HST.723J | Spring 2005 | Graduate

Neural Coding and Perception of Sound


Lec 1

Hearing and the Auditory System: An Overview

Stages of processing in the auditory system and their function. Detection, localization and recognition of sounds. Subjective and objective variables and experiments. Auditory demonstrations.

Theme 1: Masking and Frequency Selectivity
Lec 2

How the Ear Works (Functional Cochlear Mechanics)

Cochlear tuning. Hair cell transduction. Nonlinearities. The cochlear amplifier. Otoacoustic emissions.

Lec 3

Stimulus Coding in the Auditory Nerve

The AN as an information conduit. Frequency tuning. Nonlinearities. Relation of AN activity to cochlear processing. Neural variability as a limit on psychophysical performance. Compound action potential.

Lab 1 What was the Stimulus?

Lec 4

Masking and Frequency Selectivity

Psychophysical techniques. Signal detection theory. Power spectrum model of masking. Techniques for measuring auditory filters. Psychophysical effects of cochlear nonlinearities.

Lec 5 Masking and Nonlinearity

Lec 6 Masking and Nonlinearity (cont.)

Lec 7

Cochlear Implants

Electrodes and processors. Basic auditory capabilities of implantees. Effect of electrode configuration. Processor design. Bilateral implants.

Lab 2 Fundamentals of Perceptual Audio Encoding

Lec 8

Intensity Perception and Cochlear Hearing Loss

Loudness. Stevens’ law. Intensity discrimination. Weber’s law and its near miss. Relation of loudness to intensity. Consequences of reduced frequency selectivity and loss of cochlear amplifier in cochlear hearing impairment.

Theme 1 written report due
Theme 2: Cellular Mechanisms in the Cochlear Nucleus
Lec 9

Channels, Synapses and Neurotransmitters

Excitatory and inhibitory synaptic transmission. Neurotransmitters and receptors. Second messengers.

Lec 10

Cellular Mechanisms in the Cochlear Nucleus

Parallel processing pathways in the cochlear nucleus. Correlation of cell types with response types. Neural specializations for temporal processing.

Lec 11 Cellular Mechanisms in the Cochlear Nucleus (cont.)

Lab 3 Single-unit Typing in the Cochlear Nucleus

Lec 12 Cellular Mechanisms in the Cochlear Nucleus (cont.)

Theme 3: Binaural Interactions
Lec 13

Binaural Hearing

Localization and lateralization. Cues for sound localization. Sensitivity to binaural cues. The Jeffress model. The precedence effect. Binaural detection.

Lec 14

Binaural Interactions in the Auditory Brainstem

Neural circuitry and cellular specializations for binaural processing. Two basic forms of binaural interactions. Transformations of binaural information in the auditory pathway.

Theme 2 written report due
Lec 15 Binaural Interactions

Lab 4 Neuroanatomy Demonstrations

Lec 16 Binaural Interactions (cont.)

Lab 5 Compartmental Model of Binaural Coincidence Detector Neuron

Theme 4: Pitch and Temporal Coding
Lec 17

Pitch of Pure and Complex Tones

Pitch of pure and complex tones. Virtual pitch. Place and temporal models of pitch. Role of pitch in auditory scene analysis.

Theme 3 written report due
Lec 18

Neural Processing of Pitch

Rate and temporal codes. Temporal envelope and fine structure. Interspike interval representation of pitch. Tuning to modulation frequency and its possible role in pitch coding. Transformations of temporal information along the auditory pathway.

Lec 19 Pitch and Temporal Coding

Lec 20 Pitch and Temporal Coding (cont.)

Theme 5: Neural Maps and Plasticity
Lec 21

Auditory Cortex: Cortical Organization

Cortical areas and layers. Thalamo-cortical and cortico-cortical projections. Tonotopy. Columnar organization. Parallel and hierarchical processing. Functions of the cortex.

Theme 4 written report due
Lec 22

The Human Auditory System

Imaging modalities: fMRI, MEG, AEP. Tonotopy in human auditory cortex. What and where pathways. Tinnitus-related abnormalities in brain activation.

Lec 23 Neural Maps and Plasticity

Lec 24 Neural Maps and Plasticity (cont.)

Theme 6: Auditory Scene Analysis and Object Formation
Lec 25

Auditory Scene Analysis (ASA) and Object Formation

Bottom-up (“primitive”) and top-down (“schema based”) mechanisms. Simultaneous processes in ASA: Harmonicity, Onset/offset asynchrony, Co-modulation. Sequential processes: Auditory streaming.

Theme 5 written report due
Lec 26 Scene Analysis

Final Exam Theme 6 written report due