56
7.2.1;3.2.1 MOC Activation Increases CM;56
7.2.2;3.2.2 MOC Activation Decreases EP and Has Other Related Effects;57
7.3;3.3 Classic MOC Fast Effects in a Silent Background;58
7.3.1;3.3.1 Classic MOC Fast Effects on Basilar-Membrane Motion;58
7.3.2;3.3.2 Classic MOC Fast Effects on Otoacoustic Emissions;59
7.3.3;3.3.3 Classic MOC Fast Effects on IHC and AN Responses;62
7.4;3.4 Classic MOC Fast Effects in a Noisy Background;63
7.5;3.5 Nonclassic MOC Fast Effects in a Silent Background;65
7.5.1;3.5.1 Nonclassic MOC Fast Effects in the Basal Half of the Cochlea;66
7.5.2;3.5.2 Nonclassic MOC Fast Effects in the Apical Half of the Cochlea;67
7.6;3.6 MOC Slow Effects;69
7.7;3.7 MOC-Fiber Responses to Sound;70
7.8;3.8 MOC Acoustic Reflexes;73
7.8.1;3.8.1 Sound-Elicited MOC Effects on AN Fibers;73
7.8.2;3.8.2 Sound-Elicited MOC Effects on Otoacoustic Emissions;75
7.8.2.1;3.8.2.1 MOC Reflex Tuning;77
7.8.2.2;3.8.2.2 MOC Reflex Amplitude as a Function of Elicitor Bandwidth;78
7.8.2.3;3.8.2.3 MOC Reflex Laterality;79
7.8.2.4;3.8.2.4 MOC Reflex Strength;80
7.8.3;3.8.3 Descending Influences on MOC Acoustic Reflex Properties in Humans;80
7.9;3.9 MOC Function in Hearing;82
7.9.1;3.9.1 MOC Activity Changes the Dynamic Range of Hearing and Thereby Increases the Discriminability of Transients in Background Noise
;83
7.9.2;3.9.2 MOC Activity Helps to Protect Against Acoustic Trauma;84
7.9.3;3.9.3 Possible Roles of MOC Activity in Attention and Learning;84
7.10;3.10 LOC Physiology and Function;85
7.10.1;3.10.1 LOC Effects in the Cochlea;86
7.10.2;3.10.2 LOC Response to Sound;86
7.10.3;3.10.3 LOC Function in Hearing;86
7.11;3.11 Summary and Future Directions;87
7.12;References;88
8;Chapter 4: Pharmacology and Neurochemistry of Olivocochlear Efferents;97
8.1;4.1 Introduction;97
8.1.1;4.1.1 Overview of Biochemical and Biophysical Steps in Efferent Activation;97
8.1.2;4.1.2 Historical Perspective of Issues in the Pharmacology of the Olivocochlear Efferents;98
8.2;4.2 Cholinergic Medial Efferent Transmission;100
8.2.1;4.2.1 The Medial Efferent Synapse;100
8.2.2;4.2.2 Events at the Efferent Terminal;101
8.2.3;4.2.3 ACh Metabolism;101
8.2.4;4.2.4 Presynaptic Cholinergic Receptors;102
8.2.5;4.2.5 Synaptic Facilitation of Efferent Effects;103
8.2.6;4.2.6 Postsynaptic Cholinergic Receptor;103
8.2.6.1;4.2.6.1 Overview;103
8.2.6.2;4.2.6.2 Pharmacology of Medial Efferent Transmission;104
8.2.6.3;4.2.6.3 Pharmacology of KCa Channels;106
8.2.6.4;4.2.6.4 Medial Efferents: In Vivo vs. In Vitro Findings;106
8.3;4.3 Other Efferent Neurotransmitters;106
8.3.1;4.3.1 Overview;106
8.3.2;4.3.2 Lateral Efferent Origins;107
8.3.3;4.3.3 Acetylcholine;107
8.3.4;4.3.4 Opioid Peptides;108
8.3.5;4.3.5 Calcitonin Gene-Related Peptide (CGRP);108
8.3.6;4.3.6 GABA;108
8.3.7;4.3.7 Serotonin (5-Hydroxytryptamine);109
8.3.8;4.3.8 Glycine;109
8.3.9;4.3.9 Dopamine;109
8.4;4.4 Summary;110
8.5;References;111
9;Chapter 5: Cholinergic Inhibition of Hair Cells;116
9.1;5.1 Introduction;116
9.2;5.2 Historical Background;117
9.3;5.3 Cellular Physiology;119
9.3.1;5.3.1 Intracellular Recordings from Hair Cells of the Fish Lateral Line;119
9.3.2;5.3.2 Details of Inhibitory Postsynaptic Potentials and Effect on Receptor Potentials in Turtle Hair Cells;120
9.3.3;5.3.3 Application of ACh to Isolated OHCs;121
9.3.4;5.3.4 Tight-Seal Recordings in the Mammalian Organ of Corti;124
9.3.4.1;5.3.4.1 Responses to ACh in IHCs and OHCs;124
9.3.4.2;5.3.4.2 Spontaneous and Evoked Synaptic Currents in IHCs and OHCs;125
9.3.4.3;5.3.4.3 Cholinergic Inhibition of IHC Action Potentials;125
9.4;5.4 Summary of “Two-Channel Hypothesis vs. Second-Messenger Mechanisms”;129
9.5;5.5 Determination of Molecular Components;130
9.5.1;5.5.1 Cloning of a9;131
9.5.2;5.5.2 Cloning of a10;131
9.6;5.6 Genetically Modified Mouse Models;132
9.6.1;5.6.1 a9 and a10 Knockouts;132
9.6.2;5.6.2 a9 and a10 Overexpressors;135
9.6.3;5.6.3 SK2 Knockout Mice;136
9.6.4;5.6.4 a9 Knock-in Mice;138
9.7;5.7 Summary and Conclusions;140
9.8;References;141
10;Chapter 6: The Efferent Vestibular System;147
10.1;6.1 Introduction;147
10.2;6.2 Afferents and Hair Cells;148
10.2.1;6.2.1 Afferent Discharge Properties;148
10.2.2;6.2.2 Hair Cells and Their Innervation;149
10.2.3;6.2.3 Afferent Morphology and Physiology;152
10.3;6.3 Efferents: A Historical Perspective;154
10.4;6.4 Neuroanatomical Organization of the EVS;155
10.4.1;6.4.1 Location of Cell Bodies and Their Dendritic Morphology;155
10.4.2;6.4.2 Axonal Pathways to the Periphery;157
10.4.3;6.4.3 Peripheral Branching Patterns;159
10.4.4;6.4.4 Synaptic Ultrastructure of Efferent Terminals;159
10.5;6.5 Efferent Neurotransmitters and Receptors;161
10.5.1;6.5.1 Acetylcholine;161
10.5.2;6.5.2 Adenosine 5'-Triphosphate
;162
10.5.3;6.5.3 Calcitonin Gene-Related Peptide;163
10.5.4;6.5.4 Opioid Peptides;163
10.5.5;6.5.5 g-Aminobutyric Acid;163
10.5.6;6.5.6 Nitric Oxide;164
10.6;6.6 Afferent Responses to Electrical Activation of the EVS;165
10.6.1;6.6.1 Mammals;165
10.6.2;6.6.2 Oyster Toadfish (Opsanus tau);168
10.6.3;6.6.3 Anurans (Frogs and Toads, Rana and Bufo Species);168
10.6.4;6.6.4 Red-Eared Turtles (Trachemys scripta elegans);170
10.7;6.7 Sites of Efferent Actions: Hair Cells or Afferents;171
10.8;6.8 Pharmacology of Efferent Neurotransmission;173
10.8.1;6.8.1 Hair-Cell Inhibition;174
10.8.2;6.8.2 Hair-Cell Excitation;176
10.8.3;6.8.3 Fast Afferent Excitation;178
10.8.4;6.8.4 Slow Afferent Excitation;179
10.9;6.9 Efferent Modulation of Afferent Responses to Natural Stimulation;180
10.10;6.10 Functional Studies of the EVS;181
10.10.1;6.10.1 Response of EVS Neurons to Natural Stimulation;181
10.10.2;6.10.2 Efferent-Mediated Modulation of Afferent Discharge;183
10.10.3;6.10.3 Possible Functions of the EVS;186
10.11;6.11 Summary;188
10.12;References;188
11;Chapter 7: Development of the Inner Ear Efferent System;199
11.1;7.1 Introduction;199
11.2;7.2 Central Development;202
11.3;7.3 Defects of Efferent Development Revealed Through Targeted Mutations;204
11.4;7.4 Neurochemical Development of Auditory Efferents;206
11.4.1;7.4.1 Cholinergic Development;206
11.5;7.5 Peripheral Development;209
11.6;7.6 Onset of Neurotransmitter-Related Expression Within Cochlea;213
11.7;7.7 Acetylcholine Receptors on Hair Cells;216
11.8;7.8 Nicotinic Synapse Formation and Maturation of ACh Receptors;217
11.9;7.9 Maturation of Efferent Connections and Efferent-Induced Hair Cell Responses;218
11.10;7.10 Efferent Connections to Vestibular hair Cells;219
11.11;7.11 Conclusion and Outlook;222
11.12;References;222
12;Chapter 8: Evolution of the Octavolateral Efferent System;229
12.1;8.1 Introduction;229
12.2;8.2 Anatomical Layout and Neurochemistry of the Efferent System;229
12.2.1;8.2.1 The Origin of Octavolateral Efferents;230
12.2.2;8.2.2 The Plesiomorphic Condition as Seen in Fish;231
12.2.2.1;8.2.2.1 A Small Number of Efferent Neurons Innervates a Large Number of Both Lateral-Line and Inner-Ear Hair Cells;231
12.2.2.2;8.2.2.2 Are There Any Subpopulations of Efferents?;233
12.2.2.3;8.2.2.3 Bilateral Distribution of Efferent Somata and Dendrites;234
12.2.2.4;8.2.2.4 Efferent Transmitters and Neuropeptides;236
12.2.3;8.2.3 The Most Derived Case: Separate Subsystems of Vestibular and Auditory Efferents of High Complexity in Mammals;236
12.2.4;8.2.4 An Intriguing Case with Many Similarities to Mammals: The Archosaurs (Birds and Crocodilians);237
12.2.4.1;8.2.4.1 Separation of Auditory and Vestibular Efferents;237
12.2.4.2;8.2.4.2 Bilateral Distribution in Archosaurs (Crossed and Uncrossed Efferents);240
12.2.4.3;8.2.4.3 Evidence for Subpopulations of Auditory Efferents;240
12.2.4.4;8.2.4.4 Tonotopic Distribution Along the Avian Basilar Papilla;244
12.2.4.5;8.2.4.5 Efferent Transmitters and Neuropeptides;244
12.2.5;8.2.5 When and Why Did Vestibular and Auditory Efferents Separate?;246
12.2.5.1;8.2.5.1 Amphibians;246
12.2.5.2;8.2.5.2 Turtles;247
12.2.5.3;8.2.5.3 The Lepidosauromorphs (Tuataras, Lizards, Snakes, and Amphisbaenids);248
12.3;8.3 Function of Efferent Innervation to Hair Cells;250
12.3.1;8.3.1 Transferring the Efferents’ Neurochemical Heritage to Hair Cells;250
12.3.1.1;8.3.1.1 Cholinergic Inhibition;250
12.3.1.2;8.3.1.2 CGRP;251
12.3.2;8.3.2 Adding New Levels of Sophistication to the Auditory Efferents;253
12.3.2.1;8.3.2.1 Specializing Together with the Hair Cells: Modulating the Cochlear Amplifier;253
12.3.2.2;8.3.2.2 Modulating Afferents Instead of Hair Cells: A Mammalian Speciality?;255
12.3.2.3;8.3.2.3 Branching Out to Nonsensory Cell Types;255
12.3.3;8.3.3 Still an Enigma: Natural Conditions of Efferent Activity;256
12.3.3.1;8.3.3.1 Protection from Predictable Damage;256
12.3.3.2;8.3.3.2 Improving Signal Detection;258
12.3.3.3;8.3.3.3 A Role for Efferents in Auditory Development?;258
12.4;8.4 Conclusions and Outlook;259
12.4.1;8.4.1 A Plausible Story of Efferent Evolution;260
12.4.2;8.4.2 Interesting Open Questions;261
12.5;References;261
13;Chapter 9: Central Descending Auditory Pathways;272
13.1;9.1 Introduction;273
13.2;9.2 Overview of Central Auditory Structures and the Ascending Pathways;274
13.3;9.3 Brief Historical View of the Descending System;275
13.4;9.4 Divergent Descending Projections from Specific Auditory Regions;277
13.4.1;9.4.1 Projections from the Superior Olivary Complex;277
13.4.2;9.4.2 Projections from the Nuclei of the Lateral Lemniscus;279
13.4.3;9.4.3 Projections from the IC;279
13.4.4;9.4.4 Projections from the Thalamus and Nearby Areas;280
13.4.5;9.4.5 Projections from the Auditory Cortex;282
13.4.5.1;9.4.5.1 Auditory Cortical Projections to the Thalamus;282
13.4.5.2;9.4.5.2 Auditory Cortical Projections to the IC;283
13.4.5.3;9.4.5.3 Auditory Cortical Projections to Nuclei Below the IC;284
13.5;9.5 Convergence of Descending Pathways and Targets in Individual Nuclei;285
13.5.1;9.5.1 Projections to the CN;286
13.5.2;9.5.2 Projections to the SOC;288
13.5.3;9.5.3 Projections to the NLL;289
13.5.4;9.5.4 Projections to the IC;290
13.5.5;9.5.5 Projections to the Thalamus from the AC;291
13.6;9.6 Loops, Chains, and Branches;293
13.7;9.7 Summary and Questions for Future Research;296
13.8;References;297
14;Chapter 10: Central Effects of Efferent Activation;302
14.1;10.1 Introduction;302
14.2;10.2 Single-Neuron Recordings In Vivo;305
14.2.1;10.2.1 Technical Issues;305
14.2.2;10.2.2 Early Work;308
14.2.3;10.2.3 Recent Studies in CN and IC;310
14.2.3.1;10.2.3.1 Effects in Quiet;310
14.2.3.2;10.2.3.2 Effects in Background Noise;313
14.2.4;10.2.4 In Vivo Evidence for MOCS Collateral Involvement in Novel Central Effects;315
14.3;10.3 In Vitro Studies;316
14.4;10.4 Mechanisms of Nonclassic MOCS Effects in Central Neurons;317
14.5;10.5 Behavioral Experiments;319
14.6;10.6 Functional Significance;319
14.7;10.7 Summary;320
14.8;References;321
15;Chapter 11: Corticofugal Modulation and Beyond for Auditory Signal Processing and Plasticity;324
15.1;11.1 Introduction;324
15.2;11.2 Necessity of Multiparametric Corticofugal Modulation;325
15.3;11.3 Research Performed Before 1995;326
15.4;11.4 Experimental Philosophy and Methodology;326
15.4.1;11.4.1 Experimental Philosophy;326
15.4.2;11.4.2 Electric Stimulation of the Primary Auditory Cortex;327
15.4.3;11.4.3 Drug Applications to the Primary Auditory Cortex;327
15.5;11.5 Research After 1995 (General);328
15.6;11.6 Corticofugal Modulation in the Frequency Domain;330
15.6.1;11.6.1 Frequency-Dependent Facilitation and Inhibition and Best Frequency Shifts;330
15.6.2;11.6.2 Expanded and Compressed Reorganizations of Tonotopic Maps;333
15.6.3;11.6.3 Role of Excitation and Inhibition in Producing Two Types of Reorganizations;336
15.6.4;11.6.4 Corticofugal Modulation of Cochlear Hair Cells;337
15.6.5;11.6.5 Ipsilateral vs. Contralateral Corticofugal Modulation;339
15.7;11.7 Multiparametric Corticofugal Modulation;340
15.7.1;11.7.1 Modulation of Duration Tuning in Eptesicus fuscus;340
15.7.2;11.7.2 Modulation of Delay Tuning in Pteronotus parnellii parnellii;342
15.7.3;11.7.3 Modulation of Response Latencies in Eptesicus fuscus;342
15.7.4;11.7.4 Modulation of the Minimum Threshold in Mus domesticus and Eptesicus fuscus;344
15.7.5;11.7.5 Modulation of Spatial Tuning in Eptesicus fuscus;345
15.7.6;11.7.6 Important Principles of Corticofugal Modulation Emerged in Eptesicus fuscus;345
15.8;11.8 Tone-Specific Plasticity (BF shift) Elicited by Auditory Fear Conditioning;345
15.9;11.9 Findings Important for the Understanding of the Neural Circuit Eliciting Tone-Specific Plasticity (the BF Shifts);349
15.9.1;11.9.1 The Corticofugal Auditory System;350
15.9.2;11.9.2 The Primary Auditory Cortex, AI;350
15.9.3;11.9.3 The Thalamic Auditory Nuclei: MGBv vs. MGBm;351
15.9.4;11.9.4 ICc: The Central Nucleus of the Inferior Colliculus;352
15.9.5;11.9.5 The Primary Somatosensory Cortex;352
15.9.6;11.9.6 The Cholinergic Neuromodulator;352
15.9.7;11.9.7 The Amygdala: Inputs from the Sensory Thalamus and Cortex;353
15.9.8;11.9.8 The Prefrontal Cortex;353
15.9.9;11.9.9 The Ascending Reticular Activating System;354
15.10;11.10 The Neural Circuit for Tone-Specific Plasticity: Working Mode;354
15.11;11.11 Corticofugal Differential Gating for Cortical Plasticity: Nonspecific Plasticity Elicited by Pseudo-Conditioning;356
15.12;11.12 Reorganization of the Tonotopic Map Caused by a Cochlear Lesion;357
15.13;11.13 Concluding Remarks: Corticofugal Modulation Shared by Different Animal Species and Different Sensory Systems;357
15.14;References;358
16;Index;364