Basal Ganglia

Question 1

3 Roles of Basal Ganglia

Answer 1

1. Planning & initiation of movement
2. Regulation of muscle tone & movement
3. Regulate CC activity through feedback loops

Question 2

Inhibitory NT

Answer 2

Dopamine

Question 3

Excitatory NT

Answer 3

Glutamate

Question 4

Major Input

Answer 4

CC

Question 5

Major Output

Answer 5

Tophographical output back to cortex

Question 6

Extrapyrimidal

Answer 6

Diverse interconnect brain locations

Question 7

Dysinhibition

Answer 7

Excitation by inhibition of an inhibitory segment

Question 8

Name 5 components of BG

Answer 8

1. Striatum
2. Globus Pallidus
3. Substantia nigra
4. Clasustrum
5. Lentiform Nucleus

Question 9

Parts of striatum

Answer 9

Caudate nuclei
Putamen nuclei
Medium spiny neurons

Question 10

Parts of Globus Pallidus (G.P.)

Answer 10

Medial or Internal Division

Lateral or External Division

Question 11

Parts of substantia nigra

Which part is similar to G.P.

Answer 11

Pars reticulate - similar to GP

Pars Compacta

Question 12

Where is the claustrum located & what is its role?

Answer 12

Between putamen & insular cortex

Receives input from and sends output to sensory cortices

Question 13

What are the parts of the lentiform nucleus

Answer 13

Globus pallidus & putamen

Question 14

Role of Direct Pathway

Answer 14

Selective of specific movements

Question 15

5 steps in Direct Pathway

Answer 15

1. Excitiatory input from CC and\or Substantia nigra pars compacta (D1 receptor)
2. Excites inhibitory Striatum
3. Straitum sends inhibitory signals to inhibitory GP
4. Inhibited GP sends fewer inhibitory signals Thalamus (VA\VL nucleus)
5. Thalamus (under less inhibition) send more excitatory signals to Frontal or Premotor Cortex

Question 16

Role of Indirect Pathway

Answer 16

Provides Background Inhibition

Question 17

7 steps of indirect pathway

Answer 17

1. Excitatory inputs from CC & INHIBITORY input from S. N. P. C (D2 receptors)
2. Less activation of the inhibitory Striatum
3. Less inhibition of inhibitory G. P. Ecternal
4. More inhibition of inhibitory subthalamic nucleus
5. Less inhibition of inhibitory GP internal
6. More inhibition to Thalamus VA\VL segment
7. Decreased output to premotor/frontal cortex

Question 18

Overactive Indirect Pathway

Answer 18

Extreme lack of movement (Parkinson’s)

Question 19

Overactive Direct Pathway

Answer 19

More movement

Question 20

Motor Loops (5 steps)

Answer 20

1. Pre-motor, motor & somatosensory
2. Striatum putamen
3. Globus Pallidus (lateral & internal)
4. Thalamus (VA\VL)
5. Cortex (and back to top)

Question 21

Oculomotor Loop

Answer 21

1. Posterior parietal + prefrontal cortex
2. Straiatum caudate
3. Globus pallidus (internal)
4. Thalamus (Mediodorsal + ventral nuclei)
5. Cortex

OR

1. Posterior parietal + prefrontal cortex
2. Straitum caudate
3. Substantia Nigra Pars Compacta
4. Superior colliculus
5. Thalamus (Mediodorsal & ventral nuclei)
6. Cortex

Question 22

Prefrontal Loop (5 steps)

Answer 22

1. Dorsolateral Prefrontal Cortex (Excutative function)
2. Anterior Straitum Caudate
3. Globus Palatdus + S.N.P.R
4. Thalamus (Mediodorsal & ventral anterior nuclei)
5. Cortex

Question 23

Limbic Loop (5 steps)

Answer 23

1. Anterior cingulate + orbital frontal cortex
2. Amygdala, hioppocampus, orbitofrontal, anterior cingulate cortex & temporal cortex
3. Ventral striatum
4. Thalamus (mediodoral nucleus)
5. Cortex (mesolimbic system)

Question 24

Four characteristics decribing connectivity

Answer 24

1. Segregated loops for primary, associational motor areas
2. Somatotropic organization of basal ganaglia
3. Parrales circyts
4. Increased cobnvergance = integration

Question 25

Symptoms of Parkinsons

Answer 25

Bradykinesia Rigidity Tremor at rest

Question 26

Pathophysiology of Parkinsons

Answer 26

Low dopamine for S.N.P.C = reduced direct pathway | Decreases inhibitory inbut to subthalamic nucleus

Question 27

Name 2 pharaotherapeutic treatment options

Answer 27

Levodopa | Amantadine

Question 28

How does levodopa\L-dopa work?

Answer 28

Increases D1 and D2 in striatum so increases Dopamine | Precurssor of dopamine and crosses blood\brain barrier

Question 29

How does amantadine work?

Answer 29

Dopamine agonist Increases activity from inhibitory subthalmic nucleus GP internal inhibited more so it inhibits the thalamus less More movement

Question 30

Name 2 surgical interventions

Answer 30

1. Pallidoctomy | 2. Deep Brain Stimulation

Question 31

What is the target of pallicoctomy

Answer 31

Medial globus pallidus

Question 32

What is the target of DBS

Answer 32

Subthalmic nucleus | Globus Pallidus Internus (direct pathway)

Question 33

What is gene therapy role

Answer 33

Increase GABA levels to increase inhibition of subthalamic nucleus

Question 34

2 symptoms of Hungtington's disease

Answer 34

1. Chorea | 2. Quick, jerky, randon & involuntary movement

Question 35

Pathophysiology

Answer 35

1. Excess of dopamine | 2. Striatal degeneration

Question 36

What is athetosis? What is damaged?

Answer 36

Slow writhering, snake like movement (striatum injury)

Question 37

What is dystonia? What is damaged?

Answer 37

Twisting of limbs, trunkor neck | Basal Ganglia injury

Question 38

What is hemiballism? What is damaged?

Answer 38

Twisting frequent movements of limbs | Subthalamic nucleus injury