Midterm 2 - Unit 5 Lecture 2 Flashcards

1
Q

function of Basal Ganglia

A

Used in the planning and control of complex movements
Organizes sequencing of movements

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2
Q

does the Basal Ganglia act directly or indirectly to lower motor neurons

A

indirectly

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3
Q

is the Basal ganglia involved with the SMA or PMA

A

SMA
Programs self-initiated movements
Self-initiated movement rather than stimulus triggered movement
Control of habitual, skill-based behaviours

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4
Q

The basal ganglia selectively activates some movements while suppressing others. true or false

A

True

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5
Q

the basal ganglia inhibits unwanted movements and releases this inhibition to trigger movement. True or false

A

true

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6
Q

what are the Group of nuclei at ‘base’ of cerebral cortex:

A

Caudate
Putamen
Globus Pallidus
Substantia Nigra
Subthalamic Nucleus

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7
Q

what makes up the striatum

A

Caudate and Putamen

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8
Q

what makes up the lenticular nucleus

A

Globus pallidus and putamen

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9
Q

what is the shape/structure of the caudate

A

C shaped structure

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10
Q

how is the caudate divided

A

Divided into three parts:
Head, body and tail

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11
Q

What part of the brain is the putamen in?

A

The putamen is a round structure located at the base of the forebrain (telencephalon)

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12
Q

how are the putamen and caudate connected

A

Cellular bridges to caudate nucleus

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13
Q

what are the two segments of the Globus Pallidus

A

Internal, medial component; GPi
External, lateral component; GPe

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14
Q

GPi is one of the major outputs of the basal ganglia. true or false

A

true

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15
Q

the Subthalamic Nucleus is inferior to which structure

A

thalamus

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16
Q

what is the shape of the Subthalamic Nucleus

A

‘Spindle’ or ‘lens’ shaped

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17
Q

the Subthalamic Nucleus communicates with the

A

Globus Pallidus

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18
Q

what are the two segments of the Substantia Nigra

A

Pars compacta: more dorsal, contains darkly pigmented dopaminergic neurons

Pars reticulata: more ventral, involved in output, inhibits thalamus

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19
Q

what is the input nuclei associated with the Basal ganglia

A

Striatum: Putamen and Caudate

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20
Q

the basal ganglia receive Inputs from widespread areas of Cerebral Cortex including

A

Sensory areas
Motor areas
Association areas
thalamus

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21
Q

what is the output nuclei associated with the Basal ganglia

A

Globus pallidus internal segment
Substantia nigra pars reticulata

22
Q

does the Basal Ganglia Output have an inhibitory or an excitatory effect

A

inhibitory, GABA

23
Q

where does the Basal Ganglia output to

A

Thalamus
Superior colliculus

24
Q

The basal ganglia output nuclei have inhibitory projections to ______________

A

thalamus

25
Q

BG modulates this tonic inhibitory output through two main pathways:

A

Direct and Indirect

26
Q

At rest we know the Globus Pallidus internal has an _____________output and it talks to the ____________

A

inhibitory, thalamus

27
Q

what happens at rest in the Basal Ganglia Pathways

A

At rest GPi and SNpr they are ticking away at some resting discharge rate

And this inhibition is causing the thalamus which has an excitatory connection with the cortex, its being inhibited = less excitatory effect

28
Q

what is the direct pathway of Basal Ganglia

A

circuit best known for its hypothesized role in movement

29
Q

The direct pathway, its net outcome is to

A

increase that thalamus output

30
Q

how does the direct pathway increase that thalamus output

A

by reducing the Globus Pallidus internal segment

doing so reduces its inhibitory effect

31
Q

The direct pathway starts with the ______________ and produces an ____________ output

A

cortex, excitatory

32
Q

(Direct pathway) From the cortex, the ______________which is the main input nuclei, has an _______________effect on the ____________________

A

striatum, inhibitory effect, GPi

33
Q

how does the striatum inhibiting the GPi reduce the inhibitory effects on the thalamus

A

because we know the GPi inhibits the thalamus, so because we’re inhibiting the GPi, we’re having less inhibitory effect on the thalamus

34
Q

what is disinhibition

A

removing the inhibition on the thalamus

35
Q

what happens when you take away that inhibition on the thalamus

A

you can increase the excitatory effect on the cortex, which will increase the descending drive

36
Q

does the basal ganglia have indirect or direct effect on lower motor neurons

A

indirect

37
Q

the direct pathway is all about ______________the lower motor neuron activity

A

increasing

38
Q

The indirect pathway is all about ____________

A

decreasing thalamus output

39
Q

how does the indirect pathway decrease thalamus output

A

when we increase that GPi, this effect is stronger, there is more inhibition on that thalamus

1.cortex excites striatum
2.striatum inhibits the GPe
3. GPe has an inhibitory effect on the STN(subthalamic nucleus)
4. the STN has an excitatory connection on the GPi,
6. GPi and has an inhibitory connection on the thalamus which is being strengthened

40
Q

what does a greater inhibition on the Thalamus do

A

means we can’t excite the cortex as much
It eventually leads to a decreased descending drive

41
Q

what are the Effect of Dopamine on these pathways

A

Dopamine allows you to produce the movement that’s desired, turning down the brake and turning up the gas

42
Q

name a Basal Ganglia Dysfunction

A

Parkinson disease

43
Q

what causes parkinson disease

A

Caused by neuron death in substantia nigra
loss of dopamine

44
Q

What happens to the basal ganglia in Parkinson’s?

A

Disrupts normal modulation of BG output
So all of a sudden you can’t turn off the gas and theres too much break

45
Q

what are the Classic Symptoms of Parkinson’s Disease

A

Akinesia and Bradykinesia
Difficulty initiating movement and slow small movements

Resting tremor
Rhythmic oscillation in distal limbs (usually hand or upper extremity)

Rigidity
Increased muscle tone and stiffness: “Lead pipe” or “cog-wheel” rigidity

Postural instability
Leading to unsteady gait

46
Q

Other Symptoms of Parkinson’s Disease (Posture and gait related)

A

Stooped posture
Shuffling gait with freezing and difficulty turning
Diminished arm swing while walking

47
Q

Other Symptoms of Parkinson’s Disease

A

Micrographia and Hypophonia
Diminished facial expressions

48
Q

what is another Basal Ganglia Disorder that we learned

A

Huntington’s Disease

49
Q

what is Huntington’s Disease

A

Hyperkinestic movement disorder
Degeneration of striatal neurons in caudate and putamen
Neurons of indirect pathway more severely affected
Not enough inhibition (for the unwanted movements)

50
Q

symptoms of Huntington’s Disease

A

Hyperkinetic movements: Chorea and dystonia