Figure 2: Classic model of basal ganglia in normal condition, parkinsonian, and dyskinetic conditions. During LID the different population of striatal cells from direct and indirect circuit are opposite to parkinsonian state. LID would result from a decrease in the inhibitory pathway by striatal neurons in the indirect pathway to the GPe, leading to an inhibitory increment over the STN and consequently reducing STN and GPi/SNr activity. This is facilitated by the increase in the inhibitory striatal activity of GPi by the direct pathway from striatum.