Times Online

It’s December 15, the morning after The Times’ Christmas party, and I have a single, looming appointment: 10.30am, Brain Zapping, UCL. I have agreed — in what now seems a moment of complete recklessness — to take part in a scientific experiment in which my brain will be temporarily “switched off”.

With some anxiety, and a little fear, I set out to meet my fate, which I have placed in the hands of Dr Joe Devlin, a neuroscientist at University College London. Devlin is using a technique called transcranial magnetic stimulation, or TMS, to investigate how the brain engages in arguably the most human of all activities: language. Administered via a large, key-shaped paddle held to the surface of the head, TMS sends powerful magnetic pulses through the skull and into the brain’s cortex and has the effect of a quick-acting, short-lasting stun gun. In my case, I’ve agreed to have an area of the brain that is vital for speech zapped into a state of dormancy. If all goes to plan, the experiment should render me quite literally speechless.

The underlying principle of TMS — knock out a particular brain region and see what your volunteer can (or can’t) do without it — is one that has driven neuroscientists since the first methodical studies of the brain in the 1800s. Until as recently as the 1990s, researchers were mainly reliant on freak accidents and surgical blunders to find out how people coped when an area of the brain was suddenly removed. In fact, neuroscientists refer to the effect of TMS as a “virtual lesion”, darkly hinting at the real injuries that litter the subject’s past.

A dramatic example is the case of Phineas Gage, a 19th-century US railway worker, who accidentally shot himself through the head with a metal pole that he was using to compress gunpowder. Despite the rod passing through Gage’s cheek and exiting through the top of his skull, destroying a large part of his brain en route, the 25-year-old somehow survived with most of his mental faculties relatively unimpaired. The one exception was his personality. Hard working and good natured before his accident, Gage became an ill-tempered, raving and, by all accounts, nasty individual. The transformation was so radical that his friends declared that he was “no longer Gage”. Personally tragic for Gage, the case was a milestone in brain science, providing the first evidence that the frontal lobe plays an important role in personality.

Sitting in the reception of UCL’s psychology department, the scientist in me says: “Relax. This is definitely safe.” The other 99 per cent of me is pondering a more disturbing possibility: what if, afterwards, like Phineas Gage, I am never the same again? What if I am wheeled out of UCL unable to utter anything apart from the word broccoli? It feels a bit late to pull out, though, and, as well as being nervous, I am also very curious to know how it feels to have your power of speech unplugged.

The morning’s session begins with Devlin taking a detailed MRI scan of my brain, down to a resolution of one cubic millimetre. Crucially, the image also captures my skull, ears and nose, which will be used later as reference points to match my head in the real world to a three-dimensional image of my brain on the computer screen. This allows the investigators to be sure about exactly which bit of the brain they are zapping.

After lying quietly and still in the scanner for about 15 minutes, listening to the machine’s inner clunkings and whirrings, the scan comes to an end and the bed zooms out, leaving me free to hop off and be led into the TMS room.

Devlin fits my head with a special headset, featuring four “tracking” beads, the movement of which is followed by an infra-red camera. Tracking the beads allows the position of my head — and by association my brain — to be matched to the MRI image. The TMS device, which looks like a giant black key and is powered by a cable as thick as a shower hose, also has a tracking bead. As Devlin waves the paddle around, its position shows up on the computer screen like a car on a GPS monitor — except that, rather than roads, the map shows my brain.

I learn that TMS works by generating a powerful magnetic field, which sends the neurons in the patch of brain directly below it into a frenzy of activity — to the point where they are temporarily exhausted. The stronger the magnetic field and the more pulses you receive, the more noticeable the effect. Today we’re aiming for a region in the left side of the brain called Broca’s area, named after the 19th-century anatomist Paul Broca. He deduced that the region was important after studying a patient called Tan — so-called because that was the only word he could say — who had damaged that part of his brain.

Devlin instructs me to start counting down while he lines up the TMS paddle ready for the first pulse. I take a deep breath: “Sixty, fifty-nine, fifty-eight …” Click! The paddle makes a loud snapping sound and I feel the muscles in the side of my face contract in a painless but unpleasant twitch. I’m still counting, though. Click! Click! Devlin ratchets up the power. “Fifty-seven, fifty-six …” Click! Click! Click! My left eye is twitching like mad and I feel a quivering sensation in my throat, but I’m still going. “Hmmm. You’re a difficult case,” says Devlin.

Some people require higher levels of TMS to silence them than others — possibly because their Broca’s area is buried deeper into the folds of the cortex, possibly because they have a thicker than average skull.

Devlin shifts the position of the paddle slightly, increases the power and tries again. The whole left side of my face is twitching like crazy. “Fifty-five, fifty-four, fifty-three …” Click! Click! Click! Click! And then it happens: “Fi … fi … fi …”

I’ve got the word right there in my head. I know how it sounds, but it just won’t come out. I want to speak but I can’t. “That’s it!” says Devlin triumphantly.

The next time I open my mouth — to say “Argh! That was weird!” — my speech is back. The experience of being muted is over almost too quickly to analyse what has happened.

Afterwards I ask how TMS has changed scientists’ views on language. “A lot,” Devlin tells me. The problem with the textbook case studies such as Phineas Gage and Tan is that there was no scientific way of measuring them before and after their accidents to find out exactly which abilities they had lost. After the onset of brain damage Tan couldn’t speak, but he was also partially paralysed and it was not clear how much he really understood. Concluding from this that Broca’s area controls speech is a bit like saying that an arm amputee has lost his or her “writing area”: true, but not the whole story.

However, until recently (so recently that you’ll find this in most neuroscience textbooks) the conventional view was that language is largely taken care of by just two brain regions. Broca’s area was credited with language production and a region called Wernicke’s area farther back in the left-hand side of the brain, had comprehension covered. If this sounds improbably simplistic, it is worth bearing in mind that many brain functions really do seem to be housed in their own distinct bit of brain — long-term memory in the hippocampus, vision in the occipital lobe (the back section of the brain), smell in the olfactory bulb (located at the front).

However, TMS studies are gradually overthrowing the textbook view and revealing that language involves a more complex network of activity. “Something like two thirds of the brain is involved in language processing. It’s a whole brain experience,” says Devlin.

One researcher who has pioneered this theory is Professor Friedemann Pulvermuller, a language specialist at the University of Cambridge. He is particularly interested in the relationship between language and action, and supports the philosopher Wittgenstein’s view that language “is woven into action”.

It is well established that listening to action words such as lick, pick and kick activates the brain areas that control the tongue, hand and foot. Pulvermuller’s research goes a step farther, suggesting that the brain’s action system does more than respond to meaning — he believes that it contributes to it.

To test this theory, Pulvermuller ran a study in which he stimulated different parts of the action system using TMS while volunteers listened to tongue, hand and foot-related words. The level of TMS was enough to increase the neuronal activity, but not enough to knock out the region. He found that stimulating the hand region made people quicker to comprehend hand-related words, such as stitch and pick. The same was true for foot-related words, such as kick and run, when he stimulated the foot area of the brain. “We found it wasn’t just a one-way flow from the language system to the motor system. People actually use these brain areas to understand the word,” he said.

Showing that we use our “foot area” to know what “kicking” means may sound like a trivial advance. But it demonstrates scientifically what great writers have instinctively known all along: that we don’t just understand words, we feel them.

The realisation paves the way for a framework in which our personal experiences subtly alter the way that we experience meaning. Pulvermuller’s next study will look at people, such as musicians, who are highly specialised in particular actions. He predicts that they will respond differently to non-specialists to certain action-related words, which for them have taken on a slightly different meaning.

Pulvermuller believes that linking action to language could be used therapeutically for people with language problems. He is investigating the relationship between language and action in people with autism, who typically have both communication problems and reduced motor control. He also thinks that practising simple actions, for instance tapping the fingers while practising saying hand-related words, could help to speed a person’s recovery of language after a stroke.

Purposely tapping into the physical power of language to manipulate the feelings of the reader could offer business opportunities far beyond producing the bestselling Mills & Boon of all time. It is an area that advertising and business executives are increasingly keen to explore.

Professor Michael Morris, a psychologist at Columbia University in New York, is interested in the metaphors used in the media to describe movements in stock prices. He says that the choice of words can influence an investor’s confidence in predictions. Agent metaphors — those linked to physical actions — are particularly potent, he says.

Morris led a study of three groups of university students who received graphs of stock market activity along with one of three versions of a commentary. One version described the price trends with agent metaphors — words such as jumped or climbed. Another used mechanical metaphors, implying that the movements were the result of external forces. Prices might have “dropped off a cliff” or “bounced back”. The third used non-metaphors such as increased or decreased.

“Regardless of the direction of the trend, people who had been exposed to the agent metaphors were more likely to forecast, or predict, that the market trend they had observed one day would continue on the following day,” says Morris.

He suggests that people engage more strongly and believe that they are more in control when they feel part of the action. “If you hear that ‘the market rallied’, you can imagine yourself taking part in the comeback,” he says.

Since publishing the study, a number of companies have contacted Morris for advice on how to take advantage of people’s reaction to agent metaphors. However, Morris believes that shrewd marketing officials take advantage of these effects instinctively.

In a separate study, he analysed companies’ ann-ual reports and letters to shareholders and found that they consistently described positive trends in terms of agent metaphors and negative trends in terms of passive ones. “You’ll typically see things like ‘We were swept down’ and ‘We fought our way back up’. People know intuitively that you can take ownership of the positive things and shirk blame for the negative,” he says.

The idea that we feel words as well as understand them, he adds, has wider implications for the “theory of mind” — the way that we attribute thoughts, desires and intentions to other people. There has been a long debate about whether we relate to other people by theorising about their point of view or simulating what it must be like to be them. Morris says that the latest research tilts the balance towards the more empathetic view. “It shows that simulation is implicitly embedded in language processing,” he says.

Morris’s favourite example of this is sports commentary. “When you listen to the boxing and hear your hero’s head was ‘pummelled’ you can almost feel it,” he adds.

Another researcher supporting the “whole brain” theory of language is Professor Matthew Lambon Ralph, a cognitive neuroscientist at the University of Manchester. He hopes to find out how language is represented in the brain by observing how it is gradually lost in dementia patients.

One of the most obvious symptoms of dementia is anomia — the inability to find the appropriate word for an object or concept. It differs from the language loss that I momentarily experienced (and that is often experienced by stroke patients) in that not only words but entire concepts are lost.

One thing that Lambon Ralph is keen to do away with is the idea of a “mental dictionary”. He sees words as being positioned on a mental grid, where those with similar meanings are clustered together. With the onset of dementia, neighbouring words slowly begin to merge into each other and concepts that were once distinct are lost. The ability to distinguish between a golden retriever and a springer spaniel might be the first to go. Then cat and dog might become confused, until the person is left with only the general concept of “an animal”.

“Words don’t drop out as though someone’s ripping pages out of a book. It’s more like losing your eyesight, they go fuzzy,” says Lambon Ralph. He illustrates the idea with an example of a female patient with semantic dementia. On being asked to copy an image of a duck, she sketched it almost perfectly, showing that she was quite capable of taking in information and following instructions, but when asked to wait and draw from memory, a very different effect was seen.

With a ten-second delay, she gave the duck a turkey-like head, a hint of an eyebrow and started to draw a third leg before remembering that they had only two. With a 60-second delay, the duck became a four-legged abstraction with a frilly tail, a pronounced eyebrow and a smile.

“The initial copy was very good, but with a delay you have to rely on recalling the meaning of what you have seen,” says Lambon Ralph. “As understanding is distorted, confusion sets in. Birds start to be confused with other animals and the end result is a four-legged duck.”

He shows me similar examples in which two patients were asked to copy a picture of a rhinoceros. After 60 seconds, it had lost its horns, developed a more dog-like face and grown large ears. There is a consistent tendency among patients to gravitate towards the most generic animal traits. Unusual traits, such as rhinoceros horns, are typically omitted; standard traits, such as tails, are often added to tail-less animals.

Interestingly, this sort of over-generalisation is not restricted to language, but tends to extend to many aspects of behaviour. For instance, during a meal with Lambon Ralph, a patient who was accustomed to drinking tea stirred sugar into his glass of wine.

Lambon Ralph believes that this is indicative of how we arrive at concepts in the first place — from a recipe of distinct contributions from the more primary systems in the brain. Any concept is made from a unique combination of inputs and as these are lost, so is the ability to understand and express distinct concepts. “I see it like baking,” he explains. “If you’re baking a sponge, biscuits or croissants, although the products are different, they all use the same ingredients. As you lose ingredients, the number of things you can make becomes more limited.”

Just as revealing, the professor says, are the aspects of language that are the last to go. Even in the advanced stages of dementia, patients can retain a good grasp of grammar. In one study he asked a patient to explain the meaning of the sentence: “The boy rides the horse”. Her response? “If you tell me what a boy is and what a horse is then I’ll tell you what it means.”

An understanding of the structure and syntax of language endures even after the meaning of the words is lost. Some neuroscientists argue that this demonstrates the extent to which language is hard-wired into the human brain.

The idea of language being stripped back to the bare bones of its grammatical architecture puts my own momentary speech loss into perspective. It is still impossible to imagine thinking without language — all that happened to me was that I lost the ability to broadcast my thoughts.

Language may not have a corner of the brain that it truly can call its own; but that it hijacks almost all of the brain for its own ends is what makes it perhaps the crowning glory of human evolution.