When doing nothing is an option: the neural correlates of deciding whether to act or not.

The neural basis of intentionally deciding between different response alternatives has been extensively investigated and associated with the rostral cingulate zone (RCZ). However, from daily experience we know that the decision whether to do something is often prior to the decision what to do. This raises the fundamental question whether the decision to act and the decision not to act can be considered as functionally equivalent. Interestingly, in the legal domain such an equivalence is implicitly assumed by punishing crimes of omission. The aim of the current study was to explicitly test this assumption by comparing the neural representation of intentional actions with intentional non-actions. Our results suggest, that weighing whether to act or not involves similar areas of the brain, namely RCZ and dorsolateral prefrontal cortex, independent of the outcome of this decision. This finding strongly supports the assumption that intentionally not acting can be considered as a mode of action.