Marilyn Albert, PhD, a neuroscientist at Johns Hopkins University.And theres more: Scientists have also found that not everybody experiences age-related changes in cognition. Some older adults perform much more poorly on tests of mental ability than younger individuals, which tends to make the average for the group decline, notes Albert. But other older individuals perform in the same range as people many decades younger than themselves. This variability suggests that there must be factors that influence brain aging, even among healthy individuals.Genetics certainly plays a role, but so does, according to growing evidence, environmental and lifestyle factors. Epidemiological studies conducted in many countries and across many cultural and socioeconomic backgrounds have found that three important factors help predict how well healthy adults maintain cognitive function as they age: mental activity, physical activity, and social engagement.Much work remains to be done to understand the mechanisms by which lifestyle factors affect brain aging and thereby permit specific recommendations for individuals, says Albert. The findings to date, however, suggest that as the 21st century unfolds, we will learn much more about ways in which we can maintain brain function at an optimal level into old age.Some scientists are examining the nature of age-related changes in the brain. Using a new statistical technique to analyze the results of structural magnetic resonance imaging (MRI) of the brain, researchers at Columbia University were recently able to identify, for the first time, brain patterns or networks implicated in the normal aging process and to assess the impact of these interrelated patterns on changes in cognition. Previous MRI studies of the aging brain tended to use analytic techniques that considered each region of the brain independently.For the study, researchers recruited 113 subjects who tested negative for medical, neurological, psychiatric or cognitive impairment. The subjects were divided into a younger group (average age =24) and an older group (average age = 73). The brains of all the subjects were scanned with high-resolution MRI and evaluated with a brief series of neuropsychological tests. The MR images were segmented so that grey and white matter of the brain could be examined separately. A multivariate technique based on a subprofile scaling model was then used to identify age-associated patterns of grey and white matter. The degree to which individuals expressed this pattern was compared to their performance on the neuropsychological tests.Our results suggest that there are identifiable networks of grey and white matter regions that systematically decline with age, says Adam M. Brickman, PhD. Many areas of the brain appear to be involved in these networks. For grey matter, the network includes areas along the surface of the brain (cortical) and deep within the brain (subcortical). For white matter, the network includes deep frontal regions, areas surrounding the ventricles (cavities within the brain that that contain cerebrospinal fluid), and the large fiber tracts that connect the various parts of the brain.We also found that the expression of both grey and white patterns is associated with performance on cognitive tests, particularly tests that measure memory, attention, and executive function, adds Brickman. That is, the more