What happens to our brain structure as we age? We know our bodies start to lose their muscle tone and as many say, “gravity takes over.” Is that basically what happens to our brain? Does our brain lose the elasticity it needs in order to make the connections, and is that the reason why our reactions are slower and our mental abilities begin to taper off?

Dr. Timothy A. Salthouse, professor of psychology at the University of Virginia has set out to answer that very question. Salthouse, along with his colleagues, have investigated the complex occurrences that take part in our brains as we age. The Association published their research in a recent edition of the journal Psychological Science, a publication for Psychological Science.

As we age our ability to make decisions, form memories and perform cognitive tasks declines. What once came to us easily becomes more difficult. Scientists believe our brains possess a hierarchical structure, where various skills are on different levels of the structure. At the bottom of the pile are specific tests that involve word memory or story memory. The second layer holds various skills involved in cognitive ability, such as memory, perception of speed, and reasoning. The third level, or the general (G factor, according to the scientists) level is a combination of all thinking abilities.

“There are three hypotheses about how this works,” says Salthouse. “One is that abilities become more strongly integrated with one another as we age.” This would suggest that general factors have the greatest impact from aging. The second theory is based on the belief that the connections between brain functions decrease with age. Salthouse says, however, that the fact “is almost the opposite: that the changes in cognitive abilities become more rather than less independent with age.” The third hypothesis, which is what Salthouse’s and his team believe, is that the structure remains constant throughout the aging process.

Testing 1,490 volunteers between the ages of 18 and 89, Salthouse’s team analyzed the scores from 16 tests focusing on five cognitive abilities, which include reasoning, spatial relations, vocabulary, memory and perceptual speed. They measured the subjects over a 2-1/2 year span and noted the changes in test scores during that period.

The researchers’ hunches were confirmed, “The effects of aging on memory, on reasoning, on spatial relations, and so on are not necessarily constant. But the structure within which these changes are occurring does not seem to change as a function of age.” In normal, healthy people, “the direction and magnitude of change may be different when we’re 18 or 88,” he says. “But it appears that the qualitative nature of cognitive change remains the same throughout adulthood.”

Another study, out of the Howard Hughes Medical Institute, as we age everyone’s brain breaks down to some extent, even when disease is not a factor. This deterioration leads to a weakened memory and reasoning ability, but is still part of the aging process. “The brain can be divided into major functional regions, each responsible for different processes, like memory, sensory analysis, planning and internal thoughts,” they say. Never fibers connect each portion of the brain through a network of “white matter.” Although scientists have been aware for some time that aging degrades memory they still don’t understand why.

Previous studies have focused on one specific region, concentrating mostly on the frontal lobe, which does shrink or lose some function even in the absence of disease. Salthouse’s group findings are important because they worked at the neural activity in two large-scale networks across the span of the brain, as opposed to concentrating on one specific area. They looked at the default network, which is used when we worry, think about the past or future, or use imagination to dream of people in our lives. The other area was the attention network, used when we are trying to focus on a specific task, such as solving math problems or processing words. These two brain regions are usually in sync, but as we age they seem to lose that compatibility, especially as we hit the age of 60 or over.

These results suggest that cognitive decline as part of normal aging comes from some sort of disruption in the coordination of large-scale brain systems. These findings are interesting, and important, and more research as to what brings about this decline is in the future.




About the author:

Ron White is a two-time U.S.A. Memory Champion and memory expert. As a memory speaker he travels the world to speak before large groups or small company seminars, demonstrating his memory skills and teaching others how to improve their memory, and how important a good memory is in all phases of your life.




Deric Bownds’ Mindblog – Brain Network Distruption During Aging: http://mindblog.dericbownds.net/2008/04/brain-network-disruption-during-aging.html

Neuron – Disruption of Large-Scale Brain Systems in Advanced Aging: http://www.cell.com/neuron/abstract/S0896-6273%2807%2900864-1

Science Daily – Study Looks At the nature of change in our aging brains: http://www.sciencedaily.com/releases/2011/11/111128174528.htm