Basal Ganglia

Question 0

Huntingtons: etiology

Answer 0

• Destruction of the D2 neurons in the striatum Results in Disinhibition of the GPe Inhibiting the subthalamic nucleus which decreases stimulation of the GPi Disinhibited and the thalamus
• hyperkinesia, choreaform gait, cognitive degeneration

Question 1

Basal ganglia: direct and indirect pathways

Answer 1

Direct: SNc -stimulates-> striatum (D1) -inhibits-> GPi/SNr -inhibits-> thalamus

• initiates movement (inhibiting the GPi disinhibits the thalamus)
  indirect: SNc -inhibits-> striatum (D2) -inhibits-> GPe -inhibits-> subthalamic nucleus -stimulates-> GPi -inhibits-> thalamus

Question 2

Parkinson’s: etiology

Answer 2

• Loss of substantia negra pars compacta dopaminergic neurons results in increased activity of GPi/SNr inhibiting the thalamus
• hypokinetic, mask, neurodegeneration

Question 3

Striatum function

Answer 3

Primary input to BG

• stimulates GPi/SNr (D1)
• inhibits GPe (D2)

Question 4

Internal capsule

Answer 4

Somatotopic organization: FALEE

- face (genu), arm and leg, (posterior), eye retrolenticular), ear (subleticular)

Question 5

T1/T2 MRI

Answer 5

CSF is intense on T2