Sph 380 Test #1

Front 1

What are the four pieces of info that one can obtain from a rate-level function?

Back 1

Spontaneous rate, threshold, dynamic range and saturation

Front 2

How does the neural-response threshold depend on the spontaneous response rate?

Back 2

High Spontaneous Rate=Low threshold

Front 3

List three pieces of information that a tuning curve shows

Back 3

best frequency
sensitivity
sharpness

Front 4

What is the ‘dynamic-range problem’ in hearing?

Back 4

Single nerve only covers 30 dB but all of hearing is 120 dB

Front 5

How does the auditory system overcome the dynamic-range problem, list two mechanisms?

Back 5

1. Combine fibers at same best frequencies with different thresholds
2. Combine fiber at different best frequencies with same thresholds

Front 6

What is the basis for the place coding of stimulus frequency?

Back 6

Place theory- frequency mapped to place

Hint 6

Think how each frequency corresponds to a specific place on BM, and how a change in stimulus frequency will cause the maximum neural response to move from one neuron (location on BM) to the next neuron.

Front 7

What is the basis for the temporal coding of stimulus frequency?

Back 7

Temporal theory- frequency represented by temporal pattern of discharges

Hint 7

Think how each frequency coresponds to a specific temporal pattern in the neural discharge (ex the regular intervals at which the peaks are in an interval histogram), and how a change in stimulus frequency will cause the temporal pattern to change (ex increasing fq leading to shortened intervals between peaks in the interval histogram)

Front 8

Which type of histograms of auditory nerve discharge shows the neural activity can follow the temporal variation of the stimulus amplitude?

Back 8

PST
period
interval

Front 9

List four pieces of information or characteristics that can be observed in a PST histogram in response to a steady tone.

Back 9

spontaneous activity
onset response
adaptation
recovery

Front 10

In a two-tone suppression, describe what happens to the neural response to a primary tone is affected when a second tone at an adjacent frequency is introduced.

Back 10

reduction of discharge rate

Front 11

What combinations of level and frequency for the second tone are necessary for two-tone suppression to occur?

Back 11

Look for the shaded region and if the tone is in that level of frequency and level of dB it will mask it

Hint 11

remember the tuning curve with a shaded area on each side

Front 12

What is the significance in auditory function of two-tone suppression?

Back 12

masking

Hint 12

two tone suppression serves as a mechanism in a important phenomenon of auditory perception

Front 13

(Very Important) Describe the sequence of events that takes place in the inner ear during sound stimulation from the stapes to the auditory nerve.

Back 13

Stapes vibrates,
fluid vibrates,
Basilar Membrane vibrates,
bends outside hair cells and
OHC depolarizes and contracts and expands,
pumps energy back to BM
energy picked up by IHCs, depolarizes IHCs
leads to release of neurotransmitter
auditory nerve

Hint 13

ALL these activities follow the stimulus frequency!

Front 14

Which scala inside the cochlea houses the hair sells?

Back 14

Scala Media

Front 15

What is the fluid and the potential inside the scala media?

Back 15

Endolymph
+80 mV

Front 16

What’s the fluid and the potential inside the other two scalas?
(scala vestibuli, scala tympani)

Back 16

perilymph

Front 17

Of which ion does the endolymph fluid have a high concentration?

Back 17

K+

Front 18

Perilymph has a high concentration of what ion?

Back 18

Na+

Front 19

What is the resting potential inside the hair cells?

Back 19

-70 mV

Front 20

Describe how the physical properties (width and stiffness) and the resonant frequency change along the basilar membrane.

Back 20

stiff and narrow near the base, tuned to high frequencies

Front 21

What the typical length of a human cochlear

Back 21

35mm

Front 22

How many turns does the cochlear coil?

Back 22

2.5 turns

Front 23

Which OAE is evoked by clicks?

Back 23

TEOAE

Front 24

Which OAE is evoked by a pair of tones?

Back 24

DPOAE

Front 25

The vast majority of the auditory afferent nerves are of this type of nerve fibers.

Back 25

type I

Front 26

On which hair cells do the auditory afferent nerve fibers have synapses?

Back 26

IHC

Front 27

Which hair cells receive about 90% afferent fibers?

Back 27

IHC

Front 28

From how many IHCs does each auditory nerve receive input?

Back 28

ONE

Front 29

Within the nerve bundle leaving the cochlea, to what frequencies are the nerves in the middle tuned?

Back 29

low fq

Front 30

What are the two major functions of the OHC amplification?

Back 30

sensitivity and
frequency selectivity

Front 31

Which two hearing abilities will be affected by damages to the OHCs?

Back 31

Lose sensitivity and frequency selectivity
(tuning curve will not be as sharp and lose soft sounds)

Front 32

What is the major function of the IHCs?

Back 32

transduction from mechanic vibration to neural activity

Front 33

What happens to the hearing in a frequency region where the OHC are intact but the IHCs are gone?

Back 33

no hearing

Front 34

Which two membranes are the hair cells sandwiched in between?

Back 34

TM and BM

Front 35

During sound stimulation, what causes the stereocilia to bend?

Back 35

Relative motion between the TM and BM

Front 36

Why does the BM have the max response to low frequency tones near the apical end, and a max response to high frequency tones near the basal end?

Back 36

Resonance

Front 37

What are the two arguments supporting that BM traveling wave is not the same kind of traveling wave as the travels on a long rope after a person shakes it at one end?

Back 37

1. You can cut it
2. it doesn't have to travel away from the source

Front 38

Which structure is likely the source of the endocochlear potential?

Back 38

striavascular

Front 39

The relative motion between the TM and the BM leads to_______, which leads to ________

Back 39

The relative motion between the TM and the BM leads to BENDING CILIAS, which leads to DEPOLARIZATION

Front 40

Which of the cochlear potentials is present in the absence of the acoustic stimulation

Back 40

resting potential

Front 41

Why is the Alternating Current component of the cochlear potential the “cochlear microphonic”?

Back 41

bc you can hook it up to a PA system

Front 42

What is the potential difference across the top of the hair cells between the inside and outside of the hair cells?

Back 42

150mV
(the highest is +80, inside resting is -70)

Front 43

List the major outer and middle ear structures (that are of functional importance) in the correct order from pinna to oval window

Back 43

Pinna
cocha,
ear canal,
tympanic membrane,
three ossicles,
oval/round windows;
middle ear ligaments/muscles
E. tube

Front 44

What is the amount of the maximum boost in dB to the sound due to the ear-canal resonance?

Back 44

10-15 dB

Front 45

What is the frequency of the maximum boost in dB due to ear canal resonance?

Back 45

2-3 kHz

Front 46

What is the maximum boost in dB to the sound due to the concha resonance

Back 46

10 dB

Front 47

What is the frequency of the maximum boost in dB due to concha resonance?

Back 47

5 kHz

Front 48

What is the primary function of the middle ear?

Back 48

overcome inpedance

Front 49

Describe the three middle-ears mechanisms that contribute to overcoming mismatch of impedance.

Back 49

Area 25 dB; lever 2 dB, buckling motion 6 dB

Front 50

What is the amount of the peak of max gain in DB that the middle ear transfer function shows?

Back 50

30 dB

Front 51

At what frequency does the middle ear transfer function show the max gain

Back 51

1000 Hz

Front 52

What is the primary function of the E tube?

Back 52

equalizing pressure

Front 53

Due to the presence of pinna, sounds coming from different directions will be affected differently upon reaching the eardrum. In which aspect does the pinna cause the sounds to change?

Back 53

spectral shape

Front 54

what's the consequence of blocking the E tube

Back 54

hearing loss

Front 55

The inner ear includes the following structures:
vestiblue
scala tympani
basilar membranek
all of the above

Back 55

all of the above

Front 56

The basilar membrane is:

narrow and stiff at the base and wide and flexible at the apex

narrow and flexible at the base and wide and stiff at the apex

wide and stiff at the base and narrow and flexible at the apex

wide and flexible at the base and narrow and stiff at the apex

Back 56

narrow and stiff at the base and wide and flexible at the apex

Front 57

Select the best answer from the following statements about BM responses to tones:
a. The basal end has max response to low frequency tones and the apical end to high frequency tones
b The basal end has max response to high frequency tones and the apical end to both high and low frequency tones
c The basal end has max response to high frequency tones and the apical end to low frequency tones
d Both the basal and the apical ends respond to all frequencies

Back 57

c The basal end has max response to high frequency tones and the apical end to low frequency tones

Front 58

Which of the following structures will respond to a tone at its frequency?
Basilar membrane
inner hair cells
stapes and outer hair cells
All of above

Back 58

All of above

Front 59

Which of the following is responsible for the frequency analysis by the basilar membrane?
The travelling wave moves from the base to apex within the cochlea

Different parts of the basilar membrane have different resonant frequencies

Low-frequency tones take longer time to travel down the BM than higher-frequency tones

The travelling wave moves away from the the oval window

Back 59

Different parts of the basilar membrane have different resonant frequencies

Front 60

Which of the following structure is likely the source of the endocochlear potential?
OHC tip links
Exchange of fluid at helicotrema
modiolus at the center of the cochlea
stria vascularis

Back 60

stria vascularis

Front 61

The relative motion between the tectorial membrane and the basilar membrane leads to
the bending of the OHC cilia and the OHC depolarization
the bending of the IHC cilia and the IHC depolarization
the OHC motility and the release of neurotransmitter in the IHC
All of above

Back 61

All of above

Front 62

While the ___ serve to enhance sensitivity and frequency selectivity the ___ serve a role in sensory transduction for hearing
OHCs; efferent fibers
IHCs; OHCs
IHCs; ANs
OHCs; IHCs

Back 62

OHCs; IHCs

Front 63

In human cochlea, each auditory nerve innervates mostly ______ IHC(s) and each IHC receive ____ auditory nerve(s)
one; eight
16 to 20; one
one; 16 to 20
10; 10

Back 63

one; eight

Front 64

Within the nerve bundle leaving the cochlea
the ANs innervating high frequency are in the middle
the ANs innervating low frequency are in the middle
the ANs innervating the base of the BM are in the middle
the ANs innervating the apex of the BM are on the outside

Back 64

the ANs innervating low frequency are in the middle

Front 65

A Rate-Level function of an AN includes the following information
Spontaneous discharge rate
Ssturation discharge rate
Dynamic rage of a single nerve
All of above

Back 65

All of above

Front 66

Choose the correct statement from the following:
ANs with high spontaneous rate tend to have low threshold
ANs with high spontaneous rate tend to have high threshold
ANs with low spontaneous rate tend to have low threshold
Threshold has nothing to do with the spontaneous rate

Back 66

ANs with high spontaneous rate tend to have low threshold

Front 67

Tuning curve of a single nerve reflects
How sharply the nerve is tuned to its best frequency
The stimulus level needed to excite a fixed discharge rate at different frequencies
the frequency selectivity of the BM responses to sounds
All of above

Back 67

All of above

Front 68

The neural representation of stimulus spectrum is called
an excitation pattern
a Rate-level function
a Tuning curve
All of above

Back 68

an excitation pattern

Front 69

The entire range of audible sound intensity is likely encoded in the auditory system by
the amplitude of individual spike
the dischsrge rate of a single AN
the dischsrge rate of a group of ANs with high spontaneous discharge rate
the discharge rate of ANs with different spontaneous rates and different best frequencies

Back 69

the discharge rate of ANs with different spontaneous rates and different best frequencies

Front 70

The sound frequency is encoded in auditory nerve by
a place code
a temporal code
All of above
none of above

Back 70

All of above

Front 71

functions of external ear

Back 71

1. Protecting middle ear

2. Providing sound boost (gain) for mid to high frequency range (A. canal,
B. concha, C. pinna, *D. spherical head)

3. Providing cues for sound localization (Pinna)