The Cerebellum and Motor Learning Flashcards
What is the role of the cerebellum?
- Maintenance of … and …
- … of voluntary movements
- … learning
- … functions
- Maintenance of balance and posture
- Coordination of voluntary movements
- Motor learning
- Cognitive functions
The motor control of hierarchy

Principles of organisation of the cerebellum
- The cerebellum is the ‘great …’
- It compares movement … to movement actually …
- … movement
- The cerebellum is the ‘great comparator’
- It compares movement intended to movement actually occurring
- Voluntary movement

Where is the cerebellum?

MRI scan showing anatomy of cerebellum

Gross anatomy of the cerebellum

3 lobes of the cerebellum - anterior, posterior, … … lobe
3 lobes of the cerebellum - anterior, posterior, floccular nodular lobe
Gross anatomy of the cerebellum

Functional subdivision of the cerebellum and it’s inputs
- 3 key inputs:
- … - vestibular organs
- … - spinal cord
- … - brain cortex
- 3 key inputs:
- Vestibulocerebellum - vestibular organs
- Spinocerebellum - spinal cord
- Cerebrocerebellum - brain cortex

Cerebellum inputs
- Spinocerebellum - map onto …
- Cerebrocerebellum - either side
- Vestibulocerebellum - … lobe

- Spinocerebellum - map onto vermis
- Cerebrocerebellum - either side
- Vestibulocerebellum - flocculonodular lobe
Somatotropic maps of the body surface in the cerebellum

Lobar anatomy of the cerebellum
- Outputs to nuclei - dentate, interposed, fastigial
- … - fastigial
- Blue paravermal area - interposed
- Cerebellar hemispheres - … nucleus

- Outputs to nuclei - dentate, interposed, fastigial
- Vermis - fastigial
- Blue paravermal area - interposed
- Cerebellar hemispheres - dentate nucleus

Cerebellar Output
- Vermis - …
- Paravermis - …
- Hemispheres - …
- Vermis - fastigial
- Paravermis - interposed
- Hemispheres - dentate

Spinocerebellum - control of muscle tone/posture
- Inputs - v… - … and … nuclei - form descending tracts
- Inputs - vermis - fastigial and interposed nuclei - form descending tracts

Cerebrocerebellum
- … - pass through pons - synapse - pontocerebellar tracts - hemispheres - outflow - … nuclei - brain via … - central relay
- Cortex - pass through pons - synapse - pontocerebellar tracts - hemispheres - outflow - dentate nuclei - brain via thalamus - central relay

Vestibulocerebellum pathways
- Vestibular organ - vestibular nuclei - info … lobe - bypasses deep nuclei in cerebellum - back out to … nuclei
- Vestibular organ - vestibular nuclei - info flocculonodular lobe - bypasses deep nuclei in cerebellum - back out to vestibular nuclei

Gross anatomy of the cerebellum

Cerebellar peduncle pathways
- Spinocerebellar - … cerebellar peduncle
- Fibres from top - go through … cerebellar peduncle
- All outputs go through … cerebellar peduncle
- Inflow through middle and inferior, outflow through superior
- Spinocerebellar - inferior cerebellar peduncle
- Fibres from top - go through middle cerebellar peduncle
- All outputs go through superior cerebellar peduncle
- Inflow through middle and inferior, outflow through superior

Effects of lesions to the cerebrocerebellum pathway
- …: movement is not stopped in time (overshoot)
- Dsynergia: decomposition of complex movements
- …: reduced ability to perform rapidly alternating movements
- Intentional …: tremor arising when trying to perform a goal-directed movement
- … – articulation incoordination: incoordination in the respiratory muscles, muscles of the larynx, etc. Uneven speech strength and velocity.
- Dysmetria: movement is not stopped in time (overshoot)
- Dsynergia: decomposition of complex movements
- Dysdiadochokinesia: reduced ability to perform rapidly alternating movements
- Intentional tremor: tremor arising when trying to perform a goal-directed movement
- Dysarthria – articulation incoordination: incoordination in the respiratory muscles, muscles of the larynx, etc. Uneven speech strength and velocity.

Effects of lesions to the cerebrocerebellum pathway
- …: movement is not stopped in time (overshoot)
- …: decomposition of complex movements
- Dysdiadochokinesia: reduced ability to perform rapidly alternating movements
- Intentional tremor: tremor arising when trying to perform a goal-directed movement
- … – articulation incoordination: incoordination in the respiratory muscles, muscles of the larynx, etc. Uneven speech strength and velocity.
- Dysmetria: movement is not stopped in time (overshoot)
- Dsynergia: decomposition of complex movements
- Dysdiadochokinesia: reduced ability to perform rapidly alternating movements
- Intentional tremor: tremor arising when trying to perform a goal-directed movement
- Dysarthria – articulation incoordination: incoordination in the respiratory muscles, muscles of the larynx, etc. Uneven speech strength and velocity.

Effects of lesions to the cerebrocerebellum pathway
- Dysmetria: movement is not stopped in time (…)
- Dsynergia: … of complex movements
- Dysdiadochokinesia: reduced ability to perform … … movements
- Intentional tremor: tremor arising when trying to perform a …-directed movement
- Dysarthria – articulation …: … in the respiratory muscles, muscles of the larynx, etc. … speech strength and velocity.
- Dysmetria: movement is not stopped in time (overshoot)
- Dsynergia: decomposition of complex movements
- Dysdiadochokinesia: reduced ability to perform rapidly alternating movements
- Intentional tremor: tremor arising when trying to perform a goal-directed movement
- Dysarthria – articulation incoordination: incoordination in the respiratory muscles, muscles of the larynx, etc. Uneven speech strength and velocity.

Vestibular-ocular pathway
- Eye signs pick up
- Vestibular Organ - vestibular nucleus - … nucleus
- 3 and 6 connected via … longitudinal fasciculas - Connects … nucleus and … nucleus
- 6 pons, 3 midbrain
- Allows to have … gaze
- Evidence of …

- Eye signs pick up
- Vestibular Organ - vestibular nucleus - abducens nucleus
- 3 and 6 connected via medial longitudinal fasciculas
- Connects abducens nucleus and oculomotor nucleus
- 6 pons, 3 midbrain
- Allows to have horizontal gaze
- Evidence of nystagmus
Effect of lesions to the vestibulocerebellar pathway
- …- involuntary, rhythmical, repeated oscillations of one or both eyes, in any or all directions of view
- Movement of the eyes minimises the ability to focus the eyes on one point (…).
- Eyes are key to look at - to pick up … signs
- Nystagmus- involuntary, rhythmical, repeated oscillations of one or both eyes, in any or all directions of view
- Movement of the eyes minimises the ability to focus the eyes on one point (fixation).
- Eyes are key to look at - to pick up cerebellum signs
Effect of lesions in the spinocerebellar pathway
- Gait … (unsteadiness of walking), and disturbance of limb tone (…) and posture
- Alcohol intoxication - affects the v…

- Gait ataxia (unsteadiness of walking), and disturbance of limb tone (hypotonia) and posture
- Alcohol intoxication - vermis
Cerebellar peduncle pathways
- 2 nerves - … fibers from inputs from spinal cord and brain stem and … fibres from inferior olive in medulla

- 2 nerves - mossy fibers from inputs from spinal cord and brain stem and climbing fibres from inferior olive in medulla
Cerebellar circuitry - schematic

Cerebellar Cortex
- … fibre - what you want to do
- … fibres - meant to catch ball but didn’t - error signal
- Mossy fibre - what you want to do
- Climbing fibres - meant to catch ball but didn’t - error signal
- … fibre synapse on granule cells
- Many parallel fibres - one purkinje cell - with one or a few synapses each - …gence
- One … fibre - each purkinje cell - but many synapses - …gence

- Mossy fibre synapse on granule cells
- Many parallel fibres - one purkinje cell - with one or a few synapses each - convergence
- One climbing fibre - each purkinje cell - but many synapses - divergence
Slice through cortex
- Molecular layer - parallel fibres
- Purkinje layer - purkine fibres
- Granule layer - granule cells
- … fibre interact with granule cell layer - lead on to parallel fibres - synapse with dendrites of purkinje cell (convergence)
- … fibres - climb around dendrites interacting with purkinje cell (divergence)

- Molecular layer - parallel fibres
- Purkinje layer - purkine fibres
- Granule layer - granule cells
- Mossy fibre interact with granule cell layer - lead on to parallel fibres - synapse with dendrites of purkinje cell (convergence)
- Climbing fibres - climb around dendrites interacting with purkinje cell (divergence)
Motor learning - long-term depression
- How can brain learn and correct mistakes
- Intend to do - … fibres interact with granule cells - parallel fibres - synapse with dendrites of purkinje cell
- Feedback from when you make a mistake - error signal generated - through to inferior olive - through … fibres - climbs around dendrites of purkinje cell
- FOR LTD - Both activate at same time - … synapse
- Granule cell layer and ,,, fibre both activate the purkinje cell at the same time, it … the synapse between the parallel fibre and the purkinje cell - causes loser association - long-term depression

- Intend to do - Mossy fibres interact with granule cells - parallel fibres - synapse with dendrites of purkinje cell
- Feedback from when you make a mistake - error signal generated - through to inferior olive - through climbing fibres - climbs around dendrites of purkinje cell
- FOR LTD - Both activate at same time - weaken synapse
- Granule cell layer and climbing fibre both activate the purkinje cell at the same time, it weakens the synapse between the parallel fibre and the purkinje cell - causes loser association - long-term depression
Motor learning - long-term depression
- How can brain learn and correct mistakes
- … to do - Mossy fibres interact with granule cells - parallel fibres - synapse with dendrites of purkinje cell
- Feedback from when you make a … - … signal generated - through to inferior olive - through climbing fibres - climbs around dendrites of purkinje cell
- FOR LTD - Both activate at same time - weaken synapse
- Granule cell layer and climbing fibre both activate the purkinje cell at the same time, it weakens the synapse between the parallel fibre and the purkinje cell - causes loser … - long-term …

- Intend to do - Mossy fibres interact with granule cells - parallel fibres - synapse with dendrites of purkinje cell
- Feedback from when you make a mistake - error signal generated - through to inferior olive - through climbing fibres - climbs around dendrites of purkinje cell
- FOR LTD - Both activate at same time - weaken synapse
- Granule cell layer and climbing fibre both activate the purkinje cell at the same time, it weakens the synapse between the parallel fibre and the purkinje cell - causes loser association - long-term depression
Long-term … - required really for motor learning
Long-term depression - required really for motor learning
Genetic causes of cerebellar dysfunction (Inherited)
- Inherited (rare)
- Frederich’s ataxia (Spinocerebellar …)
- (Ataxia may occur if major connections disrupted)
- Ataxia-… - capillaries in mucosa of skin - bruise easily or bleed
- Von Hippel … - tumour (haemangioblastoma)
- Frederich’s ataxia (Spinocerebellar …)
- Inherited (rare)
- Frederich’s ataxia (Spinocerebellar degeneration)
- (Ataxia may occur if major connections disrupted)
- Ataxia-telengiectasia - capillaries in mucosa of skin - bruise easily or bleed
- Von Hippel Lindau - tumour (haemangioblastoma)
- Frederich’s ataxia (Spinocerebellar degeneration)

Genetic causes of cerebellar dysfunction (Inherited)
- Inherited (rare)
- Frederich’s … (Spinocerebellar degeneration)
- (… may occur if major connections disrupted)
- …-telengiectasia - capillaries in mucosa of skin - bruise easily or bleed
- … … Lindau - tumour (haemangioblastoma)
- Frederich’s … (Spinocerebellar degeneration)
- Inherited (rare)
- Frederich’s ataxia (Spinocerebellar degeneration)
- (Ataxia may occur if major connections disrupted)
- Ataxia-telengiectasia - capillaries in mucosa of skin - bruise easily or bleed
- Von Hippel Lindau - tumour (haemangioblastoma)
- Frederich’s ataxia (Spinocerebellar degeneration)

Cerebellar dysfunction - Acquired Symmetrical Ataxia
- Eg-
- … - cerebellar atrophy
- … (B12/Thyroid/Coeliac) e.g. anti purkinje cells
- … (eg phenytoin) - anti … drugs can cause problems
- Degenerative (familial, MSA) - … plus conditions
- Immune (paraneoplastic) - more prevalent - antibodies formed - infection - fight other parts of body - other - tumour - antibodies attack cells at the molecular layer
- Eg-
- Alcohol - cerebellar atrophy
- Metabolic (B12/Thyroid/Coeliac) e.g. anti purkinje cells
- Drugs (eg phenytoin) - anti epileptic drugs can cause problems
- Degenerative (familial, MSA) - parkinson’s plus conditions
- Immune (paraneoplastic) - more prevalent - antibodies formed - infection - fight other parts of body - other - tumour - antibodies attack cells at the molecular layer

Cerebellar dysfunction - Acquired Symmetrical Ataxia
- Eg-
- Alcohol - cerebellar …
- Metabolic (B12/Thyroid/Coeliac) e.g. anti purkinje cells
- Drugs (eg …) - anti epileptic drugs can cause problems
- … (familial, MSA) - parkinson’s plus conditions
- … (paraneoplastic) - more prevalent - antibodies formed - infection - fight other parts of body - other - tumour - antibodies attack cells at the molecular layer
- Eg-
- Alcohol - cerebellar atrophy
- Metabolic (B12/Thyroid/Coeliac) e.g. anti purkinje cells
- Drugs (eg phenytoin) - anti epileptic drugs can cause problems
- Degenerative (familial, MSA) - parkinson’s plus conditions
- Immune (paraneoplastic) - more prevalent - antibodies formed - infection - fight other parts of body - other - tumour - antibodies attack cells at the molecular layer

Alcohol - cerebellar atrophy

Focal cerebellar pathology (Asymmetrical)
- Ataxia often … profound if cerebellar nuclei, brainstem nuclei or white matter tracts involved (MS) than cerebellar cortex as some degree of …
- … more important than the …
- Ataxia often more profound if cerebellar nuclei, brainstem nuclei or white matter tracts involved (MS) than cerebellar cortex as some degree of plasticity
- Location more important than the size
