Cerebellum Flashcards
Where does the cerebellum develop from
From rhombic lips of metencephalon
Cerebellum=’little brain’
Where is the cerebellum located
In posterior cranial fossa between temporal and occipital lobes and brainstem
What separates the cerebellum from cerebrum
Dural fold–> tentorium cerebelli
What is the role of the cerebellum
- Modulates and coordinates skilled voluntary movements and speech by comparing actual motor output to intended motor output and then adjusting the movement as necessary
- regulates movement in response to sensory feedback
- maintenance of posture and balance
- coordination of voluntary motor activity
- maintenance of muscle tone
- ‘feed forward’ mechanism–>motor learning pattern, something that you’ve already learnt to do, and it feeds that forward so that can apply that to movt. as you do it
What is the cerebellum though to play a role in
- Participation in learning patterns
- sensory functions
- cognitive functions
- may be involved in other types of learning and emotional reactivity
What sort of influence does the cerebellum have on body
ipsilateral influence
How many cerebellar hemispheres are there
2
continuous with the vermis
What are the deep transverse fissures in cerebellum
- Primary fissure (deepest)
- Dorsolateral fissure
What does the primary frissure separate
anterior and posterior lobes
what does the dorsolateral fissure separate
flocculonodular lobe from remainder of cerebellum
What are the 3 anatomical lobes of cerebellum
Anterior
Posterior
Flocculonodular
What separates the cerebellum hemispheres
Superior vermis
What is the cerebellum cortex made up of
Folia
grey atter
Where and how many pairs of central nuclei are there
4 pairs of central nuclei
in Medullary centre
How many peduncles are there are where are they located
3 pairs of peduncles
brainstem to cerebellum
What are the 3 cortical layers in cerebellum
Molecular cell Layer (most superficial) contains stellate and basket cells
- Purkinje Cell layer –> principle cells of cerebellar cortex
- Granular cell layer–> (deepest, closed to white matter) contains granule and golgi cells
How many different neuronal types are found in the 3 cortical layers
5
What are the 3 pairs of pudencles
Inferior cerebellar pudencle
Middle cerebellar peduncle
Superior Cerebellar pudencle
Where does the inferior cerebellar pudencle go to
medulla to cerebellum
Where does the middle cerebellar pudencle go to
pons to cerebellum
Where does the superior cerebellar pudencle go to
midbrain to cerebellum
What tracts does the inferior cerebellar peduncle carry, and from where
- DSCT and CCT–> from ipsilateral side
- OCT fibres from contralateral inferior olivary nucleus
- VCT from vestibular ganglion and vestibular nuclei
- All afferent inputs
What information does th DSCT carry
-DSCT= unconscious proprioception from C8-L3
What information does the CCT (cuneocerebellar tract) carry
unconscious proprioception from C7 and above
What information does the vestibulocerebellar tract (VCT) carry
Info regarding equilibrium from the vestibular apparatus and nuclei
What tract does the middle cerebellar peduncle carry and from where
PCT–> Pontocerebellar tract from contralateral pontine nuclei
What info does the PCT carry
info about brain telling you motor and sensory wise whats going on
What role does the superior cerebellar peduncle play for the cerebellum
Primary efferent (output) ‘highway’ for the cerebellum
What fibres does the superior cerebellar peduncle carry
fibres that have synapsed with deep cerebellar nuclei and are on their way ‘out’ of cerebellum
-Efferent fibres continue rostrally to synapse with contralateral red nucleus or thalamus
where do afferent cerebellar inputs come from
- cerebral cortex
- brainstem nuclei
- spinal cord
- multiple sensory modalities from: vestibular, visual, auditory and somatosensory system
What are cerebellar inputs carried by
Mossy fibres
EXCEPT input from the inferior olivary nucleus (OCT)
Fibres from inferior olivary nucleus are carried by climbing fibres (OCT)
What are mossy fibres
terminate in synaptic contact with granule cells of the innermost layer
What are climbing fibres
enter molecular layer, wind around dendrites of purkinje cells
What is the importance of the purkinje cells
- The only axons that leave the cortex are purkinje cells that terminate in the central nuclei of cerebellum
- All output from cerebellar cortex is carried by purkinje cells
What are the 4 pairs central nuclei in the medullary central
Dentate nucleus
Globose Nucleus
Emboliform nucleus
Fastigial nucleus
What makes up the interpose nucleus
Globose and emboliform nucleus
What are the functional zones of cerebellum
- Vermis and flocculonodular lobe
- Intermediate zone
- Lateral zone
What is the vermis and flocculonodular lobe (vestibulocerebellum) responsible for
Proximal limb and trunk coordination, balance and vestibulo-ocular reflexes
Where does the vermis and flocculonodular lobe (vestibulocerebellum) receive fibres from
Olivocerebellar tract
- cuneocerebellar tract
- dorsal spinocerebellar tract
- vestibulocerebellar tract
Where does the vermis and flocculonodular lobe (vestibulocerebellum) project to
Fastigial nucleus
What does the vermis and flocculonodular lobe (vestibulocerebellum) influence
- Ventral corticospinal tract (affects tone)
- reticulospinal tract
- vestibulospinal tract
- tectospinal tract (coordinating eye movt)
- medial longitudinal fasciculus
What is the intermediate zone/spinocerebellum responsible for
distal limb coordination
where does the intermediate zone/spinocerebellum receive fibres from
- Olivocerebellar tract (OCT)
- cuneocerebellar tract (CCT)
- DSCT
- Pontocerebellar tract (PCT)
where does the intermediate zone/spinocerebellum project to
interposed nucleus
what does the intermediate zone/spinocerebellum influence
- lateral corticospinal tract–> more about mvt.
- rubrospinal tract–> tone
where is the intermediate zone/spinocerebellum located
lateral to vermis
What is the lateral zone/cerebrocerebellum responsible for
motor planning for extremities
where does the lateral zone/cerebrocerebellum receive fibres from
Olivocrebellar tract (OCT) pontocerebellar tract (PCT)
where does the lateral zone/cerebrocerebellum project to
dentate nucleus
what does the lateral zone/cerebrocerebellum influence
lateral corticospinal tract
What is the blood supply to the superior surface of cerebellum
SCA- superior cerebellar artery
what is the blood supply to the inferior and anterior surfaces of cerebellum
AICA- anterior inferior cerebellar artery
PICA- posterior inferior cerebellar artery
What side of the blody does lesion to cerebellum cause
ipsilateral S&S
what is the impairment associated with a cerebellar lesion
Ataxia
What is ataxia
neurological sign consisting of lack of voluntary coordination of muscle movements
What is dystaxia
a milder version of ataxia
