GA: Auditory Pathways

Question 1

What are the 2 types of auditory pathways?

Answer 1

1. Primary afferent CN 8 cochlear part
2. Cochclear nuclei

Question 2

Where are cell bodies located in the primary afferent CN 8 cochlear part?

Answer 2

In the spiral ganglion

Question 3

Horizontal localization of the sound is accomplished via?

Answer 3

Ventral cochlear nucleus

Question 4

Identifying sound source elevation is accomplished via?

Answer 4

Dorsal cochlear nucleus

Question 5

In a monaural tract, information about sounds from a single ear is routed to?

Answer 5

The contralateral side

Question 6

Where do monaural tracts cross?

Answer 6

In the dorsal cochlear nucleus (via dorsal acoustic stria)

Question 7

What is the pathway for the monaural tract?

Answer 7

Dorsal cochlear nucleus –> cross –> lateral lemniscus (ascend) –> Brachium of Inferior Colliculus –> Medial geniculate nucleus –> Primary auditory complex (Heschl’s gyrus)

Question 8

What is binaural information?

Answer 8

Information about differences between sounds at both ears

Question 9

Where does binaural information project bilaterally to?

Answer 9

Trapezoid body

Question 10

What is the tract for binaural information?

Answer 10

Ventral cochlear nuclei –>bilateral to trapezoid body –> superior olivary complex –> lateral leminiscus –> brachium of inferior colliculus –> medial geniculate nucleus –> layer 4 of primary auditory cortex (Heschl’s gyrus)

Question 11

For auditory paths, where does everything eventually synapse?

Answer 11

Primary auditory complex

Medial geniculate nucleus

Inferior colliculus

Question 12

Question 13

If you damage some of the itty bitty auditory pathways, will you go deaf?

Answer 13

NO

There is way too much crossing in the auditory pathways.

crosses @ trapezoid body, posterior acoustic stria, commissure of inferior colliculus

But, you will have trouble localizing sound.

Question 14

Define conduction deafness:

Answer 14

External/middle ear problem from an obstruction that prevents sound from crossing the tympanic membrane properly.

Question 15

If you have damage to the cochlear part of CN 8 what happens?

Answer 15

Ipsilateral deafness

Question 16

If you have damage to the central pathways in the ear what happens?

Answer 16

You won’t be able to localize sound

Question 17

Blood supply for the cochlea + auditory nuclei of pons + medulla:

Answer 17

Basilar A.

Question 18

Which artery supplies the inner ear + cochlear nuclei?

Answer 18

Internal auditory (labyrinthine) A. –> branch off AICA

Question 19

What type of hearing loss will you get if you occlude the AICA?

Answer 19

Monaural hearing loss w/ possible ips. facial paralysis (facial N. runs through there)

Question 20

What do the short circumferential branches of the basilar A. supply?

Answer 20

Superior olivary complex + lateral leminiscus

Question 21

What supplies the inferior colliculus?

Answer 21

Superior cerebellar + quadrigeminal A.’s

Question 22

What do the thalamogeniculate A.’s supply?

Answer 22

the medial geniculate bodies

Question 23

What supplies the primary auditory + association cortices?

Answer 23

M2 segment of the middle cerebral A.

Question 24

Which hemisphere is dominant in 94% of adults?

Answer 24

Left

Rt. handed = left side dominant

Question 25

What does Wernicke's area do?

Answer 25

Comprehension of spoken language Trying to think of a word

Question 26

What does Broca's area do?

Answer 26

Produces speech (motor aspect) grammar Instructions for language output

Question 27

What is the function of the area analogous to Wernicke's?

Answer 27

Interpreting nonverbal signals from other people Sarcasm Pitch/tone of voice to phrase as a question

Question 28

What is the function of the area analogous to Broca's area?

Answer 28

Instructions for producing non-verbal communication including emotional gestures + intonation of speech

Question 29

What is the function of the arcuate fibers and what do they connect?

Answer 29

Arcuate fibers allow you to **repeat** things (word repitition) They connect Wernicke's + Brocas

Question 30

Answer 30

Question 31

In the parietal lobe, what 3 things form Wernicke's area?

Answer 31

1. Superficial temporal gyrus 2. Angular gyrus 3. Supramarginal gyrus

Question 32

What does the lateral temporal cortex do?

Answer 32

Word recognition

Question 33

What does motor programs for articulation?

Answer 33

Dorsal premotor cortex

Question 34

The inability to describe a sound that has been heard (ex. fire alarm) =

Answer 34

Auditory agnosia

Question 35

A lesion of the unimodal sensory association cortex produces what symptom?

Answer 35

auditory agnosia

Question 36

Wernicke's aphasia is due to a lesion of wernicke's area (temporal). What does this mean?

Answer 36

They can't understand what is being said to them. They can speak fine, but like if you say the word cat, it means nothing to them. If you talk to them their responses back to you won't make sense. They aren't really aware that they can't understand you. They can't read/write

Question 37

If someone has lost the abillity to speak fluently, this likely means they have a lesion in \_\_\_\_\_\_\_\_\_\_\_.

Answer 37

Broca's area (left inferior frontal gyrus) They often get frustrated + depressed and leave out their ands, ifs, and buts (less severe). More severe = mutism

Question 38

A global lesion means:

Answer 38

Both Wernickes + Brocas areas got hit (lesion of lateral sulcus), and the person won't even speak usually.

Question 39

An infarction in the ACA-MCA border zone produces:

Answer 39

Transcortical motor lesion

Question 40

An infarction in the MCA-PCA border zone produces:

Answer 40

Transcortical sensory lesion

Question 41

A lesion of the supramarginal gyrus + **arcuate fasciculus** causes what?

Answer 41

Conduction aphasia -**can't repeat,** but fluency = intact

Question 42

How does a transcortical motor aphasia present?

Answer 42

Like Broca's but CAN REPEAT

Question 43

What is anomic aphasia?

Answer 43

They can't think of what the word is

Question 44

How does transcortical sensory aphasia present?

Answer 44

Like Wernicke's, but they CAN REPEAT