Lecture 8 Flashcards

(11 cards)

1
Q

auditory nerve anatomical arrangement

A

high frequency fibres located on outside

low frequency fibres located in the middle

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2
Q

what type of neuron encodes sound information

A

Type I

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3
Q

auditory nerve spontaneous activity

A

there is activity in regions of the auditory nerve that are not being maximally displaced or even in the absence of sound

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4
Q

parameters that contribute to pitch perception (frequency coding)

A
  1. Place of stimulation (place code, passive)
  2. OHC contribution (active)
  3. Temporal code (phase locking)
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5
Q

tuning curves along the cochlea

A

base –> sharp tuning curves (high freq)
apex –> broad and wide tuning curves (low freq)

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6
Q

Is temporal code/phase locking more important in the base or the apex

A

APEX: low frequencies phase lock well

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7
Q

what is the origin of phase locking

A

the hair cell, the receptor potential

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8
Q

phase locking in low vs high frequency

A

low: action potential fires at the same angle of sound pressure wave, phase locks well

high: sound pressure waves are much narrower, so AP firing occurs at different angles of the sinusoidal wave, some but maximum 30% phase locked

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9
Q

intensity coding: the three neural parameters coding loudness

A

Number of neurons firing (louder it is the more neurones fire)

Rate of Neural firing (louder, higher firing)

Threshold of neurons firing (Type I)

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10
Q

intensity coding: threshold of type I auditory nerve fibres variation

A

Low S/R
- high threshold (fire with high intensity sound)
- located modiolar side of IHC
- smaller synapse wth IHC

High S/R
- low threshold (fire in low intensity sound)
- located pillar side of IHC
- larger synapse with IHC

S/R = spontaneous rate

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11
Q

Which threshold Type I neurons normally lost first

A

low S/R –> they discriminate sound in noise, think cocktail effect

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