Lecture 9 Cerebellum

Question 1

What functions is our cerebellum involved in?

Answer 1

• coordination
• balance and equilibrium
• muscle tone
• motor control
• motor learning

Question 2

Where is the cerebellum located?

Answer 2

• posterior fossa
• infratentorial
• dorsal to midbrain and 4th ventricle

Question 3

How is the cerebellum similar in structure to the cerebrum?

Answer 3

• has 2 hemispheres that are split down the middle

- Latin for little brain

Question 4

What is the target structure for the superior cerebellar peduncle and what type of fibers does it carry?

Answer 4

• cerebellum to midbrain

- afferent and efferent fibers

Question 5

What is the target structure for the middle cerebellar peduncle and what type of fibers does it carry?

Answer 5

• cerebellum to pons

- afferent fibers

Question 6

What is the target structure for the inferior cerebellar peduncle and what type of fibers does it carry?

Answer 6

• cerebellum to medulla

- afferent and efferent fibers

Question 7

What is the only way in and out of the cerebellum?

Answer 7

through the cerebellar peduncles

Question 8

What cerebellar peduncles connect ipsilaterally?

Answer 8

middle and inferior cerebellar peduncle

Question 9

Which peduncle decussates?

Answer 9

superior cerebellar peduncle

Question 10

What structures/regions are involved with cerebrocerebellum? What are the function?

Answer 10

• input to/from the cortex

- involved with planning and initiation of movement

Question 11

What structures/regions are involved with spinocerebellum? What are the function?

Answer 11

• Input to/from spinal cord
• vermis - posture, proximal limb movement, eye movement
• intermediate zone - integrates input re: appendicular limb positions and somatosensory

Question 12

What structures/regions are involved with vestibulocerebellum? What are the function?

Answer 12

• input to/from vestibular labyrinth

- maintenance of equilibrium, balance, and posture

Question 13

What are the two types of fibers involved in synaptic input to the cerebellum? Where do they project from and where do they synapse?

Answer 13

Climbing fibers
- Excitatory fibers from contralateral inferior olivary nucleus (medulla) that synapse w/: deep cerebellar nuclei and Purkinje cells

Mossy fibers
- Excitatory fibers from all areas of afferent input except inferior olivary nucleus that synapse with:
Deep cerebellar nuclei, Granule Cells, Parallel Cells, Purkinje Cells, Golgi cells

Question 14

What are the 3 layers found in the cerebellar gray matter?

Answer 14

• Molecular layer
• Purkinje cell layer
• Granule cell layer

Question 15

What can be found in the molecular layer?

Answer 15

• interneurons
• unmyelinated granule cell axons
• Purkinje dendrites
• Parallel fibers

Question 16

What can be found in the Purkinje Cell Layer?

Answer 16

Purkinje cell bodies

Question 17

What can be found in the Granule cell layer?

Answer 17

• granule cells

- golgi cells

Question 18

What are the basic functions of Parallel fibers?

Answer 18

• telephone wires

- form excitatory synapses with cells

Question 19

What are the basic functions of Purkinje fibers?

Answer 19

• output fibers of cerebellum
• inhibit deep cerebellar nuclei and vestibular nuclei to modulate activity of their output onto descending cortical system

Question 20

What are the basic functions of Granule Cells?

Answer 20

• excitatory cells that bifurcate with parallel fibers to turn them on

Question 21

What are the basic functions of Golgi cells?

Answer 21

• inhibitory neurons that inhibit granule cells

- needed when we get the movement right the first time

Question 22

Describe the basic pathway taken by pontocerebellar fibers. Where do these fibers receive input from?

Answer 22

• receive input from primary somatosensory cortex, primary motor cortex, visual cortex, vestibular and auditory
• cortex through internal capsule to ipsilateral Pontine nuclei then mossy fibers decussate prior to entering contralateral middle cerebellar peduncle then project to cerebellar cortex

Question 23

Describe the basic pathway taken by olivocerebellar fibers. Where do these fibers receive input

Answer 23

• receives input from red nucleus, cortex, brainstem, spinal cord
• then sends info down central tegmental tract to inferior olivary nucleus, then climbing fibers decussate prior to entering contralateral inferior cerebellar cortex then on to cerebellar cortex

Question 24

Describe the somatotopic organization seen within the cerebellum

Answer 24

• towards the middle and medial is head and as you go inferior it goes arms then legs

Question 25

What are the 4 sets of deep cerebellar nuclei?

Answer 25

• dentate
• emboliform
• globose
• fastigial

Question 26

What structures does the posterior inferior cerebellar artery supply?

Answer 26

• lateral medulla
• inferior half of cerebellum
• inferior vermis

Question 27

What structures does the anterior inferior cerebellar artery supply?

Answer 27

• inferior lateral pons
• middle cerebellar peduncle
• middle of cerebellum
• flocculus

Question 28

What structures does the superior cerebellar artery supply?

Answer 28

• upper lateral pons
• superior cerebellar peduncle
• most of superior half of cerebellar hemisphere
• deep cerebellar nuclei
• superior vermis