Tuesday, July 27, 2010

The aging brain

IQ studies have always shown that IQ peaks in the late teens, flatlines until the mid 30s and then declines. The report below challenges that. But I don't think it is very persuasive. NOBODY has ever said that ability is the only factor in problem solving. Knowledge is usually very important too. All that seems demonstrated below is that knowledge accumulates as we age, which is not exactly controversial

According to the Secret Life Of The Grown-up Brain, by science writer Barbara Strauch, when it comes to the important stuff, our brains actually get better with age.

In fact, she argues that a raft of new studies have found that our brain hits its peak between our 40s and 60s - much later than previously thought.

Furthermore, rather than losing many brain cells as we age, we retain them, and even generate new ones well into middle age. For years it's been assumed that the brain, much like the body, declines with age.

The accepted view is that we gradually lose brain cells - up to 30 per cent of our neurons - as we get older, hence the forgetfulness, lack of focus and mental slowness we associate with senescence.

But the longest, largest study into what happens to people as they age, the Seattle Longitudinal Study, suggests otherwise.

This continuing research has followed 6,000 people since 1956, testing them every seven years. It has found that, on average, participants performed better on cognitive tests in their late 40s and 50s than they had in their 20s.

Specifically, older people did better on tests of vocabulary, spatial orientation skills (imagining what an object would look like if it were rotated 180 degrees), verbal memory (how many words you can remember) and problem solving.

Where they fared less well was number ability (how quickly you can multiply, add, subtract and divide) and perceptual speed - how fast you can push a button when prompted.

However, with more complex tasks such as problem-solving and language, we are at our best at middle age and beyond. In short, researchers are now coming up with scientific proof of what we've all known for years - we do get wiser with age.

Meanwhile, job-related studies have found that middle-aged people out-perform younger ones. In two trials, air traffic controllers and pilots were put simulators to see how they responded to demanding tasks and emergencies. While the younger colleagues were a little bit faster in their reaction times, the experienced professionals did as well or better in actually doing the job at hand — keeping the planes apart.

So what is it about our older brain that is so good? Traditionally, neuroscientists thought that millions of our brain cells died as we aged. Now, new studies show that while we can lose brain connections if they are unused, we keep most of our brain cells for as long as we live.

Furthermore, researchers have found that the amount of myelin increases well into middle age, boosting our brainpower. Myelin is the fatty substance which insulates the brain’s cells (the neurons) and makes the signals between them move faster.

It used to be thought that all our myelin was laid down in our childhood and adolescence, but now we know it goes on much longer. American scientists scanned the brains of 70 men aged 19 to 76, and found that in two crucial areas, the amount of myelin peaked at the age of 50, and in some cases in people’s 60s.

The study found that the amount of myelin increased in the parts of the brain we use the most — the frontal lobes (which control emotion, risk-taking and decision-making) and the temporal lobes (responsible for language, music and mood).

The neuroscientist who led the trial said this increase in myelin can boost our brain’s ability by up to 3,000 per cent, and is ‘the brain biology behind becoming a wise middle-aged adult’.

Scientists have also found that as we age, we start to use both sides of our brains instead of just one — a skill called bilateralisation.

For example, studies in which volunteers learned pairs of words revealed that younger adults used only their right frontal lobes when recalling the two words, while older adults used both the left and right side.

Scientists compare this to lifting a chair with two hands rather than one.

Drawing on these extra brain reserves is why older people can get to the point of an argument faster than a 20-year-old, and why they can analyse situations more accurately and solve problems.

Last month, U.S. scientists also found that the decisions we make when we are older are much better.

Researchers looked at the brain scans of 3,000 Californians between 60 and 100 and found that older people were more rational and wise in their solutions to problems.

This is because their brains are less susceptible to surges of dopamine — a hormone that can lead to impulsive decisions in young people.

Speaking at an international conference in Edinburgh, Professor Dilip Jeste from the University of California said: ‘The elderly brain is less dopamine-dependent, making people less impulsive and controlled by emotion.

‘Older people are also less likely to respond thoughtlessly to negative emotional stimuli because their brains have slowed down compared to young people. This, in fact, is what we call wisdom.’

Other good news is that we keep our long-term memory with age. True, as we get older our short-term memory deteriorates. The problem is not that the information has vanished, but that you have trouble retrieving it because we have so much other information stored in our brains — it’s like trying to finding the right book in a huge library.

However, our long-term memories survive. Research by the Mount Sinai School of Medicine in New York looked at the effect of ageing on the brains of rhesus monkeys.

In older monkeys, the brain lost half of message ‘receptors’ responsible for learning new things, but nearly all those associated with long-term memory remained intact.

And even though we may have more responsibilities and stresses, neuroscientists are finding that we are happier with age. A recent U.S. study found older people were much better at controlling and balancing their emotions.

It is thought that when we’re younger we need to focus more on the negative aspects of life in order to learn about the possible dangers in the world, but as we get older we’ve learnt our lessons and are sub-consciously aware that we have less time left in life — and it therefore becomes more important for us to be happy.


Anti-vaccination fanatics in Australia

It was precisely the imperfect takeup of vaccination that caused the death below. Universal vaccination would have made any whooping cough transmission very unlikely. So the fanatics do bear some responsibility for the death reported. In the circumstances, it is no wonder that they were very defensive

When their four-week-old baby daughter Dana died from whooping cough Toni and David McCaffery sought love and healing to ease their grief.

Instead, they say they were subjected to a campaign of harassment and abuse at the hands of anti-vaccination campaigners, a group who were yesterday labelled a serious threat to the public's health and safety.

The Health Care Complaints Commission issued a public warning against the Australian Vaccination Network after it refused to display a disclaimer on its website to inform readers its information should not be taken as medical advice.

Earlier this month the commission investigated the network, run out of Bangalow on the north coast by Meryl Dorey, and found its website presented incorrect and misleading information that was solely anti-vaccination and quoted selectively from research suggesting that vaccination may be dangerous.

Its investigation was sparked by two complaints, one from Toni and David McCaffery, whose four-week-old daughter Dana died from whooping cough last year.

The couple, from Lennox Head, allege they were subjected to months of harassment and abuse by Ms Dorey and anti-vaccination campaigners, accusing them of lying about the cause of their daughter's death. They received anonymous letters and emails that said whooping cough was not fatal and vaccinations were not needed.

Mrs McCaffery, whose daughter was too young to be vaccinated when she caught whooping cough, said Ms Dorey also tried to get her baby's medical records from the hospital without permission. "Instead of love and healing in the weeks after Dana's death, we got ugliness … it has been terrible," she said.

Mrs McCaffery also complained that Ms Dorey had quoted misleading statistics, spread misinformation through seminars and the internet, and gave poor telephone advice.

The second complaint against the network was made by Ken McLeod, a member of a group called Stop the AVN. He said Ms Dorey had claimed that meningococcal disease was harmless and "hardly kills anybody"; that vaccination was being used to spread AIDS in Third World countries; and homeopathy could take the place of vaccination.

His group now wants the state government to apply for a court injunction against the network and have it closed down. The group's website says Ms Dorey believes "vaccines are part of a global conspiracy to implant mind control chips into every man, woman and child and that the 'illuminati' plan a mass cull of humans".

Ms Dorey did not return calls yesterday but issued a statement on her website which said the HCCC's recommendation was "laughable" and she was seeking legal advice.

"Nobody would expect nuclear safety advocates to issue statements on the benefits of nuclear power; Greenpeace to make films on the pleasures of killing and eating whales … Why then should we be expected to make statements we don't believe are factual and that are not supported by the medical literature?

"If the AVN is expected to show both sides of this issue, why aren't the medical community and the government likewise cited for their lack of disclosure on the risks and ineffectiveness of vaccines?"

A spokesman for the HCCC said it could take no further action but it was disappointing the network was refusing to make its position clear.


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