Basal Ganglia

Question 1

What are the various structures related to the basal ganglia?

Answer 1

1. Caudate
2. Putamen
3. Globus pallidus
4. Substantia nigra
5. Subthalamus

Question 2

T/F: The putamen is a large nucleus with a head, body, and tail.

Answer 2

FALSE

Caudate

Question 3

T/F: Of the basal ganglia components, the caudate is the most involved with cognitive functions.

Answer 3

TRUE

Question 4

Which basal ganglia structure travels just lateral to the lateral ventricle?

Answer 4

Caudate

Question 5

In a coronal section, put these in order from lateral to medial: putamen, globus pallidus, insula, thalamus.

Answer 5

1. Insula
2. Putamen
3. Globus pallidus
4. Thalamus

Question 6

What are the two parts of the substantia nigra?

Answer 6

1. Compact

2. Reticular

Question 7

The ______ part of the substantia nigra is a basal ganglia output nucleus.

Answer 7

Reticular

Question 8

The _______ part of the SN contains densely packed, pigmented neurons.

Answer 8

Compact

Question 9

A 50 year old man presents with chorea, muscle rigidity, and cognitive disturbances. A brain scan shows degeneration of the striatum. What is the disease?

Answer 9

Huntington’s Disease

Question 10

What are the four basic loops of the basal ganglia?

Answer 10

1. Motor loop: learned movements
2. Cognitive loop: motor intentions
3. Limbic loop: emotional aspects of movement
4. Oculomoter loop: voluntary saccades

Question 11

Which nucleus of the BG does the motor loop utilize?

Answer 11

Putamen

Question 12

Which nucleus of the BG does the cognitive loop use?

Answer 12

Caudate

Question 13

While learning a movement the _______ loop is used, once it is learned the _____ loop is used.

Answer 13

Cognitive; motor

Question 14

What parts of the BG are important in the oculomotor loop?

Answer 14

Caudate and Substantia nigra

Question 15

What is the major excitatory neuron in the direct pathway?

Answer 15

Glutamate (cerebral cortex and thalamus)

Question 16

What is the major inhibitory neuron in the direct pathway?

Answer 16

GABA (striatum and GPi)

Question 17

Describe the direct pathway of the motor loop in the BG.

Answer 17

Cerebral cortex excites striatum -> striatum inhibits GPi -> inhibited GPi now sends less inhibition to thalamus -> thalamus is more active in exciting cerebral cortex -> more movement

Question 18

What two pathways come together to form the thalamic fasciculus on the way to the thalamus?

Answer 18

Lenticular fasciculus and ansa lenticularis

Question 19

T/F: The direct pathway is used to move.

Answer 19

TRUE

Question 20

What are the added steps in the indirect pathway?

Answer 20

Striatum inhibits GPe -> inhibited GPe sends less inhibition to subthalamus -> subthalamus excites GPi -> GPi inhibits thalamus -> thalamus sends less excitation to cerebral cortex -> suppressed movement

Question 21

In the direct and indirect pathways, which structures are excitatory?

Answer 21

1. Cerebral cortex

2. Subthalamus 3. Thalamus

Question 22

In the direct and indirect pathways, which structures are inhibitory?

Answer 22

1. Striatum

2. GPi and GPe

Question 23

In the indirect pathway the ___ is inhibited, causing the ______ to excite the ___.

Answer 23

GPe; subthalamus; GPi

Results in more inhibition of thalamus and less movement

Question 24

What would damage to the subthalamus result in?

Answer 24

More unsuppressed cortical output

Question 25

What is the role of the subthalamus?

Answer 25

Uses disinhibition to suppress unwanted movement

Question 26

T/F: The direct and indirect pathways work simultaneously.

Answer 26

TRUE

Question 27

What causes parkinson's disease?

Answer 27

Degeneration of nigrostriatal fibers

Question 28

In a patient with parkinson's disease, _________ will be seen in the compact part of the substantia nigra.

Answer 28

Lewy bodies

Question 29

What are the three cardinal features of Parkinson's?

Answer 29

1. Bradykinesia (slow movement) 2. Resting tremor 3. Rigidity

Question 30

Which pathway is favored in a Parkinson's disease patient?

Answer 30

Indirect

Question 31

How does levadopa treat Parkinson's?

Answer 31

Replaces dopamine

Question 32

What is a pallidotomy?

Answer 32

Selectively damage the GPi so there is less inhibition on the thalamus