As discussed earlier, the explanation of N2 as reflecting conflict monitoring processes and effortful processing is supported by the findings of the present study. The findings of higher NoGo N2 amplitude at frontal regions and current density in the ACC in the absence of a bias towards Go response may also reflect inhibition, at least in part. These observations are consistent with the views expressed in a recent editorial review (Falkenstein, 2006). Furthermore, findings of group difference on sLORETA (Figures 6a, b) in the present study suggest that the reduction of current density at the source in the time range of NoGo N2 in alcoholics may reflect deficits in “cognitive branching” (Koechlin and Hyafil, 2007) or in SAG (Burgess et al., 2007a). However, this interpretation is speculative at best since the task was not designed to assess anterior prefrontal cortical functions. Studies are needed with tasks that specifically assess functions related to the anterior prefrontal cortex involving alcoholic samples to test this hypothesis.
