Vestibular System And Cerebellum - 4/26 Stephens

Question 1

Where does the vestibular nerve enter the brainstem And how does it course?

Answer 1

Pontomedullary sulcus and courses beneath (anterior to) the restiform body

Question 2

Which structure serves as the critical link in the Oculomotor system and serves control horizontal gaze?

What CNs associated?

Answer 2

MLF

CN 3,4,6

Question 3

The Paramedian Pontine Reticular Formation (PPRF) sends fibers to where?

Where does it also project fibers to?

Answer 3

Abducens nucleus on ipsilateral side

Contralateral MLF to contralateral Oculomotor nucleus

Question 4

Where does the lateral vestibuospinal tract (LVST) originate from?

Terminates where?

Responsible for what?

Answer 4

Lateral vestibular (Deiter’s) nucleus

Ipsilateral intermediate gray of spinal cord

Extensor tone and reflexes of antigravity axial and appendicular musculature

Question 5

The flocculonodular lobe sends info to where?

Then where?

Eventually output goes to where?

Via what?

Answer 5

Fastigial nucleus

Vestibular nuclei

Axial musculature

MVST and LVST

Question 6

The Fastigial nucleus sends info to the vestibular nuclei but can also send information to where?

Goes where next?

Finally to what?
Via what?

Answer 6

Ventral lateral nucleus

Primary motor cortex

Axial musculature
Anterior corticospinal Tract

Question 7

Doll’s eyes maneuver is testing what movement of the eyes?

What CNs involved?

Answer 7

Horizontal gaze

3, 6

Question 8

If the head turns to the right and the right eye ADDucts but the left eye remains neutral, where is the lesion?

Answer 8

CN 6

Question 9

If the head turns to the right and the right eye is neutral and the left eye ABducts where is the lesion?

Answer 9

CN 3

Question 10

If the head turns to the right or left and there is no response of the eyes (neutral gaze) where is the lesion?

Answer 10

Midbrain damage

Question 11

In caloric testing of the ears, if there is no response from the left or right ear, what is lesioned?

Answer 11

CN 8 nerve palsy
Midbrain damage (deep coma state)

Question 12

In caloric testing of the left ear, if the right eye ADDucts and the left eye has no response, where is the lesion?

Answer 12

CN 6

Question 13

A unilateral lesion to the MLF superior to the Abducens nerve results in what?

What muscle is impaired?

Answer 13

Contralateral disturbance of horizontal gaze

middle rectus of ipsilateral eye

Question 14

Patients with a right side INO have abnormal horizontal gaze in which direction?

Answer 14

Left (opposite side)

Question 15

How do you name INO?

How do you name a lesion to the right MLF?

Answer 15

According to side of Oculomotor impairment

Lesion to Right MLF means right horizontal gaze normal and left horizontal gaze impaired

Therefore Right INO

Question 16

Unilateral lesion of the PPRF results in what?

Lesion of Left PPRF results in what?

Answer 16

Paralysis of horizontal gaze on the same side of the lesion

Inability to move both eyes in conjugate horizontal gaze to the left

Question 17

Which nucleus of the cerebellum is the most medial and has vestibular connections and function?

Answer 17

Fastigial nucleus

Question 18

Which nucleus of the cerebellum projects to the red nucleus and is where the majority of efferents from the neocerebellum originate?

Answer 18

Dentate nucleus

Question 19

The Fastigial nucleus sends information to the vestibular system via what?

Answer 19

Inferior cerebellar peduncle

Question 20

The Dentate nucleus sends out cerebellar efferents via what?

Answer 20

Superior cerebellar peduncle

Question 21

What does the dorsal spinocerebellar tract (DCST) convey?

Answer 21

Unconscious, PRECISE proprioception to LOWER half of the body and extremities

Question 22

What does the Direct Arcuate Fibers/Cuneocerebellar Tract convey?

Answer 22

Unconscious PRECISE proprioception to the UPPPER half of the body and extremities

Question 23

What does the Trigeminocerebellar Tract convey?

Answer 23

General proprioception to the head

Question 24

What do the olivocerebellar fibers represent and terminate as?

Answer 24

Afferent fibers that originate in the ION and terminate as climbing fibers in the contralateral cerebellar hemisphere

Question 25

What tract is the critical link between the extrapyramidal system and the cerebellum?

Where does it arise from?

Answer 25

Central Tegmental Fasciculus (CTF)

Red nucleus, PAG, midbrain Tegmentum

Question 26

Which structures course through the Inferior cerebellar peduncle (Restiform body)?

Answer 26

DDT Always Ruins Olives

DCST DAF Trigem AF RF Olivo Fibers

Question 27

What forms all of the middle cerebellar peduncle?

Answer 27

Pontocerebellar fibers

Question 28

What does the Ventral Spinocerebellar Tract (VSCT) convey?

Answer 28

General proprioception from lumbosacral (lower limb) to the cerebellum

Question 29

What does the Trigeminocerbellar Tract convey?

Answer 29

PRECISE tactile and proprioceptive info from head to the cerebellum

Question 30

Both the VSCT and Trigeminocerbellar tract course through what before terminating on the anterior vermis of the cerebellum?

Answer 30

Superior Cerebellar Peduncle

Question 31

What is a major cerebellar efferent pathway?

Answer 31

Dentato-rubro-thalamic pathway

Question 32

What is the only efferent from the cerebellar cortex?

Where does it terminate?

Answer 32

Purkinje cells

Deep cerebellar nuclei

Question 33

What are the most direct afferents to the cerebellar cortex?

Terminals of what?

Excite what?

Answer 33

Climbing fibers

Olivocerebellar fibers

Purkinje cells

Question 34

What are some major clinical signs of cerebellar lesions?

Answer 34

Dysmetria
Dysdiadochokinesia
Asthenia

Question 35

Dysdiadochokinesia, dysmetria, nystagmus and intention tremors bilaterally indicate what type of condition?

Answer 35

Friedreich’s Ataxia

Question 36

The long central processes of the neurons from what form the vestibular nerve?

Where is it found?

Answer 36

Vestibular (Scarpa’s) ganglion

Vestibular portion of the membranous labyrinth