The connections among the different components of the basal ganglia, the thalamus, and the frontal cortex in the rat are organized in a series of parallel circuits. The basic principle of a parallel organization of connections among the forebrain structures also holds for the rat. This chapter focuses on the organization of basal ganglia-thalamocortical circuits that involve different parts of the PFC (prefrontal cortex) and on the association of the midline and intralaminar thalamic nuclei and the amygdala with these circuits in the rat. The topographical organization in the corticostriatal, striatopallidal, pallidothalamic, and MD-PFC connections recognizes at least four circuits that involve cytoarchitectonically distinct areas of the PFC. The projections of individual nuclei of the nonspecific thalamic complex and of particular parts of the amygdala to the prefrontal cortical and striatal way stations of the principal circuits are in register with the parallel arrangement of these circuits. The principle of a parallel organization in the basal ganglia-thalamocortical circuit's cortex is diagrammatically represented in the chapter. A possible way of integrating certain aspects of different parallel circuits is through the dopaminergic system.