One overarching view of the C-BG-C circuits is that they form a sophisticated brain network for action control (Jin and Costa 2015, O'Doherty 2016). This idea encompasses all facets of action learning, including the association of unconditioned actions with new environmental events, the learning of new actions under the control of the internal and external context combined with outcomes produced by these actions, the cognitive components of action planning and selection, and many aspects of the performance of the actions themselves. By integrating information from a vast array of forebrain, midbrain and hindbrain sources, the mammalian C-BG-C circuits allow organisms to modify and extend their behavior repertoire to maximize the likelihood of survival and reproduction. Unfortunately, drugs of abuse and certain predispositions to excessive drug use can divert these circuits to behaviors that are maladaptive with respect to the normal goals of the organism. We will consider in-depth how ethanol interacts with C-BG-C circuits to produce these unfortunate consequences.
