Cerebellum Flashcards
What type of memory is the cerebellum involved in forming?
procedural memory
If you lesion the cerebellum, what do you NOT have?
paralysis
What 3 nuclei of the cerebellum do you need to be able to see on slides?
emboliform nucleus
globose nucleus
dentate nucleus
Where is the molecular layer of the cerbellum and what types of cells lie there?
closest to pial surface
basket and stellate cells are there
What is the deepest gray matter layer of the cerebellum and what types of cells lie there?
granular layer
contains granule cells and a few golgi cells
What is the only excitatory neuron in the gray matter of the cerebellum?
Wat NT does it use?
granule cells
use glutamate
What are the output cells of the cerebellum gray matter?
purkinje cells
inhibit the cerebellar nuclei and vestibular nuclei
NT is GABA
purkinje –> deep nuclei –> contralateral cortex via superior peduncle
Where are stellate cells found and what do they do?
in the molecular layer
only synapse w/ purkinje cells –> inhibit them
Where are golgi cells found and what do they do?
in granular layer of cerebellar cortex
inhibitory neuron using GABA
Where are basket cells and what do they do?
found in molecular layer of cerebellar cortex
synapse w/ purkinje cells and inhibit them using GABA
What are the types of neurons in gray matter of the cerebellum?
both afferent and excitatory:
climbing fibers from inferior olive –> excitatory to purkinje
mossy fibers from SC, reticular formation, vestibular system and pontine –> granulocytes
What type of info do climbing and mossy fibers convey?
climbing: info regarding movement errors to cerebellum
mossy: somatosensory, arousal, equilibrium and cerebral cortex motor info to cerebellum
Besides sending info to the cerebellar cortex, where do mossy and climbing fibers send collaterals?
to deep cerebellar nuclei
What is the vestibulocerebellum?
fxnal name for the flocculonodular lobe
receives info directly from vestibular receptors –> output to vestibular nuclei
also receives input from visual areas
influences eye movements and postural ms of head and body
What is the spinocerebellum and what does it do?
fxnal name for the vermis (midline) and paravermal (just lateral) region
somatosensory info, internal feedback from spinal interneurons, and sensorimotor cortex
controls ongoing movement via the brainstem descending tracts
What to medial upper motor neurons of the spinocerebellum do?
Lateral upper UMNs?
medial –> go to posture muscles
lateral –> to limbs, gate, and station
What is the pontocerebellum?
also called the neocerebellum or cerebrocerebellum
lateral hemispheres of the cerebellum
input from cerebral cortex via pontine nuclei
coordinates voluntary mvt, planning of movements, and timing
Where does the pontocerebellum send fibers to?
purkinje to dentate nucleus –> then to red nucleus and VL nucleus of thalamus
What is the posterior spinocerebellar tract?
carries unconscious proprioception from lower limb
1st order neurons enter via DRG and ascend in gracile fasciculus –> synapse in nucleus dorsalis of clark (gray matter from C8-L2) –> 2ndary neuron ascends in dorsolateral funiculus (posterior spinocerebellar tract) –> enters cerebellum via inferior cerebellar peduncle
*stays ipsilateral*
What is the cuneocerebellar tract?
axons carry unconscious proprioception from upper limb
1st order neurons enter DRG –> ascend in cuneate fasciculus –> synapse in accessory cuneate nucleus (lower medulla) –> 2ndary fiber ascends to cerebellum and enters via inferior cerebellar nucleus
*stays ipsilateral*
What does the anterior spinocerebellar tract?
carries proprioception info to cerebellum
crosses once at anterior white commissure –> to superior cerebellar peduncle –> crosses again to cerebellum
ends up crossing 2x - info ends up on ipsilateral side of cerebellum
From where does info entering the cerebellum via the inferior peduncle arise?
inferior olive
spinal cord
vestibular nuclei
From where does info come that enters the cerebellum via the middle cerebellar peduncle?
pontine nuclei
What efferent routes go through the superior cerebellar peduncle?
from globose, emboliform and dentate nuclei
What cerebellar nuclei go to the red nucleus and thalamus?
dentate nucleus
globose and emboliform nuclei
What is the efferent path from the spinocerebellum?
purkinje fibers to globose and emboliform nuclei –> through paravermal area –> to red nucleus and VL nucleus of thalamus
What does the fastigial nucleus receive fibers from and where does it send efferents to?
receives from: spinocerebellum and vestibulocerebellum
to: reticular formation and vestibular nucleus
What is the efferent path from the vestibulocerebellum?
purkinjes to fastigial nucleus or directly to vestibular nucleus via juxtarestiform body
fastigial nucleus -vermis-> reticular formation or vestibular nucleus
Where do fibers from the reticulospinal tract come from?
medullary reticular formation
pontine reticular formation
Where do fibers from the red nucleus go?
to inferior olivary nucleus –> cerebellar cortex
or to rubrospinal tract –> muscles
What do unilateral cerebellar lesions cause?
affect the ipsilateral side
ataxia is common to all cerebellar lesions = voluntary, normal strength, jerky, and inaccurate movements not assoc w/ hyperstiffness
wide gait, fall toward side of lesion
What do you see in lesions of the vestibulocerebellum?
nystagmus
truncal ataxia = difficulty maintaining sitting and standing balance
truncal instability (titubation) = ant-post tremor
can’t tandem walk
What do you see in lesions of spinocerebellum?
gait and truncal ataxia
What is midline ataxia?
caused by vestibulocerebellar and spinocerebellar disease
truncal instability: titubation, gait ataxia
equilibratory ataxias (gait)
what do you see in lesions of cerebrocerebellum?
dysarthria: slurred, poorly articulated speech
ataxic gait
decomposition of movements
dysdiadochokinesia: inability to rapidly alt movements
dysmetria: inability to accurately move an intended distance
action tremor
What is appendicular ataxia?
dysfunction of cerebellar hemispheres
ataxia of the extremities and speech
see hypotonia and decomposition of mvt
What are the differences btw cerebellar ataxia and sensory ataxia?
cerebellar: romberg test +, unable to stand w/ feet together (w/ or w/out eyes open), normal vibratory sense, propriosense, and ankle reflexes
sensory: can stand w/ feet together w/ eyes open, but not closed (+ romberg test), abnormal vibratory, prprioception, and ankle reflexes
