36-38,93 The link between age-related changes in neuroanatomy and performance
on such tasks has not been established. To evaluate how these effects extend across agegroups, we have examined whole-brain volumes for young and older adults. The correlation between age and total intracranial volume was nil (r=0.02), indicating no secular drift in head size. For the young (<50 years) sample considered separately, there was a. small yet significant correlation Inhibitors,research,lifescience,medical between age and GM volume (r=-0.17, df=130, P<0.05). This correlation was higher in men (r=-0.27, df=74, P<0.01) than in women (r=-0.01 , df=54, ns). Age did not correlate significantly with WM or CSF volumes in this age-group. For the entire age range, GM continues to decline in volume with aging, r(184)=-0.49, r(92)=-0.52, and r(90)=-0.40 for the whole sample, males and females, respectively, all P<0.0001, whereas the volume of CSF continues Inhibitors,research,lifescience,medical to increase with age (the corresponding correlations were 0.31, 0.45, and 0.29, all P<0.0001). WM changes are less clear. Although the correlation with age is not significant for the entire sample, r=0.09, within each sex the correlations were small but positive, r=0.28, P=0.01 and r=0.24, P=0.02. This likely reflects the large sex difference
in the volume of WM’. We conclude that GM volume Inhibitors,research,lifescience,medical is reduced with aging, CSF volume increases concomitantly, while WM volume does not change appreciably and is perhaps increased slightly. While the effects of GM and CSF agree with a recent study Inhibitors,research,lifescience,medical by Guttmann et al,79 their conclusion regarding WM. was that its percentage of the intracranial compartments is reduced with aging. In comparing our results on WM, it appears that they examined only percentages and not raw volumes. In the case of Guttmann et al’s79 study, reduced %WM could reflect age effects on another compartment, for example, increased CSF. Perhaps the paucity of subjects in our elderly group is matched by the paucity of theirs in the young group (10 participants <40 years). This underscores the need for Inhibitors,research,lifescience,medical large samples across the life
span. Our sample also enabled examination of whether these volume changes are related to cognitive performance. While the young and elderly participants received age-appropriate neuropsychological batteries, both groups received several identical Brefeldin_A tests. Most relevant, is the CVLT, which measures rate of verbal learning. The total number of items recalled during the memorization trials was correlated with the volumes of brain parenchyma (GM. and WM combined), partialling out age. As can be seen in Figure 6, parenchymal volume goes down with age, number of words recalled also declines, and the parenchymal volume is associated with memory (even with age effects partialled out). Figure 6. Scatterplots of age by parenchymal volume (left), age by the selleck Dasatinib California Verbal Learning Test (CVLT) word recall (middle), and volume by CVLT word recall (right) in men (solid squares) and women (empty circles).