GA: Cerebellum Flashcards
What are the general functions of the cerebellum?
Coordinating mvmts
Maintaining Posture
Motor Learning (Procedural memory)
What is this?
Cerebellum
How is gray matter organized in the cerebellum?
Molecular layer (by pia mater)
Purkinje layer
Granular layer
White Matter
What is special about granule cells?
They are the only excitatory neurons (n gray matter)
What type of cells are purkinje cells?
Efferents (output)
*not motor, just take things out from the cerebellar cortex*
Stellate cells, Golgi cells, and basket cells do what?
Synapse on purkinje cells and inhibit them
What are the 2 types of afferent fibers in the cerebellum?
*bring info into the cerebellum*
- Climbing fibers
- Mossy fibers
Where do climbing fibers come from and where do they synapse?
From the inferior olive –> purkinje cells
Information regarding movement errors is conveyed via which fibers?
Climbing fibers
Where do mossy fibers come from and where do they go?
From the SC, Reticular formation, vestibular + pontine nuclei –> granulocytes
Somatosensory, arousal, equilibrium, and cerebral cortex motor info is conveyed to the cerebellum via which fibers?
Mossy fibers
What is special about the afferent fibers of the cerebellum (climbing + mossy)?
They are EXCITATORY!
They also send collateral branches to deep cerebellar nuclei.
What are the 3 different functional divisions of the cerebellum?
- Vestibulocerebellum
- Spinocerebellum
- Cerebrocerebellum
Vestibulocerebellum:
-functional name + function
Flocculonodular lobe
Functions to influence eye movements + postural muscles of the head and body (neck + trunk gravity, balance)
-Spinocerebellum
Functional name + function
Vermis (medial)+ Paravermal region
It controls ongoing movements via the brainstem + descending tracts
Gait + Station
Cerebrocerebellum
Functional name + function
Input from the cerebral cortex via the pontine nuclei
Functions in precise, fine mvmt (via coordinating voluntary mvmts, planning of mvmts, and timing of extremities)
Climbing fibers use the __________ pathway to enter the cerebellum.
Cortico-olivocerebellar pathway in the cerebral cortex
Pathways in the Vestibular system, SC, and cerebral cortex are used by ______ fibers to enter the cerebellum.
mossy
What is important about the anterior spinal cerebellar tract?
It crosses TWICE
In the cerebellum, there are 2 afferent pathways carrying information about unconsicious proprioception about limb movement in the SC.
The pathway for the lower limb =
The pathway for the upper limb =
Lower limb = Posterior spinocerebellar tract
Upper Limb = Cuneocerebellar tract
The afferent posterior spinocerebellar tract (leg) and cuneocerebellar tract (arm) are _____________.
IPSILATERAL
What are the steps for the posterior spinocerebellar tract?
(1) DRG –> Gracile fasciculus (leg)
Synpase in nucleus dorsalis of Clark
(2) Dorsolateral funiculus (posterior spinocerebellar tract)
Enters cerebellum via inferior cerebellar peduncle (rustaform body)
What is the pathway for the cuneocerebellar tract?
(1) DRG –> accessory/external cuneate fasciculus (arm)
(2) enters cerebellum via inferior cerebellar nucleus
Are the cerebellar peduncles afferent or efferent?
Afferent
What runs in the superior cerebellar peduncle?
Afferent fibers from the ventral (anterior) spinocerebellar tract
(and some efferent nuclei)
What runs in the middle cerebellar peduncle?
Afferent fibers from pontine nuclei
What runs in the inferior cerebellar peduncle?
Primarily afferent pathways from SC
How does the vestibulocerebellum pathway leave the vestibular nucleus?
Via juxtareciform body by inferior cerebellar peduncle.
Deep nuclei of cerebellar gray matter
Say out loud the diagram with the 3 functional units of the cerebellum (its on this ppt like 7 times)
*clobose = paravermal and fastigial (vermis)
In the cerebellum, unilateral lesions affeect the ___________ side.
Ipsilateral
What is a common finding anytime you have a cerebellar lesion?
Ataxia
(Voluntary, normal strength, jerky, and inaccurate movements not associated with hyperstiffness)
What happens if you have a lesion of the vestibulocerebellum (connections between the vestiblar system + flocculonodular lobe)?
Nystagmus
Truncal ataxia (can’t maintain balance)
Truncal instability (can’t tandem walk –> field sobriety test)
What happens if you get a lesion between the SC & vermis/paravermis (spinocerebellum)?
Gait + Truncal ataxia (wide base)
What is it called when you have ataxic syndromes caused by both vestibulocerebellar + spinocerebellar lesions?
Midline ataxia
What symptoms present in midline ataxia?
truncal instability –> titubation (tremor of trunk)
Equilibratory (gait) ataxias –> wide base, irregular steps
What symptoms does a patient present with if they have a lesion of the cerebrocerebellum?
Dysarthria (slurred speech)
Ataxic gait
Deompostion of mvmts
Limb ataxia:
- Dysdiadocokinesia, dysmetria, action tremor
Limb ataxia:
- Dysdiadochokinesia =
- Dysmetria =
- Action tremor =
- Dysdiachokinesia = can’t rapidly aternate mvmts (tapping fingers)
- Dysmetria = can’t move an intended distance (finger to nose, pulling elbow)
- Action tremor = shaking of limb
What is appendicular ataxia?
Results from dysfunction of the cerebellar hemispheres. You get speech ataxia (scanning dysarthria)
Does cerebellar ataxia or sensory ataxia have abnormal vibratory sense + proprioception + ankle reflexes?
Sensory ataxia
In _______ ataxia the romberg test = postive, but proprioception is intact.
Cerebellar ataxia
These things test what?
Station
Walking
Tandem gait (drunk test)
Vestibulocerebellum + Spinocerebellum
These things test what?
Rapid alternating mvmts
Finger-to-nose
heel-to-shin
rebound reflex
speech
Cerebrocerebellum
