Independent Component Analysis Reveals the Unity of Cognitive Control

In reaction time tasks, when subjects commit an error, a negative wave peaking approximately 50-100 ms after the erroneous response is recorded with EEG. This negativity, called “Error (Related) Negativity” (Ne or ERN[1, 2]), is maximal fronto-centrally, above the Anterior Cingulate Cortex and/or Supplementary Motor Area and was first interpreted as reflecting an error detection mechanism. However, after Laplacian estimation, a similar component was later observed on correct trials [3]. If this component on correct trials were to be the same as the one observed on errors, this would put important constraints on computational models of cognitive control. To address this issue we used Independent Component Analysis (ICA) to evaluate whether a single component (in ICA terms) could account for the waves observed in both erroneous and correct trials. For all the participants, a single component that accounts for the waves observed in the three categories of trials was found. The localisation of the sources is consistent with a rostral-cingulate zone origin, where control mechanisms are likely implemented [4]. This novel use of ICA allowed us to conclude that the negativities observed on error and correct trials are reflecting the same physiological mechanism whose amplitude is modulated as function of the performance.