Exam #2: Basal Ganglia Flashcards Preview

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Flashcards in Exam #2: Basal Ganglia Deck (49):
1

What are the two general functions of the basal ganglia?

1) Inhibition of involuntary movements at rest
2) Starting & stopping voluntary movements

2

Specifically, what movements does the basal ganglia inhibit?

- Tremors
- Chorea
- Tics

3

Specifically, what voluntary movements does the basal ganglia facilitate?

- Initiating movement
- Maintaining normal speed of movement
- Stopping movement

4

What are the five major nuceli that compose the basal ganglia?

1) Caudate nucleus
2) Putamen
3) Globus Pallidus
4) Subthalamic Nucleus
5) Substantia nigra

5

What are the two components of the "Lentiform Nucleus?"

- Putamen
- Globus Pallidus

*Note that Lentiform= "Lens-shaped" i.e. appearance on cross-section

6

What are the components of the "Corpus Striatum?'

- Caudate Nucleus
- Putamen
- Globus Pallidus (or pallidum)

7

What is the striatum?

- Putamen
- Caudate nucleus

****vs. Corpus Striatum that contains that Globus Pallidus as well

8

What is the Pallidum?

This is another name for the Globus Pallidus

9

What white matter tract runs between the lentiform & caudate?

Internal capsule

10

Where is the caudate in reference to the lateral ventricle?

Inferior and lateral

11

What is the striatum? What are the three major inputs to the striatum?

- Putamen & caudate nucleus

1) Cortex
2) Thalamus
3) Substantia nigra

12

What are the corticostriate fibers?

Input fibers from cortex to the striatum

13

What are the thalamostriate fibers?

Input fibers from the thalamus to the striatum

14

What are the nigrostriate fibers?

Input fibers from the SN to the striatum

15

What are the dopaminergic neurons from the SN primarily associated with behaviorly?

Movement

16

What does the loss of DA neurons in the SN result in, in PD?

Inability to INHIBIT unwanted movements

17

What is the two major outputs from the striatum?

Output from the Striatum is funneled to the:
1) GLOBUS PALLIDUS via striatopallidal fibers
2) SUBSTANTIA NIGRA via straitonigral fibers going to the SN

18

What are the two major inputs to the pallidum?

1) STRIATUM via the striatopallidal fibers
2) SUBTHALAMIC NUCLEUS via the subthalamaic fasiculus

19

What is the major output from the pallidum?

1) THALAMUS via pallidothalmic fibers
2) SUBTHALAMUS via pallidosubthalamic fibers i.e. the subthalamic fasiculus

20

What are the major divisions of the Pallidothalamic fibers? Where are they going?

1) LENTICULAR FASICULUS
2) ANSA LENTICULARIS

****BOTH are going to the THALAMUS

21

What nuclei are the Pallidothalamic fibers traveling to in the thalamus?

1) VENTRAL ANTERIOR nuclei of the THALAMUS
2) VENTRAL LATERAL nuclei of the THALAMUS

VA/VL--these are the motor nuclei of the thalamus

22

Draw the motor loop of the basal ganglia. What is the purpose of this loop?

Information relayed from basal ganglia to motor cortical areas

Cortex
- Supplementary motor cortex*
- Somatosensory cortex
- Primary motor cortex
- Premotor cortex

Striatum
Pallidum
Thalamus

23

Draw the association loop of the basal ganglia. What is the purpose of this loop?

Planning & direction of movement

Cortex
- Prefrontal cortex= decision making*
- Premotor cortex
- Posterior parietal cortex

Striatum
Pallidum
Thalamus

24

Draw the Oculomotor loop of the basal ganglia. What is the purpose of this loop?

Integration of eye movements & visual guidance

Cortex
- Frontal eye field*
- Prefrontal cortex
- Posterior parietal cortex

Striatum-->Superior colliculus
Pallidum
Thalamus

25

Draw the limbic loop of the basal ganglia. What is the purpose of this loop?

Emotional & motivational influences on movements

Cortex
- Anterior cingulate gyrus*
- Orbitofrontal cortex*
- Hippocampus
- Amygdala
- Entorhinal area

Striatum= specifically, the Nucleus Accumbens
Pallidum
Thalamus

26

Where do the "closed" loops go back to?

Cortex

27

What is the general function of the primary motor cortex?

Execution

28

What is the general function of the premotor cortex?

Orientation

29

What is the general function of the PFC?

Planning movement

30

What is the general function of the posterior parietal cortex?

Visual guidance

31

What is the general function of the frontal eye field?

Visual tracking

32

What is the general function of the superior colliculus?

Visual reflexes

33

What is the general function of the inferior colliculus?

Auditory reflexes

34

What is the general function of the amygdala?

Emotion

35

What is the general function of the entorhinal area?

Olfactory information

36

What is the nucleus accumbens?

This is a subnucleus of the striatum that processes the emotional aspects of movement

37

Where is the nucleus accumebens on cross-section?

Area where the caudate & putamen come together--anterior

38

Is the pallidum excitatory or inhibitory?

Inhibitory

39

Is the thalamus excitatory or inhibitory?

Excitatory

40

What is the general function of the indirect pathway?

Increased inhibition & suppression of inappropriate movements

41

What is the general function of the direct pathway?

Excitation of the cortex via disinhibition of the thalamus--allows voluntary movements

42

Define dyskinesia.

Unintentional, disorderly, & purposeless movements

43

Define athetosis.

Condition in which the individual displays slow, vermicular or "worm-like" involuntary movements

44

Define hemiballismus.

Condition of involuntary ballistic or striking movements on one side of the body

45

Define bradykinesia.

Slowness in the execution of movement

46

Define chorea.

Sequence of rapid, jerky, & somewhat agile flowing movements of the hands, feet, tongue, & facial muscles

47

What are the current diagnostic criteria for Tourette's Syndrome?

A. Both multiple motor and one or more vocal tics have been present at some time during the illness, although not necessarily concurrently.

B. The tics may wax and wane in frequency but have persisted for more than 1 year since first tic onset.

C. Onset is before age 18 years.

D. The disturbance is not attributable to the physiological effects of a substance (e.g., cocaine) or another medical condition (e.g., Huntington’s disease, postviral encephalitis).

48

In Huntington's Disease, neurons of what "loop (direct vs. indirect) degenerate?

Indirect

49

In Huntington's Disease, specifically what neurons degenerate?

Striatal GABAergic neurons, which results in a loss of GABA inhibitory influence via the striatonigral pathway