Auditory Pathways

Question 1

Where do the primary afferents of CN8 (cochlear part) enter the brainstem?

Answer 1

Pontomedullary Junction

Question 2

Where do the afferents of the Cochlear nerve synapse? How?

Answer 2

Dorsal and Ventral Cochlear Nuclei. Splits into Ascending and Descending. Ascending goes to Anterior

Question 3

What is the function of the Dorsal (or Posterior) Cochlear Nuclei?

Answer 3

Identify sound source elevation and identifying complex characteristics of sound.

Question 4

What is the function of the Ventral (Anterior) Cochlear Nuclei?

Answer 4

Horizontal location of sound.

Question 5

Describe the path of Monoaural information.

Answer 5

Cell bodies go to contralateral side via dorsal acoustic stria and synapse in inferior colliculus. From there, axons go to medial geniculate nucleus, to Layer 6 in primary auditory cortex.

Question 6

Describe the path of Binaural information.

Answer 6

Ventral cochlear nuclei to Superior olivary complex(bilaterally), to inferior colliculus, to medial geniculate nucleus to the Primary Auditory Cortex.

Question 7

What are ways that deafness can occur?

Answer 7

Damage to conducting structures (tympanic membrane to malleus, incus, stapes), Damage to cochlear part of CN 8 or nuclei, or damage to central pathways

Question 8

What artery supplies the inner ear? What is it a branch off of?

Answer 8

Labyrinthine Artery, Off of the AICA

Question 9

What artery supplies the superior olivary complex and lateral lemniscus?

Answer 9

Short circumferential branches of basilar

Question 10

What artery supplies the inferior colliculus?

Answer 10

Superior Cerebellar and Quadrigeminal.

Question 11

What artery supplies the medial geniculate bodies?

Answer 11

Thalamogeniculate Arteries

Question 12

What artery supplies the Primary Auditory Cortex?

Answer 12

M2 of MCA

Question 13

Which hemisphere is typically dominant for language?

Answer 13

Left Hemisphere.

Question 14

What is Wernicke’s Area responsible for on the left and right hemispheres, respectfully

Answer 14

Left- Comprehension of spoken language

Right- Interpreting non-verbal signals

Question 15

What is Broca’s Area responsible for on the left and right hemispheres, respectfully.

Answer 15

Left- Instruction and planning to produce speech.

Right- Producing non-verbal communication and intonation

Question 16

Describe the flow of synapses to produce language

Answer 16

Primary auditory cortex to Auditory association cortex to Wernicke’s Area to connection to Broca’s and Broca’s to cortical output and speech muscles

Question 17

What is auditory agnosia? How is it caused?

Answer 17

Inability to describe a sound that has been heard. Lesion in sensory association cortex

Question 18

How does a patient with a Wernicke’s Area Lesions present?

Answer 18

Can’t understand what is told to them, also can’t read or write comprehensible language. Can talk in paragraph but may not make sense.

Question 19

How does a patient with a Broca’s Area Lesion spresent?

Answer 19

Can Understand spoken and written language but are unable to speak fluently, have broken words, small words. Will mainly consist of responses of nouns and verbs (telegraphic)

Question 20

How does a Transcortical motor Lesion present?

Answer 20

Non fluent speech but grammar and everything else is normal

Question 21

How does a Transcortical sensory Lesion present?

Answer 21

Cannot name items well.

Question 22

How does a conduction aphasia present?

Answer 22

Can’t repeat and writing is impaired