Many brain regions flexibly adapt their representations to the current task, but little is known about how these representations support different aspects of complex decision making. I will present a series of human neuroimaging studies in which we studied the relation of task-dependent representations in orbitofrontal cortex, medial prefrontal cortex and hippocampus. Our results indicate that (a) OFC supports representations of partially observable task states and (b) mPFC is involved in representational changes that underlie self-initiated strategy changes. Furthermore, preliminary results hint at a role of the hippocampus in consolidating task state representations and forming a continuous decision making space. These findings shed light on how different aspects of a ‘decision space’ might be reflected in prefrontal and hippocampal representations.