Chapter 11: The Auditory Brain and Sound Localization

Question 1

Inner hair cells in cochlea are also known as the…

Answer 1

auditory nerve fibers

Question 2

________ nerve fibers are sensitive to specific frequencies

Answer 2

Afferent

they respond to a bit higher and a bit lower

the range: tuning curve

Question 3

Nerve fiber code for ____________

Answer 3

frequency

Question 4

Auditory nerve fibers form part of the
_____________________ (three words)

Answer 4

eighth cranial nerve

Question 5

The auditory tract is made up of:

Answer 5

1) Cochlear Nucleus
* Trapezoid body
2) Superior Olive
3) Inferior Colliculus
4) Medial geniculate nucleus (MGN)
* w/ feedback loops
5) Auditory cortex

Question 6

Nucleus:

Answer 6

a group of cell bodies inside the CNS

Question 7

Where is the superior olive located?

Answer 7

on the brain stem

Question 8

What does the superior olive do?

Answer 8

First real area that starts to integrate signals from both ears

Receives input from both ears

Cross-over point

Helps in sound localization

Question 9

Where is the inferior colliculus?

Answer 9

on the brain stem

Question 10

What does the inferior colliculus do?

Answer 10

Sends signal that helps us orient towards sound (attention

Startle reflex to sound
- important for evolutionary perspective

More complex processing such as discriminating pitch/rhythm (not solidified research)

Question 11

Where is the medial geniculate nucleus (MGN) located?

Answer 11

It is located in the thalamus.

Question 12

The MGN has lots of _______________ (two words) with cortex.

Answer 12

feedback loops

it is also a “relay station” but likely lots of processing happens, because of the feedback loops.

Question 13

Primary auditory corttex is also referred as

Answer 13

A1

Question 14

Auditory cortex is a large area in ________ lobe.

Answer 14

temporal

(it is bilateral- on both sides)

complex organization

Question 15

The primary auditory cortex (A1) is responsible for __________________ (two words).

Answer 15

tonotopic organization

cells fire specifically for different frequencies; organzied

Question 16

The secondary auditory cortex is also known as

Answer 16

A2

Question 17

The secondary auditory cortex (A2) is responsible for

Answer 17

sound localization, to analyze complex sounds

auditory memory (??)

Question 18

The auditory cortex has what is somewhat similar “what” and “where” systems. How is this? What is the what and the where?

Answer 18

What: the identity of a sound: tones/pitch, etc.

where: location information

Question 19

Cochlear nucleus:

Answer 19

a structure in the brain stem that receives input from the inner hair cells

Question 20

Trapezoid body:

Answer 20

a structure in the brain stem that plays a role in determining the direction of sounds

Question 21

Superior olive:

Answer 21

a structure in the brain stem that receives input from the inner hair cells and from the cochlear nucleus

Question 22

Inferior colliculus:

Answer 22

a structure in the midbrain that receives input from the superior olive

Question 23

Medial geniculate nucleus:

Answer 23

a structure in the thalamus that receives auditory input from the inferior colliculus and sends output to the auditory cortex

Question 24

Auditory cortex:

Answer 24

the areas in the temporal cortex that process auditory stimuli

Question 25

Primary auditory cortex:

Answer 25

the first area in the auditory cortex, whic receives input from the medial geniculate nucleus

Question 26

Tonotopic organization:

Answer 26

the organization of neurons within a region in the brain according to the different frequencies to which they respond

Question 27

Auditory core region:

Answer 27

an area of the auditory cortex, consisting of the primary auditory cortex, the rostral core, and the rostrotemporal core

Question 28

Rostral core:

Answer 28

an area in the auditory core region of the auditory cortex

Question 29

Rostrotemporal core:

Answer 29

an area, in addition to the rostral core, in the auditory core region of the auditory cortex

Question 30

Belt:

Answer 30

a region of the auditory cortex that wraps around the auditory core regions

Question 31

Parabelt:

Answer 31

a region of the auditory cortex, in addition to the belt area, that wraps around the auditory core regions

Question 32

Azimuth:

Answer 32

the left-right or side-to-side aspect of sound localization

Question 33

Elevation:

Answer 33

the up-down dimension of sound localization

Question 34

Distance:

Answer 34

how far a sound is from the listener and whether it is in front of or behind the listener

Question 35

Describe detecting distance.

Answer 35

* Different than ITD and ILD * Mostly top-down factors related to the strength of the signal – How loud it is * Knowledge of how loud familiar sounds typically are. * Another cue for distance: – Direct vs reflected sound * Further away sounds- more reflected sound * Close-by sounds have larger ratios of direct to-reflected sound than farther-away sounds * Reflected sounds have altered frequencies

Question 36

Comparison sounds: What question "is the object to the left or right of us" asking for? ___________ What is the question " is it in front of us or behind us" asking for? ___________ What is the question "is it above us or below us" asking for? ___________

Answer 36

azimuth; distance; elevation

Question 37

Interaural time difference:

Answer 37

the time interval between when a sound enters one ear and when it enters the other ear * A sound coming from the left will hit our left ear a fraction of a second before the right ear, and vice versa * Gives us location along the azimuth (left-right aspect) * Medial Superior Olive

Question 38

Information from the cochlea makes a synapse in the ________________ (two words) and then travels to the ________________ (three words), where information from the right and left cochleae is first combined.

Answer 38

cochlear nucleus; medial superior olives

Question 39

Interaural level difference:

Answer 39

the difference in loudness and frequency distribution between the two ears * As sound travels, its strength dissipates * Slightly louder in the ear that is closer to sound * An acoustic shadow forms on the side of the head that’s away from the sound * More prominent for high freq sounds than low freq sounds * Lateral Superior Olive uses all these characteristics to analyze levels of loudness and frequency across ears and estimate location

Question 40

Acoustic shadow:

Answer 40

the area on the side of the head opposite from the source of a sound in which the loudness of a sound is less because of blocked sound waves

Question 41

Cone of confusion:

Answer 41

a region of positions in space in which sounds create the same interaural time and interaural level differences * Only an issue for you if you’re not moving * Moving changes the location of both ears, and estimates of location can be made again.

Question 42

Spectral shape cue:

Answer 42

the change in a sound’s frequency envelope created by the pinnae; it can be used to provide information about the elevation of a sound source

Question 43

Auditory scene analysis:

Answer 43

the process of identifying specific sound-producing objects from a complex set of sounds from different objects at varying and overlapping frequencies

Question 44

Temporal segregation:

Answer 44

the process whereby sounds that are linked in time are grouped together, whereas sounds that are not correlated with one another are not grouped together ex: hearing an orchestra

Question 45

Spatial segregation:

Answer 45

the process whereby sounds that are coming from the same location are grouped together, whereas sounds that are coming from different locations are not grouped together * We can compare loudness, timing, and frequency to estimate a sounds location in space * If sounds are coming from different spatial locations, they may be coming from different sources ex: in a dog shelter, a specific sound pertaining to a specific space let's us know that a specific bark is in the specific space of a dog

Question 46

Spectral segregation:

Answer 46

the process whereby sounds that overlap in harmonic structure are grouped together, whereas sounds that do not overlap in harmonic structure are not grouped together * Uses harmonic coherence: – sounds have fundamental frequencies + associated higher harmonics

Question 47

Harmonic coherence:

Answer 47

when frequencies present in the environment resemble the possible pattern of a fundamental frequency and higher harmonics

Question 48

Biosonar:

Answer 48

a process whereby animals emit sounds and then use comparisons of the emitted sounds and their returning echoes to sense the world around them

Question 49

Target range:

Answer 49

the distance of a predator from its potential target, determined by timing an echo’s return

Question 50

Rate of approach:

Answer 50

the measure of whether a predator is approaching a target or receding from it

Question 51

Architectural acoustics:

Answer 51

the study of how physical spaces such as concert halls affect how sounds are reflected in a room

Question 52

Reverberation time:

Answer 52

the difference between the onset of direct sound and the first onset of indirect sound

Question 53

You are sitting in a park listening to a rock band play through two mounted speakers. Even though the music from each member of the band is coming through as a separate audio stream, you group them all together as coming from the same band. This example shows ______.

Answer 53

harmonic coherence

Question 54

Which of the following is an accurate statemen about the biosonar used by forest bats? (a) It determines distance by the size of the echo. (b) It determines the size of the target by the rate of approach. (c) It involves the use of CF-FM calls. (d) It uses low-frequency sound.

Answer 54

It involves the use of CF-FM calls.

Question 55

A symphony orchestra plays in a concert hall with a reverberation time of 6 seconds. Considering this, which of the following is most likely TRUE? (a) The listeners will hear mostly direct music with little echoing. (b) The slightest noises in the audience will likely drown out the music. (c) The listeners will hear music that may be distorted by echoing. (d) The space will have good enough acoustics to use for recording.

Answer 55

The listeners will hear music that may be distorted by echoing.

Question 56

While sitting in a chair on a balcony, Hans hears someone singing somewhere above him and another person singing somewhere below him. However, he cannot place the location of either sound. Hans is experiencing the ______.

Answer 56

cone of confusion

Question 57

Interaural level difference is the time interval between when a sound enters one ear and when it enters the other ear. T/F

Answer 57

False

Question 58

Temporal segregation involves grouping together sounds linked by ______.

Answer 58

time

Question 59

The azimuth refers to the up-down dimension of sound localization. T/F

Answer 59

false

Question 60

Harmonic coherence happens when frequencies present in the environment resemble the possible pattern of a fundamental frequency and higher harmonics. T/F

Answer 60

true

Question 61

A bat hears a series of echoes coming from a target, and the echoes have a gradually increasing frequency. This phenomenon tells the bat that ______.

Answer 61

it is gaining on its prey

Question 62

To have good acoustics, a concert hall should have ______.

Answer 62

NOT a large amount of indirect sound

Question 63

Which of the following is an accurate statement about spatial segregation? (a) It can be used to distinguish where in space sounds are coming from. (b) It uses harmonic coherence to group frequencies into one experience. (c) It refers to a number of separate grouping rules. (d)It groups together sounds that are linked by time.

Answer 63

(a) It can be used to distinguish where in space sounds are coming from.

Question 64

The rostral core is an area in the auditory core region of the auditory cortex. T/F

Answer 64

True

Question 65

The interaural time difference will be the longest when sound comes to a person’s ears at a ______.

Answer 65

90 degree angle

Question 66

Koki hears the sounds of talking, ticking, and purring coming from the same location, a nearby couch. He identifies these sounds as coming respectively from his friend, a clock his friend is holding, and a cat on his friend's lap. By identifying the different sources of these sounds, Koki is using ______ segregation.

Answer 66

spectral

Question 67

Bats calls are louder than dolphin calls. T/F

Answer 67

false dolphin calls are louder than bat calls

Question 68

The interaural level difference is the difference in loudness and frequency distribution between the two ears. T/F

Answer 68

true

Question 69

Tina had the tops of her ears pierced. As a result, she temporarily lost the ability to ______.

Answer 69

localize sounds

Question 70

To have good acoustics, a concert hall should have ______.

Answer 70

a reverberation time of 2 seconds or less

Question 71

At louder volumes, there is less reverberation of the walls and ceiling of the concert hall. T/F

Answer 71

False "As the loudness of the music increases, the importance of good acoustics increases. At softer volumes, there is less reverberation off the walls and ceiling of the concert hall, but this increases as the loudness increases" (txtbk)

Question 72

The auditory system is organized by ________________.

Answer 72

tone (frequency) – Tonotopically