28 - NeuroScience - Cerebellum

Question 1

Cerebellar Functions

Answer 1

Timing and pattern of muscles activated in limb, head and eye movement.

Contributes to balance, posture and muscle tone

Question 2

Cerebellar Location

Answer 2

Posterior Fossa

Question 3

What separates cerebellum from the cortex?

Answer 3

Tetorium Cerebelli

Question 4

What is ventral to the cerebellum?

Answer 4

IVth Ventricle

Question 5

What is inferior to the cerebellum?

Answer 5

Cisterna Magna

Question 6

Vermis

Answer 6

Medial cortico-nuclear zone of the cerebellum

Question 7

Blood supply of the posterior and inferior portions of the cerebellum

Answer 7

PICA

Question 8

Blood supply of the superior portion of the cerebellum

Answer 8

SuCeA

Question 9

Blood supply of the anterior portion of the cerebellum

Answer 9

AICA

Question 10

What happens if there is a blockage of a vessel in the cerebellum?

Answer 10

Not much. There are anastomoses.

Question 11

What happens if there’s a blockage of a major artery feeding the cerebellum (PICA, AICA, SuCeA)?

Answer 11

UGHGHGHGH!!!!!!

Compromise of either the nuclei themselves, or of the tracts allowing communication.

Question 12

Cerebellar Divisions

Answer 12

Spinocerebellum
Cerebrocerebellum
Vestibulocerebellum

Question 13

Spinocerebellum

Answer 13

Vermis & Intermediate Hemisphere

Control of limbs and trunk

Question 14

Cerebrocerebellum

Answer 14

Lateral Hemisphere

Planning of movement+

Question 15

Vestibulocerebellum

Answer 15

Flocculonodular Lobe

Control of eye & head movements
Balance

Question 16

Deep Cerebellar Nuclei

Answer 16

Fastigial
Interposed
Dentate

Question 17

Extrinsic Cerebellar Inputs

Answer 17

Mossy Fiber

Climbing Fiber

Question 18

Fastigial Nucleus

Answer 18

The most medial of the nuclei

Receives the output of the Vermis and FlocculonodularLobe

Involved in balance and postural control, eye movements

Medial descending system

Question 19

Interposed Nuclei

Answer 19

Between Fastigial Nucleus and Dendate Nucleus

Receives input from the intermediate hemisphere

Lateral descending system

Question 20

Dentate Nucleus

Answer 20

Most Lateral of the nuclei

Receives its inputs from the lateral hemisphere

Fine movements in all regions of cerebral cortex

Question 21

Vestibular complex

Answer 21

Serves as a deep cerebellar nucleus of the flocculonodular lobe.

Afferent projections from CN VIII go to vestibular complex to flocculonodular lobe, back to vestibular complex. It serves as a “nucleus”

Question 22

Model of a deep cerebellar nucleus

Answer 22

Input hits nucleus
Projects to cerebellar cortex
Projects back to nucleus

Question 23

Mossy Fiber

Answer 23

Inputs that come from all areas

Question 24

Climbing Fiber

Answer 24

Inferior Olivary Nucleus is the only source!!!!!!

Question 25

5 inputs to the cerebellum

Answer 25

``` Cortical Inputs (via pons) DSCT (Spinal cord afferent) VSCT (Spinal cord afferent) Lateral Reticular Nucleus Inferior Olivary Nucleus Vestibular Afferents and second order neurons from the vestibular complex ```

Question 26

Cortical Inputs

Answer 26

Pontine nuclei receive inputs from all regions (especially frontal cortex) Project via contralateral middle cerebellar peduncle, primarily to the lateral hemisphere (and dentate nucleus). Lesions affect planning and execution of fine movements.

Question 27

Spinal Cord Afferents - Dorsal Spinocerebellar Tract (DSCT)

Answer 27

Proprioceptive and other sensory information from FA(accesory cuneate nucleus)TL(clark's nucleus) ascend to the cerebellum. Project via ipsilateral inferior cerebellar peduncle to innervate vermis and intermediate hemisphere (and fastigial and interposed nuclei) Lesions affect gait and balance

Question 28

Spinal Cord Afferents - Ventral Spinocerebellar Tract (VSCT)

Answer 28

Another input from spinal cord conveys information about error signals from ongoing activity Projects to various regions of the cerebellum via contralateral superior cerebellar peduncle.

Question 29

Lateral Reticular Nucleus

Answer 29

Indirect spinal afferents Projects to entire cerebellum via ipsilateral inferior cerebellar peduncle Receives input from spinal cord as well as cerebral cortex and red nucleus.

Question 30

Inferior Olivary Nucleus

Answer 30

Projects climbing fiber inputs to all regions of the cerebellum Projects via contralateral inferior cerebellar peduncle. Receives input from spinal cord, brainstem, cortex & feedback from cerebellum via parvocellular red nucleus Lesions affect ALL cerebellar functions

Question 31

Vestibular afferents & second order neurons from the vestibular complex

Answer 31

Project via inferior cerebellar peduncle to the flocculonodular lobe and vermis (via fastigial nucleus) Inputs important for eye movements, posture & head/neck movements. Lesions affect balance & eye movements.

Question 32

5 neurons in the cerebellar cortex

Answer 32

``` Purkinje Cells Excitatory Interneurons Inhibitory Interneurons Mossy Fiber Climbing fiber ```

Question 33

Single output neuron

Answer 33

Purkinje Cell

Question 34

How many climbing fibers synapse on each Purkinje cell?

Answer 34

1 But it synapses thousands of times on that one cell.

Question 35

Neurotransmitter released by purkinje cells

Answer 35

GABA Thus, they inhibit their deep cerebellar nuclei

Question 36

Mossy fibers synapse on which excitatory interneurons?

Answer 36

Granule cells These synapse on thousands of purkinje cells

Question 37

Granule cells synapse on which inhibitory interneurons?

Answer 37

Basket cells | Stellate cells

Question 38

Granule cells synapse on which feedback inhibitor cells?

Answer 38

Golgi cells (receive input, and feed back inhibition back to that same granule cell)

Question 39

3 Layers of Cerebellar Folia

Answer 39

Molecular Purkinje Granular

Question 40

Molecular layer

Answer 40

Parallel fibers of granule cells synapse with purkinje cells Inhibitory interneurons live here too

Question 41

Granular Layer

Answer 41

Granule cells live here!!!!! | Excitatory interneurons

Question 42

White matter

Answer 42

Inputs and outputs flow

Question 43

Clarke's Nucleus

Answer 43

T1 - L2 Proprioception & muscle spindle afferents from lower extremities and trunk Gracile fasciculus synapses on thurr. Projects out to form DSCT

Question 44

Spinal Border Cells

Answer 44

Inputs from interneurons in many regions Project in VSCT

Question 45

Accesory Cuneate Nucleus

Answer 45

Trigeminal and upper extremity propriocpetion It's like the Clarke's nucleus of the head and upper extremity!!!!!!

Question 46

Cerebellar signs - ipsilateral or contralateral?

Answer 46

Ipsilateral to the lesion Why??!?! Double crossing!!!!