Fig. 2. HEP morphology and results.

a Grand average waveforms across the scalp time-locked to the onset of the R‐wave which is the biggest electrical wave generated during normal conduction (time 0 ms, see “Methods” section). The set of electrodes clustered by ROIs (colour‐coded) for the frontocentral and central-parietal electrodes are represented for further analyses (b–d) HEP waveforms across all trials following the onset of the R‐wave (at time 0 ms) are shown separately (averaged all HEPs after feedback). This is presented for positive and negative signed prediction errors (PEs) for the frontal cluster in (b); correct vs incorrect outcome in (c); and for high and low surprising outcomes (absolute PEs) in (d). The dotted line represents the difference between the conditions (represented in red and blue). The shaded areas represent the time windows where there is a significant difference between conditions (N = 32 participants) revealed by cluster‐based permutation analysis (two-sided).