Why am I unsure? Internal and external attributions of uncertainty dissociated by fMRI

Behavioral evidence suggests that the perceived reason of uncertainty causes different coping strategies to be implemented, particularly frequency ratings with externally attributed uncertainty and memory search with internally attributed uncertainty. We used functional magnetic resonance imaging (fMRI) to investigate whether processes related to these different attributions of uncertainty differ also in their neural substrates. Participants had to predict events that were uncertain due to internal factors, that is, insufficient knowledge. Data were compared with a preceding study in which event prediction was uncertain due to external factors, that is, event probabilities. Parametric analyses revealed the posterior frontomedian cortex, that is, mesial Brodmann Area 8 (BA 8) as the common cortical substrate mediating processes related to uncertainty no matter what the cause of uncertainty. However, processes related to the two differently attributed types of uncertainty differed significantly in relation to the brain network that was coactivated. Only processes related to internally attributed uncertainty elicited activation within the mid-dorsolateral and posterior parietal areas known to underlie working memory (WM) functions. Together, findings from both experiments suggest that there is a common cerebral correlate for uncertain predictions but different correlates for coping strategies of uncertainty. Concluding, BA 8 reflects that we are uncertain, coactivated networks what we do to resolve uncertainty. (C) 2004 Elsevier Inc. All rights reserved.