Sensory Systems - Hearing
Page 1: References
Holger Schulze's contact: uk-erlangen.de
Key References:
Schmidt, Lang. Physiologie des Menschen, 30 Aufl. 2007, Springer
Lang, Lang. Basiswissen Physiologie, 2. Aufl. 2007, Springer
Schmidt, Schaible. Neuro- und Sinnesphysiologie, 5. Aufl. 2006, Springer
Müller, Frings. Tier- und Humanphysiologie, 3. Aufl. 2007, Springer
Kandel, Schwartz, Jessel. Principles of Neural Science, 3rd Ed. 1991, Prentice-Hall Intern. Inc.
Moore. An Introduction to the Psychology of Hearing, 4th Ed. 1997, Academic Press
Brady et al. Basic Neurochemistry, 8th Ed. 2012, Academic Press
Squire et al. Fundamental Neuroscience, 2nd Ed. 2003, Academic Press
Page 2: Quote by Helen Keller
"Blindness separates people from things; deafness separates people from people."
Helen Adams Keller (1880-1968): American author, disability rights advocate, political activist, and lecturer
Lost her sight and hearing after an illness at 19 months old.
Page 3: Types of Waves
Sound Waves:
Transversal Waves: Particle motion is perpendicular to wave direction.
Longitudinal Waves: Particle motion is parallel to wave direction.
Page 4: Wave Characteristics
Frequency: Number of cycles per second (Hz)
Phase: Position of a point in time on a waveform cycle.
Amplitude: Maximum extent of a sound wave's oscillation.
Period (s): Time taken for one complete wave cycle.
Illustrated with a diagram showing period and phase relationships.
Page 5: Waveform and Spectrum
Fourier Transformation:
Converts time-domain waveform into frequency-domain spectrum.
Examples included:
Pure tone, square wave, train of pulses, single pulse, white noise
Time in milliseconds vs. Frequency in cps (cycles per second).
Page 6: Mammalian Auditory System Anatomy
Key Structures:
Outer Ear: Pinna
Middle Ear: Ossicles (Malleus, Incus, Stapes)
Inner Ear: Cochlea, Auditory Nerve
Diagram: Cross section of the cochlea showing auditory pathways and components.
Page 7: Sound Detection in Outer Ear
Polar Diagrams:
Schoeps MK4: Freefield polar response, showing amplitude in dB at various frequencies for sound localization.
Page 8: Cochlea Structure and Function
Inner vs. Outer Hair Cells: Different roles in hearing, including vibration detection and sound amplification.
Details on sound propagation through cochlea, oval and round windows, Scala vestibuli, etc.
Page 9: Frequency Analysis and Cochlea Response
Tonotopic Organization: Different frequencies activate different areas along the cochlea length.
Diagram showing responses to various frequency sounds (e.g., 25Hz to 1600Hz).
Page 10: Auditory Transduction
Cupula and Stereovilli:
Mechanisms of sensory cell depolarization and hyperpolarization as hair cells respond to sound waves.
Information transmission to CNS.
Page 11: Endocochlear Potential and Alport Syndrome
Alport Syndrome: Inherited condition involving type IV collagen; affects kidneys, eyes, and ears due to collagen's structural role.
Page 12: Hair Cell Depolarization Mechanism
K+ Ion Channels: Role of potassium in hair cell activation and recovery during sound transduction.
Page 13: Adaptation in Hair Cells
Mechanisms of fast and slow adaptation in auditory hair cells.
Movement response and ion channel dynamics.
Page 14: Outer Hair Cell Function
Detailed structure and function of outer hair cells in sound amplification, including deflection mechanics due to sound waves.
Page 15: Prestin and Hair Cell Movement
Mechanism of prestin (motor protein) in outer hair cells affecting cochlear mechanics.
Page 16: Cochlear Amplification Effects
Békésy model of cochlear mechanics showing variations in wave propagation and amplification dependent on frequency.
Page 17: Organ of Corti and Innervation
A detailed overview of the complex innervation patterns and responses of inner and outer hair cells.
Page 18: Cochlear Nerve Degeneration Research
Research on cochlear nerve responses post-noise exposure, leading to phenomena like "Hidden Hearing Loss."
Page 19: Optogenetic Cochlear Implants
Development and mechanics of optogenetic cochlear implants, addressing sound detection and processing.
Page 20: Cochlear Structure Overview
Cochlear Anatomy: Scala vestibuli, Basilar membrane, Scala tympani and their roles in sound processing.
Page 21: Optogenetic Control of Neuronal Activity
Overview of optogenetic tools and their functionalities in auditory research.
Page 22: New Tools in Optogenetics
Advancements in channelrhodopsin variants and their potential applications in auditory processing research.
Page 23: Auditory Processing Pathways
Overview of sound processing along auditory pathways, including key nuclei and structures integral to sound localization.
Page 24: Sound Pressure and Frequency Coding
Receptive Fields: Activation thresholds for hair cells and their relationship with auditory nerve fibers.
Page 25: Sound Periodicity Analysis and Wever's Theory
Explanation of periodicity coding in the auditory nerve, particularly in terms of action potentials and pitch perception.
Page 26: Huygens Principle and Wave Theory
Historical perspective on wave theory as related to sound propagation.
Page 27: Nucleus Cochlearis Tonotopy
Tonotopic organization of the cochlear nucleus, outlining the processing of auditory information.
Page 28: Cochlear Nucleus Cell Types
Description of different cell types within the cochlear nucleus, including their roles in sound processing.
Page 29: Physiology of Cochlear Nucleus Cells
Characterization of various cell types and their firing rates in response to sound stimuli.
Page 30: Sound Localization Mechanisms
Examination of interaural time differences in sound localization within the superior olive complex.
Page 31: Lateral Superior Olive (LSO) Function
Function and significance of LSO in sound localization, detailing inhibitory and excitatory interactions.
Page 32: Medial Superior Olive (MSO) Mechanisms
Explanation of delay lines and coincidence detectors in sound localization tasks involved in MSO processing.
Page 33: ITD Coding in MSO
Study of ITD coding in mammalian auditory systems and the absence of delay lines.
Page 34: Sound Localization Under Water
Comparison of sound speed in air vs. water, emphasizing unique challenges in underwater acoustics.
Page 35: Functional Organization of the Inferior Colliculus
Overview of tonotopic and periodotopic organization within the inferior colliculus for auditory processing.
Page 36: Change from Temporal to Rate-Place Code
A proposed shift in coding strategies in auditory processes, including autocorrelation mechanisms.
Page 37: Auditory Cortex Organization
Structure and functional organization of the auditory cortex, emphasizing tonotopy related to cochlear base and apex.
Page 38: Auditory Cortex Tonotopy
Discordance in tonotopic representation across species, illustrating diversity in auditory processing.
Page 39: Auditory Pathways in Human Brain
Schematic representation of "What" and "Where" pathways in auditory processing.
Page 40: Tinnitus and Neural Plasticity
Discussing maladaptive changes in auditory pathways leading to tinnitus.
Page 41: Historical Accounts of Tinnitus
Overview of historical descriptions of tinnitus by notable figures.
Page 42: Socioeconomic Costs of Tinnitus in Germany
Statistical data on the impact and costs of tinnitus treatment and management in Germany.
Page 43: Animal Models in Tinnitus Research
Discussion on animal models used to assess tinnitus via various experimental methods.
Page 44: Induction of Tinnitus in Animal Models
Overview of how tinnitus is induced using salicylate and noise trauma.
Page 45: Effects of Drug vs. Noise Trauma
Comparative table showing the effects of various substances and trauma on auditory activity and tinnitus.
Page 46: Mechanisms of Salicylate vs. Trauma
Neurophysiological differences between tinnitus models induced by drugs compared to noise trauma.
Page 47: Behavioral Assessment in Tinnitus Research
Overview of behavioral assessments, particularly GPIAS (Gap-prepulse inhibition of the acoustic startle reflex).
Page 48: Testing Chamber for Tinnitus Research
Description of the experimental setup for assessing tinnitus in animal models.
Page 49: Understanding GPIAS
Explanation of Gap-prepulse inhibition and its significance in auditory research.
Page 50: Tinnitus and Stochastic Resonance
Examination of how stochastic resonance relates to tinnitus development in research.
Page 51: Hearing Thresholds in Tinnitus Patients
Statistical data and analysis on hearing thresholds among tinnitus patients.
Page 52: Stochastic Resonance Issues
Discussing the concepts around hidden hearing loss and its impact on auditory thresholds.
Page 53: Stochastic Resonance Research Findings
Findings on the implications of stochastic resonance in auditory pathways.
Page 54: Autocorrelation in Neuronal Models
Detailed explanation of neuronal autocorrelation models and their relevance to sound processing.
Page 55: Impact of Background Noise on Hearing
Research findings on how external noise may enhance auditory threshold levels.
Page 56: Proposed Therapy for Tinnitus
Exploring low-intensity noise as a potential therapeutic approach for tinnitus management.
Page 57: Low-Intensity Noise Tinnitus Suppression (LINTS)
Overview of therapeutic implementations of LINTS and its practical use in patients.
Page 58: The 5 kHz Frequency Border in Tinnitus
Discussion on the significance of the 5 kHz border in understanding tinnitus and sound processing.
Page 59: A Neurophysiological Correlate of Tinnitus
Insights into neural correlates associated with subjective tinnitus experiences.
Page 60: Cortical Activity Patterns in Tinnitus
Analysis of local field potential activity patterns related to tinnitus perception.
Page 61: Cortical Activity Cluster Analysis
Investigation of auditory cortex activity before and after the induction of tinnitus.