Cerebellum

Question 1

Through lesion studies, the cerebellum has been ascribed the basic functions of:

Answer 1

smoothing and sequencing of complex movements, supporting postural adjustments and eye movements, and playing a role in establishing and modifying motor programs

Question 2

These functions of the cerebellum, are necessary for the everyday functions we take for granted and can be attributed to:

Answer 2

interactions with the ascending sensory pathways, vision, vestibular function, as well as cortical plans of movement.

Question 3

What are the 3 lobes of the cerebellum?

Answer 3

1. anterior
2. posterior
3. floculonodular

Question 4

Is the lobe description anatomical or functional?

Answer 4

anatomical

Question 5

The cerebellum runs under powerful ___________ control and it is the release of that _____________ that allows for normal patterned movement to occur.

Answer 5

inhibitory

inhibition

Question 6

Externally, on the posterior edge of the cerebellum is a rounded “shelf” known as the:

Answer 6

cerebellar tnosils

Question 7

What is the clinical significance of the cerebellar tonsils?

If intracranial pressure is increased in the posterior fossa, what occurs?

Answer 7

their clinical significance has to do with their position next to foramen magnum.

The tonsils can be forced through the foramen magnum, pinching the medulla.

Question 8

What would pressure on the medulla due to cardiovascular and respiratory centers cause?

Answer 8

????

Question 9

How does output from the cerebellum travel?

Answer 9

by way of neurons located in deep cerebellar nuclei.

Question 10

Where do the deep cerebellar nuclei lie?

Answer 10

in the white matter of the cerebellum, deep to the cortical circuitry.

Question 11

What are the 3 nuclei of the deep cerebellar nuclei?

Answer 11

1. fastigial nucleus
2. interposed (interpossitus n.)
3. dentate nucleus

Question 12

Cerebellar cortex =

Answer 12

a laminated region with an outermost layer that is basically acellular, made up of axons and dendrites, the molecular layer.

Question 13

In the cerebellar cortex, the layer after (“second layers”) the outermost layer, is a sparsely populated layer of very large neurons, Purkinje cells that form:

Answer 13

the output of the cerebellar cortex

Question 14

How to the purkinje cells influence the activity of the deep cellular nuclei?

Answer 14

by inhibiting them

Question 15

Does this “second cerebellar cortex layer” receive afferent or efferent info?

Answer 15

one major afferent system.

Question 16

What is the final layer of the cerebellar cortex?

Answer 16

granular cell layer, that is made up of many grandular cells.

Question 17

What does the granular cell layer receive?

Answer 17

receives the majority of input from the afferent systems, mossy fibers. The axons of this layer form the majority of the axons in the molecular layer and synapse on the dendrites of the purkinje cells.

Question 18

What two pathways travel through the superior cellular pathway?

Answer 18

1. dentatorubrothalamic pathway

2. ventral and rostral spinocerebellar pathways

Question 19

Describe the dentatorubrothalamic pathway:

Answer 19

primary efferent pathway of the SCP

Question 20

Describe the ventral and rostral spinocerebellar pathways:

Answer 20

carrying integrated information of both sensory and motor activity from the ipsilateral cord. These pathways cross contralateral at a spinal cord segment level and then recross through the superior cerebellar peduncle

Question 21

What fibers does the middle cerebellar peduncle carry?

Answer 21

pontocerebellar fibers

Question 22

What does pontocerebellar fibers carry?

Answer 22

carry information relayed through pontine nuclei in the ventral pons. This relay receives cortical information from all parts of the cortex.

Question 23

What pathways travel through the inferior cerebellar peduncle?

Answer 23

1. dorsal and cuneocerebellar pathways
2. olivocerebellar pathway
3. trigeminocerebellar pathways
4. vestibulocerebellar
5. fastigovestibular

Question 24

What do the dorsal and cuneocerebellar pathways carry?

Answer 24

carry specific joint and muscle information encoded by GTOs, muscle spindles, and joint capsule receptors.

Question 25

What do the olivocerebellar pathway carry?

Answer 25

arises from the contralateral inferior olivary complex and gives rise to climbing fibers

Question 26

What do the trigeminocerebellar pathways carry?

Answer 26

carry similar somatosensory information from the face, jaw, and extraocular eye muscles.

Question 27

What do the vestibulocerebellar carry?

Answer 27

carries axons from the vestibular nuclei as well as direct fibers from vestibular apparatus.

Question 28

What do the fastigovestibular carry?

Answer 28

carries an efferent pathway from the fastigial and interposed nuclei to the vestibular nuclei and reticular nuclei. Additionally, there are some purkinje cell axons that bypass the deep cerebellar nuclei and project directly to the vestibular nuclei.

Question 29

What are the 3 functional divisions of the cerebellum?

Answer 29

1. vestibulocerebellum 2. spinocerebellum 3. cerebrocerebullum

Question 30

Vestibulocerebellum =

Answer 30

is made up of the flocculonodular lobe. This region receives input from the vestibular nuclei and apparatus and then sends that information back to influence vestibular nuclei function and reticulospinal pathwaeys. Its general function is to control equilibrium, eye movements, trunk and postural muscle tone.

Question 31

Spinocerebellum =

Answer 31

contains the majority of the vermis and the paravermal zones, as well as much of the anterior lobe. It receives information from the spinal cord, auditory, visual, vestibular, trigeminal and motor cortex. Its output is to medial and lateral descending pathways (reticulospinal and vestibulospinal) through both the interposed and fastigial nuclei. It is involved in controlling limb movements and muscle tone for error correction resulting in coordinated movements. It functions more at proximal limb joints.

Question 32

Cerebrocerebellum =

Answer 32

is made up of the lateral parts of the cerebellar hemispheres, primarily the posterior lobe. It receives information from widespread areas of the cortex via pontine nuclei. Its primary output is to motor and premotor cortex through the dentatorubrothalamic pathway. It functions in planning and coordination of voluntary movements, as well as the “memory” of those movements.