Fig. 1.

Diagram for the connections of the neuronal structures considered in the BG-thalamo-cortical model. The proposed model integrates the direct, indirect and hyperdirect pathways of the BG, in addition to some internal regulatory connections. The figure highlights the dominant activation of the direct (light red) and indirect (blue) pathways of the basal ganglia. The direct pathway is dominant if the level of dopamine is high enough. On the contrary, if the dopamine level is reduced, the indirect pathway is dominant. The inhibitory populations are in dark grey and the excitatory populations are in light grey. The connections with circles are inhibitory, the sparks show excitatory connections and the triangles show the modulatory effect of the dopamine input. The dashed lines represent a reduced signal flow as a consequence of the dopamine regulation. (Color figure online)