When goals are missed: Dealing with self-generated and externally induced failure

The posterior medial frontal cortex (pMFC) has been consistently implicated in performance monitoring. It is assumed to signal the need for adjustments whenever the outcome of an action is worse than intended. Up to now, monitoring of self-generated errors has been in the focus of research. In everyday life, however, also external reasons such as machine malfunction may cause that an action goal is missed, such that compensatory actions are needed. Using functional magnetic resonance imaging (fMRI) we tested whether the pMFC is engaged not only by self-generated errors but also by failure to achieve the goal resulting from external reasons and whether performance monitoring activity differs between the two conditions. In a modified flanker task yielding sufficient numbers of self-generated errors technical malfunctions were simulated on a subset of correct trials. Malfunctions and errors led to equal fMRI signal increases in the pMFC. The activity time course differed, however; in malfunctions the maximum occurred later than in errors. Moreover, pMFC activity was stronger with increasing time needed for actions compensating the failure to achieve the action goal in the first place. The results suggest that its activity increases when selection of the compensatory action turns out to be more ambiguous and demanding. Thus, no matter of whether adjustments are needed as a result of a self-generated error or external factors, the pMFC plays a prominent role in initiating compensatory actions and in the selection of the appropriate compensation.