Basal Ganglia

Question 1

Describe the direct pathway

Answer 1

Question 2

Describe the indirect pathway

Answer 2

Question 3

Describe the role Snc plays in the direct and indirect pathways

Answer 3

Question 4

How does the BG loop influence down stream motor pathways?

Answer 4

Question 5

Describe the dopaminergic reward pathways for the striatium?

Answer 5

VTA: located in the interpedunclar fossa, dopamine input into the ventral striatuim for reward feeling e.g. drugs and food

SNc: dopamine input into the dorsal striatuim to initate movements predicted with reward –> reinforcement learning

Question 6

Describe the hyper direct pathway

Answer 6

Question 7

Describe basal ganglia disorders which affect the indirect pathway and which nuclei has been affected

Answer 7

• Chorea HDD
  
  • Involuntary rapid trunk and and limb movement
  • Degeneration of the striatuim
• Hemiballism
  
  • uncontrolable, rapid, ballistic movments of contralateral limbs (motion produced via proximal limb joints
  • Degeneration of the STN

Question 8

Describe parkinson’s disease and the treatment options

Answer 8

• Reduced activity of the direct and increased activity of the indirect pathway
• Depigmentation of the SNc = loss of dopamine
• Reduced voluntary movements = bradykinesia
• Treatment
  
  • STN lesion = increased involuntary movement (less thalmacortical inhibition)
  • GPi lesion
  • Or symptomatic treatment via dopamine drugs ect