Audition Flashcards

1
Q

Give the sound pressure level in dB equation

A

=20Log (P/Po). 20 db means it is 100x louder than reference. 40 db means it is 100x louder than reference

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2
Q

What gives rise to timbre?

A

Sum of a variety of individual frequencies

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3
Q

What is the normal range of frequency detection among different humans?

A

20-20,000 hz

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4
Q

What is the peak sensitivity frequency for humans?

A

2-3 kHz.

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5
Q

What is presbycusis

A

hearing loss that occurs in old age

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6
Q

What is the purpose of the external meatus?

A

To boost sound pressure 30-100 fold at frequencies near 3 kHz

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7
Q

What is the attenuation reflex?

A

Stiffening of ossicles by tensor tympani/stapedius to protect ears from loud sounds

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8
Q

how does the middle ear boost sound pressure 200 fold?

A

Large tympanic membrane focuses on small oval window and mechanical advantage from ossicles

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9
Q

Endolymph can be found in the:

A

scala media

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10
Q

perilymph can be found in the:

A

Scala tympani and scala vestibuli

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11
Q

The basilar membrane lies between which two cavities in the cochlea?

A

The scala tympani and the scala media

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12
Q

What is unique about endolymph?

A

has a very high K+ concentration. As a result, it is hyperpolarized to 80 mV compared to perilymph which has a potential of 0 mV

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13
Q

How does the stiffness of the cochlea change from the base to the apex? Which frequencies pass through which parts?

A

narrow, stiffer at base (high frequencies) and wider, more flexible at apex (low frequencies)

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14
Q

Describe the process of depolarization of the inner ear hair cells.

A

As sound passes through basilar membrane, stereocilia are bent, and tip links pull open the plugs on the K+ channels that project into the scala media. K+ floods in (high K in endolymph) causing depolarization, influx of Ca2+ and neurotransmitter release.

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15
Q

How can the same cells be hyperpolarized?

A

If stereocilia are displaced in the opposite direction.

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16
Q

how many rows of outer hair cells? Inner hair cells?

A
outer= 3 rows
Inner= 1 row
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17
Q

What is the membrane potential inside cells? What is the total membrane potential between the endolymph and hair cell?

A

-45; -125mV

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18
Q

When the hair cells vibrate in the basilar membrane, they rub against the…?

A

tectorial membrane

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19
Q

What kind of neurons connect to the inner vs outer hair cells?

A

Inner hair cells connect to afferent neurons. Outer hair cells connect to efferent neurons

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20
Q

What is the electromotility of outer hair cells? What grand purpose does it serve?

A

Increase in length with hyperpolarization. When outer hair cells are longer, it lessens the extent of basilar membrane displacement. When longer, less displacement, less firing of neuron. When shorter, more displacement, more firing of afferent neurons of inner hair cells. This protects the cochlea from damage by dampening vibration. Also can dampen background noise by increasing sensitivity at select frequencies.

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21
Q

Will the afferent neuron firing rate vary with high vs low intensity sounds?

A

Yes. High intensity sounds at the same frequency will have a higher firing rate of neurons

22
Q

The dorsal cochlear nuclei conveys what information about incoming sound?

A

frequency of sound

23
Q

Which level of the CNS is the cochlear nuclei found?

A

lateral portion of rostral medulla

24
Q

What information is conveyed to the superior olive?

A

Sound localization

25
Q

Describe the neuronal pathway of the auditory neurons

A

primary neurons synapse in the cochlear nuclei of the rostral medulla, then travels up to the midpons where it decussates with the superior olive. Then it travels up to the caudal midbrain to synapse in the inferior colliculus. Last neuron travels through medial geniculate complex of the thalamus and synapses in the primary auditory complex

26
Q

how does the medial superior olive perform sound localization?

A

by comparing the time delay of sound arriving in the two ears

27
Q

What information does the lateral superior olive convey?

A

Intensity differences in the two ears. Also helps with sound localization

28
Q

Aside from intensity and time difference in receiving sound btw L and R ears, how else is sound localization performed?

A

Phase differences–good for high frequency tones

29
Q

Where is the primary auditory cortex?

A

In the temporal lobe, inside sylvian fissure

30
Q

What is unique about the arrangement of neurons within the primary auditory cortex?

A

Tonotopic projection–A “map” of frequencies is localized to different sections of the primary auditory cortex

31
Q

There is also a secondary auditory cortex. What is its significance?

A

Cells in these regions are sensitive to specific combinations of sounds used in vocalizations

32
Q

Where is wernicke’s area? What is its significance?

A

Wernicke’s area is posterior to the primary auditory cortex. It is responsible for speech comprehension and auditory/visual inputs

33
Q

What information does the ventral stream processing in auditory pathways?

A

Pitch of sound

34
Q

Where does ventral stream processing occur in the brain?

A

Primary auditory cortex and inferior frontal gyrus

35
Q

Where does dorsal stream processing occur? What information does it convey?

A

Occurs in superior parietal cortex and superior frontal gyrus. Conveys location of sound

36
Q

Where is broca’s area? What information is carried in this location?

A

anterior to the primary motor cortex. IMportant for motor control necessary for speech

37
Q

wernickes aphasia

A

can produce speech but cannot comprehend it. Production of inappropriate incomprehensible speech results

38
Q

Broca’s aphasia

A

Ability to comprehend speech but not produce it

39
Q

what is arcuate fasciculus?

A

white matter tract that connects wernicke’s and broca’s area

40
Q

conduction aphasia

A

Lesion occurring in arcuate fasciculus resulting in conduction aphasia; inability to produce speech

41
Q

Fxn of the supramarginal gyrus?

A

Matching of incoming sounds to meaningful phonemes

42
Q

Fxn of the angular gyrus?

A

Matches graphemes to phonemes

43
Q

What is the McGurk effect?

A

When presented with one sound but given a visual image of a face producing a different sound, will “hear” a third unrelated sound.

44
Q

Difference between conduction vs sensorineural deafness

A

Loss of conduction of sound in outer ear=conduction deafness.
Loss of hair cells or neurons in auditory nerve=sensorineural deafness

45
Q

How does the Rinne test distinguish between conductive versus sensorineural hearing loss?

A

With conductive hearing loss, bone conduction sound is equal or longer than air conduction
With sensorineural hearing loss, air conduction is heard longer than bone conduction, but less than 2:1 ratio

46
Q

What is hyperacusis?

A

Sensitivity to moderate or low intensity sounds

47
Q

What is auditory agnosia?

A

Inability to identify meaning of a nonverbal sound

48
Q

What is congenital amusia?

A

Tone deafness.

49
Q

What is tinnitus?

A

Ringing in the ears, in the absence of any actual sound

50
Q

What is Meniere’s disease?

A

Progressive hearing loss and episodes of vertigo and tinnitus resulting from excess fluid in inner ear