Physiology Department, S.U.N.Y. Health Science Center, Syracuse 13210, USA. The basal ganglia have long been regarded as contributing to the planning and execution of movement. In the past, output from the basal ganglia was thought to terminate in a single region of the thalamus, the ventrolateral nucleus (VL). This thalamic nucleus was believed to project exclusively on the primary motor cortex. According to this view, the function of basal ganglia loops with the cerebral cortex was to gather information from widespread regions of the cerebral cortex and funnel these signals into the motor system. It has become clear recently that the thalamic subdivisions that receive basal ganglia input gain access to wider regions of the frontal lobe than previously suspected.` Indeed, five parallel basal ganglia﷓thalamocortical loops have been proposed, each of which is focused on a particular region of frontal cortex. These loops would enable the output of the basal ganglia to influence skeletomotor, oculomotor, dorsolateral prefrontal, lateral orbitofrontal, and anterior cingulate regions of the cortex. The development of a new anatomical tracing technique, transneuronal virus transport, has allowed us to test some of these new concepts. In this chapter, we briefly present some of our recent anatomical results on the organization of the circuits that link the output of the basal ganglia with the frontal lobe. These findings have led us to propose a new scheme of organization for basal ganglia output from the internal segment of the globus pallidus (GPi); namely, that GPi contains multiple "output channels," each of which projects to a distinct cortical area in the frontal lobe. We will also present recent observations that indicate that this pattern of organization applies to the other output nucleus of the basal ganglia, the pars reticulata of the substantia nigra (SNpr). Finally, we will present some of our physiological observations that indicate individual output channels are concerned with different aspects of motor behavior.