The use of electricity to alter the functioning of the brain and body was widespread in the past. George Orwell, for one, might have been surprised how little we use it today. By the time he was shot in the throat during the Spanish Civil War in 1937, the medical treatment used to save and restore his voice included a routine blast of direct current, then known as electrotherapy.
While Thomas Edison’s team in New York was building the first electric chair, medics at Guy’s Hospital in London had established an Electrical Room to treat both physical and mental disorders. Electrical therapy was given to promote wound healing and to relieve pain and to try to treat various diseases including tuberculosis.
The ability to pass electricity through the skull and so into the brain offered the most potential to these Victorian pioneers. Nineteenth-century psychiatrists craved the respect they saw heaped onto their colleagues who specialized in physical ailments, and saw electrotherapy as the answer. Asylums of the insane gave them the opportunity to experiment, which they did with gusto. Patients with what we would now call depression, anxiety and schizophrenia sat with their bare feet in a bucket of salty water while electrodes were touched to their heads and spine.
Results were mixed, and the theoretical basis offered to support claimed clinical improvements was fuzzy. Some scientists said electricity acted as a fluid passed to the brain through the blood vessels. It was said to both increase and reduce blood flow; it was described as both a sedative and a stimulant.
Electrotherapy peaked when it was heavily used by both German and British scientists during the First World War to treat cases of the newly emerged shell shock and return men to the front line. It was generally given to the lower ranks and officers escaped. One British doctor who used it on soldiers argued it would be less effective on men of more senior rank, as their superior intelligence and education meant their mental conditions were more complex, and so they needed more sophisticated treatment.
In his semi-autobiographical novel, Voyage au Bout de la Nuit, which described his war experiences, the French writer and medic Louis-Ferdinand Céline described how an army doctor had ‘installed a complicated assortment of gleaming electrical contraptions which periodically pumped us full of shocks’. The treatment, he wrote, ‘had a tonic effect’. Céline was not the first to claim electricity applied to the head could go further than just treating and alleviating symptoms. Regular reports had surfaced by then about electrotherapy also enhancing mental performance.
The Dutch physician Jan Ingenhousz wrote that, following an electric shock in Vienna in 1783, he initially lost his memory and judgement. But, after several hours’ sleep, he woke to find his ‘mental faculties were at that time not only returned, but I felt the most lively joye [sic] in finding, as I thought at the time, my judgement infinitely more acute’. He said he could now see ‘much clearer the difficulties of everything and what did formerly seem to me difficult to comprehend, was now become of an easy solution’. At around the same time, a German doctor treating a boy with electricity for malarial fever reported he became ‘quicker of mind’.
In 1899, the French doctor Stéphane Leduc described how one of his patients, an elderly judge he had treated with electricity for facial paralysis, continued to request the treatment long after his symptoms improved. Electric current to the head, the judge claimed, improved his mental rigour.
The judge said he felt:
‘. . . lighter and my ideas are more clear. I can concentrate my attention more closely upon my work. I struggle more successfully against the sleep-producing effects of long pleadings; I grasp more clearly the arguments which are advanced before me, and I can weigh them more exactly. In fact, I find my intelligence is brighter and my work is easier to do, and for that reason I come to you for an electrical application whenever I am confronted by a fatiguing or difficult piece of work.
Mainstream science rediscovered the technique in 1999. Psychologists in Germany interested in finding new ways to treat epilepsy used electrical brain stimulation to probe working memory and motor learning. Their tinkering with electric current and the brain was not popular with colleagues. ‘It’s fucking dangerous,’ they were told. ‘You should stop this immediately’. And due to a shortage of volunteers they were forced to experiment on themselves and their families.
Since then, electricity has been applied to the brain to try to change just about every cognitive function, with some success. Probably the most well-known successful experiment was carried out by scientists in New Mexico. It gets quoted a lot because it seemed to improve the way a group of volunteers learned to spot potential threats by picking out concealed objects. It gets quoted more because it was paid for by the US military.
Before it deployed soldiers to Iraq, the US Army made them play a video game called DARWARS Ambush! to simulate what they would encounter. The game got recruits to scan virtual landscapes for potential threats – a sniper on a rooftop or a bomb in an oil barrel – and taught them to do it quicker and more accurately.
In the study, the scientists borrowed still images from this virtual reality game and showed them to civilian volunteers, who were given a matter of seconds to scan them for disguised or hidden dangers. They were told they were in charge of a mission, and the stakes were high. If they caused a false alarm by seeing a threat where there wasn’t one then they were scolded for delaying the operation. If they missed a bomb, hidden sometimes inside a dead dog or a child’s toy, then they were shown a simulated video of the explosion and its grim aftermath.
Most people struggled at first, but gradually learned and improved. And the scientists found electrical stimulation to the brain speeded this mental process. Volunteers who had a 2mA current applied to the right side of their skull, above their inferior frontal cortex or right parietal cortex, improved twice as fast as the others. (Although one dropped out because they said they experienced a burning pain.)
The effect lasted for at least an hour after the current was switched off, which suggests the stimulation might have provoked lasting change in the brains of the volunteers. As well as making neurons more responsive, such current is believed to increase the expression of proteins at the junctions between them. This might make them more prone to form connections, and see the brain moulded more easily into a lasting shape. The current, in other words, could make it easier for connections to form, and more likely that those connections would persist. Neurons that fire together, brain scientists say, wire together. Those connections, as we have seen, determine differences in cognitive performance and so intelligence.
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There is lots of hype around the potential for electrical brain stimulation. Scientists hate hype, or at least they say they do. But they know a little bit of hype in a press article or radio show draws attention, and there is no such thing as bad attention. The only thing worse than being written about, for scientists who want grant money, is to work in a field never written about.
The way most scientists try to avoid hype is to include caveats, and to stress research is preliminary. But, equally, the universities and funders who pay most of these scientists’ salaries want to know something might come out of the work they are investing in. So when scientists present their research – to bosses, politicians and journalists – they often engage in a kind of game in which they seek to emphasize the potential pay-off of their work, but avoid saying when those pay-offs could realistically be delivered.
The potential pay-off for research on brain stimulation is extraordinary. That’s not hype. Here are some statements written about the possible applications of brain stimulation by proper scientists in professional academic books and journals, to be read by their equally proper peers:
Contrary to the popular belief of ‘no pain, no gain’ [brain stimulation] has been shown to accelerate learning and skill acquisition in complex learning tasks that normally take a long time to master and in a range of fundamental human capacities from motor and sensorimotor skills to mathematical cognition, with minimal discomfort or adverse side effects.
And:
Improved attention, perception, memory and other forms of cognition may lead to better performance at work, school and in other aspects of everyday life. It may also reduce the cost, duration and overall impact of illness.
And even:
A future with people wearing portable devices helping them stay awake during nightshifts or while driving a car, or improving their motor coordination during an intense track and field training session is becoming a more and more plausible and socially accepted scenario.
We’re not there yet, but the field is growing fast, and scientists are working to improve the techniques, with research to map brain function in more detail and equipment that promises more accurate current delivery.
Given the scope and boldness of the statements above, it’s not surprising that people like Andrew, who we met at the beginning of this book, want to try brain stimulation for themselves. Largely outside bona fide research institutes and universities and beyond the reach of any regulation or control, Andrew and others like him are building brain altering equipment and using it on themselves. They swap stories, techniques and tips over specialist sites on the internet. They film their experiences and upload them to YouTube. They are attracting attention – the day after I met him, Andrew was due to be interviewed and filmed by CNN – and the underground brain stimulation movement is starting to poke its electrodes into the mainstream.
Until recently, someone who wanted to try DIY brain stimulation really did need to do-it-themselves. The kit – wires and battery chiefly – could be bought easily. But it tended to be a specialist pursuit. That changed in the summer of 2013 when a US company began to sell readymade headsets. For £179, the company promised a quick and easy plug-’n’-play brain stimulator. And forget the noble goals, or not, of raising intelligence. Its target market was to speed the reaction times of computer gamers.
Officially, most scientists in mainstream research frown on the DIY community, and not just because many of the DIYers like to be known as brain hackers. Sombre articles in scientific journals warn of potential dangers to the inexpert crowd and scoff at some of the amazing effects many of the DIY individuals claim to have achieved. But it’s a strange relationship. Brain stimulation is still a niche academic discipline, even within neuroscience, and the brain hackers are the scientists’ biggest fans. They pore over academic papers and abstracts of talks to be presented at academic conferences, rifle through the details and search for experts who are looking into specific issues and conditions.
Even the mainstream scientists aren’t fully sure what happened to my brain when Andrew fitted me with the brain stimulator and slid the switch to ‘on’ that day in his flat. But they think it goes something like this.
Electric current needs to flow in a circuit, hence the two electrodes attached to my head. One takes the juice from the batteries and floods it into my head, and the second soaks it up again and sends it back to the batteries. Part of the reason the electric chair is so messy and unpredictable is the human body isn’t a reliable conduit for electricity. Bones, skin, muscles, hair – all of it puts up more or less resistance to the current, which ends up trying to find its own, quickest, way back out again.When Andrew directs the electric current from the first electrode onto the top of my head, the path of least resistance to the second electrode is through the narrow bridge of bone that arches over the top of my head. So most of the current heads across my scalp and never actually gets into the brain at all. Electrical brain stimulation, it turns out, is mostly electrical skull stimulation, and the skull doesn’t do much in response. It warms a little, and the skin on the top gets a bit itchy.
In a grisly demonstration of this lack of electrical penetration, two scientists announced in 2016 that they had fitted an electrical brain stimulator to a human corpse. Like the US poet Walt Whitman, the deceased had left his remains to science, and this time science made sure it took advantage. Passing electrical current into the head of a cadaver in a laboratory is straight from the pages of Mary Shelley’s Frankenstein but these scientists, if anything, showed the opposite effect: hardly any of the current got through into the brain, they said, certainly not enough to directly activate tissue in a living brain and make it work.
To detect the electricity coming in, the scientists placed 200 electrodes into the corpse’s brain. But when they turned on the electrical stimulator, these brain electrodes barely noticed. Only about 10 per cent of the current applied through the electrodes pressed to the side of the dead head made it into the dead brain. To directly activate brain cells, the scientists estimated, brain stimulation would need to double the current applied to the brain from its standard of 2mA to 4mA. That’s not recommended. One of the scientists tried 5mA of stimulation on himself and said the dizzying effect was alarming.
The study received a lot of attention, and was widely presented as showing electrical brain stimulation was a waste of time. But that’s not true. For the goal of electrical brain stimulation is not to activate neurons directly, and nobody who does research with the technique ever thought it was. The effect is indirect: rather than making neurons fire, the extra applied electricity makes it easier for them to be fired. And that takes much less current – certainly the 10 per cent that made it through the corpse’s head should be enough.
The current Andrew uses penetrates about an inch into my brain. That’s not far enough to reach all useful regions, but it does cover a lot of the higher functions, which are controlled by my cortex – the wiggly furrowed layer on the outside.
Once inside my brain, the current needs to come out again. To do so, it struggles through the cells and blood of my grey matter and white tissue until it reaches the area underneath the second electrode that will carry it back to the battery and complete the circuit.
As the current continues to flow from the battery, it sets up a predictable dynamic inside my head. In a region of brain tissue under the first electrode current floods in. And in a distinct region under the second electrode, current pools to leave again.
Under the first electrode – the anode – the indirect impact on my neurons makes them more willing to activate. Exactly how this happens is unclear, but the current seems to nudge the neurons towards an electrical state known as depolarization. This makes them more sensitive to signals that arrive from other cells. So with the same amount of effort my brain can induce more activity in the charged region.
Underneath the second electrode – cathode – it’s a different story. It’s the polar opposite and the effect of the current on the neurons there is something called hyperpolarization, which makes the neurons less sensitive to incoming messages. This makes it harder for my brain to activate that region.
With correct and careful placement of the electrodes, that gives scientists the ability to turn bits of the brain up and turn other bits down. In his hands, Andrew holds a conductor’s baton, which can quieten my brain’s percussion and swell its brass section at the flick of a switch. So let’s see what type of tune it can play.