One possibility is that LD trials might have been perceived as more novel than SD trials given that they were previously encountered longer ago and, thus, could have undergone more forgetting prior to restudy. In order to evaluate whether this explanation could account for the Lhipp-LPRC findings, we examined connectivity between these same regions for the completely novel object trials

of the SS object condition. Unlike the prior analysis, however, insufficient subsequent hit SS object trials were available to KU-55933 in vivo enable this analysis to be conducted on SS subsequent hit object trials alone. Therefore, this and subsequent analyses utilizing SS object data collapsed data from all SS object trials, regardless of subsequent memory status. Inconsistent Selleckchem Erastin with the novelty explanation, SS object trial connectivity did not predict forgetting across subjects for the Lhipp-LPRC seed pair, r(16) = −0.07, p > 0.6 (nor for any other pair tested;

see Figure 6, Figure S2, and Supplemental Information), nor was SS object trial connectivity greater than that for LD object trials, F(1, 17) = 0.45, p > 0.5. However, as shown in Figure 7, BOLD activation in the hippocampal ROI, on its own, does predict subsequent forgetting in the SS condition. This (1) is consistent with published work linking hippocampal processing of new associates with successful memory formation and (2) demonstrates the power to detect such effects in the current data set. Thus,

taken together, it is unlikely that the differences seen between the LD and SD conditions are solely driven by a perceived novelty/encoding response to the LD pairs at restudy. We additionally evaluated the possibility that our across-subjects BSC-behavior correlation results for the LD object hit trials might have emerged via independent predictive relationships between BOLD signal in each ROI and behavior. To this end, we examined whether the parameter estimates derived from each of the ROIs correlated with forgetting for each consolidation interval. Critically, this relationship was not observed for LD object or SD object hit trials. BOLD Oxalosuccinic acid signal in the Lhipp and the LPRC ROIs for LD object hits did not predict subsequent forgetting, r(22) = 0, p > 0.9 and r(16) = −0.16, p > 0.5, respectively (see Figure 7). The LPPA and RPRC ROIs likewise failed to demonstrate a significant relationship between BOLD signal and forgetting for LD object hits (see Figure S3). Additionally, no relationship was identified in any ROI for SD object hits, each p > 0.15. When the analogous activity-behavior correlation analysis was repeated utilizing the SS object trial data, a significant relationship between activity and forgetting was identified in the Lhipp ROI, r(21) = −0.