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Teaching an old brain new tricks

columns Updated: Nov 10, 2013 01:55 IST
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This week, scientists got a monkey to use thoughts to control two virtual arms of its avatar using technology that will help people who are paralysed use a mind-controlled exoskeleton. For, apart from swinging from trees, humans can pretty much do everything that monkeys do, including surviving space rides and racist jokes.

In the past, monkeys and humans have moved a single prosthetic arm using electrodes placed in the brain that pick up specific patterns of electric activity that occurs when someone thinks about moving. Thought-motor coordination to move two arms, however, was too complex and proved to be a roadblock. Researchers at Duke University in Durham, North Carolina, overcame this hurdle and got their monkey to achieve bimanual movement by recording individual electrical activity from almost 500 neurons in the somato-sensory and motor cortex on both sides of the brain, the areas responsible for sensing body position, touch and movement.

And so, the monkey moved its avatar’s hands by just thinking of moving them.

This, coupled with the news that speaking a second language delays several forms of dementia in older adults by up to five years, has made this week exciting for bilinguals and people involved in brain research. The Hyderabad study found that speaking just two languages slowed the start of three types of dementia —Alzheimer’s disease, frontotemporal dementia and vascular dementia — by an average of 4.5 years. Speaking more than two languages, however, didn’t increase protection against dementia.

The Indian study confirmed findings of a 2011 Canadian study that also found bilingualism delayed symptoms of Alzheimer’s by five years. The findings held irrespective of the level of education and affluence. Being bilingual is very effective brain training because the brain has to selectively activate one language and deactivate the other. Next, the researchers are looking at whether people who learn languages later in life get the same benefits as those who grow up bilingual. Preliminary data suggests they do, so its never too late to pick up a new language to keep the brain whirring.

It’s well established that brain training keeps you mentally young, whether it is through doing crosswords, surfing the Internet, driving a car in challenging traffic, or simply playing video games. The popularity of video games that claimed to make you smarter peaked till 2010, when a study of 11,000 people showed that overarching brain-training games improved thought process only as much as surfing the Internet.

New research shows that training just one skill or ability at a time might tease apart the benefits of these games. Older people who played a 3D video game showed improvements in mental adeptness as they got better at the game over time, showed a study in the journal Nature in September this year. They continued to show improvements six months later, suggesting that the right kind of brain exercises staves off brain decline.

To train the brain, researchers created a video game called NeuroRacer that improved the players’ multitasking skills by having them drive a car with a joystick, while reacting to the signs that appear on screen. A month later, the group that played the multitasking game was significantly better not only at the game but also in tests that gauged the ability to concentrate and juggle several tasks at once. And the results lasted.

The brain is always changing and adjusting as it compensates for obstacles and adapts to circumstances. One experiment, for example, showed that the brain networks modified to deal with the loss of sight at all ages. Brain scans of people who had lost their sight at infancy and of those who’d lost it after age 10 showed that all of them, irrespective of when they had lost their vision, activated three areas in the brain related to language processing, including the area that processes visual information in sighted people.

And now the monkey’s thought-control experiment has shown that the brain can be taught to overcome physical barriers caused by injury, stroke and degenerative conditions. Apart from brain exercises, proteins called “nerve-growth factors” are being used to accelerate the reorganisation of neural activity in the brain after an injury or a stroke.

The downside of the brain’s plasticity is that this very adaptability can also slow recovery. Since the brain reorganises itself to counter changes, it has to re-adapt once again when the problem is gone. Speeding up this reorganisation can lower damage and accelerate recovery in people with stroke and other nervous-system disorders. Till scientists find a way, Duke University’s avatar option to think your way through life sounds quite attractive.