Contributed by Carla Sharetto| 14 November, 2005 18:22 GMT
As people age, some regions of the brain appear to become inactive, but challenging situations can stimulate these regions to click on again, suggests a new study by a University of Michigan professor.
Several regions in the brain, especially in the frontal cortex, are involved in helping people meet the demands of a constantly changing environment. Earlier research focused on older adults' failures to use these regions. However, the new U-M research found that older adults not only are capable of activating these parts of the brain when needed, but also may bring additional 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," says 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," she adds.
Switch On, Switch Off
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.
During the easy tasks, participants made the same kinds of decisions for every item. For the difficult tasks -- such as judging shapes or sizes -- patterns switched without warning. During 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:
Older adults increase activation in control-related brain regions in response to increased difficulty, similar to young adults.
Older adults increase activation in other frontal brain regions that young adults do not.
Young adults seem to 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.
Brain Activity and Structure
Lustig and her colleagues next plan to look for relationships between brain activity and structure, task performance and other mental tests.
This study was part of a larger research effort to understand what enables people to perform successfully in situations that demand control, and how the brain's response to control demands may change throughout an individual's lifetime. |
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