My Plastic Brain

by Caroline Williams

  The cool thing about this technology is that it has shown that, when a person learns to control activity in one brain area, such as the insula or amygdala, it not only boosts the brain region that person is working on, but, as you might expect, it improves connectivity throughout the rest of the network, too. Something similar has been found for the prefrontal cortex's links with the inferior frontal gyrus (an area associated with the “flow” state) after just a few training sessions.7

  The other big advantage of fMRI over EEG is that it can track changes in any part of the brain—whereas EEG struggles to pick up a signal from areas deeper than the wrinkly outer cortex, lots of interesting things happen deep in the brain, and it is interesting to find that these can be targeted directly, too. Of course there is a considerable downside: you need a huge MRI machine rather than the few electrodes and wires required for an EEG, so it's nowhere near being useable at home, but for research purposes—to see what is physically possible through neurofeedback—it's proving very interesting.

  The hope is that this kind of technology could one day be used to help people with brain or psychological disorders to “normalize” the workings of their brain, and eventually to give those who want to improve their brain function a good shot at selecting and working on particular skills. It's a way off yet, but it's there, being fine-tuned every day, informing the development of technologies that, one day, anyone could use. A recent review of the technique concluded that there are plenty of unanswered questions, including whether activity can be dialed down as well as up and whether people can continue to change their brain's activity outside of the scanner.8 If the answer to the second question turns out to be no, then it's a dead end for most of us unless someone makes MRI scanners considerably smaller and cheaper. On the other hand, as these new states are recognizable to the person experiencing them, and teachable by other means too, it opens the possibility of training people to work their brains in the right direction and then sending them home to carry on with it indefinitely.

  Another development that sounds way more sinister is the even newer world of covert neurofeedback. Weirdly, it seems that you don’t even need to be part of the equation while your brain's activity is being altered. At the 2015 Society for Neuroscience conference in Chicago, Michal Ramot, of the National Institute of Mental Health, in Bethesda, Maryland, presented data from her recent experiments in which volunteers learned to change neural activity in two areas of their visual cortex (at the back of the brain). When playing a game in the scanner, volunteers knew that they would earn real money for giving the right answer, but they didn’t know what the right answer actually was. Moreover, they were told that the feedback they were getting was random. Nevertheless, the volunteers were able to learn how to earn money in the game without being able to say what they had learned or how. At the conference, Ramot suggested that a similar approach could be used to treat mental disorders, to help people learn new skills without having to try too hard, or to help locked-in people communicate with the outside world. Call me pessimistic, but my thoughts immediately went toward imposed mind control and the myriad ways that marketeers and, worse, governments might be able to use the technology against our will.

  Whichever way it's done, neurofeedback is going to involve a certain investment of time and effort. If that isn’t your bag, then perhaps it's worth waiting for home brain stimulation to hit the market—preferably in a safe, properly regulated way. Using electricity to “zap yourself better” has actually been around since the first century AD, when the Roman physician Scribonius Largus persuaded headache and gout sufferers to let him put electric fish on whichever end was hurting (apparently it made the affected area go numb for a while). And for all the health warnings, when done properly, tDCS does seem to drive real changes in the brain, and real changes in behavior, at least in the short term. I have seen the benefits twice now in the lab, and, caveats aside, both times the size of the effect was pretty impressive.

  Roi Cohen Kadosh feels the same, and he has seen a lot more data than I have. There are even more promising results from studies where a different kind of stimulation is employed—transcranial alternating current stimulation (tACS)—which can be used to select particular brain-frequency bands that best suit the task at hand. “There are some very impressive findings, in my view,” Roi says, citing a recent paper from his lab in which they found that tACS boosted gamma-frequency brain waves in the prefrontal cortex; the speed at which people were able to answer logic questions increased by several seconds when they were stimulated in this way.9 This is the kind of improvement that could make a big difference in a test situation, he says: “In an IQ test, you are talking about being able to get through more items, and therefore the score is higher.” The only catch is that no one knows yet whether stimulation would change ability in the long term or just for an hour or so after stimulation. It could be that you’d have to use these tools selectively, before an important test, interview, or assessment, which brings up all kinds of ethical dilemmas about fairness. Or perhaps everyone will be doing it in the not-too-distant future.

  This reminds me of a conversation I had with Lila Chrysikou in Kansas, as we headed back to the lab after my morning in the scanner. We were both flagging and shared a caffeinated chocolate bar that boasted on the wrapper that it contained as much caffeine as a cup of coffee. Maybe in the future we’ll be able to zap our brains to wake up, instead, I suggested. “Maybe,” she replied. “It's the same principle…just more direct.”

  When it comes to directly stimulating the brain, there are a lot of things still to iron out in the lab—not least finding out what exactly it is doing to the brain, but also which types of stimulation work best for particular cognitive abilities, what kind of people benefit the most, and what the trade-offs might be in boosting one part of a very complex machine while potentially doing harm to another. And, more importantly, someone has to bite the bullet and test whether the technology is safe to use as often as we might like.

  One way that this could be achieved is if home tDCS-ers volunteered to participate in a study of long-term safety. If the experiments were done on a group of people who were using the technology anyway, the ethical concerns would presumably be less. The problem is that, at the moment, the two communities are not talking to each other. Amar Sarkar, who zapped away my math-related fears in Oxford, believes it's time for that conversation to start: “The people doing brain stimulation at home are driving the market,” he says. “They are being condemned by scientists, but the scientists are not communicating with them.” On the other hand, the neuro-hacking community is less than impressed with the scientists’ warnings over safety. “They say that we sit in our ivory towers and publish for each other. But both sides have the goal of making this available if it works.”

  It will take a while to mend these bridges and to get real answers to what the scientists—and the rest of us—want to know. The likelihood is that future studies will in turn throw up more questions as it becomes clear just how different everybody's brain is in how it reacts to stimulation. There are similar issues with all brain-changing technologies, though—and indeed in standard medicine. It is becoming increasingly obvious that not all drugs work well for all people and that ideally we need personalized medicine tailored to each person's individual needs. In the same way, just because I found tDCS to be useful and working-memory training to be no help at all, it doesn’t mean that the same would be true for everyone. With tDCS, the subjective feeling of being stimulated is different for everyone—in Kansas, I felt zoned out and wonky, but Lila told me that some people don’t feel anything at all. She also told me that one volunteer got so freaked out by the whole idea of brain stimulation that he fainted before the current was even switched on.

  Susanne Jaeggi, the main researcher in the pro-working-memory training camp, says that this is her main beef with the idea that cognitive training can be thrown out before it has even got going. “It's not one size fits all—if you
have major depression, for some people, cognitive behavioral therapy is the way to go; for others, psychodynamics works better…. I think the same is true for cognitive functioning. For one person, targeting working memory is the thing to do that they like, but for another person it might be tDCS, or for another person it might be musical training or learning a new language or practicing impulse control skills or doing mindfulness meditation. I don’t think we should think about it as ‘everyone should do the same thing’—that's not the way we work,” she told me. “You wouldn’t tell someone wanting to get fit that the only way to do it was running,” she adds—they might prefer swimming or cycling or dancing, and that would work better for them. “It has to be something that you like, that is tailored to your personality as well. That is [why] I think we are not there yet. That's what we are currently working on. Ask me again in ten years, probably.”

  With all of these caveats in mind, the one thing that I did find in all of the neuroscience and psychology labs that I visited was a huge amount of excitement about what should be possible in the future.

  There are other tools in the mix, which I haven’t personally experienced. One of these—vagus-nerve stimulation—sounds particularly interesting for the future. The vagus nerve meanders through the body, linking the brain to every organ in the body, and has a huge number of branches in the gut. It's part of the information highway by which the body and the brain communicate with each other. The main message that the vagus nerve sends is to calm down. After a bout of stress—which has the heart rate, breathing, and inflammation going—activity in the vagus nerve reverses all of those changes and puts things back to a resting state.

  Vagus-nerve stimulation has been used to treat epilepsy since the 1990s, via electrodes implanted in the neck—the idea being that stimulating the “calm down” response in the brain will help when a seizure is building. It is also being used as a last-resort therapy for people with depression who have had no relief from any other treatment, and, because of its ability to suppress the inflammatory part of the immune system, it has been used to provide relief from rheumatoid arthritis, an autoimmune disorder that causes painful inflammation in the joints. Other potential applications include other inflammatory diseases, like Crohn's disease, as well as migraine and chronic pain.

  So we know that electrically stimulating the vagus nerve calms the body down. We also know that people in general vary in the strength of their vagus-nerve response—known as vagal tone. This, by the way, is why some people are able to think rationally in the midst of a crisis while others are running around, panicking, and looking for the door. These two things together have led some to speculate that gaining better control over our vagus nerve would be a good idea for all of us.

  Having electrodes inserted into your neck is clearly quite extreme, but recently a company has gained approval in the United Kingdom, Canada, Australia, Germany, and Italy to trial a noninvasive vagus-nerve stimulator for migraines and cluster headaches.10 The stimulator fits in the palm of your hand and can be used for a couple of minutes, two or three times a day. The device is still being tested and isn’t available outside of clinics yet—but it's not out of the realms of possibility that one day we could slip a handheld vagus-nerve stimulator into a bag and use it before a big interview, or when work is getting a little too much, or when a migraine threatens to pop up and ruin the day. It's one to watch, that's for sure—and there is yet more evidence that if you want to control the brain, you should take a good look at what is happening in the rest of the body, too.

  Also on the subject of altering the body to affect the mind, the most unexpected brain control tool that I came across in my experiments made it possible to bolt a totally new sense onto the body, and for my brain to translate that information into something it can use. The weirdest—and coolest—thing about the feelSpace belt was that it was possible to take a completely unnatural sensation (buzzing on the waist) and attach new meaning to it: in this case, a sense of magnetic north. With this information, it was possible to do things I couldn’t do with my brain alone—such as develop a far more accurate mental map of my hometown, helpfully aligned to magnetic north.

  My experience with the feelSpace belt got me wondering what else might be possible to add onto the human brain. On one level, the idea of supplementing our natural senses is not that different to using night vision goggles to turn infrared light—which is outside of the natural limits of human vision—into something we can see. Or a bat detector, which picks up bats’ ultrasound calls and brings them down a few notches into an audible set of clicks. The difference between slightly altering the frequency of sounds we can hear and what something like the feelSpace does is that the feelSpace adds a sense that no human has any built-in version of—feeling the magnetic field—and it does this by hijacking another sense designed for something else entirely.

  Actually, researchers have been adding senses by co-opting spare bits of skin for several decades, at least in the lab. As long ago as 1969, researchers turned visual information into a physical sensation on the upper back, which blind people were able to use as a substitute for vision.11 Neuroscientist David Eagleman, of Stanford University, is currently doing something similar for deaf people: transmitting sound, via an intricate pattern of vibrations, into a smart vest. It works so well that deaf people have been able to use the technology to decode human speech in real time.

  Using the skin to bolt on new skills makes perfect sense. When you think about it, we have a lot of the stuff; it is packed with sensory neurons and, most of the time, is sitting under our clothes not doing very much. If we could use those sensory neurons for something else, it could take us way beyond the senses that we naturally have on board. Emergency rescue workers, for example, could be fitted with a vest that was linked to an infrared camera, enabling them to feel where earthquake survivors might be buried under the rubble, using their body-heat signature. Or, perhaps, a chemical sensor, plugged into some kind of tactile band, could detect subtle subconscious signals of fear, arousal, or comfort in the sweat of people around you.

  Eagleman is thinking beyond just adding senses: he is currently trying to use the vest to represent huge amounts of data—for example, from the stock market—that people could learn to understand and react to, quickly and subconsciously. He has even floated the idea of a couples’ version, where you could keep track of your spouse's emotional state in real time. (Personally, I’m not sure that is such a great idea.)

  I arrange a chat with Eagleman to find out what he thinks the limits to all of this are. I manage to secure a slot of five minutes as Eagleman drives to the airport to give one of many talks about his research. Thanks to his popular books, TV shows, and his 2015 TED talk, Eagleman is a busy man—he is, as the Times newspaper put it in the days before we talk, the “rock star of neuroscience.”12 I think what they mean by that is that he is enthusiastic about the future of neuroscience, can explain it in a way that other people can understand, and seems like an all-round nice bloke. Actually, I’ve met a lot of people like that this year—when you take the time to go and talk to neuroscientists, it turns out that they are normal people like the rest of us and have lots of interesting things to say. Not all of them have the fireman's hose of enthusiasm that Eagleman does, but still, it's a field packed with very interesting people indeed, and I’ve had a great time hanging out with them.

  After checking that he's on speakerphone while he is driving (I don’t want to be responsible for killing off the rock star of neuroscience), I ask him to explain how the brain goes about integrating a new sense. With the feelSpace belt, I knew that the buzzing indicated magnetic north, and I could then overlay that onto other knowledge of my surroundings, like the position of the river. Now I know not only where the river is but also its position in relation to north. How on earth do you go about making sense of hundreds of vibrations that could, at the beginning, stand for anything?

  “Everything in the brain is about cross-correlatin
g the senses and being able to compare one data input that it gets with another data input that it is trying to figure out,” he tells me. It's not magic: the wearer has to know what kind of information is encoded in the buzzes or it won’t mean anything. The deaf volunteers aren’t told the content of the words, for example, but they know that the buzzing represents language. Speech is actually a fairly easy one to learn this way, he says, because deaf people already feel their own speech as a vibration in the body. In principle, though, the brain's ability to learn a totally new input is limitless, so long as it has something to compare the new input to.

  He also gives me the example of a drone pilot who learned to fly a drone better by wearing a vest that translates heading, pitch, and yaw into sensory vibrations on the body. The pilot can only put the sensations on his body together with what is happening to the plane by practicing with both. “When it's close up, he can see that when the heading changes I feel this and when it rolls I feel that,” says Eagleman. Then, “when the thing is farther or out of his sight or it's nighttime, he now knows what the correlation is between these different data streams.” This, he adds, is how a baby learns to work out that banging something it can see and hold makes a sound. The baby bashes objects onto surfaces, drops them, throws them, and eventually works out how sight, sound, and touch all fit together.

  Like the baby, who is working out what fits with what, it might be possible to add on pretty much whatever we like this way. One of Eagleman's favorite things to say is that the brain is locked in a dark box, and all it has to work with are electrical signals from the rest of the body. If it gets new information via the body, it doesn’t care where that comes from; it just figures out what to do with it. This suggests that there is no limit to what our brains could use, if only we can bolt on the right sensors.