Lateralized anterior cingulate function during error processing and conflict monitoring as revealed by high-resolution fMRI

Recent studies have reported that functional subdivisions of anterior cingulate cortex (ACC) may be selectively responsible for conflict and error-related processing. We examined this claim by imaging ACC activation to correct and erroneous response inhibitions in a GoNogo task. After localizing the ACC cluster in individual subjects using functional magnetic resonance imaging (fMRI) at standard resolution (2 x 2 x 4 mm(3)), high-resolution fMRI (1.5 x 1.5 x 1.5 mm(3)) of the ACC was performed in a second session to investigate its precise functional anatomy. At standard resolution, and in agreement with previous studies, ACC was activated for correct and incorrect responses, albeit more so for errors. High-resolution maps of activated ACC clusters revealed localized and reproducible foci in 9 out of 10 volunteers. Multisubject analysis suggested a bilateral distribution of error-related processes in ACC, whereas correct inhibitions only seemed to activate ACC in the right hemisphere. Subsequent region of interest analysis largely confirmed the activation maps. Our results contribute toward a better understanding of the microanatomy of ACC and demonstrate the potential of fMRI for mapping the functional architecture of brain regions involved in cognitive tasks at a previously unaccomplished spatial scale.