Mensa magazine's cover story, January 2015

Want to work better, play faster, react quicker? Devices which enhance cognition are set to be the must-have gadgets of 2015. As Rita Carter explains, they have taken a long time to arrive...

I was researching "Mapping the Mind," my first book about the brain, when I came across transcranial Direct Current Stimulation. "You’ve got to go and see Vince Walsh," insisted various informants, "he’s doing some really way-out stuff in his lab."

So, some 20 years ago, I found myself in a small room in Oxford University amid heaps of wires, batteries, oddshaped bits of plastic and empty food containers. The last could have been the remnants of someone’s lunch or - just as likely - one of the components of an early version of the world’s first non-invasive electronic brain enhancer. It didn’t look pretty, and I declined Vince’s generous offer of a "go". My excuse was that the saline needed to carry the current through my skull would muss up my hair. Actually, I was chicken.

tDCS, as it is now known, consists of a battery-powered current generator connected to two wires which end in sponge electrodes. You clamp the electrodes to your skull, turn on the generator, and a tiny current - something between one and two milliamps - passes from one electrode to the other via your cortex. Neurons beneath the "in" electrode (the anode) are stimulated, while those beneath the "out" electrode (cathode) are inhibited. The effect is to alter your brain and thus change your feelings, thoughts, perceptions and capabilities in - one hopes - a good way.

That’s the basic idea. It is not a new one and it wasn’t new in 1995. The technique is more or less what Luigi Galvani used in the mid-18th Century to make frogs’ legs twitch. Through this and other experiments - Duchenne’s grisly manipulation of facial nerves for example - it has been known for centuries that electricity can activate neurons.

Until recently the knowledge wasn’t much use for therapy or enhancement because no-one knew which neurons to target. ECT, in its early days, delivered a stonking great shock to the whole brain, sending it into convulsions. This sometimes had a remarkable therapeutic effect, but it also tended to leave people with holes in their memory. Not surprisingly, when effective mind drugs came along in the mid 20th Century the idea of using electricity on the brain was largely consigned to history. Then came modern neuroimaging techniques, PET and fMRI and other snazzy machines which reveal which bit of neural circuitry does what.

As the functional brain map got filled in the idea of electropsychiatry re-emerged. Only this time the idea was to target specific brain areas using a minute current. Stimulate Broca’s area, for instance, to increase your language capabilities. Improve movement by aiming at the motor cortex. In University labs like Walsh’s neuroscientists started to cobble wires and batteries together. Neuroscientific studies of tDCS came first as a trickle, then a flood. They reported, with various degrees of credibility, significant therapeutic effects on a massive range of brain-based conditions: depression, addiction, post-stroke aphasia and motor disability, migraines, tinnitus, autism, chronic pain - even Alzheimer’s disease and schizophrenia. The beneficial effect was not limited to fixing problems. It soon became clear that tDCS could help healthy people too, perking up learning and memory, speeding visual acuity and focusing attention.

Anything you want to do, it seems, tDCS could help you do better. What’s more, it was proving to be astonishingly safe. Apart from a scratchy sensation beneath the electrodes none of the study participants suffered significant adverse effects.

By 2010 word about tDCS was leaking out of the labs. The US military leaked the fact that its use had halved the time it took to train their drone pilots, and a New Scientist writer, Sally Adee (clearly less of a wuss than I) described how she put on the electrodes while playing a shoot-’em-up war game and was instantly transformed into a crack shot.

"I felt clear-headed and like myself, just sharper. Calmer. Without fear and without doubt. From there on, I just spent the time waiting for a problem to appear so that I could solve it. It was only when they turned off the current that I grasped what had just happened. Relieved of the minefield of self-doubt that constitutes my basic personality, I was a hell of a shot."

By this time commercial manufacturers were producing devices, but only at huge cost and for sale exclusively to research establishments.

Hence an enthusiastic tDCS-DIY community developed. Throughout the world people (mainly young men) started cobbling together batteries and wires and exchanging their circuit drawings and user experiences online.

About three years ago I borrowed one of the commercial tDCS machines - a £5000 chunk of East German engineering that came in an aluminium suitcase. The effect was life-changing.

My daily ‘stim sessions’ cheered me up, calmed me down, and, like Sally Adee, I found they shut up the insistent, nagging voice of excessive self-criticism and allowed me to concentrate on what I needed to do rather than all the reasons why I couldn’t do it.

Since then I have been one of a seemingly small group of people determined to get this potentially revolutionary technology out of the laboratory and onto the market.

Unlike ECT, tDCS does not necessarily cause neurons to fire during the treatment. Rather, the current causes molecular changes in the targeted cell walls so that the neurons are more (or less) likely to fire when they subsequently receive an appropriate stimulus.

For full effect a course of treatment is necessary - say five 20-minute sessions - ideally combined with brain-training.

Yet tDCS often produces immediate cognitive changes. For example, Allan Snyder, Director of the Centre for the Mind in Sydney, claims that tDCS can provoke instant creativity. In one study he linked two groups of volunteers to tDCS machines and gave both the giveaway "tingle" that suggested the current was flowing.

Then, unknown to them, he turned one group’s machines off, then asked all the volunteers to tackle the nine dots problem - a famously difficult one to solve. The challenge is to join all the dots without taking your finger (or pen) off the page or retracing your steps. Previous studies showed that the proportion of people you might expect to get it with out help was a fairly reliable zero.

In Snyder’s study, however, 40 per cent of the volunteers receiving active tDCS worked out how to do it, compared to none of the "sham" treatment group.

In another study tDCS was given to people while they looked at various works of art. Compared to another group who had the "sham" stimulation, those receiving active tDCS found the art more pleasurable. A similar study in which people were shown strangers’ faces found that tDCS caused them to see others as more attractive.

All of which makes the idea of a consumer device very appealing. But there are problems. The main one is the old one - knowing where to aim the current.

Practically all the research studies on tDCS have used montages (as electrode placements are called) arrived at by theory. For instance, it is known that the dorsolateral prefrontal cortex (DLPFC) - a spot on the front sides of the brain - is part of the working memory system and that it modulates emotions. Left DLPC is active when a person is engaged in a goal-oriented task, happily disregarding distracting self -criticism and even pain. Right DLPFC, by contrast, tends to be fired up by internally generated thoughts and tasks. Hence it figures that stimulating left DLPFC and inhibiting the right should reduce depression, which usually involves self-criticism, mental and or physical pain, and inability to direct attention outwards. In this case theory works a dream. Hundreds of research studies have now shown that this electrode placement gives depressed people relief that in some cases is equivalent to using an antidepressant drug. The DLPFC montage also boosts memory and helps control cravings. So far so good. But other montages, while theoretically sound, have failed to show consistent results. To reduce pain, for instance, researchers have tried placing the electrodes over the somatosensory cortex - the strip of brain which receives incoming stimuli from the body, including pain signals.

Theoretically it should work, and sometimes it does. But sometimes it doesn’t. More confusingly, sometimes what works seems to be a completely different set-up - placing the electrodes over motor cortex. No-one is quite sure why. And in some studies the anode and cathode - theoretically stimulatory and inhibitory - have been reversed and yet achieved the same result. One solution to this is to look inside the person’s brain before using tDCS . By seeing which brain areas are over or under-active you could work out which need to be inhibited or stimulated and the placement can be precisely targeted for the individual. The best research studies use fMRI machines to do this, but that sort of imaging technology is not available outside the best-endowed establishments.

A practical alternative is to use a new technique called quantative EEG (qEEG). Conventional EEG "reads" brain activity (in the form of brainwaves) through tiny electrodes placed on the skull.

The data is shown as wavy lines, each one corresponding to activity of the neurons beneath the electrodes. It has been in use for decades and is used mainly to look for brain injury, seizures and other neurological disorders.

qEEG uses the same hardware, but instead of displaying the brain’s output as wavy lines it computes the whole brain activity in real time and displays it as a movie. A skilled interpreter can see from it exactly which parts of the brain are "up to speed" and which are not. Using qEEG as a guide, tDCS can be targeted precisely for every individual. qEEG-guided tDCS is now available in the UK, but it is not possible for people to do it at home because there are still relatively few people qualified to interpret the scans.

Without the ability to look at brain function before using tDCS, the technology will remain a bit hit and miss. For this reason many people, including some of the neuroscientists who pioneered the technology, say tDCS is not ready to be let out into the wild.

The chance of brain stimulation attracting enough money to allow a full understanding of it in a short time is nil, however. As Professor Vincent Clark, a tDCS expert at the University of New Mexico, points out: "The pharmaceutical corporations get one third of a trillion dollars each year to do what they do... a simple, cheap, device like tDCS can’t compete".

Meanwhile pharmaceutical solutions to mental distress are notoriously ineffective. Even those that work often have horrible side-effects.

Another problem for tDCS is fear, especially among those people old enough to have seen the film One Flew Over the Cuckoo’s Nest on the big screen. "People are very scared about electricity and the brain," says Professor Clark, "but we need to make intelligent decisions here, not decisions based on having seen Frankenstein as a kid and been frightened by it. Those fears are not rational."

Certainly there is nothing in the data to suggest that tDCS is riskier than, say, taking a ski-ing holiday. Hundreds of thousands of people have now used it without harm. In fact the danger of people using tDCS casually probably has less to do with what harm the technology might do them and more to do with the harm they might do to the reputation of the technology. It would be all too easy for people to use tDCS so badly that it is ineffective and so becomes relegated to the category of complementary medicine (as in "probably-doesn’t-work").

If you are confident enough to use tDCS unaided, the first consumer tDCS devices are already on sale and in 2015 at least two more are due to come on the market. You can be sure that their arrival will be accompanied by the usual "don’t try this at home, folks" type of newspaper article.

This is not one of them - but please be careful with this technology. Casual misuse could do it great harm.

Brain stimulation