Auditory Tracts and Language

Question 1

Where are the cell bodies for primary afferents of CN VIII (cochlear part)?

Where do they enter the brainstem?

Where do they synapse?

Answer 1

Cell bodies are in the spiral ganglion.

They enter the brainstem at the pontomedullary junction.

They synapse at the cochlear nuclei.

Question 2

Function of the dorsal cochlear nucleus (DCN):

Answer 2

To identify sound source elevation and changes in sounds.

Question 3

Function of ventral cochlear nucleus (VCN):

Answer 3

To determine the horizontal localization of sound.

Question 4

Monaural tract (5)

Answer 4

1. Cell bodies from DCN cross to CL via acoustic stria.
2. Fibers ascend in the lateral lemniscus.
3. Synapse in the inferior colliculus.
4. Fibers travel via the brachium of the inferior colliculus to the medial geniculate nucleus and synapse.
5. Fibers synapse in layer IV of primary auditory cortex.

Question 5

Binaural tract (4)

Answer 5

1. Cell bodies from VCN project BL through the trapezoid body to superior olivary nucleus and synapse.
2. Axons ascend in the lateral lemniscus to inferior colliculus and synapse.
3. Axons travel via brachium of inferior colliculus to medial geniculate nucleus.
4. Axons from MGN synapse in layer IV of primary auditory cortex.

Question 6

Conduction deafness

Sensorineural deafness

Central deafness

Answer 6

Deficit from obstruction causing altered transmission of sound.

Damage to cochlea, cochlear part of CN VIII or cochlear nuclei.

Damage to central pathways.

Question 7

BS to auditory nuclei of pons and medulla

Answer 7

Basilar a.

Question 8

BS to inner ear and cochlear nuclei

Answer 8

Labyrinthine a. (from AICA).

Question 9

What do the short circumferential branches of the basilar a. supply? (2)

Answer 9

Superior olivary complex

Lateral lemniscus

Question 10

BS to inferior colliculus (2)

Answer 10

Superior cerebellar a.

Quadrigeminal a.

Question 11

Thalamogeniculate a. supplies:

Answer 11

Medial geniculate bodies

Question 12

M2 supplies:

Answer 12

Primary auditory and associated cortices.

Question 13

Wernicke’s area (dominant)

Wernicke’s area (non-dominant)

Answer 13

Comprehension of spoken language

Interpreting non verbal signals

Question 14

Broca’s area (dominant)

Broca’s area (non-dominant)

Answer 14

Producing speech

Producing non verbal communication, emotional gestures, and intonation of speech

Question 15

Pathway of language comprehension to speaking (6)

Answer 15

1. Primary auditory cortex
2. Auditory association cortex
3. Wernicke’s
4. Subcortical connections (arcuate fibers)
5. Broca’s
6. Oral and throat regions of sensorimotor cortex

Question 16

Lateral temporal cortex is used for:

Answer 16

Word understanding

Question 17

Word retrieval

Answer 17

Wernicke’s

Question 18

Arcuate fasciculus is used for:

Answer 18

Word repetition

Question 19

Auditory agnosia

What is the lesion?

Answer 19

Cannot describe a sound that has been heard.

Lesion is unimodal sensory association cortex BL.

Question 20

Wernicke’s aphasia (5)

Answer 20

Cannot comprehend language.
Expression is fine.
Cannot read.
Cannot write.
Display fluent paraphasic speech.

Question 21

Broca’s aphasia (3)

Answer 21

Cannot speak fluently.
Can understand spoken and written language.
Spectrum d/o.

Question 22

Global lesion (3)

Answer 22

Lesion of lateral sulcus.
Cannot hear or speak.
Poor reading and writing.

Question 23

Transcortical sensory or motor aphasia

Answer 23

TCM is non fluent, understands fine, and can repeat.

TCS is fluent, does not understand, can repeat.

Question 24

Which arteries are damaged to create Transcortical motor aphasia?

Answer 24

ACA-MCA border zone infarct

Question 25

Which arteries are damaged to create Transcortical sensory aphasia?

Answer 25

MCA-PCA border zone infarct

Question 26

Damage to what causes Broca’s aphasia?

Answer 26

Left inferior frontal gyrus

Question 27

Damage to what causes Wernicke’s aphasia?

Answer 27

Left superior temporal gyrus

Question 28

What layer of the primary auditory cortex does fibers in the auditory tracts synapse?

Answer 28

Layer IV