Abstract
Human subjects often rely on evaluative feedback to gauge their actions. There is a wealth of studies about the neurophysiolgy of this complex mental process, with some of them emphasizing the prominant role of reward, while others contend that expectancy is probably the main ingredient that guide it. In different studies, we have harnessed EEG in human subjects to determine the specific contribution of reward, expectancy and motivation to evaluative feedback processing. Results show that event-related brain potentials (ERPs) and frontal midline Theta (FMT) can capture different effects during this process. More specifically, standard ERP components such as the feedback related negativity reflect the rapid and phasic integration of reward with expectancy following feedback onset, whereas FMT power seems to covary with a higher-level and non-overlapping change in motivation that depends on the current affective state of the participants. As such, these results dovetail with the assumption that different neurophysiological signals likely underpin evaluative feedback processing, each of them contributing to a specific facet of it, and making of it a rather efficient but flexible ability.