Realizing one has missed an opportunity can influence decision behavior in the future, such that a large missed opportunity leads to more risk taking in the next round. To investigate the neuronal mechanism of this phenomenon we used functional magnetic resonance imaging (fMRI) in combination with a sequential decision task in which the magnitude of possible gains linearly increased, but at the same time the gain probability decreased. After subjects decided to stop a trial and to collect the gains, not only the chosen option (actual outcome), but also the alternative option (maximum possible gain in this round) was revealed. Our data show that a missed chance influenced volunteers' decision behavior: volunteers took more risk after rounds in which they had missed a large opportunity. This was paralleled by signal changes in a lateral area of the ventral striatum that scaled with the difference between what could have been gained and what was actually gained in this round. In addition, after gains signal changes in dopaminoceptive structures including the midbrain and ventral striatum together with the insula predicted individual choice behavior in the subsequent round. Thus, our data provide a neural mechanism for how missed opportunities influence future decisions.
