80, p < 0.001; right t(53) = 7.51, p < 0.001). In addition, coordinate-based analysis of hippocampal volume and RM appeared to capture a memory benefit associated with a longer Selleckchem SB431542 pHPC and shorter aHPC ( Figure 2C), especially in the left hemisphere (peak left pHPC t(52) = 3.87, p < 0.001; left aHPC t(52) = −2.42, p < 0.05; right pHPC t(52) = 2.27, p < 0.05; right aHPC t(52) = −1.84, p = 0.071). However, pHPC volume ratios were predictive of RM even after separating variance associated with pHPC length ratios (left t(52) = 2.01, p < 0.05; right t(52) = 3.48, p < 0.001), whereas the opposite pattern did not hold (left

t(52) = 1.02, p > 0.3; right t(52) = −0.49, p > 0.6). That is, hippocampal Vorinostat nmr volumetric information contributed the same information provided by apex position, plus additional information. Just as concurrent increases in pHPC volume and decreases in aHPC volume have been observed following massive accumulation of spatial memories by London taxi drivers (Maguire et al., 2000), a negative relationship was observed between left pHPC and aHPC volumes in our combined analysis

(t(52) = −3.36, p < 0.005) confirming that a tradeoff effect was present (although this effect did not reach significance in the right hemisphere, t(52) = −1.22, p > 0.2). That pHPC and aHPC also made opposite, but overlapping, predictions about RM further suggests a tradeoff effect. Along these lines, although variance in pHPC was predicted

by HPC (left t(52) = 4.12, p < 0.001; right t(52) = 5.63, p < 0.001), it was the non-HPC portion of pHPC variance that predicted RM in both hemispheres. pHPC was in fact a slightly better predictor in the left hemisphere after controlling HPC (t(51) = 4.48, p < 0.001; without control t(52) = 4.02, p < 0.001) and in the right hemisphere after controlling HPC (t(51) = 3.91, p < 0.001; without control t(52) = 3.38, p < 0.005). This pattern may explain why HPC has failed to predict RM in past studies involving healthy adults, even though pHPC volume Farnesyltransferase ratio was a reliable predictor in all of the studies we analyzed. In part because there is both little direct communication between pHPC and aHPC (Moser and Moser, 1998 and Fanselow and Dong, 2010) and in part because different large-scale connectivity (i.e., neural context; McIntosh, 2000) has been associated with each region (Moser and Moser, 1998, Kahn et al., 2008, Fanselow and Dong, 2010 and Poppenk et al., 2010b), the notion of functional specialization along the long hippocampal axis has gained favor (Moser and Moser, 1998 and Fanselow and Dong, 2010). Drawing upon this idea, we tested the hypothesis that pHPC neural context differs from that of aHPC and is supportive of RM. We began by searching for patterns in the ambient functional networks associated with left pHPC, left aHPC, right pHPC, and right aHPC in our resting-state fMRI data.