11a: Basal Ganglia

Question 1

Which structure of the basal ganglia is the oldest?

Answer 1

Amygdala

Question 2

The striatum are (X) structures interconnected. They’re also interconnected with which other structures? These are essential for proper functioning of:

Answer 2

X = caudate and putamen

1. GP
2. SN
3. Subthalamic nuclei

Voluntary motor systems

Question 3

The basal ganglia give rise to (X) descending tract(s), innervating LMN.

Answer 3

NONE

Question 4

The basal ganglia give rise to (X) descending tract(s), innervating CN.

Answer 4

NONE

Question 5

Which structure of basal ganglia is most recently developed?

Answer 5

Striatum (aka “neostriatum”)

Question 6

Afferents to the striatum arise mainly from layer (X) neurons.

Answer 6

X = Layer 5

Question 7

Prefrontal cortices terminate in (putamen/caudate).

Answer 7

Caudate

Question 8

Temporal and parietal association areas terminate in (putamen/caudate).

Answer 8

Caudate

Question 9

Motor cortices terminate in (putamen/caudate).

Answer 9

Putamen

Question 10

Somatosensory cortices terminate in (putamen/caudate).

Answer 10

Putamen

Question 11

(Caudate/putamen) sends inhibitory efferents to (external/internal) segments of GP. Which NT used at the synapse?

Answer 11

Both; Both

GABA

Question 12

The pallidum is another name for:

Answer 12

GP

Question 13

The “lentiform nucleus” is made up of:

Answer 13

Pallidum and putamen

Question 14

GP external segment sends (excitatory/inhibitory) projections to (X). Which NT is used?

Answer 14

Inhibitory (GABA);

X = Subthalamic nucleus

Question 15

GP internal segment sends (excitatory/inhibitory) projections to (X). Which NT is used?

Answer 15

Inhibitory (GABA);

X = VA/VL Thalamus

Question 16

(X) structure as actually part of pallidum, but was separated by the cerebral peduncle. Like (external/internal) GP, it receives (excitatory/inhibitory) afferents from (Y) and sends (excitatory/inhibitory) efferents to (Z).

Answer 16

X = SN (pars reticulata)
Internal;
Inhibitory; Y = striatum
Inhibitory; Z = thalamus

Question 17

The (internal/external) segment of pallidum sends efferents to thalamus via which white-matter tracts? Star the one that penetrates (X).

Answer 17

Internal;
X = internal capsule

1. Lenticular fasciculus*
2. Ansa lenticularis

Question 18

Cerebellar input to (X) of thalamus, specifically from (Y) nucleus, (mirrors/contrasts) that of the pallidum.

Answer 18

X = VA/VL;
Y = dentate
Contrasts (is excitatory)

Question 19

SNpc is (identical/different) from SNpr. It’s composed of (GABA/glutamin/dopamin)-ergic neurons. It receives (excitatory/inhibitory) in put from (X) and sends its efferents to (Y).

Answer 19

Different;
Dopaminergic;
Excitatory 
X = cerebral cortex;
Y = striatum

Question 20

Dopamine released by SN(pr/pc) has which effect on the targeted (X) structure?

Answer 20

SNpc;
X = striatum

1. Excitatory if D1 receptor
2. Inhibitory if D2 receptor

Question 21

The subthalamic nucleus is located in the (telencephalon/diencephalon/midbrain) and is reciprocally connected with (X). It receives (excitatory/inhibitory) input from (X) and projects (excitatory/inhibitory) output to (Y).

Answer 21

Diencephalon;
X = GP
Inhibitory from external X = GP
Excitatory;
Y = internal GP

Question 22

Overall, activation of subthalamic nucleus via (increase/decrease) GP(i/e) output has (excitatory/inhibitory) control over thalamus.

Answer 22

Decrease
GPe
Inhibitory (since subthalamic nucleus excites GP internal, which inhibits thalamus)

Question 23

Overall, (activation/inhibition) of subthalamic nucleus via cortex has (excitatory/inhibitory) control over thalamus.

Answer 23

Activation;

Inhibitory (since subthalamic nucleus excites GP internal, which inhibits thalamus)

Question 24

Overall, activation of subthalamic nucleus has (excitatory/inhibitory) control over cortex.

Answer 24

Inhibitory

Question 25

List the components of the "direct path" of motor control via the basal ganglia. Put +/- following each component to indicate whether it's sending excitatory/inhibitory efferents.

Answer 25

1. Cortex (+) 2. Striatum (-) 3. GP/SNpr (-) 4. VA/VL (+) 5. Cortex

Question 26

The "direct path" of motor control via basal ganglia has net (excitatory/inhibitory) effect.

Answer 26

Excitatory (on select motor programs)

Question 27

List the components of the "indirect path" of motor control via the basal ganglia. Put +/- following each component to indicate whether it's sending excitatory/inhibitory efferents.

Answer 27

1. Cortex (+) 2. Straitum (-) 3. GP external (-) 4. Subthalamic nucleus (+) 5. GP internal (-) 6. VA/VL (+) 7. Cortex

Question 28

The basal ganglia are located in (telen/dien/mesen)-cephalon.

Answer 28

Specific BG nuclei found in all three

Question 29

List the key nuclei of the basal ganglia. Put "T", "D", or "M" next to each, depending on if it's in telen/dien/mesen-cephalon.

Answer 29

1. Striatum - Caudate, Putamen (T) 2. Pallidum (T) 3. Subthalamic nucleus (D) 4. Substantia Nigra (M)

Question 30

Direct pathway neurons in (X) structure have (D1/D2) dopamine receptors, which (hyper/de)-polarize the cell in response to dopamine.

Answer 30

X = striatum; D1 Depolarize

Question 31

Indirect pathway neurons in (X) structure have (D1/D2) dopamine receptors, which (hyper/de)-polarize the cell in response to dopamine.

Answer 31

X = striatum; D2 Hyperpolarize

Question 32

The nigrostriatal pathway, aka (X) sending efferent signals to (Y), has the dual effect of :

Answer 32

``` X = SNpc Y = striatum ``` 1. Exciting direct (stimulatory) pathway 2. Inhibiting indirect (inhibitory) pathway

Question 33

Excitation of the nigrostriatal pathway has the net effect of (exciting/inhibiting) cortex.

Answer 33

Exciting

Question 34

Which pathway is compromised in Parkinson's disease?

Answer 34

Nigrostriatal (SNpc to striatum)

Question 35

Hemiballismus is caused by (unilateral/bilateral) destruction of (X). What does the condition present as?

Answer 35

Unilateral; X = subthalamic nucleus; Involuntary/irregular flinging of contralateral extremity

Question 36

Huntington's Disease is caused by early degeneration of (X). What does the condition present as?

Answer 36

X = striatum; Involuntary, writhing movements

Question 37

What are the three cardinal symptoms of Parkinson's?

Answer 37

1. Bradykinesia 2. Rigidity 3. Tremor

Question 38

What are the symptoms of Dopamine excess in PD treatment?

Answer 38

1. Dyskinesias (involuntary discoordinated movement) 2. Dystonia (involuntary abnormal postures) 3. Delusions/hallucinations/misperceptions

Question 39

One FDA approved treatment for PD is (uni/bi)-lateral stimulation of (X) structure. This (raises/lowers) its firing rate.

Answer 39

Bilateral; X = subthalamic nucleus; Lowers (thus decreasing GPi activation)