Several regions in the brain, especially in the frontal cortex, are involved in helping people meet the demands of a constantly changing environment. While earlier research focused on older adults' failures to activate these regions, the new U-M research found that older adults can activate these regions in response to a challenging task, and may also bring additional brain regions online to help their performance.
"Older adults' brains can indeed rise to the challenge, at least in some situations, although they may do so differently than young adults," said Cindy Lustig, a U-M assistant psychology professor who designed the study, which was conducted at Washington University in St. Louis. "We are continuing to collect data from these groups and are also beginning to test young children and middle-aged adults as well."
Lustig and her colleagues used functional magnetic resonance imaging (fMRI) to measure brain activity in young adults (ages 18 to 30) and older adults (ages 65 and up) while they performed easy or difficult tasks.
For the easy tasks, participants made the same kinds of decisions for every item in the task. For the difficult tasks, such as shape judgment or size judgment, patterns would switch without warning. In the difficult tests, people had to pay very close attention to the task and be ready to respond to the change.
Three important findings emerged:
- Similar to young adults, older adults increase activation in control-related brain regions in response to the increase in difficulty.
- Older adults increase activation in other frontal brain regions that young adults did not.
- Young adults seem to deactivate, or turn off, some other regions of the brain---perhaps reflecting a redirection of attention---but older adults do not do this to nearly the same degree.
Lustig and her colleagues will now look for relationships between brain activity and structure, task performance and other mental tests. The study was part of a larger research effort to understand what enables people to successfully perform in situations that demand control, and how the brain's reaction to control demands may change throughout their lifetime.
The study was presented Nov. 13 at the Society for Neuroscience meeting in Washington, D.C. For more on Lustig and her work, visit: http://www.
For more on U-M's Department of Psychology, visit: http://www.