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Praise for Ed's previous novel, Lost in Translation:

"Edward Willett has arrived, and SF is the richer for it." -  Robert J. Sawyer, Hugo Award-winning author of Hominids

"A believable, absorbing, thought-provoking and highly enjoyable read." - Kathy Tyers, Author of the Firebird trilogy, Star Wars: The Truce at Bakura, and Star Wars: Balance Point

Over the weekend I locked myself out of the house. I went out to shovel the walk, fully aware my keys were not in my pocket--and then, on the doorstep, turned around and very deliberately locked the door.

Which, I'm sure, since I am still very young, has nothing to do with this week's topic--how our brains change as we age.

That our brains do change is indisputable, but those changes aren't as drastic as once thought, nor is the end result necessarily senility (as many a clear-thinking senior citizen can tell you)...although that was the view just 30 years ago. That's when Harold Brody, a New York anatomist, published a study that indicated that the cortex, the "thinking" part of the brain, loses up to 40 percent of its brain cells (called neurons) during aging. From those studies came the frequently repeated belief that we lose a million brain cells a day.

There's no question the brain shrinks--men's more than women's. While men's brains start out 15 percent larger, on average, than women's, by age 45 they're the same size and after that the women's brains are larger. But newer anatomical studies indicate that although neurons shrink, they don't disappear. It now appears that changes in cognitive function may have more to do with the loss of a fatty substance called myelin that sheaths axons, the conduits which transmit nerve impulses. Loss of myelin slows that process. It's the problem-solving tasks that rely on rapid transmission of nerve impulses that elderly people perform less quickly and accurately than younger people. As well, certain brain chemicals also decline with age.

Here's a brief rundown of the way your brain ages. In your 30s, changes in the hippocampus, which helps convert short-term thought to long-term memories, mean you're a little less likely to remember what you heard on the radio this morning or the names of people you just met.

In your 40s, you may find it harder to discern shapes and colors. As well, if you're introduced to 14 people at a party, by the time you leave, you'll remember only 11--whereas in your 20s you would have remembered 13. (Personally, I'd be lucky to remember three.) On the plus side, you have three times the vocabulary you had in your 20s.

By the time you're in your 50s, you probably couldn't score as high on an IQ test as you did in your 20s. Changes which affect motor control can lead to a loss of coordination. You may also find it harder to place an event or remember where you were when it happened.

All of these changes progress further as you continue to age. But there are bright spots. For example, someone in their 60s or 70s has a much larger store of knowledge than any college student (something no college student likes to admit). As well, "crystallized memory," the memory built up by years of doing something--building houses, for instance--remains intact. In other words, Grandpa really does have a thing or two to teach you, you young whippersnapper!

Even better, exercising your brain can boost its performance just as exercising your body can strengthen your muscles.

A study of more than 1,000 people from age 70 to 80 showed that four factors influence mental agility: education (which increases the number and strength of connections among brain cells--educated people are at less risk for Alzheimer's for example), strenuous activity (which improves blood flow to the brain), lung function (which ensures the blood has enough oxygen in it) and the feeling that what you do makes a difference in your life. As well, people with flexible minds--willing to consider new ideas and try new approaches to things--also seem to do better than those who are "set in their ways."

Chronic disease of any kind has a negative impact on brain function. Much of that may arise from the forced indolence of the invalid. Mental exercise, again, can help prevent this decline--even return mental function to the level it was at years earlier. You're never too old to use your brain!

All through life, your brain builds new connections among its cells. That's why even people with serious brain damage sometimes recover to a remarkable degree; the brain routes around any damage. By harnessing this power through mental activity, you can ensure your brain remains nimble into old age.

In other words, if I do more crossword puzzles, maybe I won't lock myself out of the house again.

These weekly columns on science appear in the Regina (Saskatchewan) Leader Post and Red Deer (Alberta) Advocate..  They are available for one-time publication or regular syndication to any interested newspapers, magazines or on-line publications.  E-mail me for details.

Posted January 27, 2001

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