PSYCH 454 Lecture Notes - Lecture 11: Spiral Ganglion, Cochlear Nerve, Arnold Tongue
24 May 2018
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Lecture 11: From Ear to Thalamus- Auditory Responses/Nerve (3)
Auditory Nerve
●Pathway: hair cell → spiral ganglion cell → many form auditory nerve
●Cochlea sends information via auditory nerve
○Hair cells connected to spiral ganglion cells
○Axons of spiral ganglion cells form auditory nerve
○Spiral ganglion contains cell bodies of spiral
ganglion cells
●Each spiral ganglion cell has “best frequency”
○Also called “characteristic frequency”
○@ low frequency→ little response from spiral
ganglion cells
■@ 1600 hz → MAXIMAL response from
spiral ganglion cells
■@ 2500 Hz→ low response again
○@ high frequency: same pattern just a little higher overall
○Note: if you increase sound level → increase in response
●Main point: each spiral ganglion ganglion cell has maximal response → called
characteristic frequency
○Some respond to low freq maximally, vice versa
●Auditory nerve tonotopically
organized
○Best frequency changes systematically across nerve→ some respond to high
frequencies, some respond to low
Auditory Nerve Responses types of cells in auditory nerve responses:
●At low frequencies (<4kHz)
○Neurons fire AP @ particular phase of the sound wave
■→ called “phase locking
” → in that AP’s are locking in a particular phase
of sound wave
■Can have 2 types… 1) phase locked every cycle or 2) phase locked, but
not on every cycle
●**Provide frequency information
●At high frequencies (>4khz)
○Phase locking does NOT occur → AP is not fired at a specific moment in
frequency
○Frequency information must be derived from tonotopic arrangement
of auditory
nerve fibers
Document Summary
Lecture 11: from ear to thalamus- auditory responses/nerve (3) Pathway: hair cell spiral ganglion cell many form auditory nerve. Hair cells connected to spiral ganglion cells. Axons of spiral ganglion cells form auditory nerve. Spiral ganglion contains cell bodies of spiral ganglion cells. Each spiral ganglion cell has best frequency . @ low frequency little response from spiral. @ 1600 hz maximal response from. @ 2500 hz low response again spiral ganglion cells ganglion cells. @ high frequency: same pattern just a little higher overall. Note: if you increase sound level increase in response. Main point: each spiral ganglion ganglion cell has maximal response called characteristic frequency. Some respond to low freq maximally, vice versa. Best frequency changes systematically across nerve some respond to high frequencies, some respond to low. Auditory nerve responses types of cells in auditory nerve responses: Neurons fire ap @ particular phase of the sound wave.
