Cerebellum

Question 1

Name the 3 lobes of the cerebellum.

Answer 1

anterior, middle (posterior), and flocculonodular lobes

Question 2

What separates the anterior and posterior lobes?

Answer 2

primary fissure

Question 3

what is the oldest lobe of the cerebellum?

Answer 3

follulonodular lobe

Question 4

What is the function of the follulonodular lobe?

Answer 4

receives input from vestibular nerve/nuclei and coordinates reflexive equilibrium and balance via efferent connections with vestibular and reticular formation nuclei in the brainstem

Question 5

How does the follulonodular lobe project to the vestibular system?

Answer 5

directly, only lobe without a synapse in a deep cerebellar nuclei

Question 6

Name the layers of the cerebellum

Answer 6

Molecular, Purkinge, Granule

Question 7

Molecular layer is composed of what?

Answer 7

synapses: dendrites of Purkinje cells extend “candelabra” dendrites into the molecular layer
basket and stellate interneurons are found in the molecular layer

Question 8

Purkinje Cell layer is the only cell layer to do what? What type of output are almost all purkinje cells?

Answer 8

project outside of the cerebellar cortex; inhibitory

Question 9

What type of cells are found in the granular cell layer?

Answer 9

interneurons

Question 10

Granule cells have axons that project up into the Purkinje cells layer, where they synapse with the dendrites of Purkinje cells. What are these axons called?

Answer 10

Parallel fibers

Question 11

What are the deep nuclei of the cerebellum?

Answer 11

Fastigial nucleus
Globuse nucleus
Emboliform nucleus
Dentate nucleus

Question 12

Fastigial Nucleus efferents go where?

Answer 12

vestibular and reticular nuclei in the brainstem

Question 13

Globuse and Emboliform nuclei efferents go where?

Answer 13

red nucleus and to motor nuclei of the thalamus (VA, VL)

Question 14

Globuse and Emboliform nuclei are collectively called what?

Answer 14

interpositus (or interposed) nuclei of the cerebellum

Question 15

Dentate nucleus provides major outflow of the cerebellum to where?

Answer 15

red nucleus (via dento-rubral tract) and to VA/VL (via the dento-thalamic tract)

Question 16

Inferior Cerebellar Peduncle connects what?

Answer 16

connects the spinal cord and medullary areas/nuclei to the cerebellum

Question 17

Middle Cerebellar Peduncle connects what?

Answer 17

connects the pons with the contralateral cerebellum

Question 18

Superior Cerebellar Peduncle connects what?

Answer 18

efferents from interpositis and dentate deep nuclei of the cerebellum project to thalamus (VA, VL) and red nucleus

Question 19

Describe the afferent pathway of proprioceptive information from C8-L2 to the cerebellum

Answer 19

1. Central processes of DRG cells carrying proprioceptive information enter enter the spinal cord and synapse in Clarke’s nucleus/column
2. Clarke’s column neurons then project axons ipsilaterally into the dorsal spinocerebellar tract
3. ascends and enters the inferior cerebellar peduncle to project to the ipsilateral cerebellar cortex (same side as the 1st order neurons)

Question 20

Describe the afferent pathway of proprioceptive information from the lumbosacral region to the cerebellum

Answer 20

1. collaterals from fasciculus gracilis synapse in an ill-defined area of the spinal cord gray matter
2. then immediately cross in the spinal cord and form the ventral spinocerebellar tract (VSCT)
3. which ascends the brainstem to enter the superior cerebellar peduncle
4. decussates in the midbrain, with the VSCT projecting to the cerebellar cortex (same side as the 1st order neurons)

Question 21

Describe the afferent pathway of proprioceptive information above C8 to the cerebellum

Answer 21

1. collaterals from fasciculus cuneatus enters the caudal medulla and synapses onto neurons of the accessory cuneate nucleus
2. sends axons (via the cuneocerebellar pathway) to the cerebellar cortex ipsilaterally via the inferior cerebellar peduncle

Question 22

Climbing fibers originate in what specific nucleus? In what peduncle would they enter to synapse in the cerebellar cortex?

Answer 22

Climbing fibers are the axons of inferior olive neurons; climbing fibers enter the inferior cerebellar peduncle to project to the cerebellar cortex.

Question 23

What peduncle do the vestibular nuclei travel through?

Answer 23

Inferior cerebellar peduncle

Question 24

Pontine nuclei receive input from what collaterals and go through which peduncle?

Answer 24

collaterals from corticospinal tract axons descending to the spinal cord; pontine nuclei project axons to the contralateral cerebellar cortex via the middle cerebellar peduncle

Question 25

What are the major efferents of the cerebellum?

Answer 25

vestibular and reticular formation nuclei | red nucleus and thalamus (VA,VL)

Question 26

Vermal Zone is involved in what functions?

Answer 26

1. Involved in the coordination of ongoing movement of axial musculature 2. Receives afferents from axial body regions via spinocerebellar and cuneocerebellar tracts, and the vestibular system 3. Sends efferent axons to fastigial nucleus which then projects to vestibular and reticular formation nuclei

Question 27

Intermediate Zone is involved in what functions?

Answer 27

1. Involved in the coordination of ongoing movement of distal musculature 2. Receives afferent sensory input from distal body regions via spinocerebellar and cuneocerebellar tracts 3. Sends efferents to deep interpositus nuclei (globose and emboliform) which then project out of the cerebellum to the red nucleus and motor nuclei (VA, VL) of the thalamus

Question 28

Lateral Zone is involved in what functions?

Answer 28

1. Involved in the planning, sequencing and timing of motor movement; also plays a role in cognitive behavior (not well-understood at this point in time) 2. Receives afferent input from the cerebral cortex via connections with pontine nuclei; note that pontine nuclei receive input from many cortical areas as well as some brainstem (e.g., superior colliculus) nuclei 3. Efferents project to the dentate nucleus, which then projects to the red nucleus and VA, VL of the thalamus

Question 29

How does the cerebellum influence tone of muscle?

Answer 29

projections to vestibular nuclei, reticular formation nuclei and the red nucleus

Question 30

Patient comes in with truncal ataxia, a wide-based stance and gait, cerebellar dysarthria, ocular ataxia and nystagmus; difficulty swallowing. Where may the lesion be?

Answer 30

Midline (vermis) lesion

Question 31

Patient comes in with ataxia, dysmetria (difficulty in the timing of movement finger-to-nose test), dysrhythmia, tremor (intention [action] tremor), and hypotonia. Where may the lesion be?

Answer 31

Cerebellar Hemisphere lesion

Question 32

Cerebellar Hemisphere lesion symptoms are ipsi contra or bilateral?

Answer 32

ipsilateral

Question 33

What is the most common infratentorial primary tumor and signs/symptoms and complications arising from it?

Answer 33

medulloblastoma Midline (vermis) symptoms blocking of 4th ventricle - non-communicating hydrocephalus

Question 34

Most common adult cerebellar tumors metastasize from what primary cancers?

Answer 34

brain are lung, breast and melanoma

Question 35

What is mass effect?

Answer 35

hydrocephalus and/or tonsillar herniation or any other complication due to space occupying quality of tumor or hemorrhage

Question 36

Friedreich's Ataxia description (inheritance pattern, s/s, etiology)

Answer 36

autosomal recessive age of onset <25, mutation in Chromosome 9 GAA triplet repeat involving frataxin - messes up mitochondrial functioning ataxia, areflexia, impaired fine touch, vibration and conscious proprioception, and progressive weakness with a Babinski scoliosis, high arches, cardiomyopathy and diabetes heart failure mortality

Question 37

Alcoholic Degeneration of Cerebellum results from and leads to what symptoms?

Answer 37

degeneration of both Purkinje and granule cells causing atrophy of the cerebellar cortex disequilibrium and ataxia

Question 38

Chronic Alcoholism or malnourishment can lead to what vitamin deficiency effecting cerebellar functioning?

Answer 38

Vit B1 (thiamine) deficiency

Question 39

Wernicke's Encephalopathy cause and clinical triad

Answer 39

``` Vit B1 (thiamine) deficiency acute symptoms of cognitive dysfunction, ataxia and oculomotor abnormalities (ophthalmoplegia and/or nystagmus) ```

Question 40

Cerebellar Paraneoplasia effects what part of the cerebellum and arises generally from what primary cancers?

Answer 40

autoantibodies attach and destroy Purkinje cells; lung, breast and ovarian cancer