Prefrontal and anterior cingulate cortex is important in learning and decision making but it does not carry out these roles in isolation but as a result of interactions with other subcortical and cortical brain regions. In order to elucidate the mechanisms of learning and decision making it is necessary not just to record activity in these areas but to examine the impact of manipulating activity on behaviour and the impact of manipulating activity in one area on the activity recorded elsewhere in the circuit. Such studies have begun to construct a picture of the interactions between prefrontal and cingulate brain regions and areas such as the basal forebrain, amygdala, and hippocampus that are central to learning and decision making.