Error-likelihood prediction in the medial frontal cortex: a critical evaluation

Abstract

A recent study has proposed that posterior regions of the medial frontal cortex (pMFC) learn to predict the likelihood of errors occurring in a given task context. A key prediction of the error-likelihood (EL) hypothesis is that the pMFC should exhibit enhanced activity to cues that are predictive of high compared with low error rates. We conducted 3 experiments, 2 using functional neuroimaging and 1 using event-related potentials, to test this prediction in human volunteers. The 3 experiments replicated previous research in showing clear evidence of increased pMFC activity associated with errors, conflict, negative feedback, and other aspects of task performance. However, none of the experiments yielded evidence for an effect of cue-signaled EL on pMFC activity or any indication that such an effect developed with learning. We conclude that although the EL hypothesis presents an elegant integrative account of pMFC function, it requires additional empirical support to remain tenable.

Figure 1

Example sequence of stimulus events in Experiment 1. See text for details about actual colors. “Fout” is Dutch for “error.” ITI = intertrial interval.

Figure 2

Results from Experiment 3. All graphs show data from electrode Cz. (A) Grand-average cue-locked ERP waveforms associated with high and low EL cues. The 2 dotted lines mark the time window to which summary measures and statistical analyses were constrained. (B) Average signal amplitude as a function of EL condition and time-on-task. (C) Grand-average ERP waveforms elicited by go signals preceded by high and low EL cues (go trials only). (D/E) Grand-average ERP waveforms associated with various trial types (unsuccessful change, successful change, go), presented separately for high and low EL trials. To construct the go-trial ERP, the EEG signals were aligned to the onset of a “virtual change signal”: the moment a change signal would have occurred if the trial were a change trial. The waveforms in (D) and (E) were low-pass filtered (<20 Hz) for presentation purposes only.