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Mental muscle: six ways to boost your brain

http://www.newscientist.com

Breathe in, breathe out. Breathe in, breathe out. I crack open an eye. Everyone else has theirs closed. I shut it again. Breathe in, breathe out. Around me people are sitting crossed-legged, meditating. For some it’s spiritual, for others an oasis of calm. Me? I’m building a better brain.

A few months ago I would probably have bought a brain-training game, but alas, it turns out they are probably useless. Although your performance on the games improves, that effect doesn’t seem to translate into the real world (see “The rise and fall of brain training” at end of article). With that in mind, I wondered if there was anything else I could do to give my grey matter a boost.

Our brains are constantly adapting to information from the world around us. However, some activities make a bigger impression than others. In recent years, researchers have been probing how outside influences, from music to meditation, might change and enhance our brains.

One of the most promising is music – and not via the famous but controversial “Mozart effect”, whereby merely listening to classical music is supposed to improve brain performance. Learning to play an instrument brings about dramatic brain changes that not only improve musical skills but can also spill over into other cognitive abilities, including speech, language, memory, attention, IQ and even empathy. Should I dust off my trumpet and get practising?

Musical training, especially at a young age, seems to significantly alter the structure of your brain. For instance, after 15 months of piano lessons young children had more highly developed auditory and motor areas than their untrained peers. These brain areas are very active when you play an instrument (Journal of Neuroscience, vol 29, p 3019).

Professional musicians have an increased volume of grey matter, which routes information around the brain, in areas that deal with motor control, audition and visuo-spatial processing (Journal of Neuroscience, vol 23, p 9240). Musicians who started training before the age of 7 also have a thicker corpus callosum, the bundle of nerve fibres that shunts information between the two halves of the brain (Neuropsychologia, vol 33, p 1047).

These structural changes have been shown to tally with the development of musical ability. But can music reach outside of its own domain and improve other aspects of cognition?

The tentative answer is yes. Musically trained people perform better on tests of auditory memory – the ability to remember lists of spoken words, for example – and auditory attention. Children with a musical training have larger vocabularies and higher reading ability than those who do not (Nature Reviews Neuroscience, vol 11, p 599). There is even some evidence that early musical training increases IQ (Psychological Science, vol 15, p 511).

Better learning

Patrick Ragert at Ruhr-University Bochum in Germany and colleagues have an idea why this should be so. They found that professional pianists were much better than non-musicians at a standard test of spatial acuity – the ability to discriminate two closely separated points. Crucially, they also improved faster with practise (European Journal of Neuroscience, vol 19, p 473). This is evidence that the brains of trained musicians are more plastic, says Ragert, suggesting that learning an instrument may enhance your capacity to learn other skills.

This can even extend to languages. Trained musicians are better at discriminating pitch changes in made-up words similar to those found in Mandarin, a “tonal” language where such changes can alter the meaning of a word. This is evidence that they are better equipped to learn new languages (Applied Psycholinguistics, vol 28, p 565). And that is not all. Music training has even been shown to enhance empathy because it fine-tunes your ability to recognise emotional nuances in speech (Annals of the New York Academy of Sciences, vol 1169, p 209).

Much of this research has been done in children or professional musicians who started training very young. Developing brains are known to be more malleable than adult ones – for music, there seems to be a sensitive period at around 7. So would the same kind of training make any difference to me? “Those who begin musical training earlier in life see greater enhancements,” says Dana Strait, who works in music cognition at Northwestern University in Evanston, Illinois. “But all signs point toward musical training being powerful at any point in life.”

So if I resumed trumpeting where I left off, I could potentially enhance my brain in all sorts of ways (while simultaneously delighting my neighbours, no doubt). But years of practise seemed a little daunting, so I went off in search of a shortcut.

That’s why I found myself sitting in a small room with two electrodes stuck to my head. It sounds like something you’d see in an episode of 24, but I was being set up for a trial of transcranial direct current stimulation (tDCS), a way of enhancing brain activity using an electrical current.

The current is tiny – just 1 to 2 milliamps – and though the mechanism is not fully clear, tDCS appears to increase the excitability of neurons, making active areas of the brain work even harder. Depending where you place the electrodes, it can lead to an enhancement in cognitive functions including attention and vision (Neuropsychologia, vol 48, p 2789).

Roi Cohen Kadosh, a neuroscientist at the University of Oxford, is particulary interested in tDCS’s potential to give our brains a boost. He has been looking for the part of the brain that is responsible for mathematical ability. In 2007, he pinpointed this to the right parietal lobe, just above the right ear. When his team “short-circuited” this area using transcranial magnetic stimulation (TMS) – a stream of magnetic pulses which temporarily disables a targeted area of the brain – they found that people got worse at numerical tasks. In fact, their performance resembled people with dyscalculia, who have difficulty comprehending mathematics.

Having disrupted our ability to use numbers, Cohen Kadosh wondered whether he could improve it too.

He now has his answer. Cohen Kadosh managed to improve numeracy in volunteers by applying tDCS to the right parietal cortex.

He zapped his volunteers while they familiarised themselves with made-up symbols representing the numbers 1 to 9. The volunteers had no idea which symbols stood for which number but had to work it out by trial and error. After each training session they were given tests to see how well they could perform calculations using the symbols.

Those given tDCS learned the symbols faster and did better in the tests than those given a sham procedure. It did not affect other brain functions, Cohen Kadosh’s team found.

Cohen Kadosh, who announced his results at a conference at the University of Oxford in June, had another surprise in store – the improvements have lasted six months so far.

Since we constantly encounter numbers in our daily life, Cohen Kadosh said it is really important that people who have difficulties with numbers know about these kind of options for improving their cognition, as an alternative to drug therapies.

Electricity can also boost visual memory. Richard Chi and colleagues at the University of Sydney, Australia, used tDCS to increase activity in the right anterior temporal lobe, near the temple, which is involved in visual perception and memory. His volunteers experienced a 110 per cent improvement in a subsequent visual memory task compared with a group who received a sham treatment (Brain Research, vol 1353, p 168).

It doesn’t take a huge leap of imagination to see where this could all be heading. Cohen Kadosh reckons tDCS could be packaged into a portable gadget. “In the future I can see it being of use in schools or at home, to advance the abilities of children with learning difficulties.” He says that it is much safer than other types of brain stimulation because tDCS does not cause neurons to fire directly, it merely makes them more responsive.

Bright lights

Direct current may not be the only way to boost your brain at the flick of a switch. Light, too, can have some surprising effects on cognition that have nothing to do with vision.

We understand pretty well how our brains process visual information and use light to regulate the body clock and hormone secretion, but have only just begun to realise the extent to which light can directly affect brain function. Several studies have shown that simply exposing people to light improves performance on many cognitive tasks.

In these studies, volunteers with normal vision were given a variety of tests while exposed to bright light during the day. Their performance in visual searches, mathematics, logical reasoning and reaction time all improved with exposure to bright light (Trends in Cognitive Sciences, vol 13, p 429).

This appears to be because light boosts alertness. In another study, volunteers had their brains scanned as they performed a short-term memory task while exposed to either violet, blue or green light. The scans revealed that after just a few seconds of light exposure an area of the brain stem known to play a role in alertness became more active (PLoS One, vol 2, p 1247). Blue light was the most potent. Similarly, in simple reaction tasks, exposure to blue light is more effective in sustaining cognitive performance than green light (Sleep, vol 29, p 161).

These effects are probably mediated by a recently discovered pigment in the retina called melanopsin, which is not involved in vision. Melanopsin absorbs pale blue light better than other wavelengths, which is not surprising as natural light contains a lot of blue. But exactly how it boosts cognition remains unclear.

“No doubt further research will expand our understanding of the characteristics of the light environment that are required to optimise brain function,” says Gilles Vandewalle, a neuroscientist at the University of Montreal, Canada.

That, however, is one for the future. I am looking for a brain boost right now. Perhaps I should stop thinking about my brain and concentrate on my stomach.

Brain food

Many foods contain chemicals that have been claimed to boost mental performance. Perhaps the most famous are omega-3 fatty acids, found naturally in oily fish, walnuts and green vegetables, and increasingly added to processed foods such as bread and yoghurt. For years these have been touted as the quintessential brain food – but the most recent evidence suggests that they do little or nothing to improve mental powers (New Scientist, 15 May, p 32).

Even so, the dream of brain-boosting through diet lives on. Attention has now shifted to another group of chemicals, the flavonoids, found in fruits such as blueberries and blackcurrants and also in cocoa, green tea and red wine.

Jeremy Spencer at the University of Reading, UK, is investigating the brain-enhancing effects of food. In experiments on rodents his team has shown that eating dietary quantities of flavonoids can lead to enhancements in memory and protect against degeneration of the brain (Chemical Society Reviews, vol 38, p 1152).

A pilot study suggests that something similar applies to humans. “We looked at the effect of blueberries and found they improve attention,” says Spencer.

Spencer also took blood samples from the volunteers. These suggest that flavonoids activate biochemical pathways that increase the expression of genes linked to memory.

For example, flavonoids are able to raise levels of brain-derived neurotrophic factor (BDNF), a protein known to be important for learning and memory. BDNF is a growth factor that stimulates the development of axons linking one brain cell to the next.

Spencer suggests that the effect may also trigger increased communication between brain cells. However, flavonoids are also known to affect the circulatory system, lowering blood pressure and increasing elasticity of blood vessels. In this way, they have been shown to increase blood flow to the brain. This is known to be good for mental performance, possibly via the generation of new neurons in the hippocampus through the triggering of stem cell differentiation. “Eating blueberries could stimulate neuronal growth through increased blood flow to this area,” says Spencer.

“They appear to have almost drug-like effects,” Spencer adds. “It’s quite possible that these food-derived components may be used in the future as precursors for mind-enhancing drugs.”

Chris Bird, a neuroscientist at University College London, says that the preliminary results look promising, but questions whether a flavonoid-rich diet would have noticeable effects in the real world. “I will continue to eat them and hope that they might be doing something good for me,” he says.

Another promising compound is based on magnesium. Earlier this year Guosong Liu and colleagues at the Massachusetts Institute of Technology reported the results of feeding a magnesium compound, magnesium-L-threonate (MgT), to rats. They found it significantly raised magnesium levels in the brain and led to increases in both spatial and associative memory in young and old rats (Neuron, vol 65, p 165). Liu also showed that boosting magnesium in the brain increases synaptic plasticity in neurons and neurogenesis – the production of new neurons – in the hippocampus. If it can be safely adapted to humans, the authors suggest that this dietary supplement could boost cognition.

And after all that brain food, it might be time to pay a visit to the gym. While regular exercise certainly increases blood flow to the brain, in rats at least, whether it holds true for humans is still a matter of debate.

Since monkeys are more comparable to humans, Judy Cameron at the University of Pittsburgh, Pennsylvania, trained monkeys to use treadmills to see if it affected their mental agility. One group of monkeys worked out for an hour a day five days a week. Another group spent the time sitting on an immobile treadmill. Five weeks in, all the monkeys were given a task where they had to learn which object covered a food reward. The monkeys that had worked up a sweat were twice as fast at this exercise as those that had been sedentary (Neuroscience, vol 167, p 1239).

Analysis of brain tissue showed that the runners had a greater volume of blood vessels. Since blood delivers oxygen and nutrients to the brain, this could explain why exercise increased their cognitive function.

Concrete evidence that exercise improves brain function in humans has been harder to find. Numerous studies have shown that moderate exercise can slow age-related decline. But in August, researchers at the University of Illinois at Urbana-Champaign showed that daily walking improved executive functions such as planning and abstract thinking in younger adults (Frontiers in Ageing Neuroscience, vol 2, article 32).

Although scientists still do not know how exercise benefits the brain, studies like these, together with those in animals, hint that physical activity may spur the growth of neurons in regions important to memory and improve activity in areas that are responsible for executive function.

Key chemicals that might be involved include BDNF and vascular endothelial growth factor (VEGF), which aids blood vessel growth. Several animal studies have shown greater concentrations of these chemicals in animals that have exercised, suggesting that a workout literally helps them grow a better brain. In humans BDNF levels have also been shown to increase after exercise.

In both animals and humans, excessive exercise had the opposite effect, diminishing levels of BDNF, which might mean that moderate bursts of activity promote the right chemical building blocks for a better brain.

So if I can improve my brain with music, light, blueberries and exercise, why am I here, sitting crossed-legged, concentrating on my breathing?

Humans have strived to gain enlightenment and control over the mind through meditation for centuries. But while practitioners have claimed a number of brain benefits, few have been well tested scientifically.

Meditate to accumulate

So when, in 2005, the Dali Lama famously challenged neuroscientists to test the memories of monks, several groups of investigators jumped at the chance. They travelled to monasteries in Nepal to test Buddhist monks. The initial results were disappointing. They found no difference in visual memory tests between monks who meditated regularly and non-meditators.

Then they tested a monk immediately after a meditation session. “He showed unbelievable performance,” says Maria Kozhevnikov, then at George Mason University. It turns out just 20 minutes of daily yoga meditation improved both visual memory and spatial skills dramatically, but the boost was short-lived (Psychological Science, vol 20, p 645).

Since then, evidence has piled up that intensive meditation training – say 10 hours a day for three months – enhances attention and executive function. And earlier this year a team led by Fadel Zeidan of Wake Forest University School of Medicine in Winston-Salem, North Carolina, reported that just four 20-minute training sessions improved visuo-spatial processing, working memory and executive functions in people who had never meditated before (Consciousness and Cognition, vol 19, p 597). Bruce O’Hara at the University of Kentucky in Lexington even showed that meditation appears to improve vigilance and reaction times (Behavioral and Brain Functions, vol 6, p 47).

Do these findings suggest that it’s worth practising meditation before doing something mentally challenging? Although the data is limited, O’Hara thinks it might help. “Meditating prior to studying or taking an exam could be beneficial. The improvements may be small, but worthwhile.”

So who needs brain training? With so many options at my disposal, I have no excuse for not keeping my brain in tip-top condition. The right diet, a spot of exercise and meditation and a bit of sunshine are all I need. Perhaps some of it really will help me to build a better brain over the coming years. At the very least, I’ve got an excuse for a glass of red wine.

The rise and fall of brain training

Once touted as the fastest way to hone your mental powers, brain training software has now been consigned to the shelf of technologies that failed to live up to expectations. What went wrong?

The big question was whether getting better at the game would translate into general cognitive improvements. Some trials have shown success, but have been criticised for being too small to produce meaningful results.

No large, published trial has yet shown concrete evidence that brain training has an effect on real world activity. In fact, the largest trial ever found that it doesn’t work.

Early this year, a team led by Adrian Owen of the MRC Cognition and Brain Sciences Unit in Cambridge, UK, got over 11,000 volunteers to do either online brain training or surf the web to find answers to a set of obscure questions.

All the volunteers showed improvements in the task they were assigned, but there was no difference between the groups on other tests of cognition. The conclusion? There’s no evidence that brain trainers improve general cognitive functioning (Nature, vol 465, p 775).

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