basal ganglia and cerebellum L14 Flashcards
(103 cards)
1
Q
What initiates command
A
the cerebral cortex
2
Q
Cerebellum function
A
coordination of ongoing movement reducing error in movement
3
Q
Basal ganglia function
A
selection/ initiation of voluntary movement
4
Q
What do basal ganglia and the cerebellum both do; (2)
A
Increase accuracy of movement
Modify signals only of UMN
5
Q
overall effect of damage on the cerebellum
A
jerky movements, uncoordination & inaccurate
6
Q
overall effect of damage to the basal ganglia
A
uncontrolled movements
7
Q
Example of disease from basal ganglia damage (2)
A
Parkinsons
Huntingtons
8
Q
Where is the cerebellum found
A
hind brain
9
Q
what are the folds on the dorsal surface of cerebellum called (2)
A
folia (ridges)
Lobules
10
Q
How many hemispheres of the cerebellum
A
2
11
Q
What does the cerebellum have 50% of the CNS____
A
neurons
12
Q
The majority of the cerebellum is ___ matter
A
grey matter
13
Q
In the cerebellum there is a small portion of ___matter on the inside
A
white matter
14
Q
What is motor memory of the cerebellum
A
stores learned movements, consciousness –> unconscious movements e.g bike
15
Q
3 divisions of the cerebellum
A
cerebrocerebellum
spinocerebellum
vestibularcerebellum
16
Q
large area in humans of the cerebellum
A
cerebrocerebellum
17
Q
Which part of cerebellum receives inputs from the cerebral cortex
A
cerebrocerebellum
18
Q
What is the cerebrocerebellum involved in
A
regulation of highly skilled movements
19
Q
Where does the spinocerebellum receive inputs from
A
spinal cord
20
Q
What are the lateral parts of the spinocerebellum involved in
A
movement of distal muscles
21
Q
what are the central parts (vermis) of the spinocerebellum involved in
A
movement of proximal muscles
22
Q
What does the vestibulocerebellum include
A
nodulus and flocculus (see picture)
23
Q
Where does the vestibulocerebellum receive inputs from
A
the vestibular nuclei in brainstem
24
Q
How is the cerebellum attached to the pons in the brainstem?
A
cerebellar peduncles
25
The superior cerebellar peduncle is
an (almost) entirely efferent pathway from cerebellum
26
The middle cerebellar peduncle is
an afferent pathway to the cerebellum via pons
27
The inferior cerebellar peduncle is
both afferent and efferent pathways
28
Where are the main inputs into the cerebellum from (2)
motor cortex and parietal cortex
29
Where are less main inputs into the cerebellum from
spinal cord
| vestibular nucleus
30
Where do motor inputs from the cerebral cortex cross to the opposite cerebellar hemispheres
relay neurons in the pons
31
What does the inferior olive input into the cerebellum
learning, timing, memory
32
What are the main output structures of the cerebellum
deep cerebellar nuclei
33
where does the cerebrocerebellum project information to
dentate nucleus
34
where does the vestibulocerebellum project information
vestibular nuclei (and via fastigal nucleus)
35
Where does the central (vermis) spinocerebellum project information
fastigial nucleus (proximal/ trunk)
36
where does the lateral spinocerebellum project information to
interposed nucleus (distal limbs)
37
Main cell types of the inputs of cerebellum (2)
climbing fibres
| mossy fibres
38
main cell type of outputs of the cerebellum
purkinje cells
39
Main interneuron in the cerebellum
granule
40
What are the three main cell layers of the cerebellar cortex
molecular layer (top)
purkinje cell layer (middle)
granule cell layer (bottom)
41
which fibres carry most inputs from cerebral cortex, spinal cord and vestibular system
mossy fibres
42
what fibres modify the output of the purkinje fibres (inferior olive)
climbing fibres
43
Where/ what do mossy fibres synapse with
granule cells in the granule layer
44
What is specialised about granule cells
they have an axon which goes up to the molecular layer and forms long parallel fibres
45
Where do granule cells synapse
onto the dendrites of the purkinje fibres
46
What cells output the response from the cerebellum
purkinje cells
47
What kind of signals do climbing fibres carry
error signals
48
Where do purkinje fibres synapse
deep cerebellar nuclei
49
What neurotransmitter does purkinje fibres use
GABA
50
IS GABA excitatory or inhibitory
Inhibitory
51
How many inferior olive neurons (climbing fibres) input purkinje fibres
just 1 (but strong input)
52
Which side of the body are movement errors from cerebellar damage
same side
53
lesions to spinocerebellum cause
impaired gait (wide base, slow shuffling )
54
Lesions to the cerebrocerebellum
impairment in highly skilled movement
55
Lesions to the vestibular cerebellum
disturbance of balance and eye movements
56
Cerebellar ataxia=
jerky, uncoordinated movements
57
dyssynergia=
loss of synergistic multi-joint movement (finger to nose move other joints first)
58
Dysmetria
inability to judge movement
59
dysdiadochokinesia
inability to perform rapid, alternating movement
60
Intention tremor
tremor when trying to move
61
Ataxic dysarthria
slurred speech
62
Which area of the cerebellum does alcohol damage
anterior cerebellum
63
What does damage to the anterior cerebellum affect most
movement of the lower limbs
64
Anterior spinocerebellum includes
lower limb movements
65
5 basal ganglia nuclei
```
Caudate nucleus
Putamen
Globus pallidus
Substantia nigra
Sub-thalamic nucleus
```
66
Striatum=
input zone
67
striatum is made from
caudate nucleus+ putamen
68
Globus pallidus+ substantia nigra (pars reticulata)=
outputzone
69
The basal ganglia role
exerts inhibitory influences to modulate the initiation and termination of motor commands
70
Glutament=
excitatory
71
A lot of inputs into the basal ganglia are from__
frontal lobes (motor cortex) and parietal lobes (sensory association areas)
72
What neurons in the striatum receive inputs
medium spiny neurons
73
What neurotransmitter does the nigrostriatal pathway use
dopamine
74
Two parts of the substantial nigra
Pars compacta
| Pars retticulata
75
Nigrostriatal pathway goes from the
substania nigra pars compacta ---> striatum
76
What are the two pathways from the basil ganglia
direct pathway
| indirect pathway
77
Which pathway inhibits the thalamus
indirect pathway
78
Which pathway removes inhibition on the thalamus
direct pathway
79
Both pathways follow the_______loop
cortical striatal loop
80
Direct pathway has how many negatives
2
81
indirect pathway has how many negatives
3
82
basic direct pathway (not including dopamine)
1. motor cortex sends impulses to the striatum
2. increasing the striatums inhibition of the globus pallidus (internal)
3. Globus pallidus is more inhibited and can't inhibit the thalamus as much
4. Thalamus can send more excitatory impulses to the motor cortex
5. initiating movement
83
Direct pathway substania nigra
Dopamine from the substania nigra (pars compacta) further excites the striatum increasing inhibition on the globus pallidus
84
Indirect pathway simple
1. motor cortex excites striatum
2. excited striatum increases inhibition of globus pallidus external
3. more inhibition of the globus pallidus external--> less inhibition of the subthalamic nucleus
4. The subthalamic nucleus can now send more excitatory signals to globus pallidus internal
5. Globus pallidus internal is more excited and can send more inhibitory signals to thalamus
6. inhibited thalamus--> decrease in movement
85
Weird part of indirect pathway
The globus pallidus external also inhibits the globus pallidus internal, this would decrease the activity of the internal part decreasing movement (not what the indirect pathway usually does)
86
What effect does the substantia nigra (pars compacta) have on the indirect pathway
inhibits the indirect pathway via D2 receptors in the striatum, decreasing the effect of the indirect pathway.
87
TRAP in parkinsons=
Tremor of hands
Rigidity of muscles
Akinesia
Postural problems
88
Akinesia=
absence or poverty of movement
89
What does Parkinsons do biologically
Degeneration of neurons in substania nigra
| so decrease in dopamine availability
90
Wha result does parkinsons have on the indirect pathway
increased activity of the indirect pathway
91
What effect does parkinsons have on the direct pathway
decreased activity
92
What is L-DOPA (levodopa)
A precursor of dopamine, boosts dopamine levels in substania nigra
93
Side effects of L-DOPA
drug resistance,
involuntary movements (dyskinesia)
Psychosis.
94
What do dopamine agonists do
stimulate postsynaptic dopamine receptors in striatum
95
Side effects of dopamine agonists
sudden sleepiness
96
What are fetal cell transplants
transplantation of metal mesencephalic cells (stem cells) into putamen
97
Other surgery options for parkinsons
implanted electrode to inactivate globus pallidus
| / remove globus pallidus or thalamus
98
Which chromosome does huntingtons effect
number 4
99
What is huntingtons disease
loss of output neurons of striatum
100
What is the result of huntingtons
cortical motor areas become overactive
| Excessive jerky movements
101
Which pathway does huntingtons affect
indirect pathway
102
What is hemiballismus
rapid flinging and violent movements of limbs (on one side of body) caused by damage to subthalamic nucleus
103
treatment of hemiballismus
deplete dopamine levels (similar to hungtintons)
