Sensation & Perception Final Exam Study Guide (new material only)

Lecture 14: Intro to Sound & Hearing

• Basics of Sound
  • Sound as (longitudinal) waves of pressure
  • Amplitude, wavelength, frequency
  • How does the speed of sound change with the medium carrying it?
  • Relationship between intensity → loudness, and frequency → pitch
  • Units for measuring intensity and frequency
    • be sure to know both of these units and how they are defined
  • Range of human hearing (in frequency and intensity)
  • Sound waves/pure tones
  • Fourier analyses
  • Harmonic spectrum, harmonics, timbre
• The Mammalian Auditory System
  • Peripheral auditory system
    • be sure to know the major parts and functions of each
    • Outer ear: pinnae & ear canals
    • Middle ear: tympanic membrane, ossicles
      • amplification in middle ear
    • Inner ear: the cochlea and auditory nerve
      • Oval window, round window
      • Major canals and membranes
      • Organ of corti
  • Operation of the Cochlea
    • Hair cells/stereocilia
      • Inner hair cells vs. outer hair cells
    • Vibration of basilar membrane
    • Shearing of hair cells, tip links → neural transduction
• Encoding Sound
  • The place code & properties of the basilar membrane
    • coding of amplitude vs. frequency
  • Auditory nerve (AN) fibers, threshold tuning curves, & characteristic frequencies
  • AN fiber tuning:
    • Influence of outer hair cells
    • Effects of intensity
    • High vs. low spontaneous fibers
  • The temporal code for sound frequency
    • Phase locking
    • The volley principle and combining information across AN fibers
• Auditory Brain Structures:
  • Superior olive
  • Medial geniculate nucleus (MGN)
  • Primary auditory cortex (A1)
• Structure of Auditory vs. Visual System
  • Locus of processing
  • Topography
• Psychoacoustics
  • Frequency masking and critical bandwidths
  • White, broadband, and narrowband noise
• Hearing Loss
  • Conductive vs. Sensorineural loss
  • Causes of sensorineural loss (e.g., aging & noise-induced loss)
  • Hearing aids and cochlear implants

Lecture 15: Hearing in the Environment (Chapter 10)

• Sound localization
  • The problem of auditory vs visual auditory discrimination
  • Directions in sound localization: azimuth, elevation, & distance
• Sound localization cues
  • Interaural time difference (ITD)
    • ITD as a function of azimuth and frequency
    • Physiology of ITD and the role of medial superior olive (MSO)
    • Coincidence-detector model (Jeffress model) of ITD detection
  • Interaural level differenc (ILD)
    • Cause: sound shadow
    • ILD as a function of azimuth and frequency
    • Explanation for differential frequency effects (long vs. short waves)
    • Physiology of ILD and the role of lateral superior olive
  • Strengths and weaknesses of ITD vs. ILD
  • Cone(s) of confusion: ambiguities in auditory localization via ITD and ILD
  • Head related transfer functions (HRTFs)/ Directional transfer functions (DTFs)
    • Direction-related filtering
    • Depend on characteristics individual pinnae
    • provide information about source location in 3D
  • Auditory distance perception
    • Intensity (inverse square law)
    • Spectral composition
    • Reverberant energy
• Complex sounds
  • Harmonics
    • Pitch perception and the “missing” fundamental
  • Spectrograms
  • Timbre
  • Attack and Decay

Lecture 18: Somatosensation (Chapter 13)

• Different classes of somatosensation
  • Tactile (“touch”) sensation
  • Thermal sensation
  • Pain sensation
  • Proprioception & Kinesthesia
• Physiology of somatosensation
  • Physiology of tactile (touch) sensation
    • Touch receptors in and under epidermis
    • Receptor classifications
      1. Type of stimulation
      2. Size of receptive fields: small vs. large → type I vs. type II
      3. Rate of adaptation: slow vs. fast
    • Meissner corpuscles, Merkel complexes, Pacinian corpuscles, Ruffini endings
  • Physiology of thermal sensation (thermoception)
    • Thermoceptors: warmth vs. cold fibers
    • bare nerve endings
  • Physiology of pain sensation (Nociceptors)
    • bare nerve endings
    • Two groups of nociceptors: A-delta vs. C fibers
    • Benefits of pain perception
  • Physiology of kinesthesia
    • Kinesthetic receptors: muscle spindles and Golgi tendon organs
    • Ian Waterman and importance of kinesthetic sensation
  • Physiology of touch in spinal cord
    • labeled lines
    • dorsal horn
    • two pathways
      • spinothalamic (for thermoception and nociception)
      • dorsal column medial lemiscal (DCML; for tactile perception and kinesthesia)
  • Cortical physiology
    • S1 and S2
    • The somatosensory homunculi
    • Neural plasticity
    • Pain: anterior cingulate and prefrontal cortex
  • Body images
• Somatosensory perception
  • Pain
    • analgesia
    • gate theory of pain
    • pain sensitization
  • Tactile sensitivity
    • Psychophysics
      • monofilament touch detection
      • detection of a raised bump
      • two touch discrimination
    • Sensitivity and acuity as a function of position on the body
    • Effects of aging
  • Haptic perception
    • Perception for action
    • Action for perception
      • exploratory procedures
      • vibration frequency and haptic texture recognition
    • The What system of touch
    • The Where system of touch
    • Biases and distortion in the perception of haptic space
    • Multimodal/intersensory perception