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Much work on aging brains has focused on their failings, but two new studies look at how they succeed. In both a University of Michigan at Ann Arbor report on which brain regions respond to challenging tasks and a Johns Hopkins University look at older rats, researchers found that aging brains function differently than young brains.
Cindy Lustig of Ann Arbor used functional magnetic resonance imaging to observe the brains of young adults (aged 18 to 30) and seniors (65 to 92) as they tackled simple and difficult mental exercises. For the easy tasks, brain activity was very similar, but tougher challenges prompted differences. The seniors activated several frontal brain regions that the others did not. In addition, the younger people “turned off” parts of the brain not used during the tasks, but the elders kept those regions active. Lustig concludes that “older adults’ brains can indeed rise to the challenge, at least in some situations, but they may do so differently.”
Michela Gallagher of Johns Hopkins compared the brains of six-month-old rats with those age two (old by rat standards). Her team also divided the elder rats into age-impaired and age-unimpaired groups. When Gallagher compared the synapses—the tiny gaps between neurons where intercellular connections are made—she found that the impaired rats had lost the ability to adjust the activity of synapses appropriately but that the unimpaired rats had not. These connections are how memories are formed and preserved.