Cerebellum Flashcards
What are the 4 functions of the cerebellum?
Essential for production of coordinated movement - coordinates time, force and duration of muscle action = synergy
Maintaining balance and posture
MAY store instructions for patterns of movement
MAY have linguistic and cognitive functions
What is synergy?
coordination of time, force and duration of muscle action
What is the midline on the dorsal aspect of the cerebellum called?
vermis - see slide 4 for image
What are the two outgrowths towards the midline on the ventral aspect on the cerebellum called?
Tonsil - see slide 4 for image
What does the primary fissure separate and on what side of the cerebellum is it?
Anterior and posterior lobe
Dorsal view - see slide 4 for image
Where is the flocculus located?
posterior border of the middle cerebellar peduncle anterior to the biventer lobule - see slide 4 for image
What are the 3 functional subdivision of the cerebellum and what part of the cerebellum do they include?
SEE SLIDE 6 FOR IMAGE
Archicerebellum/vestibulocerebellum - Comprises flocculonodular lobe and part
of vermis
Paleocerebellum/Spinocerebellum - Comprises most of vermis and
adjacent region of hemispheres
Neocerebellum/Cerebrocerebellum - Comprises lateral parts of hemispheres
What do the 3 functional subdivisions of the cerebellum do?
Vestibulocerebellum - coordinates muscles involved in balance and maintenance of visual fields despite head movements, input from VESTIBULAR APPARATUS of the ear
Spinocerebellum - coordinates muscles involved in posture and locomotion (an act or the power of moving from place to place)
cerebocerebellum - coordinates fine movements of distil limbs
Describe the homunculus layout of the functional cerebellum
SEE SLIDE 8 FOR IMAGES
Vestibulocerebellum = CNS
Spinocerebellum = back muscles/gluts
Cerebrocerebellum = hands/feet
What nerve is responsible for taking information from the vestibule apparatus to the cerebellum/floccular lobe & vermis to detect head movement?
vestibular nerve
When does synapsing in the vestibular nucleus occur and where is it?
Open medulla
1) Vestibular nerve from vestibule to the cerebellum
2) Cerebellum to the LMN in the vestibulospinal tract - controls posture
Apart from neurons going from the cerebellum to the LMN in the vestibulospinal tract, where else do they go?
via CN 3, 4 and 6 to move the eyes
Where to neurons going in and out from the cerebellum in the vestibulocerebellar tract travel through?
Inferior cerebellar peduncle
Does the cerebellum affect the body contralaterally or ipsilaterally?
Ipsilaterally - IMPORTANT TO REMEMBER
What information does the spinocerebellar information carry from and to? On which side is the information from?
SEE SLIDE 13 FOR IMAGE Carries information from fibres from muscle spindles/Golgi tendons (proprioception) Through the inferior cerebral peduncle To the vermis and adjacent areas Info from the SAME SIDE
What information does the cerebelocerebellar information carry from and to? On which side is the information from?
SEE SLIDE 14 FOR IMAGE
1) From pontine nuclei to lateral hemispheres of the cerebellum via the middle cerebral peduncle
2) From inferior olivary nucleus to lateral hemispheres of the cerebellum via the inferior cerebral peduncle
Info from the OPPOSITE SIDE
Describe the routes of the motor fibres from the cerebellum
From the cerebellum to: Motor cortex Reticular nuclei Red nucleus Via the Superior cerebellar peduncle Info CROSSES the midline but then descending tract crosses again further down = IPSILATERAL
What experiment proved that cerebrocerebellum is involved in motor learning/learned responses?
Blink response in rabbits
What is ataxia?
Lack of coordination
What is truncal ataxia and what functional area of the cerebellum is affected?
Unable to stand/sit without falling over or support - falls to the more affected side
Nystagmus may occur
Lesion in vestibulocerebellum/midline
Loss of visual field and posture joint control
Most commonly due to medulloblastoma
What is gait ataxia?
Lower limbs most affected - produce staggering, wide gait
Head tremor
Sensory ataxia
Tendon reflexes depressed
Lesion in spinocerebellum
Common in chronic alcoholics - degeneration of cerebellar neurons
What occurs in a neocerebellar lesion?
Incoordination of involuntary movements
Tremor of intent
Past pointing/dysmetria
Adiadochokinesia - inability to perform rapid, alternating movements
Dysarthria - slurring
Nystagmus - continuous uncontrolled movement of the eyes when focusing on something
