Chap. 4- Cerebellum

Question 1

How is the cerebellar lobes divided?

Answer 1

Vermis, paravermis, hemispheres

Question 2

What are the phylogenetic divisions?

Answer 2

1. Paleo or spino
2. Archi or vestibulo
3. Neo or cerebro

Question 3

What does the paleo or spino do? And what happens with a lesion?

Answer 3

Maintains muscular tone and posture
Causes increased tone of antigravity or extensor muscles - decerebellate

Question 4

What does the neo or cerebro do? What happens if lesion here?

Answer 4

Participates in planning and initiation of movements involving multiple joints
Causes intention tremor and hypermetria
Connected with associative and sensorimotor cerebral cortical regions

Question 5

What does arch or vestibulo do?

Answer 5

Regulates balance and eye movement

Question 6

What are the three nuclei in the gray matter?

Answer 6

Fasitgial
Interpositus
Dentate (lateral nuc of cerebellum)

Question 7

What does fastigial control?

Answer 7

Posture by acting on the antigravity muscles

Question 8

What does interpositus nuclei do?

Answer 8

Amplitude and frequency of movements

Question 9

What does the dentate do?

Answer 9

Controls initiation of movement

Question 10

What does the white matter do?

Answer 10

Keeps ipsi relationship with locomotor apparatus and contra one with pyramidal and extrapyramidal

Question 11

What do the peduncles do?

Answer 11

Connect cerebellum with brainstem

Question 12

Rostral peduncle

Answer 12

Cerebellum to mesencephalon
Afferent and efferent fibers

Question 13

Middle peduncle

Answer 13

With pons
Afferent fibers only

Question 14

Caudal peduncle

Answer 14

With medulla
Afferent and efferent fibers

Question 15

Rostral- afferent and efferent?

Answer 15

Afferent from spinal cord
Efferent to red nucleus and thalamus
- Efferent fibers cross at level of decussation of the rostral peduncles is mes tegmentum
- afferent cross in cerebellum

Question 16

Middle- afferent?

Answer 16

From the pontine nuclei
Receive inputs via Corticopontine tract

Question 17

Caudal- efferent and afferent?

Answer 17

Afferent from contra olivary nuc, ipsi vestibular nuc and vest receptors on inner ear and from ipsi and contra spinocerebellar tracts
Efferents are ispi and contra to most nuclei of brainstem

Question 18

Afferent- what are the two lines of input to cerebellum

Answer 18

Both are excitatory to Purkinje
- climbing
- mossy

Question 20

What are climbing fibers?

Answer 20

Terminal fibers of olivocerebellar tracts
Make synaptic connections with purkinje cells and cerebellar nuclei

Question 21

What are climbing fibers involved in?

Answer 21

Learning process and correcting mismatch between intended and actual movement

Question 22

What are mossy fibers

Answer 22

Terminal fibers of other cerebellar afferent tracts
Diffuse excitatory effect stimulating many purkinje fibers through granule cell layer

Question 23

What enters the middle peduncle?

Answer 23

Axons from pontine nuclei cross midline and enter cerebellum

Question 24

What enters through the caudal peduncle?

Answer 24

From brainstem come from olivary nucleus and from nuclei of medulla

Question 25

What is the rostral peduncle for?

Answer 25

Ventral spinocerebellar tract

Question 26

What does the cerebro phylo receive?

Answer 26

Corticopontine tracts from somatosensory, motor, visual and cognitive areas through mossy fibers

Question 27

What does the spinocerebellum receive?

Answer 27

Spinocerebellar tracts through mossy fibers and from brainstem nuclei through climbing fibers

Question 28

What does vestibulo receive?

Answer 28

Vestibular tracts through mossy fibers and from optokinetic centers in brainstem through climbing fibers

Question 29

What is the output from the cerebellum?

Answer 29

Axons from the purkinje fibers

Question 30

Where do these output axons end?

Answer 30

Cerebellar nuclei and some from flocculonod lobe to vestibular nuclei

Question 31

What is the excitatory activity of the cerebellar nuclei regulated by?

Answer 31

Inhibitory afferents (GABA-ergics) from purkinje cells and excitatory from mossy and climbing fibers - some in cerebellar nuclei project inhibitory axons to olivary nucleus as feedback

Question 33

Where do purkinje cells from the vermis end ?

Answer 33

In fastigial nuclei, through caudal cerebellar peduncle Fibers cross midline inside cerebellum and project to nuclei at brainstem and to ventral horn cells of the cervical spinal segments

Question 34

Where do axons leaving through the corpus juxtarestiforme and restiforme reach?

Answer 34

Juxtarestiforme- medial portion of the caudal peduncle- end on ipsi and contra vestibular nuclei Restiforme- lateral potion of the caudal- brainstem nuclei Lesions- increased muscle tone and titubation

Question 35

Which nuclei do the purkinje axons from the paravermis reach?

Answer 35

Interpositus Axons leave cerebellum through rostral peduncle and cross midline at thr decision of rostral peduncle Majority of fibers are connected with the red nucleus and thalamus then go to cortex Lesion- intention tremor and hypermetria

Question 36

How do axons from flocculonod and lateral strip of vermis leave cerebellum?

Answer 36

Through corpus juxtarestiforme to reach vestibular nuclei to regulate equilibrium Lesion- vestibular signs