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Flashcards in Basal Ganglion Deck (75):
1

What 2 histologically similar structures make up the striatum?

- Caudate nucleus
- Putamen

2

What is the function of the striatum?

Motor control

3

What 2 structures make up the globus pallidus?

- Internal/ external globus palldius

4

What is the efferent limb of the basal ganglion?

Globus pallidus

5

What is the afferent limb of the basal ganglion?

Striatum

6

What structures make up the lenticular nucleus?

- Putamen
- Globus pallidus

7

What substance is produced in the substantia nigra?

Dopamine

8

What 2 structures make up the pedunculopontine tegmental nucleus?

- Pars compacta (PPPNc)
- Pars dissipata (PPPNd)

9

What neurotransmitter is utilized in the pars compacta?

Acetylcholine

10

What neurotransmitter is utilized in the pars dissipata?

Gluatamte

11

What functions does the peduncolopontine tegmental nucleus play?

Postural control and locomotion in the absence of dopamine

12

What does the ventral tegmental area synthesize?

Dopamine

13

What chemicals influence the ventral tegmental area? What receptors do they act on?

Endorphins act on opiate receptors

14

What structure does the ventral tegmental area's axons project to?

The Nucleus Accumbens

15

What 2 neurotransmitters are balanced by the nucleus accumbens? What is the function of each in the "reward circuit"?

Dopamine: Desire
Serotonin: Safety and inhibition

16

Which cortex acts as a relay in the reward circuit?

Prefrontal cortex

17

What is the function of the basal ganglion?

Smooths integration of emotions, thoughts, and physical movements

18

What is the "Action Selection Hypothesis"?

- Basal ganglion determines which of the potential actions generated by the cerebrum will be acted upon with dopamine acting as the reward system to influence future actions

19

What is the function of the direct pathway?

Promotes execution of correct execution and sequencing of motor command

20

What is the function of the indirect pathway?

Suppresses commands of movements opposing the correct movement, and turns down motor groups when it is not their turn in the sequence of events

21

Describe the direct pathway.

- Cortex facilitates the inhibitory neurons of the striatum
- Striatum inhibits the inhibitory neurons of the internal/ medial globus pallidus
- Thalamus disinhibited by striatums action of IGO
- Thalamus stimulates the motor cortex
- Motor cortex simulates contralateral lower motor neuron

22

What is the overall effect of the direct pathway?

Motor thalamus disinhibited, facilitating the motor cortex

23

How does the internal globus pallidus reach the VA-VL motor nuclei of the thalamus?

Via the Ansa lenticularis nad lenticular fasciculus

24

How does the motor cortex reach the lower motor neurons in the spinal cord?

Via the lateral corticospinal tract

25

Describe the indirect pathway.

- Cortex stimulates inhibitory neurons of the striatum
- Striatum inhibits the inhibitory neurons of the external globus pallidus
- Subthalamic nucleus is disinhibited by the striatum acting on the EGP
- Subthalamic nucleus facilitates the inhibitory neurons of the internal globus pallidus
- Internal globus pallidus inhibits the motor thalamus (via the ansa lenticulars and lenticular fasciculus
- Thalamus sends a decreased drive to the motor cortex and contralateral lower motor neuron

26

What neurotrasmitter facilitates most of the basal ganglion? What structure does not utilize this NT for facilitation?

- Glutamate
- Substantia nigra ultilizes dopamine

27

What neurotransmitter inhibits most of the basal ganglion? What connection has an added NT?

- GABA
- Striatum to globus pallidus utilizes Enkephalin

28

What connections int he direct pathways are tonically active?

- Subthalamus to internal globus pallidus
- Internal globus pallidus to thalamus

29

At what level of conciousness does the basal ganglion function?

Sub-voluntary/ automatic/ sub-concious

30

What 2 structures modulate pathways in the basal ganglion? What neurotransmitter is utilized by each?

- Substantia nigra (dopamine)
- Striatal interneurons (ACh)

31

How does the subtantia nigra modulate the basal ganglion?

- Facilitates direct pathway by increasing disinhibition of the thalamus through facilitation of striatum to IGP
- Inhibits indirect pathway by inhibiting the subthalamus through the EGP

32

How do the striatal interneurons modulate the basal ganglion?

- Pedunculopontine tegmental nuclei of midbrain activate ACh receptors in striatum
- Inhibits direct pathway by disinhibiting the IGP, which then inhibits the motor thalamus
- Facilitates the indirect pathway by increasing disinhibition of the subthalamus through facilitation of the EGP

33

What artery supplies the lenticular nucleus, striatum and internal capsule?

- Lateral lenticular striate artery branches of middle cerebral artery

34

What arteries supply the caudate nucleus?

- Anterior cerebral
- Medial striate arteries

35

What are the 5 parallel loops of the basal ganglion?

- Motor
- Cognitive
- Limbic
- Occulomotor
- Associative

36

Describe the 5 step motor loop.

- Somatosensory/ primary motor/ pre-motor cortex
- Putamen
- Substantia nigra/ IGP
- VA-VL of thalamus
- Supplemental motor area, premotor, primary motor

37

Describe the 5 step limbic loop.

- Medial and lateral temporal lobe, hippocampal formation
- Striatum
- Pallidum, IGP, SN
- MD, VA of thalamus
- Anterior cingulate, orbital frontal cortex

38

Describe the 5 step occulomotor loop.

- Posterior parietal, prefrontal
- Caudate
- Substantia nigra, IGP
- VA, MD of thalamus
- Frontal eye field, supplementary eye field

39

Describe the 5 step associative loop.

- Posterior parietal, premotor
- Caudate
- SN and IGP
- VA, MD of thalamus
- Prefrontal

40

What are 3 diseases of the caudate nucleus?

- Abulia
- Chorea
- Tourette syndrome

41

What pathway is affected by chorea?

Indirect pathway (at striatum to external globus pallidus)

42

How will an individual present with chorea?

- Random, uncontrolled jerking of trunk ,extremities and head
- Facial grimacing

43

What neurotransmitter can help turn the indirect pathway "back on" in Chorea?

- Acetylcholine

44

What structure in addition to the Caudate nucleus is affected in Tourette Syndrome?

Lenticular nuclei

45

What loop is affected by Tourette Syndrome?

Limbic loop (inhibitory limbic system acts on motor cortex) (motor striatum generates tics)

46

What 2 pathologies affects the Putamen?

- Dystonia
- Athetosis

47

What is dystonia?

Slow, twisting, involuntary contorting movement that is sustained and repreated

48

What other pathology is associated with Athetosis?

Cerebral Palsy

49

What is the main symptom of Athetosis?

Slow worm-like movements of distal limbs/ fingers

50

What pathalogy is associated with the Subthalamus?

Ballism

51

What is the major symptom of Ballism?

- Quick continuous flinging of the limbs

52

What pathology is associated with the Substantia Nigra?

Parkinsonism

53

How are the pathways affected by the Subtantia Nigras lack of dopamine cells in Parkinsonism?

- Decreased direct pathway
- Increased indirect pathway

54

How will passive movement through the joint be affected by Parkinsonism?

- Rigidity through the entire joint range

55

What is Palilalia (associated with Parkinsonism)?

Stuttering

56

What is Hypophonia (associated with Parkinsonism)?

Soft speech

57

What is Bradyphrenia (associated with Parkinsonism)?

Slow thinking

58

What is Retropulsoin (associated with Parkinsonism)?

Repetition of motor acts

59

What is the frequency of Parkinsonism tremors?

3 - 6 Hz

60

How are hyperkinetic disorders treated?

- Raising ACh
- Lowering Dopamine

61

Identify the basal ganglion and cerebellum as either excitatory or inhibitory.

Basal ganglion: Inhibitory
Cerebellum: Excitatory

62

Does the BG or Cerebellum affect cognitive and motivational aspects of movement?

BG

63

Is the BG or Cerebellum capable of learning?

Cerebellum

64

Does the BG or Cerebellum permit smooth progression from one movement to the next?

Cerebellum

65

Does the BG or Cerebellum optimize patterns of muscle activation so that the desired goal is achied in the most efficient way?

BG

66

Does the BG or Cerebellum perform a gating function?

BG

67

Is the BG or Cerebeluum involved with force, frequency, load, velocity, and movement direction?

Cerebellum

68

Does the BG or Cerebellum prepare for movement (targeting location in space, directing movement and muscle pattern)?

BG

69

Does the BG or Cerebellum activate during memorize motor tasks and therefore contribute to the automatic execution of a learned motor plan?

BG

70

Does the BG or Cerebellum aide in visual tracking?

Cerebellum

71

Does the BG or Cerebellum help predict movement occurring outside the body?

Cerebellum

72

Does the BG or Cerebellum suppress unwanted movement?

BG

73

Does the BG or Cerebellum affect muscle tone and participate in generation, switching and termination of movement as dictated by situational demands and emotional or attentive states?

BG

74

Does the BG or Cerebellum deal with cognitive and motivational aspects of movement?

BG

75

Does the BG or Cerebellum work at an unconcious level?

Both do