23 to .32, p < .05); there was a trend towards significance for the relationship between left DLPFC volume and Immediate verbal memory recall. These relationships were significantly lateralised to left DLPFC for Immediate recall [t (85) = 2.02, p = .046] and a trend for Delayed [t (85) = 1.70, p = .093], but not to the right for the hippocampus [Immediate: t (86) = 1.24, p = .218; Delayed: t (86) = .83, p = .411]. The

magnitude of the effect was significantly greater Veliparib concentration in the splenium than the genu in terms of FA [Immediate: t (79) = 2.23, p = .028; Delayed: t (79) = 2.31, p = .023] but not MD [Immediate: t (79) = 1.29, p = .202; Delayed: t (79) = 1.51, p = .136]. When entered into a linear regression, variability in these regions predicted 16% of the variance in Immediate and 19% in Delayed verbal memory recall for the overall sample (Table 2). Each step-wise iteration showed an increase in R2 over the previous model. Though hippocampal and left frontal lobe measures predicted memory performance, better integrity of the genu of the CC (the proposed route via which right frontal inhibition is effected) was Idelalisib purchase not related

to memory scores, partially contradicting the inhibitory hypothesis. Moreover, there was no significant relationship in the entire group between right frontal volumes and memory scores. This provides no support for the hypothesised role of this region in memory scores for the entire group, and runs contrary to the view that right frontal lobe supports retrieval processes during this type of memory test. Because the breakpoint analyses depend upon a strong scaling assumption, we graphically explored the normality

of the distribution and linearity of the relationship either side of the breakpoints, and found these to be acceptable. The results of the breakpoint search Urocanase algorithm are shown in Fig. 2. It showed that there were a large series of scores for both Immediate and Delayed verbal memory at which the relationship between memory score and right DLPFC were significantly different for performers above and below that point. No breakpoints were identified at which the relationship between either memory score and the right IFG (which lies immediately adjacent to the DLPFC on the lateral convexity of the frontal lobe) were significantly different between segments for high and low performers. To further examine intra-group differences in the predictive value of RDLPFC volumes on memory performance, we selected the significant breakpoint that most evenly distributed power between the two segments. The segmented models were re-parameterized using these breakpoints for Immediate (breakpoint z-score = −.22, p = .05) and Delayed (breakpoint z-score = −.64, p = .05) verbal memory scores ( Fig. 3). For Immediate memory score, higher RDLPFC volumes accounted for 18% of the variance in lower performers (R2 = .18, F (1, 29) = 6.47, p = .02), but not for high performers [R2 = .00, F (1, 55) = .23, p = .64].