Vestibulocochlear Nerve VIII

Question 1

Auditory information is distributed (unilaterally/bilaterally)?

Answer 1

Bilaterally

Question 2

Unilateral lesions of CNS auditory structures (do/do not) result in unilateral deafness?

Answer 2

Do not

Question 3

Damage to eh VIII or both cochlear nuclei will result in what?

Answer 3

IPSILATERAL deafness

Question 4

How is the entire system organized?

Answer 4

Tonotopically

Question 5

Where is the ultimate goal of the Auditory Pathways? ie. What is Broadmann’s Area 41 and 42 called?

Answer 5

Transverse Temporal Gyri of Heschl

—Superior surface of the superior temporal gyrus within the lateral sulcus

Question 6

Cross communication takes place between sides before arriving at cortex and allows the ability to what?

Answer 6

Localize sound to one side

Question 7

The cochlear nerve consists of axons/central processes of neurons bringing in what?

Answer 7

Afferent information to the inner ear

Question 8

The afferent info brought in via the cochlear nerve enters the brainstem where?

Answer 8

Cerebellopontine angle

Question 9

After the cochlear nerve has brought afferent information in to the Cerebellopontine angle of the brain stem what happens?

Answer 9

It bifurcates to synapse in BOTH the dorsal and ventral cochlear nuclei

Question 10

Where are the dorsal and ventral cochlear nuclei located?

Answer 10

In the rostral (open) medulla, adjacent to the base of the inferior cerebellar peduncle

Question 11

Name the order of the landmarks of the ascending system, starting with 1.) Dorsal and Ventral Cochlear nuclei?

Answer 11

1. ) Dorsal and Ventral Cochlear nuclei
2. ) Superior olivary nucleus
3. ) Lateral Lemniscus
4. ) Nucleus of inferior colliculus
5. ) Brachium of inferior colliculus
6. ) Medial Geniculate nulcues
7. ) Primary auditory cortex

Question 12

How is the superior olivary nucleus important/play a role in protective auditory reflexes?

Answer 12

Superior Olivary Nucleus projects to CN VII Stapedius muscle dampening noise at the stapes, AND CN V - tensor tympani muscle, dampening the noise at the malleus

Question 13

What is an Acoustic Neuroma?

Answer 13

A tumor growing in the cerebellopontine angle, usually benign and beginning on the VIIIth nerve

Question 14

How does a acoustic neuroma affect the Vestibular component?

Answer 14

irritative lesion that changes perception of head position causing spinning sensation and vertigo

Question 15

What is Tinnitus?

Answer 15

Ringing of the ears…and irritative lesion

Question 16

An acoustic neuroma can also involve what other CN aside from CN VIII?

Answer 16

CN VII, V, IX

Question 17

What antibiotics are toxic to the CNS and when given for ear infections effect CN VIII specifically?

Answer 17

Penicillin and Streptomyocin