Lecture 6 Cerebellum - Part II Flashcards
1
Q
Where are the climbing fibers coming from and use which neurotransmitter for communication?
A
Contralateral inferior olivary nucleus
- Glutamate or aspartate
2
Q
Where does the frontal/parietal cortex project to?
A
red nucleus and pontine nuclei
3
Q
Where does the red nucleus project to?
A
inferior olive
4
Q
Where does the pontine nuclei project to?
A
crosses midline through MCP to the cerebellar cortex/deep nuclei
5
Q
What are the 3 inputs that go into the cerebellum? through what?
A
- Inferior olive
- Spinal Cord
- Vestibular Nuclei
- through ICP
6
Q
Why is the inferior olivary nucleus’s cerebellar afferent pathway unique?
A
Crosses over medulla oblongata in midline
7
Q
What is the role of the posterior spinocerebellar tract?
A
for unconcious proprioception
8
Q
Where does the posterior spinocerebellar tract project?
A
through ICP with vestibular nuclei
9
Q
What kind of pathways are in the superior cerebellar peduncle?
A
both afferent and efferent
10
Q
How does the cerebral cortex synapse with the pontine nuclei?
A
through corticopontine tracts
11
Q
What are climbing fibers ONLY?
A
the afferent fibers from the contralateral inferior olivary nucleus
12
Q
What is the pathway of the climbing fibers?
A
Axons ascend, project to cerebellum, both nuclei ( fastigial and vermis) project to cerebral cortex molecular layer where they synapse with the dendritic trees of purkinje cells
13
Q
Where are climbing fibers found?
A
ICP
14
Q
Where do climbing fibers go?
A
to the molecular layer and cerebellar nuclei directly
15
Q
What kind of neurotransmitter do climbing fibers use?
A
glutamate or aspartate as neurotransmitters: excitatory
16
Q
How many axonal terminals do climbing fibers have?
A
multiple
17
Q
What plane are dendritic trees in?
A
Sagittal
18
Q
Where does each terminal synapse with multiple Purkinje cells?
A
In the same sagittal plane
19
Q
Where is glutamate inhibitory?
A
Visual system, excitatory everywhere else
20
Q
Where do mossy fibers project?
A
to both the nuclei and continues to project to the granular layer to synapse with granule cells
21
Q
Where do all afferent fibers of the mossy fibers go?
A
to the granular layer and cerebellar nuclei directly
22
Q
Where do mossy fibers go through the cerebral cortex and spinal cord?
A
through all three cerebellar peduncles
23
Q
What are the neurotransmitters for mossy fibers?
A
Glutamate or aspartate as neurotransmitters: excitatory
24
Q
What do mossy fibers synapse with to spread signals out?
A
Synapse with granule cells to spread signals out through parallel fibers
25
How many synapses can come from the parallel fibers with mossy fibers?
~10^5
26
What cells are activated by the signals from mossy fibers?
stellate and basket cells
27
What plane are parallel fibers in when they form the many synapses?
coronal
28
Where do multilayered fibers project?
to both the nucleus and all three layers of the cerebellar cortex
- cerebellar cortical layers
- nuclei
29
Where do multilayered fibers afferent axons from different subcortical structures go?
basal nuclei, diencephalon, RF, hypothalamus, etc.
30
What kind of neurotransmitters do multilayered fibers have?
various neurotransmitters, either excitatory or inhibitory
31
How do multilayered fibers modulate Purkinje discharge rate?
directly or via interneurons
32
What does the cortical inhibitory loop activate? inhibit?
Activating purkinje cells, thus, indirectly inhibiting the nuclei
33
How is the cortical inhibitory loop formed?
1st activate purkinje cells that release GABA, which is inhibitory
34
What does the deep excitatory loop do?
directly activate the nuclei
35
How does the deep excitatory loop work?
projects directly to the nucleus, both release glutamate to activate/excite it
36
What are climbing fibers synapsing with tin the synaptic circuit?
neurons in the cerebellar nucleus to ascend to the molecular layer of the cerebellar cortex to synapse with the dendritic tree
37
What are mossy fibers mediated by?
Granule cells, otherwise the same as parallel fibers
38
What neurotransmitter do climbing fibers and mossy fibers both release?
Glutamate/aspartate
39
What are the functions of the flocculus and nodulus of flocculonodular lobe?
* flocculus: projects to lateral vestibular nuclei for lateral vestibulospinal tract
* Nodulus: projects to fastigial then to the medial vestibular nucleus, medial vestibulospinal tract
40
Where do climbing fibers activate Purkinje cells?
sagittal plane
41
Where do mossy fibers activate purkinje cells? How?
coronal plane, through the parallel fibers
42
What are the 2 foundational pathways?
Inhibition and disinhibition
43
What do stellate cells synapse with?
dendritic tree of purkinje cells
44
What do basket cells synapse with?
cell body of purkinje cells
45
What happens when Golgi cells are activated and release GABA?
inhibits granule cells
46
What happens when parallel fibers from granule cells activate stellate and basket cells?
Inhibits purkinje cells
47
What kind of effects result from self negative circuity through Golgi cells?
temporal effects
48
What kind of effect results from negative circuitry through interneurons on Purkinje cells?
Spatial effects
49
What happens when purkinje cells are activated?
inhibits nuclei
50
What happens when purkinje cells are inhibited?
activates nuclei
51
What happens with the spatial effects of parallel fibers?
Stellate cells and basket cells are activated, axons extend to neighboring sagittal plane Purkinje cells and inhibit them
52
What do parallel fibers active the stellate and basket cell axons?
in the sagittal plane
53
What happens with indirect inhibition/disinhibition of Purkinje cells?
indirectly to inactivate neighboring purkinje cells
54
Where does the cerebrocerebellum project?
to the dentate nucleus
55
Where does the dentate nucleus project from the cerebrocerebellum?
PM cortex (motor planning and motor learning)
56
Where does the spinocerebellum project?
The interposed nuclei from the intermediate region and the fastigial nucleus from the vermal region
57
Where do the interposed and fastigial nuclei project?
the motor cortex (M1) and brainstem
58
Where does the vestibulocerebellum project?
the vestibular nuclei (the flocculus)
and the Fastigial nucleus (the nodulus)
59
Where does the vestibular nuclei project?
projects out from SCP to crossover in midbrain, LMN in spinal cord and brainstem
60
What tracts does the flocculonodular lobe control?
Flocculus and nodulus both control medial and lateral vestibulospinal descending tracts
61
What controls eye movement?
medial longitudinal fasciculus to coordinate CN III, IV, and VI
62
What happens with vision with the loss of function of the vestibulocerebellum?
- loss of smooth pursuit (saccades) (Horizontal gaze center)
- nystagmus
- dyplopia (both horizontal and vertical gaze centers)
63
What is CNVIII responsible for with eye movement?
perception of head orientation
64
What is the vestibulocerebellum responsible for with eye movement?
- eye movements
- postural control
65
What are vestibular functions "especially" controlled by?
medial vestibulospinal tract for postural control
66
What happens with balance with the loss of vestibulocerebellar functions?
- truncal ataxia (LL not stable), truncal titubation (truncal tremor)
67
Which different information is contained in the different cerebellar peduncles?
ICP: contralateral inferior olivary nucleus and ipsilateral posterior spinocerebellar tract, ipsilateral vestibular projections
MCP: contralateral pontine nuclei, relayed corticopontine tract
SCP: bilateral anterior spinocerebellar tracts, subcortical brain structures
68
What are the spino- and cerebellum impairments causing? (general)
spino: functional part
cerebro: more complicated movements motor control
69
What is the deterioration of coordination called?
decomposition of movement (dyssynergia)
70
What is dysarthria?
difficulty speaking, muscle incoordination for vocal cords
71
What are the types of dysmetria?
- hypermetria: overshoot
- Hypometria: undershoot
72
What is an intention tremor?
- involuntary, rhythmic shaking that occurs during purposeful movements
- characterized by tremors that worsen as the individual gets closer to their target
73
What is the difference in dysmetria and intention tremors?
dysmetria is in the correct direction, intention tremor has offset direction and is "worse"
74
What is decrease in muscle tone?
hypotonia
75
When can hypotonia happen?
post CVA, TBI, SCI
76
What is dysdiadochokinesia?
coordination problem, pronation/supination coordination deficit, record the time to compare the two sides
77
What is the decrease in the DTR?
Areflexia
78
What is the unsteadiness of gait in the LE?
Ataxia
79
What are the issues that can arise with the spino- and cerebrocereberebellum impairments?
- deterioration of coordination
- dysarthria
- dysmetria
- intention tremor
- hypotonia
- dysdiadochokinesia
- areflexia
- ataxia
80
What controls the cerebellum and visceral motor function?
a circuit between hypothalamus and cerebellum
81
What does the circuit between the hypothalamus and cerebellum entail?
- multilayered fibers
- autonomic nervous sysem
82
What is the autonomic nervous system responsible for?
- drives, fight/flight/rest/digest etc
- basic vital signs
83
How many vital signs are controlled by the hypothalamus? modulated by hypothalamus?
controlled: 1
modulated: 3
84
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85
What are the somatomotor deficits that will arise with a L SCA stroke?
L hand intention tremor
86
Why is SCA so important for cerebellar function?
supplies the most part of the cerebellum except for the anterior lobe, most part of superior posterior lobe and most part of deep nuclei
87
What are the accompanying visceral motor functional impairments that will come with a L SCA stroke?
- dilation of L pupil (compromised parasympathetic motor CNIII)
- Flush of L face and warmth ( compromised sympathetic motor dilates blood vessels)
88
What happens with a fastigial nucleus injury?
decreases HR and BP due to sympathetic motor loss (parasympathetic takes over and decreases these vital signs)
89
When can visceral motor impairments stop with an L SCA stroke?
when stopping L hand movement
90
What cerebellar components control emotions?
vermis and limbic system
91
What is initiation emotion?
emotion corresponding to stimuli
92
What is the recognition of emotion? What condition lacks this? Why?
being aware of the emotions of yourself and other
- those with autism lack this due to lack of mirror neurons
93
What is social cognition?
Understanding acceptable behaviors
94
What controls social cognition?
left dorsal lateral prefrontal cortex
95
Where are the different emotions encoded mainly?
around vermis
96
What were the neuroimaging techniques in 1980s?
PET scanning
97
What did we know about cerebellar involvement in cognition?
affects language
- close to Broca's area
98
What is there direct evidence on with cerebellum and cognition?
viral vector tracing techniques
99
What is the pathway of rabes?
axon terminals to the cell bodies
100
What is the pathway of herpes?
cell bodies to axon terminals
101
What kind of circuit is between the cerebrum and cerebellum?
polysynaptic
102
Where is there bidirectional projections connecting the cerebellum and cognition?
Brodmann area 46 to contralateral lobule VII (7)
103
Where is lobule VII lovated?
between cerebellar motor functional regions
104
Which signs will the patient present with if the fastigial nucleus is impaired during SCA stroke?
somatomotor functions
- nodulus: eye movements
- vermal region of the spinocerebellum: D's and intention tremor
Visceral motor functions
- emotions
- pupil size/ blood vessel tone
105
How can the cerebellum modulate ipsilateral motor functions?
decussation of the pathways associated with motor control by the cerebellum
- efferent to contralateral thalamus then to the cerebral cortex
- motor decussation in the caudal pyramid back to the same side
