A new UC Berkeley study suggests that older people’s brains which continue to perform well as they age do this by using more of the brain to complete mental tasks. The researchers observed age specific changes in network organisation when carrying out short term memory tasks which may help to compensate for overall brain aging.
The study was completed by UC Berkeley graduate student Courtney Gallen and her colleagues. They compared 18 adults in their twenties to 38 healthy adults ages 60 and older. The older subjects showed larger changes in the organisation of brain networks when moving from a task-free state to performing a task. Older people who did not show adaptation in brain signaling were less adept at performing tasks.
The researchers used functional magnetic resonance imaging to track communication within specific brain sub-networks called modules, along with with connections made across modules. The focus was on the frontal cortex, a critical area for executive functions.
During fMRI scanning, the participants were asked to perform four different tasks in two minute trials, with five trials assigned to each participant for every task. Images of faces and scenes were flashed before the subjects sequentially for six-tenths of a second each, followed by a pause. The easiest task required participants to press a button categorising the image as either a scene or a face. Other tasks included remembering the previous scene while ignoring the faces, and recalling whether the previous image matched the displayed one.
Older adults performing any of the tasks used additional between-module connection. In contrast, the younger adults did the only for the most difficult task. According to Gallen, the results “support the idea of compensatory recruitment and suggest a large scale network-level mechanism by which the aging brain reorganises to support executive control processing.”