The human brain has been called the most complex structure in the universe and even with all the research on the brain, scientists still cannot completely explain how the brain processes memory. A good many things, however, are known.

For one, a function called "working memory" occurs in the hippocampus and in the frontal cortex. Working memory is temporary storage of information and includes processes for analyzing information, decision-making and information selection. On the other hand, long term memories have been found to be stored in many different locations in the brain.

With aging, our brains change. Brain cells die off and in some people, a number of brain structures such as the hippocampus become smaller. Brain changes such as these may not have any impact on memory and the changes vary widely from person to person.

Although brain cells do die off, the process does not accelerate with age, and the areas of the brain that lose cells are not necessarily the ones that relate to memory. Researchers who study the effects of aging on the brain say that even though the hippocampus shrinks, it probably compensates for its smaller size by working harder.

Though the brain’s physical changes do not necessarily relate to loss of memory, changes do occur in memory function as we age. The way the brain processes information is often slowed, affecting the rate that people can put new information into their permanent memory, especially rote, factual information. With aging, we often experience delayed recall — not being able to remember a familiar name or word — and it becomes harder to pay attention to more than one thing at a time.

In a study done by Dr. Monte Buchsbaum, Professor at the Department of Psychiatry, Mount Sinai School of Medicine, a group of young and old people who had equally good memories were tested. They were told to look at 16 words on a screen, organize the words into categories and then memorize them. The younger people used the frontal lobe, which is the part of the brain generally used for organizational tasks such as categorizing words. The older group, on the other hand, used a different part of the brain, an area used for processing visual images.

According to the researchers, the results suggest that healthy aging may involve the ability to move tasks out of the frontal lobe into other areas of the brain. Though researchers do not know how this is done, the answer could help people train their brains to use different regions as they age.

Research also shows that though most older people tend to experience some memory deficiency, others maintain a high level of cognitive functioning into their later years. These "successful agers," as they are sometimes labeled, show less age-related memory loss. They generally have higher levels of education, stay involved in their work and spend more time doing activities that require complex thought.

People who have a positive mental outlook tend to show less decline in mental functioning as they age, as well. Research is showing that a positive relationship exists between physical fitness and memory, especially for those participating in aerobic exercise.

Though medical research continues to focus on developing a medication that will help prevent memory loss, no proven remedy is available yet. Some evidence has been found that links estrogen, ginkgo biloba, anti-inflammatory drugs and vitamin E to a delay in the onset of Alzheimer’s disease. At the present time, despite all the advertisements, there is no reliable evidence that ginkgo biloba or antioxidants enhance normal memory.

As always, the best advice for remaining mentally sharp is "use it or lose it." Doing puzzles, learning something new on a regular basis, reading and staying involved with people are all positive ways to enhance mental ability. And, of course, it is still a good idea to make lists, write yourself notes and keep a calendar for appointments.