Localization of the magnetic equivalent of the ERN and induced oscillatory brain activity.

It has been found in numerous electroencephalographic (EEG) studies that a negative potential arises following an erroneous response (so-called Error-Related Negativity, ERN). This typical component of the EEG has, however, proven more difficult to identify when transferring analogous paradigms to magnetoencephalography (MEG). The aim of this study was to devise and apply a paradigm to elicit erroneous responses and using MEG to measure both the error-related evoked brain activity (mERN) as well as accompanying induced oscillatory activity. Results clearly demonstrate that it is possible to measure the mERN and to identify cortical sources associated with it. Using distributed source modeling, it is possible to identify the mERN in source space and corroborate EEG findings, with the mERN generated in the anterior cingulate cortex (ACC). This supports notions regarding the role of the ACC in error monitoring and cognitive control of motor behavior. Furthermore, changes in induced oscillatory activity were observed in the theta and beta bands. This extends previous studies, which show that evoked theta activity could underlie the generation of the ERN.