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Abstract:
During EEG a negative event-related potential (the
error-related negativity, ERN) is elicited when an erroneous
response is made. Another negative deflection in EEG is found after
error-feedback. Dipole localization studies suggest a generator of
electrical activity for error-detection and error-feedback that is
correlated with the anterior cingulate cortex (ACC). In our study
we investigated both error-detection and error-feedback with
event-related brain potentials (ERPs). We used a modified flanker
paradigm and presented one of eight letter arrays, e.g. PPRPP,
VVVVV or VVUVV for 200 ms. The subjects were asked to focus on the
letter in the center of the array and had to press one button for
predefined letters within a time window of 550 ms. 700 ms later,
response consistent feedback was presented. ERP data show a typical
early ERN pattern over fronto-central electrodes during
error-detection. Another negative component was observed with
rather the same scalp distribution about 400ms after feedback. To
localize the neural substrate correlated with error processing the
same paradigm was realized within an event-related fMRI setup.
Consistent with most dipole localization studies the ACC revealed
maximum activity. However, fMRI data demonstrate an additional
frontal network involved in error processing that consisted of the
ACC, the right dorsolateral prefrontal cortex, the supplementary
motor area and left precentral gyrus.
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