Variants of uncertainty in decision-making and their neural correlates.

When leaving the tidy world of rules and people start judging probabilities on an intuitive basis, it revealed that they have some intuitions to choose from. One could refer to them as a family of subjective probability concepts or following Kahneman and Tversky, as variants of uncertainty. The authors distinguished between external and internal attributions of uncertainty and could show that the perceived reason of uncertainty determines the selected coping strategy. To investigate whether variants of uncertainty can also be distinguished on the cerebral level, two functional magnetic resonance imaging studies were conducted. Participants had to predict events (abstract visual stimuli) under parametrically varying degrees of (un-)certainty. In the first experiment, uncertainty was induced by the manipulation of event probability (externally attributed uncertainty). In the second experiment, uncertainty depended on participants' knowledge of valid rules of event occurrence, as trained before the experimental session (internally attributed uncertainty). As a result, parametric analyses revealed that activation within the posterior fronto-median cortex, particularly within mesial Brodmann area (BA) 8, increased with increasing uncertainty, no matter for which reason uncertainty emerged. Furthermore, it was found that different variants of uncertainty entailing different coping strategies can be dissociated due to additionally activated networks. Concluding, increasing activation within mesial BA 8 reflects that we are uncertain, additional networks what we do to resolve uncertainty in order to achieve future rewards. Hence, the phenomenological distinction between processes related to externally and internally attributed uncertainty is paralleled on the cerebral level.