What causes memory loss?
August 25th 2011 20:31
Laugh lines, a few grey hairs and a those hard-to-lose pounds — along with a frustrating inability to recall names or what you did last Tuesday, they’re signs of middle age. And while memory problems may seem inevitable, new research shows that the middle-age brain still has a few surprises of its own. We asked Barbara Strauch, the New York Times’ deputy science editor and author of the Secret Life of the Grown-Up Brain (Penguin), to explain.
We’re living longer these days, so middle age has become a time to be fit, healthy and active. But our brains seem to be aging despite that.
Yes, we’re all kind of panicked because things do vanish from our heads. Just the other day, while packing for a trip, I spent five frustrating minutes looking for my toothbrush to put in my suitcase only to find that I had, just minutes before, already put my toothbrush in my suitcase. After I’d packed it, I’d gotten distracted looking for a sweater and, whoosh, all thoughts of toothbrush-already-in-suitcase were swept out of my head. It would be nice to say that this kind of thing happens rarely. In fact, it happens all the time.
What causes memory loss?
The processing speed in our brains slows down from our 20s onward, we can lose some neurotransmitters and get distracted more easily. The truth is, by midlife, most of our brains show some fraying around the edges, and names are often the first edge to go ragged. The names are not technically gone.
Research into the cellular activity of where most memories are processed indicates that much of what we learn in the form of chemical markers is not missing, it’s just at the bottom of the pile. For the most part, it’s a problem of retrieval, not storage. If you forget your husband’s boss’s name is Ed it might be embarrassing at an office party. But it’s not Alzheimer’s, a progressive disease where you might forget you have a boss, or even what a boss is.
So memory loss is not due to dying brain cells?
They used to think that we lost 30 per cent of our brain cells. Now, in counting them, they found we don’t lose them. There are recent findings, too, that show how the middle-aged brain, rather than giving up and giving in, adapts. As we age, our brains power up, not down, to solve problems.
How does the middle age brain “power up?”
As researchers at Duke University and elsewhere have found, people in middle age begin to use two sides of their brains instead of one — a trick called bilateralization. As we age, the two sides of our brains become more intertwined, letting us see bigger patterns, have bigger thoughts. Those who recruit the strength of their brains’ powerful frontal cortex, in particular, develop what scientists call ‘cognitive reserve’, thought to be a buffer against the effects of aging.
Does bilateralization occur in all aging brains?
It’s not the weakest brains that do this but the most robust ones. A series of recent studies has found that it is the most capable who resort to this trick. It’s as if the best and the brightest older brains simply refuse to give in. Cheryl Grady at the University of Toronto recently found ... it was those adults with the most education who tapped into this premier brain region.
Does bilateralization occur naturally, or do we have to make it happen?
At a lab at the University of Toronto, neuroscientist Nicole Anderson is trying to do just that. (Participants) try to recall whether they’ve heard or seen various words ... this exercise specifically targets episodic memory, the ability to remember something in context.
There are also some studies that show people who are bilingual age better cognitively because they use more brain real estate. This is the kind of brain strength that helps us get the point of argument faster than younger peers, to get the gist, size up the situation and act judiciously rather than rashly.
You’re really talking about wisdom. Can science measure that?
Neuroscientists at UCLA and elsewhere can now watch parts of brain cells, in particular, the fatty coating of neurons called myelin, continue to grow late into middle age. As myelin increases, it builds connections that help us make sense of our surroundings. This growth of white matter, as one Harvard scientist put it, may in itself be “middle-aged wisdom.” The changes and pathways have been built up, and what’s happening is our brain is making more connections.
How else does the middle-aged brain adapt?
There are long term studies showing that our sense of well-being peaks at 65, and even more encouragingly, that at 40 to 65, you’re better at reasoning than in your 20s.
In vocabulary and reasoning we get better, we see the big picture better, and we’re better at social expertise and sizing up the situation. In fact, the amygdala is the fight or flight structure in the brain, and when they watch it in middle-aged people, it responds much less to the negative than the positive.
How is being positive an adaptation?
It’s a subconscious but motivated choice because we know we have less time and that the tribe needs elders to survive better. (In a Stanford University study) middle-aged people were much faster at picking out small details on a happy-looking face than on an unhappy one. And it’s not that our brain gets lazy and wants to live out its days in some happy haze. It suits our goals—though we do it without knowing we’re doing it—we make it our business to sort out life this way. We focus more on the positive as we age because we want to.
| 20 |
| Vote |
Add To: 
subscribe to this blog
