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Frontal lobe activation in young (left) and older adults (right) in a memory study: In this fMRI study, researchers measured activation in the frontal lobes when older and younger adults were given a relatively easy laboratory memory task. Notice on the left photo that, while regions of the left hemisphere alone are activated in young adults, the older brains (right image) are working harder to master this task—as here activation occurs in both brain hemispheres.
Data from: Reuter-Lorenz & Cappell, 2008.