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Abstract:
A previous fMRI study of performance monitoring showed
increased ACC activity with errors and with heightened conflict,
even in the absence of errors. This study employed a continuous
performance task with degraded stimuli, which introduced the
concern that we were not examining conscious error related activity
(e.g., Keihl et al., 2000). We employed rapid event related fMRI to
examine error and conflict related activity during a
speed-pressured STROOP. By driving errors without the use of
degradation we could be sure that subjects had the potential to be
aware of their errors. Thirteen healthy, young individuals
participated. Data were analyzed using an ANOVA comparing the main
effect of condition (congruency or error) at the peak of the
hemodynamic response (4-8 seconds after the beginning of each
trial). Significance thresholds were set at p=.01 with an 8 voxel
contiguity threshold. ACC activation was found in both error and
conflict activity contrasts. The error related signal extended over
a larger region of the ACC, however the conflict and error activity
overlapped completely and the conflict particle showed a
significant error effect. Our results replicated and extended
previous findings in that the same region of the ACC was active
during both high conflict trials and trials in which the incorrect
response was given, even when task conditions support fully
conscious errors.
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