The exciting and previously unknown ageing brain

The Secret Life of the Grown-Up BrainThe Secret Life of the Grown-Up Brain, by Barbara Strauch, Viking, US $26.95

Some of us  (I am speaking personally here) have been afflicted for our entire lives with the habit of running eagerly upstairs to get something, arriving in the bedroom and completely forgetting why we’re there. Some of us (me again) arrive at parties with our anticipation at a delightful evening tempered by alarm that we’ll end up having to introduce someone we know really well but whose name we cannot, for some reason, dredge up out of the slimy morass of our brains.

Even those who haven’t carried this burden throughout their lives are likely to start suffering from it in middle age. Those for whom parties have always been something of a trial are likely to find the struggle to retrieve information even harder. Partly because of this noticeable change, the assumption until recently has been that the middle aged brain is in decline. Your brain cells start dying off after the age of 19, your teenage children will tell you, while your friends speak ruefully of ‘senior moments’. Common sense suggests that brains age in parallel with bodies, sagging and greying and generally becoming less useful.

Yet in the last 10 years, developments in neuroscience have shed a whole new light on what happens to the brain as it ages, and previously commonsensical notions are looking like less than the complete picture. In this new book, Barbara Strauch, the health and medical science editor at the New York Times, canters through much of the recent academic research to produce a rather more complex picture of the resilience and plasticity of the ageing brain.

Broadly, Strauch’s conclusion is that aspects of memory do indeed decline with age, not least the ability to remember names. Yet it turns out that the Greeks were on to something when they decreed that citizens could become jury members only when they reached the age of 50. MRI scanning, genetic analysis and sophisticated long-term studies are beginning to show that the ability to make accurate judgements, to build patterns of connection and interweave layers of knowledge actually grow with age. We could yet establish a biological basis for wisdom.

brain graphicBrain science remains in its infancy, and Strauch is unable to paint a complete picture, but she does offer lots of tantalising glimpses. At UCLA, MRI scanning has shown that the fatty white coating of neurons called myelin continues to grow into late middle age; George Bartzokis, a neuroscientist involved in this work, believes this is ‘the brain biology behind becoming a wise middle-aged adult.’ The Seattle Longitudinal Study, which has tracked the mental powers of more than 6,000 people since 1956, shows better functioning in middle age than at any other time on four out of six cognitive tests.

The trend of research across different disciplines seems to point to a midlife loss of processing speed – the ability to swerve to avoid a squirrel in the road – as well as of the ability to mug up and retrieve dates in history. But it also suggests a growing mastery of vocabulary, spatial orientation and inductive reasoning. Emotions remain strong, and yet the ability to regulate them increases. Most impressive, and most convincingly researched, is the ability to recognize patterns and see connections, which persists strongly and offers hope for continued creativity, intuitiveness and social and emotional responsiveness.

Strauch’s book is in two parts, the first an overview of the current state of knowledge, and the second an attempt at a how-to-keep-your-brain-fit guide. Neuroscience has shown the brain to be nothing if not mutable. Experiments on rats and monkeys have found that those that are allowed to live in enriched and stimulating environments end up with bigger brains, making more connections. On all tests they are smarter than those living lonely, mundane lives.

Taking her cue from this, Strauch looks at how you might keep your brain working. Here she’s on less comfortable ground, because the science is so nascent and tentative that any prescription based on it looks rash. Certain general principles seem to be valid: education is good, social relationships are vital, exercise is excellent, nutrition is important. Beyond this, there are few certainties. What kind of education? The brain training industry has gone from being worth $2million in 2002 to $80 million in 2007, yet, as she points out, there is no proof that brain training games work outside the laboratory.

We can be pretty sure obesity is bad for the brain and oxidative stress and inflammation are unhelpful, yet there’s no proof that eating foods high in antioxidants or anti-inflammatory agents will make a difference. You can buy what are advertised as resveratrol pills on the internet. Resveratrol, an ingredient in red wine, has been shown to extend the life of yeast, and, at very high doses, rodents. These pills are part of a vast market in anti ageing preparations and potions. They are at best, and putting it as politely as possible, a hunch.

Strauch is too good a journalist to get drawn into too much cheerleading ‘you can save your brain’ business. But the book is sold in part as a guide to discovering that, to quote the blurb, ‘your smartest years are still ahead.’ In fact, what The Secret Life of The Grown-Up Brain leaves you with is a conviction that it will be a long time before we have definitive answers to most of our questions about the brain, because each individual brain’s development is such a complex mixture of genetics and environment. As an overview of where we are now, though, it is excellent. And, in a cautious, hopeful frame of mind, as befits the state of the science, quietly but definitely encouraging.Barbara Strauch

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