The anterior cingulate cortex (ACC) is believed to be involved in the executive control of actions, such as in monitoring conflicting response demands, detecting errors, and evaluating the emotional significance of events. In this study, participants performed a task in which evaluative feedback was delayed, so that it was irrelevant to immediate response control but retained its emotional value as a performance indicator. We found that a medial frontal feedback-related negativity similar to the error-related negativity (ERN) tracked affective response to the feedback and predicted subsequent performance. Source analysis of the feedback-related negativity and ERN revealed a common dorsomedial ACC source and a rostromedial ACC source specific to the ERN. The oscillatory nature of these sources provides further evidence that the ERN reflects ongoing theta activity generated in the mediofrontal regions. These results suggest that action regulation by the cingulate gyrus may require the entrainment of multiple structures of the Papez corticolimbic circuit.

The effects of within-class grouping on student achievement and other outcomes were quantitatively integrated using two sets of study findings. The first set included 145 effect sizes and explored the effects of grouping versus no grouping on several outcomes. Overall, the average achievement effect size was +0.17, favoring small-group learning. The second set included 20 effect sizes which directly compared the achievement effects of homogeneous versus heterogeneous ability grouping. Overall, the results favored homogeneous grouping; the average effect size was +0.12. The variability in both sets of study findings was heterogeneous, and the effects were explored further. To be maximally effective, within-class grouping practices require the adaptation of instruction methods and materials for small-group learning.

The most accurate source localization is obtained when the voltage surface is densely sampled over both the superior and inferior surfaces.

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