Cerebellum Flashcards
what happens when there is severe damage to. the cerebellum?
it does NOT cause weakness because there are no direct connections between the cerebellum and motor neurons
- causes coordination and postural control deficits
anterior lobe functon
coordination of PROXIMAL limbs
posterior lobe function
coordination of DISTAL limbs
flocculonodular lobe function
balance and eye movements
cerebrocerebellum
-motor planning (UE/LE)
-lateral hemisphere
-dentate nucleus
MID
cerebrocerebellum input
motor/premotor cortex
pontine nuclei
cross #1: MIDDLE peduncle
contralateral lateral cerebellum
cerebrocerebellum output
contralateral lateral cerebellum
dentate nucleus
cross #2: SUPERIOR peduncle
thalamus
motor cortex
L. CST/ Rubrospinal: DISTAL mvmts
spinocerebellum
-nonconscious proprioception
-vermis/intermediate hemisphere
-fastigal nucleus, interposed nucleus
NVFI: No Veggies, Fries Instead
vermis function
PROXIMAL movements
intermediate hemisphere function
DISTAL vol movement
spinocerebellum tracts
Dorsal spinocerebellar
cuneospinocerebellar
ventral spinocerebellar
rostral spinocerebellar
Dorsal Spinocerebellar tract
function: unconscious proprioception LE
1st order: type Ia (muscle spindles) in LE –> clarks nucleus
2nd order: clark’s nucleus –> INFERIOR peduncles
UNCROSSED
Cuneocerebellar tract
function: unconscious proprioception of face, neck UE
1st order: type Ia fibers (muscle spindles) –> lateral cuneate medulla
2nd order: lateral cuneate –> INFERIOR peduncles
UNCROSSED
ventral spinocerebellar tract
function: unconscious proprioception LE (reflexes)
1st order: LE type Ib fibers (GTOs) –> DRG
2nd order: DRG –> SUPERIOR peduncle
DOUBLE CROSS
- @ SC level
- cerebellum
rostral spinocerebellar tract
function: unconscious proprioception from UE (reflexes)
1st order: UE type Ib fibers (GTOs) –> dorsal horn
2nd order: dorsal horn –> INFERIOR AND SUPERIOR peduncles
UNCROSSED
Spinocerebellum outputs
via vermis and intermediate zone
vestibulocerebellum
-balance and eye movements
-flocculonodular lobe
-vestibular nuclei
Vestibulocerebellar tract input/afferents
vestibular nerve –> vestibular nuclei
–> flocculonodular lobe
vestibulocerebellar tract output/efferents
flocculonodular lobe –> vestibular nuclei –> L/M vestibulospinal tracts
M vs. L vestibulospinal tract function
m: neck muscles (crosses)
l: extensor muscles (uncrossed)
homunculus: midline vermis
trunk –> truncal/gait instability
homunculus: intermediate hemispheres
appendicular muscles–>limb ataxia
superior cerebellar peduncle
-mostly efferents (sending info OUT)
-cerebellum –> midbrain
middle cerebellar peduncle
-mostly afferents (info coming in)
-pons/superior colliculi –> cerebellum
inferior cerebellar peduncle
-afferents: inferior olivary nucleus –> cerebellum
-efferents: cerebellum –> vestibulospinal and reticulospinal tracts
dentate nucleus
-receives from lateral hemisphere
anticipatory movements
interposed nuclei
-emboliform and globose
- receives from intermediate hemisphere –> DISTAL limb
fastigal nuclei
-receives from vermis and flocculonodular lobe
-balance, trunk posture, head movements
3 layers of cortical gray matter of cerebellum
granular
purkinje
molecular
granular layer associated cells
Golgi cell
granule cell
Golgi cell
inhibitory interneuron
granular cell
excitatory interneuron: excites purkinje cells
purkinje layer cells
purkinje cell
purkinje cell
output cell that INHIBITS deep cerebellar nuclei
molecular layer cells
stellate
basket
stellate/basket cells
inhibitory interneuron: inhibits purkinje fibers
Mossy fibers
transmit afferent info (sensory pathways) from SC and pons through excitatory neurotransmitters to cerebellum
climbing fibers
transmit afferent info (movement errors) from inferior olivary nucleus to cerebellum
what is the effect of mossy fibers exciting granular cells?
increased movement
what is the effect of mossy fibers exciting Golgi cells?
decreased movement
Superior cerebellar artery
parent: basilar
supplies: superior/middle peduncles
anterior inferior cerebellar artery
parent: basilar
supplies:
- middle peduncle
- anterior/inferior cerebellum (flocculus)
posterior inferior cerebellar artery
parent: vertebral
supplies:
-tonsils
-inferior vermis
-inferior peduncle
Lesion to any part of the cerebellum results in
ataxia
Lesions to the vestibulocerebellum result in
Nystagmus
unsteadiness
truncal ataxia
disequilibrium
Lesions to the cerebrocerebellum result in
ataxic finger movements
dysarthria - slurring of speech
If tone is abnormal with cerebellar lesions, will it present as hyper or hypotonia?
hypotonia due to decreased muscle spindle activity
Lesions to the spinocerebellum result in
dysarthria
scanning speech
dysdiadokinesia
dysmetria
action tremor
intention tremor
loss of check/rebound
movement decomposition
movement decomposition
attempting to move 1 joint at a time
-. Instead of fluid motion, the movement becomes jerky, segmented, or clumsy
