Neural teamwork may compensate for aging

 The news about aging's effects on the brain is not unremittingly grim. New research suggests that people automatically compensate for age-related declines by recruiting brain areas that previously hadn't participated in a given task.

 With few exceptions, human skills degrade with age during adulthood. Memory for names and events is one of the first abilities to go, accompanied by reasoning skills and speedy perception. Wisdom, however, continues to blossom. People's knowledge of facts, as well as their vocabularies, remain strong until about age 65.

 In young adults, verbal and spatial learning occur in specialized regions of the brain. In older adults, extra regions contribute to these abilities, Patricia A. Reuter-Lorenz of the University of Michigan in Ann Arbor reported this week in Washington, D.C., at the Cognitive Neuroscience Society's annual meeting.

 Reuter-Lorenz and her colleagues used positron emission tomography (PET) to compare the brain activity of college students and people 62 to 73 years old. The participants memorized and then recalled either sets of letters presented on a computer screen or the locations of points on the screen. In young adults, as expected, the letter task activated the left hemisphere and the location task activated the right hemisphere. However, in the older subjects-who performed just as well as the students-both the right and left frontal lobes were active for both types of memory.

 In a second test, participants matched shapes on a computer screen in tasks that engaged either one brain hemisphere or both. Older people responded faster when they had to use both sides of the brain rather than just one, a pattern that younger people didn't always share.

"In older adults, when you present information in a way that promotes the use of both hemispheres, people can take advantage of that and use it to benefit their performance," said Reuter-Lorenz.

 Widespread neural activation may help seniors when they focus on one task but could cause interference when they take on many activities at once, says Ulman Lindenberger of the Max Planck Institute for Human Development in Berlin.

 Lindenberger and his colleagues have tested hundreds of people ages 75 to 103 and also younger adults. Shortly after reading a list of words that they were told to memorize, young and old participants took directed walks through the lab. If they walked a smooth oval track, both groups learned the list about equally well, the team reports. When participants had to walk a jagged path, however, older people memorized fewer words than the young did.

 Still, says Timothy A. Salthouse of the Georgia Institute of Technology in Atlanta, "the evidence that old people may be able to engage more brain regions as a task gets more difficult is very encouraging."