Basal Ganglia Circuit

Direct vs. indirect pathway control of movement — dopamine shifts the balance

Dopamine Level (SNc output)

Dopamine: Normal (50%)

→Excitatory (glutamate)

⊣Inhibitory (GABA)

Dopamine (D1/D2)

Normal dopamine: Direct pathway (D1 receptors) and indirect pathway (D2 receptors) are balanced. Thalamus is partly disinhibited → normal voluntary movement possible.