Syllabus

Anyone interested in auditory perception and the underlying neural mechanisms. The course is required for graduate students in the Speech and Hearing Bioscience and Technology Program. It is also appropriate for students in Electrical Engineering and Computer Science or Brain and Cognitive Sciences with an interest in hearing. Some familiarity with peripheral mechanisms of hearing (how the ear works) and biophysics of neurons is expected. Appropriate prerequisites include HST.714/6.551, HST.721, 6.521J/HST.541J, or 9.04. Students unsure of their background should consult one of the instructors.

The course is organized by themes typically comprising lectures, laboratory exercises and discussions of scientific papers. The six themes include:

    1. Masking and frequency selectivity
    2. Cellular mechanisms in the cochlear nucleus
    3. Binaural interactions
    4. Pitch and temporal coding
    5. Neural maps and plasticity 
    6. Deafness and hearing impairment

Below is an outline of the topics discussed within each theme.

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

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

Masking and frequency selectivity:

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

Loudness and intensity perception:

• Loudness
• Stevens' law
• Intensity discrimination
• Weber's law and its near miss
• Relation of loudness to intensity

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

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

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

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

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

Neural coding 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 in the auditory pathway

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

The human auditory system:

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

Neural maps and feature detectors:

• Echolocation in bats
• Feature detector neurons in the bat auditory cortex
• The binding problem

• Reduced frequency selectivity
• Loudness recruitment and nonlinear compression
• Spatial resolution

Cochlear Implants:

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

30%    Final exam
30%    Written theme discussion reports
25%    Laboratory reports
15%    Oral paper presentations and class participation

Theme discussion reports are due one week after the last discussion session for the theme. 

Laboratory reports are due one week after the lab session. 

The theme reports and oral paper presentations are unusual assignments that you may be unfamiliar with.