Cerebellum 2

Question 1

What are the three regulatory functions of the cerebellum?

Answer 1

1. reflex tone of skeletal muscle
2. coordination of voluntary muscle activity
3. aids in maintaining equilibium

Question 2

What is the basic function of the cerebellum?

Answer 2

Smoothing and Sequencing of complex movements.

Support postural adjustments and eye movements establishing and modifying motor programs.

Question 3

The cerebellum functions are attributed to interactions w/

Answer 3

1. Ascending Sensory Pathways
2. Vision
3. Vestibular Fxn
4. Cortical plans of movments

Question 4

The functions of the cerebellum end up providing

Answer 4

1. Comparison of internal and external feedback
2. Modifying central motor programs.
3. Center for motor learning/memory.

Question 5

What structure in the cerebellum allows for output?

Answer 5

efferents from cerebellum from deep cerebellar nuclei

Question 6

Where do efferents, neurons from deep cerebellar deep nuclei sweep out to

Answer 6

effect some sort of physiological behavior on target cell = usually excitatory

Question 7

What are deep cerebellar nuclei under inhibitory control of?

Answer 7

Purkinje Cells

Question 8

What does purkinje cell control over deep cerebellar nuclei allow for?

Answer 8

Inhibitory control allows for normal patterned movement.

Question 9

What three lobes is there cerebellum broken up into?

Answer 9

Anterior, Posterior, Flocculonodular

Question 10

How is the flocculonodular lobe broken up?

Answer 10

Nodule in the midline and Flocculus are lateral.

Question 11

Where are the cerebellar tonsils located?
What is their structural significance?
Clinical significance?

Answer 11

Posterior edge of cerebellum.

Have structural significance to connections of cerebellum.

Clinically positioned next to foramen magnum and can be forced through pinching medulla with increase of intracranial pressure.

Question 12

Where is the Vermis located?

Answer 12

Midline.

Question 13

Where are the deep cerebellar nuclei located?

Answer 13

lie in white matter of cerebellum deep to cortical circuitry.

Question 14

What are the three deep cerebellar nuclei and what is their associated functional division and anatomical location?

Answer 14

1. Fastigial Nucleus - Vestibulocerebellum: receives input from vermis and some floculonodular lobe
2. Interposted Nucleus (Globose and Emboliform) - Spinocerebellum: receive input from intermediate part of cerebellar hemispheres
3. Dentate Nucleus - Cerebrocerebellum: get projections from lateral cerebellar hemispheres

Question 15

What are the three layers of the cerebellar cortex?

Answer 15

Molecular Layer
Purkinje Cell Layer
Granular Cell Layer

Question 16

What is the Molecular Layer made up of?

Answer 16

acellular made of:

axons and dendrites

• unmylenated granule cell axons
• purkinje cell dendrites
• Interneurons

Question 17

What is the Purkinje cell layer made up of and what is its function?
What does it receive?

Answer 17

Cell bodies of large peukinje cells.
Form output of cerebellar cortex
Fxn: influence activity of deep cerebellar nuclei through INHIBITION
Receives 1 major afferent system (mossy fiber system from granular layer).

Question 18

What is the granular layer made up of?

What does it receive?

Answer 18

Granular Cells - majority of axons in the molecular layer and synapse on dendrites of the purkinje cells.

Receives most input form afferent systems = mossy fibers

Question 19

All axons going upward are excitatory/inhibitory and consist of what three fibers?

Answer 19

upward = Excitatory

1. Mossy Fibers
2. Climbing Fibers
3. Granule Cell Parallel Fibers

Question 20

All axons going downward are excitatory/inhibitory and consist of what fibers?

Answer 20

downward = Inhibitory

1. Purkinje Cells

Question 21

What is the route of mossy fibers and what do they synapse on?

Answer 21

Ascend through cerebellar white matter (excitatory) synapse onto granule cell dendrites

Question 22

Where do granule cells send axons?

Answer 22

Granule cells send excitatory parallel fibers to dendritic trees of purkinje cells.

Question 23

What is all output from cerebellar cortex carried by?

Answer 23

Purkinje cell axons to cerebellar white matter.

Question 24

Purkinje cells send synapses where?

Answer 24

inhibitory synapses onto deep cerebellar nuclei

Question 25

Where do climbing fibers arise from and where do they go to?

Answer 25

Arise from neurons in contralateral inferior olivary nucleus and send excitatory input to purkinje cells.

Question 26

What is the function of the inferior, middle, and superior peduncles?

Answer 26

Connects lower brainstem and forms wall of 4th ventricle.

Question 27

Superior Peduncle: Efferent or Afferent? Pathways?

Answer 27

Only Efferent pathway. Decussates in the midbrain at the level of inferior colliculus. 1. Denatorubrothalamic pathway 2. Ventral and Rostral Spinocerebellar Pathway

Question 28

Ventral and Rostral spinocerebellar pathway: What does it carry and what is its route?

Answer 28

Carries integrated info of sensory and motor from ipsilateral spinal cord. Pathways cross contralateral at spinal cord segment level, and recross through cerebellar peducle.

Question 29

Middle Peduncle: Efferent or Afferent? Pathways?

Answer 29

Only Afferent pathway - Massive connections to pons - Pontocerebellar fibers carrying info relayed through pontine nuclei in ventral pons. - Relay receives cortical info from all parts of cortex.

Question 30

Inferior Peduncle: Efferent or Afferent? Pathways?

Answer 30

Both Afferent and Efferent ``` Dorsal and Cuneocerebellar Pathways Olivocerebellar Pathway Trigeminocerebellar Pathways Vestibulocerebellar Pathways Fatigiovestibular Pathway ```

Question 31

What information do Dorsal and Cuneocerebellar pathways and from where?

Answer 31

Carry specific joint and motor info encoded by: - GTOs - Muscle Spindles - Jt capsule receptors

Question 32

Where does info from Olivocerebellar Pathway come from and what fibers does it have?

Answer 32

comes from contralateral inferior olivary complex -- climbing fibers

Question 33

What info does the Trigeminocerebellar Pathway transmit and where from?

Answer 33

carry similar somatosensory info from the - Face - Jaw - Extraocular eye muscles

Question 34

Vestibulocerebellar pathways carry axons from where (2)?

Answer 34

carry axons from vestibular nuclei and direct fibers from vestibular apparatus

Question 35

Fastigiovestibular pathways carry what kind of information to where?

Answer 35

carries efferent pathway from fastigial and interposed nuclei --> vestibular nuclei and reticular nuclei some purkinje cell axons bypass deep cerebellar nucli and project directly to vestibular nuclei

Question 36

``` Vestibulocerebellum: Anatomical Cerebellum Input Deep Nuclei Cerebellar Peduncle Output Target ```

Answer 36

Vestibulocerebellum: Anatomical Cerebellum: Flocculonodular Lobe Input: Vestibular Nuclei and apparatus/ganglia Deep Nuclei: Vestibular Nuclei (fastigial?) Cerebellar Peduncle: Inferior Output Target: MLF - eye mvmt pathways

Question 37

Vestibulocerebellum pathway: function ipsilatera/contralateral/bilateral

Answer 37

Sends info back to influence vestibular nuclei fxn and reticulospinal pathways -ipsilateral fxn: - control equilibrium - eye movments - trunk and postural muscle tone = proximal

Question 38

``` Spinocerebellum: Anatomical Cerebellum Input Deep Nuclei Cerebellar Peduncle Output Target ```

Answer 38

Spinocerebellum: Anatomical Cerebellum: Vermis and paravermal zones Input: General cutaneous and proprioceptive receptors: SC, auditory, visual, vestibular, trigeminal, motor cortex Deep Nuclei: Interposed Nuclei, Fastigial Nuclei Cerebellar Peduncle: Superior and Inferior Output Target: VL, Red Nucleus, Tectum, RF, Vestibular Nuclei

Question 39

Spinocerebellum: | function

Answer 39

controls limb movments and muscle tone for error correction --> coordinated movments - muscle synergy - more proximal limb joints = postural and locomotion