6a.) Movement Disorders & Basal Ganglia Flashcards
What are the basal ganglia?
Regions of grey matter situated deep to cortex in cerebral hemispheres and in midbrain
State the basal ganglia
- Caudate nucleus
- Putamen
- Globus pallidus
- Subthalamic nucleus
- Substantia nigra pars compacta
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/730/812/a_image_thumb.jpg?1580460932)
Where is the caudate nucleus found?
C shaped nucleus lining the/lying lateral to the lateral ventricle
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/730/911/a_image_thumb.jpg?1580461056)
Wher is the globus pallidus found?
Immediately medially (squished close together with) to the putamen
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/730/943/a_image_thumb.png?1580461294)
Where is the putamen found?
Lateral to the globus pallidus (but also squished against it) and connected to caudate nucleus by grey matter bridges
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/731/024/a_image_thumb.png?1580461362)
Where is the substantia nigra found?
Midbrain (mickey mouse’s eyebrows)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/731/088/a_image_thumb.png?1580461545)
Where is the subthalamic nucleus found?
Inferior to thalamus
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/731/121/a_image_thumb.jpg?1580461598)
State the two regions of the substantia nigra
- Substantia nigra pars compacta (more dorsal)
- Substanita nigra pars reticulata (more ventral)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/731/128/a_image_thumb.jpg?1580462019)
Which basal ganglia is a source of dopamine in the midbrain?
Substantia nigra pars compacta (SNc)
Which two basal ganglia make up the striatum?
Caudate and the putamen
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/731/766/a_image_thumb.png?1580462748)
Which two basal ganglia make up the lentiform nucleus?
Putamen and globus pallidus
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/731/773/a_image_thumb.png?1580462784)
Is the striatum (made up of caudate nucleus and putamen) functionally related?
Yes
*Caudate & putamen were originally a single structure however axons of the corticospinal system descended down and punctured through causing them to become partially separted (still connected by grey matter bridges)- this is why they are called the striatu due to their striated appearance
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/731/781/a_image_thumb.png?1580462891)
Are the structures in the lentiform nucleus (putamen & globus pallidus) functionally related?
No, they are structurally related but NOT ANATOMICALLY related
State the two segments of the globus pallidus
- Internal segment
- External segment
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/732/026/a_image_thumb.jpg?1580463029)
Where does the striatum receive input from?
- Substantia nigra compacta
- Cortex
The basal ganglia communicate with the motor cortex via the…..?
Thalamus
*Can think of thalamus as the bouncer/door man- to talk to the cortex you have to go through the thalamus
The thalamus is always excitatory/inhibitory on the cortex
Which one?
Excitatory
Discuss the role of the basal ganglia
Their role is unclear however we think that they have a role in reinforcing appropriate movements and removing inappropriate movements e.g. to pick up a cup of tea, you need to do certain movemtns such as finger flexion (finger extension wouldn’t allow you to pick up the cup). There are two pathways:
- Direct pathway: faciliates appropriate movements (excitatory to the motor cortex)
- Indirect pathway: inhibits inappropriate movements (inhibitory to the motor cortex)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/300/732/119/a_image_thumb.png?1580463660)
Describe the role of dopamine in the basal ganglia and their relations/functions with the motor cortex
Dopamine facilitates movements by exciting the motor cortex:
- Dopamine excites the direct pathway by activating excitatory D1 receptors on striatal neurones in the direct pathway
- Dopamine inhibits indirect pathway by activating inhibitory D2 receptors on striatal neurones in the indirect pathway
What is the main role of the basal ganglia?
Stimulate motor cortex