Cerebellum Flashcards
The superior cerebellar peduncle is mostly ______________
The middle cerebellar peduncle is mostly ___________
The inferior cerebellar peduncle is mostly _____________
Superior: efferent
Middle: afferent (ONLY afferents) - from pontine nuclei
Inferior: afferent - from brainstem and SC
Name the afferent tracts that pass through the inferior cerebellar peduncle
- Vestibulocerebellar tract
- Posterior spinocerebellar tract
- Cuneocerebellar tract
- Olivocerebellar tract
- Vestibulocerebellar tract
Name the afferent tracts that pass through the middle cerebellar peduncle
Pontocerebellar tract
Name the afferent tracts that pass through the superior cerebellar peduncle
Anterior spinocerebellar tract
Acoustic and optic information
Does the cerebellum directly control muscles?
No - most outputs go to the cortex via the thalamus, or to the brainstem nuclei to control muscles
Name the efferent tracts passing through the superior cerebellar peduncle
Dentatorubrothalamic tract
Name the efferents passing through the middle cerebellar peduncle
none!
Name the efferents passing through the inferior cerebellar peduncle
- Cerebellarolivary tract
2. Cerebellovestibular tract
Name the 3 functional cerebellar loops
- Vestibulocerebellar (oldest)
- Spinocerebellar
- Cerebrocerebellar (newest)
Which deep cerebellar nucleus is used in the the vestibulocerebellar loop?
Fastigial
Which deep cerebellar nucleus is used in the spinocerebellar loop?
- Emboliform
- Globose
- Fastigial
Which deep cerebellar nucleus is used in the cerebrocerebellar loop?
Dentate
What is the function of the vestibulocerebellar loop?
Maintain equilibrium through trunkal stability (postural responses to vestibular input)
What is the function of the spinocerebellar loop?
Control muscle tone and limb coordination?
Which cerebellar peduncle do inputs to the vestibulocerebellar loops go through?
Inferior cerebellar peduncle
What are the 3 layers of cells in the cerebellar cortex?
- Molecular layer
- Purkinje layer
- Granular layer
What is the function of Purkinje cells?
They are output cells from the cerebellar cortex
What are the 2 types of cerebellar input fibers?
Mossy fibers
Climbing fibers
Where do climbing fibers provide inputs from?
From the contralateral inferior olivary nucleus in the medulla
Where do mossy fibers provide inputs from?
All other locations (axons from vestibular nuclei, posterior spinocerebellar and cuneocerebellar, corticopontocerebellar)
What are the symptoms that can occur with damage to the flocculonodular lobe?
- Trunkal ataxia
- Loss of eqm (inability to stand)
- Staggering and wide-based gait
- Can do heel-shin test, because lower limb coordination intact
- Reflexes and muscle tone are normal
Give an example of a condition which could lead to flocculonodular lobe damage
Medulloblastoma (tumour b/w medulla and cerebellum, usually in the 4th ventricle)
Which structure on the cerebellum separates the anterior and posterior lobes?
The primary fissure
Where does the spinocerebellar loop receive inputs from? Which cerebellar peduncle does it come through?
Posterior spinocerebellar tract, cuneocerebellar tract
Inferior cerebellar peduncle
Describe the type of information that the deep cerebellar nuclei are outputting in the spinocerebellar loop
Emboliform and globose: Limb movements
Fastigial: Trunkal movements
Describe the output pathway of limb information from the spinocerebellar loop
Spinocerebellum - Emboliform and Globose nuclei - contralateral VL of thalamus - Motor cortex - lateral corticospinal tract
Outputs from the spinocerebellum for trunkal movements contribute to which tracts?
- Vestibulospinal
- Rubrospinal
- Reticulospinal
Describe the output pathway for trunkal movement in the Spinocerebellar loop
Anterior lobe and vermis/paravermal area (spinocerebellum) - Fastigial nucleus - Inferior cerebellar peduncle - OPTIONS(?): bilateral vestibular nuclei - bilateral red nuclei and reticular formation - spinal cord
What is anterior lobe syndrome?
What is is caused by?
What are the symptoms?
Can be caused by chronic alcoholism - starts at anterior lobe and progresses posteriorly
Causes lower limb ataxia, wide based staggering gait
Can’t do heel shin coordination test
What is Friedrich’s Ataxia?
What causes it?
What are the symptoms?
Is a genetic condition with progressive destruction of proprioceptive pathways (dorsal columns, dorsal spinocerebellar, cuneocerebellar) as well as of pyramidal system.
Symptoms include ataxic gait and problems coordinating movement
Describe the pathway of the Cerebrocerebellar loop (neocerebellar)
- Start in cortex
- Travel down along corticopontine tract (ipsilateral)
- Synapse @ pontine nuclei
- Cross midline along pontocerebellar tract
- Synapse at dentate nucleus
- Cross midline again along dentatorubrothalamic tract or dentatothalamic tract
- Synapse at VL of thalamus
- Back to cortex
What is a syndrome resulting from damage to the posterior-lateral lobes of the cerebellum?
What are the symptoms?
Neocerebellar syndrome/cerebrocerebellar syndrome
Results in difficulty coordinating complex voluntary movmements
- Intention tremor
- Ataxia
- Dysdiadochinesia (difficulty performing rapid back and forth movements)
- Takes longer to initiate movements
- Problems stopping movements
- Dysarthria (jerky, uncoordinated speech production)
What does intention tremor look like?
Tremor perpendicular to target
