Audition

Question 1

Give the sound pressure level in dB equation

Answer 1

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

Question 2

What gives rise to timbre?

Answer 2

Sum of a variety of individual frequencies

Question 3

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

Answer 3

20-20,000 hz

Question 4

What is the peak sensitivity frequency for humans?

Answer 4

2-3 kHz.

Question 5

What is presbycusis

Answer 5

hearing loss that occurs in old age

Question 6

What is the purpose of the external meatus?

Answer 6

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

Question 7

What is the attenuation reflex?

Answer 7

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

Question 8

how does the middle ear boost sound pressure 200 fold?

Answer 8

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

Question 9

Endolymph can be found in the:

Answer 9

scala media

Question 10

perilymph can be found in the:

Answer 10

Scala tympani and scala vestibuli

Question 11

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

Answer 11

The scala tympani and the scala media

Question 12

What is unique about endolymph?

Answer 12

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

Question 13

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

Answer 13

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

Question 14

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

Answer 14

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.

Question 15

How can the same cells be hyperpolarized?

Answer 15

If stereocilia are displaced in the opposite direction.

Question 16

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

Answer 16

outer= 3 rows
Inner= 1 row

Question 17

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

Answer 17

-45; -125mV

Question 18

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

Answer 18

tectorial membrane

Question 19

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

Answer 19

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

Question 20

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

Answer 20

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.

Question 21

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

Answer 21

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

Question 22

The dorsal cochlear nuclei conveys what information about incoming sound?

Answer 22

frequency of sound

Question 23

Which level of the CNS is the cochlear nuclei found?

Answer 23

lateral portion of rostral medulla

Question 24

What information is conveyed to the superior olive?

Answer 24

Sound localization

Question 25

Describe the neuronal pathway of the auditory neurons

Answer 25

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

Question 26

how does the medial superior olive perform sound localization?

Answer 26

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

Question 27

What information does the lateral superior olive convey?

Answer 27

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

Question 28

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

Answer 28

Phase differences--good for high frequency tones

Question 29

Where is the primary auditory cortex?

Answer 29

In the temporal lobe, inside sylvian fissure

Question 30

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

Answer 30

Tonotopic projection--A "map" of frequencies is localized to different sections of the primary auditory cortex

Question 31

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

Answer 31

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

Question 32

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

Answer 32

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

Question 33

What information does the ventral stream processing in auditory pathways?

Answer 33

Pitch of sound

Question 34

Where does ventral stream processing occur in the brain?

Answer 34

Primary auditory cortex and inferior frontal gyrus

Question 35

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

Answer 35

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

Question 36

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

Answer 36

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

Question 37

wernickes aphasia

Answer 37

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

Question 38

Broca's aphasia

Answer 38

Ability to comprehend speech but not produce it

Question 39

what is arcuate fasciculus?

Answer 39

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

Question 40

conduction aphasia

Answer 40

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

Question 41

Fxn of the supramarginal gyrus?

Answer 41

Matching of incoming sounds to meaningful phonemes

Question 42

Fxn of the angular gyrus?

Answer 42

Matches graphemes to phonemes

Question 43

What is the McGurk effect?

Answer 43

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

Question 44

Difference between conduction vs sensorineural deafness

Answer 44

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

Question 45

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

Answer 45

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

Question 46

What is hyperacusis?

Answer 46

Sensitivity to moderate or low intensity sounds

Question 47

What is auditory agnosia?

Answer 47

Inability to identify meaning of a nonverbal sound

Question 48

What is congenital amusia?

Answer 48

Tone deafness.

Question 49

What is tinnitus?

Answer 49

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

Question 50

What is Meniere's disease?

Answer 50

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