Cerebellum Flashcards
T/F. The cerebellum is located below the tentorium cerebelli.
True.
The gray matter is found on the ___ and the white matter is ___.
surface; inside
What are the functions of the cerebellum?
- Regulates equilibrium
- Controls muscle tone and posture
- Provides motor coordination for voluntary movements
What is the function of folia?
they serve to increase cortical surface area
What divides the cerebellum into lobes and lobules?
fissures
Primary ___ divides the body of cerebellum into anterior and posterior lobes.
fissure
What separates the flocculonodular from the body of the cerebellum?
posterolateral fissure
The ___ cerebellar peduncle (___ body) receives inputs from spinal cord and brainstem and monitors muscle and limb movement.
inferior; Restiform
What does the juxtarestiform body interconnect?
vestibular nuclei and cerebellum
Which cerebellar peduncle is the largest, lateral to the pons and receives afferents from the contralateral basis pontis and relays motor signals from the cortex?
Middle cerebral peduncle (branchium pontis)
The ___ cerebellar peduncle (brachium conjunctivum) sends ___ to red nucleus and thalamus.
superior; efferent
What are the three cerebellar deep nuclei? Which one contributes the most fibers to the superior cerebellar peduncle?
Dentate (contributes the most fibers in SCP)
Interposed nucleus (emboliform & globose)
Fastigal
FGED
The interposed nucleus has two parts: globose and fastigal.
False, it’s emboliform and globose
Give an overview of the cerebellar circuitry.
Inputs arrive via ICP, MCP (mostly) and project to the cortex that processes and returns info to the deep nuclei that project (mostly to SCP) to other parts of the brain.
What are the three layers of the cerebellar cortex?
molecular (top), purkinje, and granule layers
Where are the dendrites of purkinje cells and the granule neuron axons located?
molecular layer
What are the only axons to leave the cortex?
purkinje cell layer
How many granular cells are found in the granule layer?
10^11
What are the three fibers involved in the basic cortical circuitry?
climbing, mossy and parallel fibers
Where do the axons of climbing fibers originate?
contralateral inferior olivary nucleus
Where do mossy fibers receive input from?
brainstem (pons), vestibular system, spinal cord (sensory)
Parallel fibers have axons from ___ neurons/cells.
granule
Climbing fibers emerge ___ and ascend up the ___ ICP to enter the cerebellum where they divide and synapse as the only climbing fiber on a ___ cell in order to regulate its firing.
medially; contralateral; Purkinje
In addition to having numerous dendrites from Purkinje cells, what inhibitory neurons that synapse on Purkinje cells are found in the molecular layer ?
stellate and basket cells
___ cells have dendrites that are contacted by parallel fibers, whose axons divide extensively and synapse on short granule cells.
Golgi
Stellate, Basket and Golgi cells are all ___.
interneurons
___ and ___ fibers send collaterals to deep nuclei before axon enters cortex, but ___ cell axons end in deep nuclei.
Mossy; climbing; Purkinje
T/F. Deep nuclei have two neuronal populations:
- source of mossy fibers into cortex and;
- projection neurons whose axons leave cerebellum.
True.
The cerebellum is involved in what functions?
Does it make sense for the cerebellum to receive vestibular, spinal and cerebral cortical input?
- Equilibrium
- Muscle tone and posture
- Coordinating voluntary movements
Yes
T/F. Each cerebellar zone relates to all deep nuclei.
False, Each cerebellar zone is related to a particular deep nucleus.
What are the three functional subdivisions of the cerebellum?
- vestibulocerebellum
- spinocerebellum
- pontocerebellum
Which cerebellar functional zone contains the paravermal (medial hemisphere) area and interposed nucleus?
spinocerebellum
Which functional subdivision has lateral hemisphere projections to the dentate nucleus?
pontocerebellum (neocerebellum)
The vestibulocerebellum subdivision contains the ___ lobe, parts of the ___ and the ___ nucleus.
flocculonodular lobe; vermis; fastigial
What is the function of the vestbulocerebellum subdivision?
control of eye movements in response to head movements and balance
What are the output nuclei of the vestibulocerebellum subdivision?
fastigial nucleus and vestibular nuclei
Which subdivision coordinates trunk and limb movements?
spinocerebellum
The output of the spinocerebellum is the ___ nucleus, specifically the ___ nucleus and the ___/___ of the thalamus.
interposed; red; VA/VL
Where do the spinocerebellum and pontocerebellum fibers decussate?
in the superior cerebellar peduncle
What is the output of the pontocerebellum?
dentate nucleus, specifically the red nucleus and VA/VL of the thalamus
What is the function of the pontocerebellum subdivision?
- Planning the timing of movements especially those of the upper extremity
- Coordination of speech
T/F. The lateral hemisphere of the cerebellum controls adjusting limb movements and the medial hemisphere is involved in planning learned, skillful movements that become more precise and rapid with practice.
False,
Lateral hemisphere = planning learned, skillful movements, those that become more precise and rapid with practice
Medial hemisphere = adjusting limb movements
Injury to the lateral hemisphere involves the arm and speech. What specific conditions can be seen?
intention tremor
dysdiadochokinesia
dysmetria
dysarthria
Define dysdiadochokinesia.
Define dysmetria.
Define dysarthria.
Dysdiadochokinesia - rapid alternating movements
Dysmetria - finger-to-nose test
Dysarthria - scanning or explosive speech
Patients with injury to the vermis have ___ adjustments with ___ ataxia; disturbances in balance while ___, and also standing and gait ataxia.
postural; truncal; seated
What areas are injured if a patient suffers from nystagmus, back and forth eye movement?
flocculus and vermis
The cerebellum is involved in motor ___ and ___.
learning; cognition
Match the input projections from the cerebellar cortex.
- Vermis
- Medial hemisphere
- Lateral hemisphere
A. Fastigal
B. Interposed
C. Dentate
- A
- B
- C
What is the major output?
superior cerebellar peduncle
T/F. One side of the cerebellum affects the ipsilateral side of the body.
True.
One cerebral hemisphere controls ___ muscles.
One half of cerebellum influences ___ limbs.
Cerebellum projects to ___ thalamus.
contralateral; ipsilateral; contralateral
