Elders seem to rally more of their brains for short-term memory

Researchers at the University of California, Berkeley, suggest brains that continue to perform well in old age, against odds that they are slower and less accurate in short-term memory compared to those of younger people, do so by rallying more of the brain to complete mental tasks.

"We think this pattern of increased connectivity between frontal regions and other modules in the brain reflects a more integrated network architecture that is key for successful performance of executive control tasks in aging," said UC Berkeley graduate student Courtney Gallen, who worked with her colleagues on a study published in the August issue of the journal Neurobiology of Aging.

Under the direction of her thesis adviser Mark D' Esposito, a UC Berkeley professor of psychology, the researchers compared 18 adults in their 20s to 38 healthy people age 60 and older.

They found that the older study subjects showed larger changes than younger subjects in the organization of brain networks between a task-free state and performing a task, and that those who did not exhibit this adaptation in brain signaling were less adept in performing tasks.

"Executive control" functions are thought to underlie humans' ability to flexibly change thinking and behaviors and to solve problems.

Using functional magnetic resonance imaging (fMRI) to track communication within specific brain sub-networks - called modules - and connections made across different modules, the researchers also found that the structural integrity of the superior longitudinal fasciculus (SLF), which anatomically connects frontal and posterior brain regions important for short-term memory, was associated with older subjects' likelihood of exhibiting the transition to the more interconnected communication between brain regions that in turn was linked to better performance of tasks.