Cerebellum

Question 1

Cerebellum

Answer 1

Posterior cranial fossa

Crosses midline

Question 2

Vermis

Answer 2

Part that lies along midline

Question 3

Gyri

Answer 3

Many narrow gyri

Mostly run medio-lateral

Question 4

Primary fissure

Answer 4

Divides cerebellum into anterior and posterior lobe

Question 5

Small third lobe

Answer 5

Flocculus, part of the flocculo-nodular lobe

On ventral surface of cerebellum, forming part of roof of 4th ventricle

Question 6

Blood supply to cerebellum

Answer 6

Mainly through 3 pairs of arteries
SCA
Anterior inferior cerebellar artery
Posterior inferior cerebellar artery (PICA)

Question 7

Most common site of infarct in posterior circulation

Answer 7

PICA

Question 8

3 Layers in cerebellar cortex

Answer 8

Seen through Nissl or Thionin stain
Outer molecular layer
Middle layer
Inner layer

Question 9

Outer molecular layer

Answer 9

Pale

Mostly axon + few cells

Question 10

Middle layer

Answer 10

Single layer of Purkinje fibres

Question 11

Inner layer

Answer 11

Granule layer
Thick
Contains vast number of granule cells

Question 12

Superior cerebellar peduncle

Answer 12

Output fibres only

Question 13

Middle cerebellar peduncle (largest)

Answer 13

Input fibres from (contralateral) cerebral cortex + cranial nerves

Question 14

Inferior cerebellar peduncle

Answer 14

Input fibres from spinal cord

Question 15

Dorsal (posterior) spinocerebellar tract

Answer 15

Ipsilateral
Passes up into brainstem + enters cerebellum in inferior cerebellar peduncle on same side
Carries info from proprioceptors
Relay cell in lamina VII

Question 16

Ventral (anterior) spinocerebellar tract

Answer 16

Contralateral in spinal cord
Carries info about state of reflexes in spinal cord
Relay cell in lamina VII
Re-crosses in brain stem to end up on same side as it enters cord

Question 17

Cerebellar signs

Answer 17

Always on same side as lesion

Question 18

Inputs and outputs to cerebral cortex routed through the

Answer 18

Deep Cerebellar nuclei

Question 19

Deep Cerebellar Nuclei

Answer 19

From M –> L

Fastigial –> Globose –> Emboliform –> Dentate

Question 20

Hemispheres connect to

Answer 20

Dentate nuclei

Question 21

Anterior lobe connects to

Answer 21

Globose and Emboliform

Question 22

Vermis connects to

Answer 22

Fastigial

Question 23

Flocculo-nodular lobe connect to

Answer 23

Lateral vestibular nuclei of pons (serves same function for F/N lobe as the deep nuclei do for other cerebellar zones)

Question 24

Cerebellum + movement

Answer 24

Doesn’t initiate movement
Helps motor cortex produce accurate + smooth movements
–> modulates + refines motor cortex commands by using feedback from proprioceptors + other sensory organs

Question 25

Cerebellar damage

Answer 25

Clumsiness, abnormal fatigue + instability of movement --> extraocular eye movements particularly affected Exhibits neuronal plasticity so partial recovery of function possible

Question 26

Damage to deep nuclei

Answer 26

Persisting disability

Question 27

Vestibulocerebellum

Answer 27

Flocculonodular lobe connected to lateral vestibular nucleus (in pons)

Question 28

Spinocerebellum

Answer 28

Anterior lobe + vermis connected to fastigial, globose + emboliform nuclei

Question 29

Cerebrocerebellum

Answer 29

Posterior lobe (cerebellar hemisphere) connected to dentate nucleus

Question 30

Vestibulocerebellum function

Answer 30

Co-ordinates head and eye movements--> stability of gaze Controls balance of head on body, via medial vestibulospinal tract Helps balance body on ground, via lateral vestibulospinal tract

Question 31

Vestibulocerebellum MOA

Answer 31

Info from vestibular apparatus about movement of head sent to vestibular nuclei in pons + medulla Info combined with info coming from extra-ocular eye muscles + muscles in neck about head movements

Question 32

Medial vestibulospinal tract

Answer 32

Motor commands to neck + eye muscles

Question 33

Lateral vestibulospinal tract

Answer 33

Motor commands to legs

Question 34

Spinocerebellum function

Answer 34

Controls locomotion + limb co-ordination | Sends motor commands down reticulospinal tracts to coordinate postural + locomotor movements

Question 35

Cerebrocerebellum function

Answer 35

Coordinates movement initiated by motor cortex | --> includes speech, voluntary movements of hands + arms, and hand-eye coordination

Question 36

Neocerebellum

Answer 36

Output - to motor (VL) thalamus via superior cerebral peduncle

Question 37

Flocculonodular syndrome

Answer 37

``` Poor balance Disordered eye movements Nystagmus Ocular dysmetria Poor visual pursuit (tracking) Little control of axial muscles Wide based ataxic gait Tendency to fall to side of lesion Can't sit or stand without falling- severe ```

Question 38

Floculonodular syndrome common in

Answer 38

Young children with medulloblastoma in 4th ventricle

Question 39

Medulloblastoma

Answer 39

Originates 4th ventricle wall Primitive neuroectodermal tumour Most common malignant CNS tumour in children

Question 40

Anterior lobe syndrome

Answer 40

Damage to spinocerebellum Incoordination of limbs Often seen in alcoholics due to malnutrition + lack of B vitamins

Question 41

Anterior lobe damage signs

Answer 41

Ataxic gait Hypotonia Depressed or pendular reflexes (UMN lesions)

Question 42

Neocerebellar syndrome

Answer 42

Loss of hand eye coordination Dysmetria Dysdiadochokinesis Intention tremors- finger to nose) Loss of good speech articulation (slurred speech) --> stroke, tumour, trauma, degenerative diseases

Question 43

Cerebellar stroke signs

Answer 43

Usually whole cerebellar cortex on one side Headache, Vertigo, Nausea, Vomiting Eye changes- typically one eye + contribute to vertigo Dysarthria + Dysphagia Ataxia Arm weakness + incoordination- usually one arm