2015) . These networks interface with the large thalamic network via thalamo-striatal projections. The overall loop of the cortico-basal ganglia-cortical (C-BG-C) system can be separated into numerous subcircuits based on anatomical and functional divisions (Alexander and Crutcher 1990). The best known among these are circuits in which neocortical structures, mesocortical structures (e.g. cingulate and piriform cortices) and allocortical regions (e.g. hippocampus and amygdala) project to well-known dorsal and ventral striatal regions, with processing/feedback loop networks influencing those cortical regions. However, the C-BG-C loop type networks are also maintained within the olfactory system where olfactory bulb and cortical inputs converge in the olfactory tubercle. The extended amygdala also has a C-BG-like network, with the lateral and basolateral amygdala serving as the cortical substrates, and the CeA and other downstream structures having features in common with the striatum (Swanson and Petrovich 1998). Cross-talk between the different C-BG-C networks also occurs at several levels throughout the cortex, BG and midbrain.
