Pseudo Learning and Real Learning and its Contributions to the Posterior Frontomedian Cortex (pFMC)

The posterior frontomedian cortex (pFMC) was identified as being involved in decision conflict due to knowledge deficits (Volz et al., 2004a). The present study used functional magnetic resonance imaging (fMRI) to investigate if activation within the pFMC is reduced only by increasing knowledge (real learning, RL), or also by increasing the frequency of positive feedback without any gain in knowledge (pseudo learning, PL). In a simple forced-choice paradigm participants were naive about valid decision rules and asked to search for valid ones. In the RL condition participants were provided with valid feedback information, in contrast to the PL condition. Here, a pseudo learning effect was simulated by gradually increasing positive feedback according to a learning model that was derived from pilot data. Functional MRI data showed that both RL and PL in contrast to an absolute certain decision in a control task resulted in significant activation within the pFMC, the inferior frontal junction area, precuneus, intraparietal sulcus, and cerebellum. A significant increase in the BOLD response within the pFMC was also observed when directly contrasting pseudo learning trials with real learning trials, when contrasting negative feedback trials with positive feedback trials in the real learning condition, and when testing for the interaction learning task (PL, RL) by feedback quality (positive, negative). By employing a condition which controlled for feedback confidence, it was assured that differences in pFMC activation were not misleadingly attributed in this respect. Based on the present results, we suggest pFMC activation to reflect the subjective experience of uncertainty regardless of the objective feedback information. Moreover, we conclude that uncertainty in decision making is modulated by the experienced status of knowledge rather than by the amount of positive outcomes.