Unit 3: Cerebellum Pg 102-112 Flashcards
(96 cards)
1
Q
Medial portion fo the cerebellum, extending from superior surface to inferior surface
A
Vermis
2
Q
Paired structures of the cerebellum, lateral to the vermis
A
Hemispheres
3
Q
The medial part of the hemispheres of the cerebellum is often referred to as the
A
Paravermis
4
Q
What fissure is on the superior surface that separates anterior cerebellum from posterior cerebellum?
A
Primary fissure
5
Q
What lobe is on the superior surface of the cerebellum and anterior to primary fissure?
A
Anterior lobe
6
Q
What lobe is posterior to primary fissure and on the superior surface and extends into the inferior surface of the cerebellume?
A
Posterior lobe
7
Q
Which lobe is located along the anterior edge of the inferior surface of the cerebellum?
A
Flocculonodular lobe
8
Q
What are the lateral paired structures on the flocculonodular lobe
A
Flocculi
9
Q
The flocculi are near what cranial nerves
A
VII
VIII
10
Q
What structure is the midline part of the flocculonodular lobe?
A
Nodulus
11
Q
The nodulus extends into what space?
A
IV ventricle
12
Q
3 division of cerebellum
A
Archecerebellum
Paleocerebellum
Neocerebellum
13
Q
The archicerebellum also called
A
Vestibulocerebellum
14
Q
Paleocerebellum also called
A
Spinocerebellum
15
Q
Neocerebellum also called
A
Pontocerebellum
16
Q
What division of the cerebellum receives afferent input from vestibular nerve, vestibular nuclei and contralateral inferior olivary nucleus
A
Archicerebellum (vestibulocerebellum)
17
Q
What division of the cerebellum receives much of its afferent input from sensory fibers that ascend from the spinal cord
A
Paleocerebellum (spinocerebellum)
18
Q
What division of the cerebellum is the newest and largest part where input is largely from cerebral cortex after relay in pontine nuclei
A
Neocerebellum (pontocerebellum)
19
Q
What division of the cerebellum corresponds anatomically to the flocculonodular lobe
A
Archicerebellum
20
Q
What division of the cerebellum corresponds to (most of the) vermis and paravermis
A
Paleocerebellum
21
Q
What division of the cerebellum corresponds to (a portion of) the vermis, but mostly the lateral portion of the hemispheres
A
Neocerebellum
22
Q
Leif-like folds on the cerebellar cortex called
A
Folia
23
Q
The surface area of the cerebellar cortex is about ____ the surface area of the cerebral cortex
A
3/4
24
Q
Neurons in the cerebellar cortex include:
A
Purkinje **ONLY CEREBELLAR Golgi Stellate Basket Granule cells
25
What layer is the inner layer of the cerebellum called
Granular layer
26
The granular layer has this kind of neurons
Granule and Golgi cells
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What do axons of granule cells do
Ascending into the molecular layer and interact with dendrites of Purkinje cells, which allow granule layer neurons to influence Purkinje cells
28
What is the middle layer of the cerebellum called
Purkinje layer
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What layer is the Purkinje layer
Middle layer
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What do dendrites do in the Purkinje layer?
Arborize in the molecular layer
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Axons leave the cerebellar cortex and terminate on
deep cerebellar nuclei or the vestibular nuclear complex
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Purkinje cells are the ONLY
Efferent neurons of cerebellar cortex
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How many rows of purkinje cells/neurons and where are they?
Single row; middle layer
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What is the outer layer in the cerebellum
Molecular layer
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What are the number of neurons in the molecular layer?
Few
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The molecular layer serves as a major ____ field
Synaptic
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Molecular layer contains dendrites of
Purkinje cells
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The white matter forms the
core/medullary center
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Efferent fibers in the white matter are
exiting/leaving the cerebellum
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Afferent fibers in the cerebellum are
Entering cerebellum
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As white matter extends out to the cortex, it forms
Arbor vitae
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Middle cerebellar peduncle only includes what fibers
Afferent pontocerebellar fibers
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Superior cerebellar peduncle includes what tracts
Ventral spinocerebellar tract and others
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Inferior cerebellar peduncle includes what tracts
Vestibulocerebellar tract
Dorsal spinocerebellar tract
Cuneocerebellar tract
Olivocerebellar tract
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Afferent fibers form 2 structural types of fibers
Mossy fibers or climbing fibers
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Mossy fibers terminate in the granular layer in an expanded terminal called a
rosette
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Climbing fibers ascending into the molecular layer where they
Climbe dendritic trees of purkinje cells
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Mossy fibers indirectly influence purkinje cells how?
mossy fibers synapse on golgi and gradual cells. Granule cell axons project into molecular layer and influence purkinje cells.
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Climbing fibers directly influence purkinje cells how?
Climbing fibers project into the molecular layer and exert powerful control on purkinje cells
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Climbing fibers are primarily ____ while mossy fibers include:
Olivocerebellar fibers; spinocerebellar fibers, cuneocerebellar fibers, pontocerebellar fibers, vestibulocerebellar
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Central nuclei
Deep/subcritical cerebellar nuclei
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4 pairs of nuclei embedded in medullary center
Fastigial nuc, globose nuc, emboliform nuc, dentate nuc
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There are 2 sources of input into the central nuclei (4 pairs of nuclei embedded in medullary center). Most of the input come from
Purkinje cells of cerebellar cortex that provide strong inhibitory influence on cerebellar nuclei
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There are 2 sources of input into the central nuclei (4 pairs of nuclei embedded in medullary center). Some of the input comes from
Sources outside the cerebellum. These fibers provide excitatory input to cerebellar nuclei
```
Pontocerebellar fibers
Vestibulocerebellar fibers
Spinocerebellar fibers
Olivocerebellar fibers
Others
```
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Axons of central nuclei project efferent fibers out of cerebellum via
Inferior and superior cerebellar peduncles (no MCP)
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Axons of central nuclei provide
FINAL efferent output of the cerebellum
In order for the cerebellum to influence motor activity, neurons of central nuclei must project fibers of the cerebellum to modify the activity of motor areas of the brain and brainstem and also to the motor nuclei of the thalamus.
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Archecerebellum, also called:
Vestibulocerebellum
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Archecerebellum
Anatomically:
Flocculonodular lobe
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Paleocerebellum also called
Spinocerebellum
60
Paleocerebellum
Anatomically:
Vermis and paravermis
61
Neocerebellum, also called
Pontocerebellum
62
Neocerebellum
Anatomically:
Part of vermis and lateral portion of hemispheres
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Efferent output of the archicerebellum is by the neurons of
fastigial nucleus and some into brainstem
I.e purkinje neurons of the cortex of the archicerebellum send axons
to the fastigial nucleus and some into the brainstem
64
The archicerebellum is involved in
Adjustment of muscle tone in response to vestibular data
Maintenance of equilibrium and eye position in response to movement of the head
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Lesion of the flocculonodular lobe would result in
- Loss of equilibrium
- Loss of adjustment of muscle tone in response to vestibular data
- Inability to maintain proper eye position in response to head movements
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Archicerebellum receives afferent input from the
- Vestibular nerve
- Vestibular nuclei
- Contralateral inferior olivary nucleus
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Paleocerebellum receives afferent input from
- Dorsal and ventral spinocerebellar tracts
- Cuneocerebellar tract
- olivocerebellar tract
Remember: one side of paleocerebellum receives sensory input from the ipsilateral side of the body
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Efferent output of the paleocerebellum is by the neurons of
- Fastigial
- Globose
- Emboliform nuclei
I.e. purkinje cells of the cortex of the paleocerebellum project axons
to the fastigial nucleus and the globose and emboliform nuclei
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Fibers from globose and emboliform nuclei (paleo cerebellar output) traverse the SCP and terminate
1. UMNs in reticular formation
2. Reticulobulbar tract
3. Ventral/anterior reticulospinal tract
4. Lateral reticulospinal tract
Therefore the paleocerebellum receives input of proprioception and other sensory modalities and utilizes this information to influence motor output of vestibular nuclei, reticular formation (red nucleus and motor areas of cerebral cortex)
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Paleocerebellum is involved in
- Control of muscle tone
| - Synergy of muscle groups — coordination of muscle contracts especially in muscles used in postural control and gait
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Neocerebellum receives afferent input from
- Contralateral cerebral cortex via corticospinal-ponto-cerebellar projections
- olivocerebellar projections
Note: input to pontocerebellum from cerebral cortex concerns movements that are planned and movements that are in process
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Efferent output of the neocerebellum is by the neurons of
Dentate nucleus
I.e. purkinje cells of the neocerebellum project axons to the dentate nucleus
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Neurons of dentate nucleus send fibers through SPC to
1. Contralateral red nucleus and influence rubrospinal tract and rubrobulbar tract
2. Most to contralateral ventral lateral nucleus of thalamus which influences the output of motor areas of cerebral cortex including
- corticospinal and corticobulbar/corticonuclear tracts
- corticovestibular tract
- corticoreticular tract
- corticopontine p/ways
- others
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One hemisphere of the cerebellum exerts control over movements on the
Ipsilateral side of the body/face
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Asyngergy
Loss of coordination
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Asynergy affects muscles of
Axial skeleton/trunk
| Proximal extremities, especially lower extremities
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Ataxic gait
Wide-based, staggering gait
Unstable postures with lots of body sway
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Nystagmus
Involuntary and repetitive eye movements
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Disorders of movement include
Asynergy
Ataxic gait
Frequent nystagmus
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Pathologies that affect the archicerebellum will usually result in degeneration of
Midline portions of cerebellum that affect vermis and flocculonodular lobe and thus disorder movement
81
Neocerebellar syndrom is associated with pathologies to the
Hemispheres
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Neocerebellar syndrom includes interruption of
afferent input, efferent pathways, etc
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Hypotonia
Decreased muscle tone
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Ataxia
Movements lack coordination
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Dysmetria
Difficulty gauging the appropriate distance, power, speed of a movements to desired target
May undershoot or overshoot target
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Past-pointing
Difficulty finding a target
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Intention tremor
Occurs at the end of a voluntary movement as the patient tries to correct for a defective movement to a target
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Dysdiadochokinesia
Inability to perform rapid, alternating movements that are repetitive
89
Neocerebellar syndrome pathologies may include
Hypotonia
Ataxia
General asynergy; inappropriate force, range and direction of movement that may result in movements taking longer to initiate and to stop, dysmetria, past-pointing, intention tremor, ‘decomposition of a movement’ where movements are fragmented/disjointed, dysdiadochokinesia, disarthria
90
Disarthria
Slurred speech
91
archicerebellum – receives afferent input from...
vestibular ganglia
| and nuclei
92
paleocerebellum - receives much of its afferent input from...
sensory fibers that ascend from the spinal cord
93
neocerebellum - receives input largely from....
the cerebral cortex after relay in the pontine nuclei.
94
climbing fibers are primarily olivocerebellar fibers that originate from the...
contralateral inferior olivary nuclear complex
95
archicerebellum influences motor control by modifying the activity of descending motor pathways that originate from the vestibular nuclei which includes what tracts?
vestibulospinal tract
descending MLF
ascending MLF
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fibers from the fastigial nucleus (paleocerebellar and acrchicerebellar output) traverse the ICP, terminate in and influence the output of the vestibular nuclear complex, which includes:
- vestibulospinal tract
| - MLF
