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Mapping memory loss

May 13, 2006|By Kelly Strodl

Ever wonder why memory decreases as age increases?

The results of a study conducted by UC Irvine professor Michael Rugg may have brought researchers one step closer to answering that question.

Rugg, the director of UCI's Center for the Neurobiology of Learning and Memory, conducted a study comparing brain activity in two groups of people ? those 65 to 75, and those 18 to 30.

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The results surprised him: In certain brain regions, the older group showed more activity than the younger group.

"We associate your memory getting worse with older people," Rugg said. "The interesting thing is [the results were] contrary to what one might have imagined."

The results of the study, which was conducted in 2003 in London, will be published in a scientific journal this year. The researchers mapped the brains of 32 volunteers as they viewed a series of images. Their brains were mapped again as they were shown a second series and asked to recall whether any of the images had been in the previous series.

To aid the memory process, each image was accompanied by a question. A picture of a penguin, for example, was attached to the question "Animal or inanimate?" A picture of a barbecue had the question, "Could this fit in a shoe box?"

"The added information ensured that subjects successfully encode information into memory for later retrieval," Rugg said.

Each of the participants viewed pictures flashed onto a mirror while their brains were scanned with Functional Magnetic Resonance Imaging ? FMRI.

The FMRI mapped the blood sent to the areas activated, not the activity in local regions of the brain. More blood flow meant more neurons were firing.

The entire process took no more than 10 minutes for each participant.

Rugg and his colleague, Alexa Morcom, observed an "over-recruitment" of brain activity in the 65- to 75-year-old group.

"I think it's really early in terms of knowing just what the implications of these findings are," Morcom said. "The possibilities are, in broad terms, that this increased use of the brain may be helpful, or it may be unhelpful to older adults."

Morcom, a senior researcher at Cambridge University, thinks the results could indicate a way in which the brain compensates for memory loss ? a process that perhaps could be promoted in some way to prevent memory loss.

"Many people find this an exciting possibility because it suggests aging isn't just a matter of progressive loss of function," Morcom said.

According to Rugg, the next step will be to compare the brain activity of older, healthy people as they age, with those in the early stages of degenerative brain diseases, such as Alzheimer's and dementia.

"The $64,000 question is whether or not the activity is compensating ? or is it part of the problem?" Rugg said. "We simply don't know what the reason is right now."

Rugg is now searching for volunteers in the senior community to participate in his next study. Anyone interested can contact his office through his website, www.cnlm.uci.edu/rugg.htm.dpt.13-boomers-CPhotoInfoS01QTMPP20060513iz6d73ncKENT TREPTOW / DAILY PILOT(LA)Dr. Michael Rugg writes on aging's effect on memory as the director of the Center for the Neurobiology of Learning and Memory at UC Irvine.

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