Exam 3 Week 12 PP 5&6 Cerebellum Review & Connections

Question 1

3 connections of cerebellum to the brainstem

Answer 1

Inferior peduncle Middle peduncle Superior peduncle

Question 2

tracts contained in the inferior cerebellar peduncle (5)

Answer 2

Dorsal, Cuneo & Rostral spinocerebellar tracts Olivocerebellar tract Vestibulocerebellar tract

Question 3

Nuclei and neurons contained in inferior cerebellar peduncle

Answer 3

Cerebellar efferents to vestibular & reticular nuclei

Question 4

Tract in Middle cerebellar peduncle

Answer 4

Pontocerebellar tract

Question 5

What runs through the Superior cerebellar peduncle (tract & neurons)

Answer 5

• Ventral spinocerebellar tract
• Efferents from cerebellum which terminate in the red nucleus and the VL motor nucleus of the thalamus

Question 6

Alternative name for Pontocerebellum

Answer 6

neocerebellum

Question 7

General location of neocerebellum

Answer 7

Lateral zone includes more lateral regions of anterior & posterior lobes

Question 8

Alternative name for Spinocerebellum

Answer 8

paleocerebellum

Question 9

General location of paleocerebellum

Answer 9

Intermediate zone which includes medial aspects of both lobes, cerebellar tonsils and vermis

Question 10

Alternative name for Vestibulocerebellum

Answer 10

archicerebellum

Question 11

General location of archicerebellum

Answer 11

Most medial part Includes the flocculonodular lobe

Question 12

Deep nuclei of cerebellum (3)

Answer 12

1. Fastigial nucleus 2. Interposed Nuclei (Globose & Emboliform) 3. Dentate nucleus

Question 13

Where is Fastigial nuclei and what cerebellar structures is it associated with?

Answer 13

Most medial Associated with vestibulocerebellum & spinocerebellum

Question 14

What cerebellar structure is Interposed Nuclei (Globose & Emboliform) most associated with?

Answer 14

spinocerebellum

Question 15

Where is Dentate nuclei and what cerebellar structure is it associated with?

Answer 15

Most lateral & largest Associated with pontocerebellum

Question 16

3 distinct layers of cerebellar cortex

Answer 16

1. molecular layer 2. Purkinje cell layer 3. granule cell layer

Question 17

Location of molecular layer

Answer 17

most superficial

Question 18

What lays within the molecular layer?

Answer 18

It has a low neuron cell body density but has two types of inhibitory neurons: stellate & basket cells. It does contain the large Dendritic arborizations of Purkinje cells. And two sets of afferent fibers

Question 19

How are Dendritic arborizations positioned within the molecular layer?

Answer 19

Dendritic arborizations lie in a Single plane which is perpendicular to long axis of folia, which are the gyri of the cerebellar cortex

Question 20

What are the two types of afferent fibers in molecular layer?

Answer 20

1. Parallel fibers
2. Climbing fibers

Question 21

descriptive features of parallel fibers

Answer 21

Unmyelinated Granule cell axons Each runs 5 mm along (parallel to) long axis of folium

Question 22

descriptive features of climbing fibers

Answer 22

wrapping around individual Purkinje cell dendritic trees

Question 23

Which layer is the middle layer?

Answer 23

Purkinje Cell Layer

Question 24

Purkinje neurons

Answer 24

neurons are Inhibitory (GABA mediated) to the deep nuclei and some axons will exit the cerebellum

Question 25

Where is granular layer oriented

Answer 25

the innermost layer

Question 26

Features of the tightly packed granular cells

Answer 26

Axons ascend into molecular layer to form parallel fibers Each is excitatory (glutamate) on \>500 Purkinje cells

Question 27

inhibitory interneurons in granular layer

Answer 27

Golgi cells

Question 28

Two types of cerebellar inputs (think fibers)

Answer 28

1. mossy fibers 2. climbing fibers

Question 29

Which of two cerebellar inputs is most numerous

Answer 29

mossy

Question 30

Excitatory neurotransmittor acting at mossy fiber synapse

Answer 30

glutamate

Question 31

Excitatory neurotransmittor acting at climbing fiber synapse

Answer 31

aspartate

Question 32

The EPSPs of Mossy fibers end primarily on \_\_\_\_\_\_\_\_

Answer 32

granule cells (and golgi cells)

Question 33

axons of granule cells form what and where do they travel to?

Answer 33

form parallel fibers travel to molecular layer of cerebellar cortex

Question 34

What do the parallel fibers synapse with and what type of synapse is it?

Answer 34

synapse with glutaminergic excitatory endings on the dendrites of Purkinje cells Each produces small, single short duration EPSPs which summate to activate the Purkinje cells

Question 35

Where do Mossy fibers enter cerebellum?

Answer 35

Enter mostly thru inferior & middle cerebellar peduncles (few thru superior peduncle)

Question 36

Where do Mossy fibers originate from? (4)

Answer 36

1. Vestibular primary afferent fibers via inferior peduncle 2. Vestibular nuclei via inferior peduncle 3. Spinal cord (spinocerebellar tracts) via mostly inferior peduncle (ventral SCT via superior peduncle) 4. Cerebral cortex via pontine nuclei & pontocerebellar fibers (middle peduncle)

Question 37

What do Mossy fibers end on?

Answer 37

Golgi cells- inhibitory interneurons (and granule cells)

Question 38

Which of the cerebellar input fibers has the most direct to Purkinje cells

Answer 38

climbing fibers

Question 39

What originates from contralateral inferior olivary nucleus

Answer 39

climbing fibers

Question 40

What do climbing fibers produce?

Answer 40

large EPSPs which produce bursts of Purkinje cell action potential activity

Question 41

What type of input do Mossy fibers provide

Answer 41

widespread and generalized

Question 42

What type of input do climbing fibers provide

Answer 42

very specific

Question 43

ratio of Purkinje cells and single climbing fibers- receiving and innervation

Answer 43

Each Purkinje cell receives single climbing fiber Each climbing fiber to 1-3 Purkinje cells

Question 44

Why do I care about ratio of Purkinje cells and single climbing fibers?

Answer 44

It is because of the ratio that the input from climbing fibers is very specific

Question 45

Which fibers provide feedback and which provide feed foward?

Answer 45

climbing fibers = feed foward mossy fibers = feed back

Question 46

Route that info travels for feed foward

Answer 46

Provide feed forward signals from cerebral cortex to the cerebellum via cortico-olivary and olivocerebellar fibers

Question 47

Route that info travels for feed back

Answer 47

feedback signals from spinal, vestibular & other inputs

Question 48

What innervates golgi cells ?

Answer 48

both mossy & parallel fibers

Question 49

What do Golgi cells inhibit?

Answer 49

Inhibitory action (GABA) on granule cell dendrites

Question 50

Golgi cell role in feed forward and feeback

Answer 50

produces both feed forward (via mossy fibers) and feedback (via parallel fibers) inhibition of granule cells. So feed forward and feedback information can be both excitatory and inhibitory in nature

Question 51

Function of Basket Cells

Answer 51

Inhibitory action (GABA) on Purkinje cells

Question 52

Function of Stellate Cells

Answer 52

Inhibitory action (GABA) on Purkinje cells

Question 53

Prolonged inhibition produced by Basket and Stellate cells

Answer 53

related to associative learning in cerebellum

Question 54

How does outflow of cerebellar cortex occur?

Answer 54

via Purkinje neurons and GABAminergic IPSPs (inhibitory potentials) on Deep cerebellar nuclei and vestibular nuclei, (the outputs to the vestibular nuclei are via Purkinje cells of the Vestibulocerebellum)

Question 55

What modulates the principle outputs from cerebellum coming from the deep cerebellar nuclei

Answer 55

modulated by mossy and climbing fibers collaterals to deep cerebellar nuclei

Question 56

How do mossy and climbing fibers modulate outputs?

Answer 56

They create an excitatory drive which is sculpted by the inhibitory influence of the Purkinje neurons The resulting level of excitation/inhibition allows for the neurons of the deep cerebellar nuclei to influence or not the structures to which the cerebellar efferents project

Question 57

Who is MaryBeth's favorite president?

Answer 57

Rutherford B Hayes- mostly just because his wife was nicknamed Lemonade Lucy