Figure 4.

The parallel organization of functionally segregrated circuits linking the basal ganglia and cortex. The orbitofrontal cortex and basal ganglia are primary constituents of Lieberman’s automatic X-system associated with the skilled performance and expertise used in intuitive processes. The ventral semantic stream twists through the basal ganglia’s external capsule linking the posterior occipitotemporal cortex with the lateral prefrontal cortex associated with the reflective C-system. Specifically, the right anterior superior temporal gyrus is uniquely associated with insight and the caudate is associated with intuition. In this model the caudate nucleus provides the primary means by which these basal ganglia-dependent (green) and cortical systems (blue) can interact and effectively influence each other. Copyright © 1986. Alexander GE, DeLong MR, Strick PL. Parallel organization of functionally segregated circuits linking basal ganglia and cortex. Annu Rev Neurosci. 1986;9:357–381.