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Hearing

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					Hearing
   What is a sound?
   Intensity & Frequency
Hearing
       Outer Ear
Hearing
   Middle Ear
   The bones are
    designed to
    transfer an air
    pressure wave
    into a fluid
    pressure
    wave. This
    requires 20x
    amplification
Hearing
   Attenuation Reflex
   Small muscles
    respond when
    sound is too loud;
    greater attenuation
    at low frequencies;
    no protection from
    sudden loud
    sounds; protects
    you from your own
    voice
Hearing

   Cochlea
    (Snail)
Hearing

   Cochlea (Snail)
   Three
    chambers:
    Scala Vestibuli;
    Scala Media;
    Scala Tympani
   Organ of Corti
Hearing
   Organ of Corti
   Basilar
    Membrane
   Hair Cells
   Tectorial
    Membrane
Hearing
   Response of
    the Basilar
    Membrane
Hearing
   Response of the Basilar Membrane
Hearing
   Response of the Basilar Membrane
Hearing
   Organ of Corti
Hearing
   Organ of Corti
Hearing
   Organ of Corti
Hearing
   Cilia
Hearing
   Cilia
Hearing
   Cilia
Hearing
   Cilia
Hearing
   Amplification
    by the Outer
    Hair Cells
Hearing
   Pathways in the
    Nervous System
Hearing
   Processing
    Sound
    Frequency
   The Basilar
    Membrane
Hearing
   Processing Sound
    Frequency
   The Basilar Membrane
Hearing
   Processing Sound Frequency
   The Basilar Membrane
Hearing
   Processing Sound Frequency
   The Basilar Membrane
Hearing
   Processing Sound
    Frequency
   Response of Hair
    Cells to fluctuations
    in the Basilar
    Membrane
Hearing
   Processing
    Sound
    Frequency
   Characteristic
    Frequency of
    an auditory
    neuron
Hearing
   Processing Sound Frequency
   The Auditory Nerve
Hearing Sound Frequency
Phase Locking causes large numbers of neurons to
  fire in bursts with higher frequencies causing faster
  bursting
Hearing
   Processing Sound Frequency
   Tonotopic structure of the Auditory Nerve
Hearing
   Processing Sound Frequency in the Cochlea
   1. Sound pressure is communicated to the cochlea
   2. The basilar membrane vibrates consistent with the
    composite frequencies in the sound
   3. Outer hair cell cilia bend with the sound pressure
    wave
   4. The motile response of the outer hair cells
    amplifies the basilar membrane response
   5. These factors are communicated to the inner hair
    cells
   6. Neurons respond by phase-locked firing patterns
    that convey a limited range of frequency response
Hearing
   Processing Sound
    Frequency
   Cortical processing
Hearing
   Cochlear Implants
Hearing
   Processing Sound Frequency
   Periodicity or Virtual Pitch: a and c below are
    perceived almost the same
Hearing
   Processing Sound Frequency
   Pitch Streaming

				
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posted:7/22/2011
language:English
pages:33