Deep Brain Structures 1 Flashcards

1
Q

function of basal ganglia as a collective group

A

to refine movement

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2
Q

basal ganglia consist of:

A
  • caudate
  • putamen
  • globus pallidus
  • claustrum
  • amygdala
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3
Q

caudate + putamen =

A

striatum

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4
Q

putamen + GP =

A

lenticular system

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5
Q

caudate

A
  • lateral to lateral ventricles

- a circular nucleus

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6
Q

putamen

A
  • fuses w/ head of caudate

- the outside portion

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7
Q

amygdala

A
  • the end of the caudate

- related to emotion

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8
Q

internal capsule

A
  • mass of fibers between the GP/putamen and the caudate

- represents the ascending and descending fibers to and from cortex

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9
Q

basal ganglia afferents are from:

4 regions

A
  • cerebral cortex
  • substantia nigra
  • thalamus
  • subthalamic nucleus
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10
Q

where do the basal ganglia relay the afferent input that it receives?

A

GP

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11
Q

cerebral cortex as basal ganglia afferent

A
  • one of the largest projections

- excitatory to basal ganglia

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12
Q

substantia nigra as basal ganglia afferent

A
  • projects mainly to caudate but also to putamen
  • inhibitory via dopamine
  • excitatory via Ach
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13
Q

clinical correlation of substantia nigra being excitatory and inhibitory

A
  • Parkinson’s treament
  • it’s a loss of dopa so you get extra Ach
  • tx: anticholinergic
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14
Q

thalamus as basal ganglia afferent

A
  • the thalamus is sensory relay for everything except smell

- excitatory to basal ganglia

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15
Q

subthalamic nucleus as basal ganglia afferent

A

-excitatory to basal ganglia

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16
Q

what is considered the receptive portion of the basal ganglia?

A

-caudate and putamen

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17
Q

where do the caudate and putamen project to after receiving afferents?

A

GP

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18
Q

basal ganglia output is from?

A

GP

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19
Q

modality of GP

A

-ALL inhibitory

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20
Q

basal ganglia efferents go to:

3 regions

A
  • thalamus
  • subthalamus
  • red nucleus
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21
Q

basal ganglia efferent to thalamus

A
  • encourages everything to fire

- goes on to cortex

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22
Q

basal ganglia efferents to subthalamus

A

also gets back to the cortex

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23
Q

basal ganglia efferents to red nucleus

A

-goes to the spinal cord

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24
Q

what happens if you lose inhibition to the red nucleus (i.e a lesion above the red nucleus but below the basal ganglia)

A

-you’ll see a release of function
-red nucleus can fire at well
= decorticate posturing

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25
since all of the basal ganglia efferents are inhibitory, what is the neurotransmitter?
GABA
26
which of the basal ganglia project to the spinal cord?
NONE
27
since basal ganglia don't project to the SC, how is movement modulated?
it does so in the cerebral cortex and brainstem nuclei like the red nucleus
28
GP effect on motor curcuits
- GP exerts a continuous inhibitory effect on motor thalamocortical curcuits - acts as a "brake"
29
what is the outcome if the basal ganglia inhibitory feedback loop (i.e the brake) is removed?
tremor/shake "if you remove the brake you get a shake"
30
tremor is aka
dyskinesias
31
athetosis
slow, worm like, writhing of extremities or neck
32
when is athetosis seen?
cerebral palsy
33
choreaform dyskinesia
-quick, jerky, involuntary, distal extremity, tongue, face
34
in general, dyskinesias are secondary to:
- release phenomenon - i.e an inhibitor is gone so movement that it suppressed is now "released" - disinhibition
35
what is less understood about dyskinesias?
- there are also inhibition manifestions | - like in PD: flat affect and shuffling gait or in tardive dyskinesia
36
tardive dyskinesia can be caused by:
- psych meds that inhibit DA action in striatum | - ex: Haldol and prolixen
37
basal ganglia issue in PD
dopa loss from the substantia nigra
38
basal ganglia issue in Huntington's
GABA loss from caudate
39
Sydenham's chorea
- self limiting - seen in kids that were not treated for strep and develop rhuematic fever - get small hemorrhaged and develop st. vitas dance tremor
40
hemiballism
- unilateral lesion of the subthalamic nucleus - usually d/t stroke - causes huge flailing contralateral tremor
41
if there are infarcts of small vessels, what is always the answer?
- DM - HTN - smoking
42
wilson's disease
- familial disorder of copper metabolism - lesions putamen and GP - aka hepatolenticular degeneration
43
hallmark of wilson's disease
- Kayser-Fleischer rings | - flapping tremor
44
internal capsule
- contains motor fibers going out and sensory fibers going back up - has ant. and post limb - comes from all over brain but 90% are from 3 areas
45
what are the 3 areas that make up 90% of the internal capsule?
1. pre central gyrus 2. post central gyrus 3. premotor area
46
anterior limb of the internal capsule
all connections b/w the basal ganglia and the thalamus
47
posterior limb of internal capsule
- descending and ascending input | - FAL and fal areas (face arm leg)
48
FAL of internal capsule posterior limb
-location of motor fibers from pre central gyrus that give rise to the corticospinal tract
49
fal of internal capsule posterior limb
-location of sensory info that is traveling back up to the post central gyrus
50
striate arteries are branches of what artery?
middle cerebral a.
51
middle cerebral a. supplies:
the dorsolateral surface of the brain
52
outcome of stroke at the middle cerebral a.
- motor AND sensory loss | - contralateral muscle weakness and parasthesia
53
outcome of stroke at the striate arteries
-lose either motor or sensory but rarely both
54
what is a stroke to the striate arteries called?
lacunar infarct
55
brodemann's areas
-numbers of areas in the brain that individually correspond to specific function
56
brodemann area 4
- pre central gyrus - principal motor area - contributes 1/3 of the corticospinal tract
57
brodemann area 6
-pre motor area
58
result of a lesion of area 6
loss of initiation of motor function
59
area 3 2 1
postcentral principal sensory area
60
anatomy of thalamus
- one of each side of brain - related to 3rd ventricle - has hypothalamic sulcus and hypothalamus beneath it
61
what is the structure called in some people who have a connected thalamus?
massa intermedia
62
foramen monroe
opening of 3rd ventricle leading to the lateral ventricles