3A), consistent with the obtained

average behavioral scores (in both FIT and fMRI task) of about seven items in our participants. Both our behavioral and fMRI data suggest that working memory capacity can reach about seven items in adults, in contrast to Cowan’s model of working memory for which 4 is the upper limit of capacity (Cowan 2005). This latter view is not without support; however, D5 was the least demanding level of items that strongly activated areas of visual–spatial processing (see Fig. 3A); that is, four items might be adults’ lower bound of working memory. Congruently, behavioral data showed a significant difference (with a large effect size) between reaction times Inhibitors,research,lifescience,medical for difficulty level 4 and 5 (Cohen’s d = 0.81; Table 1). These findings offer a deeper understanding of limits of working memory capacity (i.e., 4 as lower bound vs. 7 as upper bound; Miller 1956; Pascual-Leone 1970; Cowan 2005; Halford et al. 2007; Pascual-Leone and Johnson Inhibitors,research,lifescience,medical 2011). Limitations In this study, we used a novel developmentally validated task to assess the neural correlates Inhibitors,research,lifescience,medical of working memory capacity in adults. While the present study shows how such approach can inform our understanding of brain-behavior relations, several limitations have to be considered. The small number of participants poses a drawback and as we were mindful of this issue we present data corrected for multiple comparisons using FDR. Another consideration in data evaluation

was our criterion for block inclusion in statistical analyses. It is typical in experiments to analyze only trials with

correct responses. In our experiment, we used block analyses and only used blocks that 70% or more correct trials. We were interested in capturing activity related to the process of solving the Inhibitors,research,lifescience,medical task and not activity elicited by potentially performing correctly at chance level. The 70% criterion was theoretically chosen and behaviorally it was found to control for blocks that were above and beyond the working memory capacity level of the participant. This criterion allows for inclusion of trials Inhibitors,research,lifescience,medical with consistent performance Luminespib within a block. Lastly, Rolziracetam the caveats of ROI-based statistics have been previously presented (e.g., Vul et al. 2009) and challenged (Lieberman et al. 2009). Although we extracted percent signal change from significant areas following whole-brain analyses, we only present independent correlations of brain activity with behavioral scores obtained outside the scanner. We remain circumspect about these limitations. Nonetheless, the possibility that a linear relation exists between brain activity elicited by variable working memory demand levels and corresponding levels of resting state is a novel finding that warrants replication and further research with developmental samples. Conclusions Our results confirm and expand previous observations suggesting a balancing of processing resources in the brain, which occurs via reallocation.