Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neurology > Basal Ganglia > Flashcards

Basal Ganglia Flashcards

1
Q

What is this basic feedback circuit of the basal ganglia?

A

Thalamus and basal ganglia communicate to modulate the output of the cerebral cortex - no link to lower motor neurones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What do the basal ganglia consist of?

A

The neostriatum - caudate nucleus and putamen

Globus pallidus - external and internal

Substantia nigra - pars compacta and pars reticulata

Subthalamic nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the primary afferents of the basal ganglia?

A

The caudate nucleus and putamen (make up the neostriatum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where does the basal ganglia receive inputs from?

A

The cortex

Basal ganglia then transmit a response back to the cortex (directly or indirectly)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the consequence of the direct pathway?

A

Release the thalamus to allow movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens in the direct pathway?

A

Neostriatum receives excitatory input from cortex
Synopses with inhibitory neurone to globus pallidus internal, inhibiting it
GPi normally inhibiting thalamus, but now switched off so thalamus excited
Thalamus sends excitatory signals to motor cortex
Motor cortex moves muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens in the indirect pathway?

A

Neostriatum inhibits the globus pallidus external
This inhibits the subthalamic nucleus
Causes the subthalamic nucleus to produce an excitatory response to the globus pallidus internal
This inhibits the thalamus, leading to less movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the aim of the indirect pathway?

A

To stop movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does the substantia nigra fine tune the direct pathway?

A

Substantia nigra has neurones synapsing with inhibitory neurones in neostriatum to globus pallidus internus
Dopamine from SN binds to D1 receptors on inhibitory neurones
Dopamine excites the inhibitory neurones, causing more inhibition of GPi, allowing thalamus to be more active

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does the subthalamic nucleus control the substantia nigra on the direct pathway?

A

Excited the substantia nigra
Therefore more dopamine released
More inhibition of GPi
More excitation of thalamus and more movement

Substantia nigra can inhibit the subthalamic nucleus when it has been excited enough -> less movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is Parkinson’s disease a result of?

A

Progressive degeneration of dopaminergic receptors on neurones from the substantia nigra to the striatum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the triad of symptoms seen in Parkinson’s?

A

Tremor at rest - pill rolling tremor
Hypertonia - lead pipe/cog wheel rigidity
Bradykinesia - slowness of movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Features of the Parkinsonian gait?

A

Stooped posture
Short, shuffling steps
Pedestal turning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the overall effect of Parkinson’s?

A

Suppression of the direct pathway and amplification of the indirect pathway
Causes increased thalamus inhibition and subsequent deduction in excitatory output to the cerebral cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is Huntington’s chorea inherited?

A

Autosomal dominant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the mutation in Huntington’s cause?

A

Produce Huntington protein, which forms aggregates and causes cell death

17
Q

Signs and symptoms of Huntington’s?

A

Chorea - jerky, involuntary movements

Development of progressive psychiatric and cognitive symptoms

18
Q

Pathology of Huntington’s?

A

Neuronal loss initially in caudate nucleus (part of neostriatum)
Reduction in inhibitory neurotransmitters - GABA and Ach
Loss of inhibitory synaptic transmission leads to decreased thalamic inhibition and increased stimulation of movement

19
Q

What is the main function of the basal ganglia?

A

Provide a feedback mechanism to the cerebral cortex for the initiation and control of the motor responses
-reduce/dampen down the excitatory input to the cerebral cortex

20
Q

What is this basic feedback circuit of the basal ganglia?

A

Thalamus and basal ganglia communicate to modulate the output of the cerebral cortex - no link to lower motor neurones

21
Q

What do the basal ganglia consist of?

A

The neostriatum - caudate nucleus and putamen

Globus pallidus - external and internal

Substantia nigra - pars compacta and pars reticulata

Subthalamic nucleus

22
Q

What are the primary afferents of the basal ganglia?

A

The caudate nucleus and putamen (make up the neostriatum)

23
Q

Where does the basal ganglia receive inputs from?

A

The cortex

Basal ganglia then transmit a response back to the cortex (directly or indirectly)

24
Q

What is the consequence of the direct pathway?

A

Release the thalamus to allow movement

25
Q

What happens in the direct pathway?

A

Neostriatum receives excitatory input from cortex
Synopses with inhibitory neurone to globus pallidus internal, inhibiting it
GPi normally inhibiting thalamus, but now switched off so thalamus excited
Thalamus sends excitatory signals to motor cortex
Motor cortex moves muscles

26
Q

What happens in the indirect pathway?

A

Neostriatum inhibits the globus pallidus external
This inhibits the subthalamic nucleus
Causes the subthalamic nucleus to produce an excitatory response o the internal
This inhibits the thalamus

27
Q

What is the aim of the indirect pathway?

A

To stop movement

28
Q

How does the substantia nigra fine tune the direct pathway?

A

Substantia nigra has neurones synapsing with inhibitory neurones in neostriatum to globus pallidus internus
Dopamine from SN binds to D1 receptors on inhibitory neurones
Dopamine excites the inhibitory neurones, causing more inhibition of GPi, allowing thalamus to be more active

29
Q

How does the subthalamic nucleus control the substantia nigra on the direct pathway?

A

Excited the substantia nigra
Therefore more dopamine released
More inhibition of GPi
More excitation of thalamus and more movement

Substantia nigra can inhibit the subthalamic nucleus when it has been excited enough -> less movement

30
Q

What is the main function of the basal ganglia?

A

Provide a feedback mechanism to the cerebral cortex for the initiation and control of the motor responses
-reduce/dampen down the excitatory input to the cerebral cortex

Neurology (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions