Cerebellum and Movement Flashcards
The cerebellum accounts for __% of the brain and __% of all of the neurons in the CNS
10%
50%
How does the cerebellum coordinate movement and postural control?
By comparing actual motor output with the intended movement and then adjusting the movement as necessary
What 3 things is the cerebellum involved in?
- learning timing and rhythm of movements
- synchronization of movements
- learning to correct motor errors
Does damage to the cerebellum interfere with sensory perception or muscle strength?
No, however coordination of movement and postural control are degraded.
What does the cerebellar cortex do?
process information
How many layers are there to the cerebellar cortex? What is contained within each layer
3
- outer layer: interneurons
- middle layer: Purkinje cell bodies
- inner layer: interneurons
What is deep to the cortex?
White matter, which consists of the cerebellar nuclei
What cells are the output cells from the cerebellar cortex?
Purkinje cells
Purkinje cells projections ____ the cerebellar nuclei and the vestibular nuclei
inhibit
What are the 2 types of afferents that enter the cerebellar cortex?
- Mossy fibers
- Climbing fibers
What type of information to the mossy fibers convey to the cerebellum?
- somatosensory
- arousal
- equilibrium
- cerebral cortex motor information
What type of information to the climbing fibers convey to the cerebellum?
- movement errors
Climbing fibers synapse with _____ cells, whereas mossy fibers synapse with _______ that convey information to the Purkinje cells
Purkinje
interneurons
What are the 3 lobes of the cerebellum?
- anterior
- posterior
- flocculonodular
Where is the flocculonodular lobe located?
tucked underneath the posterior lobe, touching the brainstem
What are the 3 cerebellar peduncles?
- Superior cerebellar peduncles
- Middle cerebellar peduncles
- Inferior cerebellar peduncles
The _____ cerebellar peduncle connects to the midbrain and contains most of the cerebellar efferent fibers
superior
Fibers from the cerebral cortex synapse in the pons, and the information then travels via axons in the ____ peduncle into the cerebellum
middle
The _____ peduncle brings afferent information from the brainstem and spinal cord into the cerebellum and sends efferent from the cerebellum to the vestibular nuclei and reticular nuclei in the brainstem.
inferior
List the 4 cerebellar nuclei from medial to lateral
- Fastigial nucleus
- Globose
- Emboliform
- Dentate
Vertically, the cerebellum can be divided into sections, what are they?
- Midline vermis
- Paravermal hemisphere
- Lateral hemisphere
What are the 3 broad classes of human movement?
- Equilibrium
- Gross movements of the limbs
- Fine, distal, voluntary movements
The ____cerebellum regulates equilibrium.
vestibulocerebellum
The vestibulocerebellum is the functional name from the _____ lobe why?
flocculonodular, because is receives information directly from vestibular receptors and connects reciprocally with the vestibular nuceli
The vestibulocerebellum also receives information from ____ areas of the brain to influence what?
visual, to influence eye movements and postural muscles
The spinocerebellum is the functional name of the ____ and the ____ region, why?
vermis and paravermal region, because of its extensive connections with the spinal cord
Information that converges in the spinocerebellum is used to control what?
Ongoing movement via brainstem descending tracts
Input to the cerebrocerebellum is received from where?
cerebral cortex fibers that synapse with neurons in the pons
The ____cerebellum coordinates gross limb movements.
spinocerebellum
The ____cerebellum coordinates distal limb voluntary movement.
cerebrocerebellum
Unilateral lesions of the cerebellum affect the ____ side of the body.
same
Cerebellar signs are ____, why?
ipsilateral, because the output paths of the medial descending tracts remain ipsilateral and because cerebellar efferents project to the contralateral cerebral cortex and red nucleus whose descending tracts cross the midline.
What type of movement disorder is common to all lesions of the cerebellum?
ataxia