1. CEREBELLUM AND BASAL GANGLIA
Hope and Jen

2. Cerebellum
Brief anatomy and functions Functions – DANISH Pathology

3. Brief anatomy What do the lobes of the cerebellum do?
Anterior cerebellum - unconscious proprioception
Posterior cerebellum - fine motor control
Flocculonodular - head & eye movements

4. functions of the cerebellum
Maintenance of balance
Posture and muscle tone
Co-ordination
Eye movements
Planning movements
Learning of motor skills.
IMPORTANT: PROPRIOCEPTION
Recieves input from spinocerebellar tract
RECAP from week 1 block 3:
What is unconscious proprioception?
Knowing where your body parts are in relation to space without looking. (eg MSK exams)

5. Blood supply Which 3 arteries supply the cerebellum?
AICA – anterior inferior cerebellar artery (basilar)
PICA – posterior inferior cerebellar artery (vertebral)
SCA – superior cerebellar artery (basilar)
NB LEARN YOUR CIRCLE OF WILLIS

6. DAMAGE TO CEREBELLUM
Causes DANISH Areas damaged

7. What could cause damage to the cerebellum?
Tumours Strokes Degeneration Haemorrhage Trauma Alcohol Hereditory disorders Viruses

8. DANISH Clinical features of cerebellar disease Dysdiadokinesia Ataxia
Nystagmus
Intention tremor
Scanning dysarthria
Hypotonia (and heel-shin test)
NB IPSILATERAL SYMPTOMS
Ask them in order of word DANISH.
Ataxia: neurological term for problems related to your speech, coordination and balance.
Nystagmus: how do you measure which direction a nystagmus is? Fast phase and slow phase – whichever side the fast phase flicks towards is the direction of the nystagmus.
JERK NYSTAGMUS = repetitive eye movement with a fast and slow phase
SLOW PHASE – eyes slowly drift to the side of the lesion
FAST PHASE – eyes move quickly back to the midline via action from SACCADE CENTRES
Jerk Nystagmus is named after the Fast Phase = opposite side to the lesion
• RIGHT lesion = LEFT Nystagmus
Scanning dysarthria – words broken up into separate syllables.

9. Damage to the cerebellum:
REMEMBER THIS?
What do the lobes of the cerebellum do?
Anterior cerebellum - unconscious proprioception
Posterior cerebellum - fine motor control
Flocculonodular - head & eye movements
What could cause damage?
Effects of damage
Flocculonodular lobe
Dizziness, nausea, vomiting and nystagmus.
Central vermal region
(Tumour in 4th Ventricle)
Midline lesions result in truncal ataxia, limb co-ordination can be ok
Anterior lobe
(alcoholic damage)
Damage affects lower limbs - ataxic wide-based gait
No heel toe walking or heel shin stroking with eyes open
Posterior lobe (most of the cerebellum)
Dysdiadochokinesia (inability to carry out rapid repeating movement)
Dysarthria
Dysmetria (inability to calculate trajectory)
Tremor (intentional)
Wide-based unsteady gait
Linguistic incoordination - Grammar and syntax misuse

10. Important conditions to remember:
PICA syndrome (Wallenberg syndrome, Lateral Medullary Syndrome) – KNOW FOR EXAM
Cause: Occlusion to PICA due to thrombosis or stroke.
Symptoms: Ataxia, vertigo, nystagmus, facial pain, dysphagia, Horner’s syndrome. Loss of pain and temperature on contralateral side of the body and ipsilateral side of the face.
Freidreichs Ataxia
Most common inherited ataxia – onset in teens before 25 yo
Cause: mutation in FRDA gene – reduced frataxin protein – tissues normally high in frataxin preferentially affected.
Symptoms: above + muscle weakness.
Outcome: Loss of ambulation at 25 – death in mid 30s.

11. Any questions?
Next up… Basal Ganglia!

12. Basal Ganglia
BRIEF anatomy Direct pathway Indirect pathway Do it yourself (Disorders)

13. Anatomy Striatum = Caudate nucleus Putamen
Pallidum = Globus pallidus internus (medius)
Globus pallidus externus (lateralis)
Substantia nigra pars reticula
Lentiform nucleus = Putamen
Globus pallidus internus
Globus pallidus externus
Subthalamic nucleus
Substantia nigra pars compacta

15. Direct Pathway = Promotes movement
VISUAL LEARNERS:
Excitatory = glutaminergic
Inhibitory = GABAergic
Substantia Nigra pars compacta activates striatum via D1 receptors
Cortex
Activity
Activates striatum
Activity
Activates Cortex
(Premotor)
Activates striatum
Striatum
Globus Pallidus Internus & SNPR
Normal activity Inhibits VLN
Therefore removal causes activation of the VLN
ThalamusVentral Anterior/Lateral Nucleus
Parkinsons – loss of dopamine from SNPC so lose striatal activation. Loss of movements as direct pathway eventually suppressed.
Activity Inhibits GPI
WORD LEARNERS
Inhibition of the inhibitory GPI allows the VLN to activate cortex
SYMBOLIC LEARNERS

16. GABA and GLUT
Green= excitatory (go!)  gluta-green-ergic (GABA is opposite)

17. Indirect Pathway = Inhibits Movement Normally Activates Cortex
SNPC inhibits striatum via D2 receptors
Cortex
Normally Activates Cortex
(Premotor)
Activates striatum
Inhibits striatum D2
Striatum
Globus Pallidus Internus & SNPR
ThalamusVentral Anterior/Lateral Nucleus
Activity Inhibits VLN
Huntingtons = degeneration of striatal input to GPE and SNPC
Thalamus is overexcited.
Activity
Activates GPI & SNPR
Activity Inhibits GPE
Globus Pallidus Externus
Normal Activity Inhibits STN therefore removal causes activation of STN
Subthalamic nucleus

18. Indirect Pathway = Inhibits Movement Normally Activates Cortex
SNPC inhibits striatum via D2 receptors
Cortex
Normally Activates Cortex
(Premotor)
Activates striatum
Inhibits striatum D2
Striatum
Globus Pallidus Internus & SNPR
ThalamusVentral Anterior/Lateral Nucleus
Activity Inhibits VLN
Activity
Activates GPI & SNPR
Huntingtons = degeneration of striatal input to GPE and SNPC
Thalamus is overexcited.
Activity Inhibits GPE
Globus Pallidus Externus
Normal Activity Inhibits STN therefore removal causes activation of STN
Subthalamic nucleus
WORD LEARNERS
Inhibiting the inhibitory GPE enables STN to activate GPI which inhibits the thalamus
SYMBOLIC LEARNERS

19. Substantia nigra pars compacta promotes movement via dopaminergic signalling
Activates direct pathway
Direct pathway normally activates movement
SNPC
(Dopaminergic)
Inhibits indirect pathway
Indirect pathway normally inhibits movement
Parkinsons – can remove globus pallidus
SNPC: A summary.
SNPC releases dopamine which acts on:
D1 in direct pathway to promote movement by activating that pathway.
D2 in indirect pathway to promote movement by inhibiting that pathway.

20. BUILD YOUR PATHWAYS
Split into two groups and make up the pathways (we will be here to help)

21. Pathology of Basal Ganglia
TRAP:
Tremor (resting)
Rigidity
Akinesia
Postural instability
Condition
Causes
Where is affected
Effects on basal ganglia pathways
Main symptoms
Parkinsons
Idiopathic/iatrogenic
SNPC
Inhibits direct pathway – to slow initiation of movement.
TRAP
Huntingtons
Genetic
Striatum
Inhibits indirect pathway – to remove ability to suppress movements.
Involuntary horeiform (writhing) movements + cognitive changes
Hemiballismus
Vascular
Subthalamic nucleus
Undesired flailing limbs (mainly proximal limb muscles)

22. THANKS FOR LISTENING Special effects: Andy
/fb us with any questions you have.
Special effects: Andy