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Cerebellum
Exam 5 cerebellum
43
Anatomy
Graduate
09/08/2010

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Term
In general, a unilateral lesion a cerebellar hemisphere manifests itself on the ___ side as the damage
Definition
ipsilateral
Term
lesions along midline of cerebellum cause:
Definition
gait problems (ataxia)
Term
lesions in lateral cerebellum result in:
Definition
symptoms involving extremeties
Term
lesions in lateral cerebellum result in:
Definition
symptoms involving extremeties
Term
the primary output (afferents) from the cerebellum is through the ___ ___ ___. The primary input (efferents) to the cerebellum is through the ___ and ___ ___ _____.
Definition
- superior cerebellar peduncle
- middle and inferior cerebellar peduncles
Term
___ cells are the only excitatory cells in the cerebellar cortex.
Definition
granule
Term
Purkinje cells are ____ neurons in the cerebellar cortex and project to and ___ the deep cerebellar nuclei.
Definition
- GABAergic
- inhibit
- deep cerebellar nuclei= dentate, globos, vestibuli
Term
the cerebellum integrates activity from the following centers:
Definition
- muscle spindles on the spinal level
- vestibular receptors from the head region

The cerebellum integrates and processes this information and then transmits signals back to these areas to make a smooth, well coordinated movement
Term
the cerebellum forms the :
Definition
roof of 4th ventricle
Term
Since the cerebellum is above the 4th ventricle, mass lesions, swelling, or compression can lead to ____.
Definition
- hydrocephalous

examples: medulloblastomas, astrocytomas, hypertensive hemorrhages, cerebelar infarcts
Term
the tentorium cerebelli is a fold of __ matter that separates the cerebellum from the ___ lobe.
Definition
- dura
- occipital lobe
Term
cerebellum fills the ___ fossa of skull
Definition
posterior
Term
purkinje cells are in ___ matter of cerebellum, while nuclei are in ___ matter.
Definition
-gray
-white
Term
composition of the cerebellum (cross section)
Definition
1. Cerebellular cortex (cell bodies, a.k.a.(gray matter)

2. Cerebellular fiber tracts, a.k.a. white matter (“arbor vitae”)

3. The deep cerebellular
nuclei are located
amongst the white matter.
Note: they are also known
as roof nuclei, since they
are located near the roof
of the fourth ventricle
Term
cerebellar peduncles attach the ___ to the ___.
Definition
- cerebellum
- brainstem
Term
the cerebellar peduncles are located above and around what?
Definition
4th ventricle
Term
what main input (afferents) to the cerebellum enter through the inferior cerebellar peduncle:
Definition
- dorsal spinocerebellar tract- ipsilateral proprioceptive inputs from the body
Term
a lesion in the inferior cerebellar peduncle would injur what and result in what?
Definition
- lesion to dorsal spinocerebellar tract resulting in ipsilateral loss of proprioception
Term
what afferent pathway enters the cerebellum via the superior cerebellar peduncle?
Definition
- ventral spinocerebellar tracts from the spional cord that decussate to the contralateral hemisphere upon entry into the cerebellumOUt
Term
List the types of afferent fibers to the cerebellum:
Definition
- Climbing fibers
- Mossy fibers
- Aminergic fibers
Term
describe climbing fibers:
Definition
1. originate in inferior olive
2. synapse on purkinje cells
3. send collaterals to deep cerebellar nuclei
Term
describe mossy fibers:
Definition
- originate from a variety of tracts
- synapse on granule cells
- sends collateral to deep nuclei
Term
describe aminergic fibers:
Definition
- locus ceruleus (noradrenergic)
- raphe nucleus (serotonergic)
Term
both climbing and mossy fibers provide ___ input. The aminergic modulate the ___ activity.
Definition
- excitatory
- cerebellar
Term
excitatory climbing fibers synapse on ___ cells which then ___ deep nuclei
Definition
purkinje cells
inhibit
Term
excitatory mossy fibers synapse on ___ cells, which then excite ___ cells.
Definition
- granule cells
- purkinje cells
Term
look at slide 22 of this lecture for good table
Definition
Term
granule cells are the only ___, ___ neurons in the the cerebellar cortex.
Definition
excitatory
glutaminergic
Term
Purkinje cells provide primary inhibitory input (GABAergic) to the ipsilateral deep cerebellar nuclei, especially the dentate nucleus.
Definition
Term
layers of cerebellar cortex :
Definition
Molecular Layer
a. Stellate cells
b. Basket cells
c. Dendrites from Purkinje cells
d. Bifurcated (T-shaped) parallel fibers
from granule cells
(synapse on Purkinje cell dendrites)
e. Dendrites of Golgi cells

Purkinje Cell Layer
a. Purkinje cells (cell bodies)
b. Basket cell projections

Granule Cell Layer
a. Granule cells
b. Golgi cells (cell bodies)
c. Mossy fiber (glomeruli)
synaptic connections
Term
cerebellum functions:
Definition
Coordination of voluntary motor activity by inflencing muscle activity:
A. Fine skilled movements
B. Gross propulsive movements (i,e,, walking)
Maintenance of posture and balance (equilibrium) via connections with the vestibular system.
Maintenance of muscle tone via connections to pathways that control the spinal gamma motor neurons.
Motor learning and memory (e.g., stereotyped movements
Term
The vermis and medial portion of the hemispheres controls coordination of muscle tone of the trunk

The hemispheres control muscle coordination and tone on the ipsilateral side of the body
Definition
Term
hypotonia:
Definition
- sign of cerebellar dysfunction, but could also be from LMN lesion or myopathy
- diminished muscle tone
Term
ataxia:
Definition
- could be due to problem with cerebellum
- loss of coordinated muscle contraction resulting in uncoordinate movements, staggering gait, tendency to fall to ipsilateral side
Term
dysmetria:
Definition
- could be due to cerebellar dysfunction
- failure to place an extremity at a precise point in space, like touching heel to shin or a finger tip to nose
Term
dysdiadochokinesia:
Definition
- failure to make rapid alternating movements
- could be due to cerebellar problem
Term
rebound phenomenon:
Definition
normal loss checks of agonist and antagonist muscle
- example: if you a patients arm away from chest but they are pushing towards chest, when you let go, they fly towards chest
Term
intention tremor:
Definition
- could be to cerebellum problem
- tremors that occur when attempting a voluntary movment (when reaching for a glass)
NOTE : tremors occur at rest with parkinsons, so if see problem with tremors at rest then its not cerebellum, may be parkinsons
Term
a unilateral cerebellum lesion will have ___ manifestations.
Definition
ipsilateral
Term
degeneration of the ___ in alcoholics is ___.
Definition
- vermis
- bilateral
and has bilateral effects
Term
the spinocerebellar tract is in the ___ and medial part of hemisphere in the ____. Normally it is associated with ___ ___ ___ like ___. If there is a lesion here you will see ___ ___ aka___ __
Definition
- vermis
- cerebellum
- sterotyped propulsive movments
- walking
- truncal ataxia
- drunken gait
Term
past pointing is the inability to do what?
Definition
- touch finger to nose, or heel to shin bone
Term
medulloblastoma specifically affects the ____ and results in ___ and ____.
Definition
- vestibulocerebellum
- falling
- nystagmus
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