The basal ganglia 

• The basal ganglia can either promote or inhibit movement, depending on the dopamine innervation of the striatum^1,2
• Normal movement is dependent on appropriate dopamine production by SNc neurons innervating the striatum^1,2
  • To facilitate this movement, the striatum receives dopaminergic motor input from the cortex 
  • The striatum sends this signal further, after modulation by the SNc (either excitatory as a result of dopamine D₁ receptor activation, or inhibitory, as a result of dopamine D₂ receptor activation) 
  • The signal is then sent through direct and indirect pathways to the GPi segment 

GPi=globus pallidus internus; SNc=substantia nigra pars compacta