Direct Brain Stimulation, a Billion Dollar Invention? Not Yet.

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Every single feeling of perception – of touch, of smell, of color – can be traced back to a particular set of neurons.

Stimulate those neurons directly and a person’s perception of reality can be controlled.

In the 1940s, neurosurgeon Wilder Penfield experimented with the brains of his patients. He sent mild electric shocks to their somatosensory cortex.

As a result, they felt as if their body was being touched even when it wasn't. A shock to one area, a feeling of their arm being pushed, a shock to another and a feeling of their upper lip being nipped.

Science fiction takes brain stimulation technology to its extreme – fully immersive virtual reality. Want the user to feel as if he's actually boxing, not just waving his hands in the air? Sense his arm and body movements. Then stimulate the neurons responsible for his fist and arm when he gives a hit and the neurons responsible for his head and nose when he takes one.

But why limit direct stimulation of the brain to physical perception?

Stimulate the brain’s happiness centers and BAM – you’ve got happiness on demand.

You can purchase a direct brain stimulation device online, plunk it on your head, pick a brain region, get zapping, and enhance your mood, memory, and attention.

You can spend 25 years working hard in order to make your life perfect and finally get those happiness neurons firing as much as you want, or just maybe, you can use tDCS for 25 days.

Isn't That What Cocaine is For?

Cocaine provides feelings of happiness on demand. Why do something as strange as zap the brain when we've got drugs that can do the same?

Because drugs have side effects and cause tolerance.

1) Drugs cause stomach cramps, weight gain, fatigue, dementia, kidney stones, psychosis, and all sorts of other problems. Caffeine isn’t the most widely consumed drug because of its effectiveness – it’s because of its safety.

2) The human body is perhaps the most complex organism in the universe. The only way something so complicated can keep itself alive is by vigorously maintaining balance. Otherwise something as innocuous as caffeine could cause it to die.

Caffeine stimulates the central nervous system, warding off drowsiness and restoring alertness. But the first time many people consume caffeine, their heart also beats much faster than it should, a condition called tachycardia.

After a couple doses the brain starts to develop tolerance, counteracting the effects of the foreign chemical. Good! Prolonged tachycardia is dangerous. But the flip side is that over time, caffeine becomes less effective.

In order to maintain the same effects, people take larger and larger doses. For many this means larger and larger side effects, like anxiety. Worse, no matter how much more caffeine they put into their body, many people are unable to reach the same effectiveness they felt at first – their brain has adapted.

Direct brain stimulation has none of those limitations.

tDCS – DYI Brain Stimulation

There was a time when brain stimulation was dangerous business. But don't let your imagination take you too far.


Over the past few decades, brain stimulation technology has become safe and non-invasive.

I'm not talking about electroshock therapy, which is non-invasive but induces seizures. I'm also not talking about transcranial magnetic stimulation, which is also non-invasive but is expensive and occasionally causes serious side effects.

Transcranial magnetic stimulation (TMS) uses a rapidly changing magnetic field to induce weak electric currents. Sounds cool, but although this technology has been around for over 30 years, its use has been limited to psychiatric patients. It was and still is expensive, with a TMS machine costing tens of thousands of dollars. Furthermore, severe side effects like pain, seizure, fainting, and mania do occasionally occur.

I'm talking about transcranial direct current stimulation (tDCS), which is non-invasive, cheap AND safe, using a pair of electrodes to deliver a constant, weak current to a specific part of your brain.

You can purchase a tDCS device for $250 to $400, or make one yourself for less than $50 if you've got some experience with electronics. Operation is simple – decide what you'd like to focus on – learning, attention, mood, or one of a dozen other things, look up where you should place your two electrodes, place them there, and then turn the device on. One device is as easy to use as a headband – pick it up, place on the head.

As long as you carefully follow the instructions, using tDCS to shock your brain is safer than it sounds. Over the past ten years tDCS has been safely used on tens of thousands of people. The worst that's been seen are headaches and fatigue which went away after a few hours.

One person reported experiencing blindness for a few hours, but he didn't follow the instructions. If you can't follow instructions, close this article and run away – I don't want to be held responsible when you've burned your skin or started hearing voices.But if you do follow instructions, long-term safety is also unlikely to be a concern – folks have used tDCS for years to no ill effect. That doesn’t mean that long-term safety should be assumed – tDCS may cause subtle changes which don't manifest into disease until decades later. But like with food sweeteners, the risk may be worth the return.

If tDCS can make me 10% happier and 15% more productive, I’m willing to risk the small chance that I might, for example, get dementia a few years earlier.

Tolerance isn't an issue because the brain has no means of changing its response to foreign sources of electricity. In fact, the opposite is true.

Because of long-term potentiation and brain plasticity, tDCS is more effective the more it's used.

Can you imagine that? Caffeine or anti-depressants without side effects that become more effective the more they're used, not less.

What Are the Benefits of tDCS?

There are two types of tDCS – anodal and cathodal.

Anodal stimulation makes neurons in a particular area more likely to fire. So if you're trying to learn a new language, anodal stimulation of your brain's language and memory centers would make neurons in those areas more likely to fire and form new connections. In other words, your learning would be faster and easier.

Cathodal stimulation makes neurons in a particular area less likely to fire. So if you're trying to break a bad habit, let's say your sugar addiction, cathodal stimulation of your brain's addiction circuitry would make neurons in those areas less likely to fire and reinforce existing connections. In other words, breaking the habit would be faster and easier.

tDCS has the potential to enhance well-being in many ways. Let's look at four in particular – accelerating learning, reducing pain, treating depression, and enhancing mood.

Accelerating Learning

The military has used tDCS to accelerate the threat detection training of its snipers. Detecting a threat five seconds late can be the difference between an enemy fighter killing an ally and the enemy fighter getting taken down before he can do any harm.

Anodal stimulation of the brain region devoted to object recognition has allowed snipers to be trained 130% faster. 1 Not only that, soldiers using tDCS have reported feeling as though they've entered flow – a state of pleasant, effortless concentration.

Other studies have confirmed these results – tDCS can be used to enhance performance, increase attention, and improve learning. 2, 3 One person went as far as creating, a tDCS device made specifically to enhance performance and attention while playing video games. Yes – we have a technology which can drastically increase well-being and its first commercial application is enhancing video game playing.

But don’t get too excited, results have been mixed. Some folks have used tDCS to no effect, probably because one size fit all solutions don't exist – each person's brain is too different. If you have lots of money, it may be worth a try.

Reducing Pain

The economic cost of chronic pain is estimated to be in excess of $500 billion every year. 4 Chronic pain is terrible – so bad that like with me in the past, it can lead to depression and ruin a person's quality of life. 5, 6

Unfortunately, current brain stimulation technology is unlikely to help. According to a Cochrane Review, considered the gold standard of systemic research analysis, tDCS and TMS reduce the severity of chronic pain by about 15%, not much better than the effects of a placebo.

On the other hand, while the average patient has reported mild results, the variance has been large – some folks have seen zero change, but others have seen life-changing improvement.

Treating Depression

People who are depressed show significantly less activity in their dorsolateral prefrontal cortex (dlPFC), a brain region associated with executive function, long-term planning, and emotion regulation.
7, 8 Not only are these folks perpetually sad, but they lack the motivation and willpower to do anything about it. So if anodal tDCS can increase activity in a depressed person’s dlPFC, anti-depressants can be replaced with a safer alternative.

tDCS has proven more effective than placebo in treating depression, with the average depressed person treated with tDCS seeing a 29% improvement in just a few weeks. 9, 10

But not to be a broken record, but again, results have been mixed. Some studies saw improvement rates of 80%, but others of less than 10%. And even within the same study, some patients had a complete remission while others saw no change.

Taken all together, 20% of patients see improvement comparable to taking an anti-depressant. If you've got lots of money and are depressed, I'd suggest giving it a try – tDCS has no known side-effects and works in weeks rather than months.

Is tDCS safe for pregnant women?

Probably. Because anti-depressants can pose a health risk to a pregnant woman's baby, safer alternatives are in high demand. tDCS has been used on pregnant women to no apparent effect, and a number of tDCS researchers believe the device to be safe for pregnant women. In addition, studies were done on TMS and ECT, more dangerous brain stimulation therapies, have shown few risks. However, no clinical studies on the safety of tDCS to a pregnant women's baby have yet to be completed, although 2 are currently in progress and are slated to finish in 2015.

Enhancing Mood

A common complaint of those in positive psychology is that applied psychology focuses almost exclusively on disease and dysfunction. When it comes to brain stimulation research, this complaint is valid.

In writing this article, I was able to find over 40 studies which examined the possibility of using tDCS to treat depression, but just 1 examining the possibility of using tDCS to enhance mood in folks who are healthy. Just one. What the hell!?

A cheap and easy DYI therapy which could increase mood by 10% would be worth hundreds of billions of dollars, increasing well-being, worker productivity, relationship satisfaction, physical health, mental health, and more.

Unfortunately, you and I are going to have to wait a few years for that. Current technology and knowledge aren't enough. Using tDCS in the same way that it's used to treat depression seems to have no effect on folks who aren't depressed. 11 In other words, going from happy to very happy requires something different than going from unhappy to happy, something which has yet to be investigated.

Isn't it cheating to use tDCS? Mood enhancement should be natural.

Cheating? What are you talking about? Cheating is only possible if the game that you're playing is fair. There's nothing fair about the game of life – some people are born happier, healthier, richer, more charismatic, and more attractive than the rest.

I absolutely don't endorse using tDCS to become so happy that a person just sits around all day doing nothing but smiling, also known as wire-heading.

I'm talking about my awkward friend using tDCS to reduce his social anxiety so that he has the confidence to ask more women out on dates.

I'm talking about my friend with ADHD using tDCS to enhance his focus so that working is more enjoyable.

I'm talking about my dad using tDCS to increase his mood so that he has more love and compassion to share with patients.

I'm talking about my uncle using tDCS to increase his happiness so that he can stop working in order to earn even more money, and start spending more time with his friends, family, and hobbies.

I'm sure that in a few decades the technology will develop to the point where wire-heading is possible – where it's possible to feel as if you're on cocaine all the time without any side-effects or tolerance. When that time comes society will have many tough problems to tackle. But for now we're left with more mild technology – a 10% increase in mood, not 1000%. 10% is safe and healthy, 1000% not so much.

Can Direct Brain Stimulation Do More?


The science of direct brain stimulation has barely begun. Consider all of the variables which need to be explored – the position of the electrodes, the strength, frequency, and duration of the current, the unique characteristics of the user’s brain, and what the user is doing while being shocked.

For example, that one study above which found that tDCS has no ability to enhance mood in folks who aren't depressed may not be valid – the participants weren't doing anything special while being shocked.

tDCS doesn't trigger a set of neurons, it merely makes them more or less likely to fire. If we want to create long-term changes in the brain's happiness regions, the neuronal connections we want to strengthen need to be triggered while the tDCS is active, perhaps by listening to upbeat music or doing loving-kindness meditation.

Another limitation is a lack of focality. The image below compares the effects of traditional tDCS with newer technology. The areas colored in light blue and green are the areas being stimulated, while the area in deep blue is unaffected.


Traditional tDCS is more a gigantic hammer than a precise scalpel – almost 50% of the brain is getting shocked. Trying to learn tennis faster? Not only is the motor cortex is stimulated, but so is the frontal lobe, the parietal lobe, and the somatosensory cortex. 12

I'll soon purchase a tDCS device, but more for experimentation – although the potential benefits are sky-high, we're years or more away from seeing a reliable protocol that works for most people. But if I were an angel investor, this is where I’d be putting my money.

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22 thoughts on “Direct Brain Stimulation, a Billion Dollar Invention? Not Yet.”

  1. You always do amazing research, Amit. But the amount of analysis – and from my perspective, the synthesis of that analysis in ways that help me – is truly top notch here.

    Count me among the people who had never heard of tDCS before reading your article. Also count me among the many people who definitely care about the future of tDCS. In fact, the advancements with tDCS seem so important after reading your article and the linked Reddit FAQ that I would love to see regularly scheduled update posts on the topic. Once a year may be enough, but I’d be game for a semi-annual tDCS review from you.

    If tDCS could help me break the very habit that you use as an example in this article – emotional and physical sugar abuse – I’m ready for some cathodal stimulation … assuming someone can give me the right protocol. I’m good at following instructions, but not always creating instructions.

    • It seems like living in Silicon Valley has its perks! The reason I heard about tDCS is because I met someone who wants to combine brain sensing and tDCS technology to directly apply micro rewards and punishments to the brain to help create and break habits.

      On the one hand I’m pessimistic because the brain is super complex, but on the other hand I’m optimistic because there have already been successes, the military is funding research, and scientific interest in the field has been increasing dramatically.

      An annual tDCS review sounds like a great idea, thanks Joel!

  2. Wow…that’s fascinating! I’d never heard of tDCS. It absolutely sounds like science fiction to me, and you nailed my mental image with that “Your Imagination” image. But thanks to your post, I feel like I have a good, solid overview of what it is and where we are with it. It sounds like this technology could be seriously useful on a still untold number of fronts, and I appreciate the introduction.

    I agree with Joel — I’d love to hear updates as the technology evolves and as you experiment with your own device.

    • I look forward to sharing my brain zapping adventures 🙂

      Occulus Rift sounded like science fiction to me, but then I tried the device on. One of the first things I did after putting it on was to turn around. Holy shit!@ There was a chasm right there, and it looked and felt so real that my heart went pumping. I don’t think we’ll have fully immersive virtual reality for decades, but even the baby steps are impressive.

  3. Huh. That’s pretty cool. I’ve always been wary of chemical enhancements– too much like performing surgery with a chainsaw, and the potential of starting a chain reaction you can’t correct is awfully high. tDCS seems likewise rather clumsy, but at least there are no side effects. What I wouldn’t give to enter a flow state on command– or to accelerate learning and reaction time! I’ll follow the developments of this technology with interest.

    • Yes! Being able to enter flow on command would be great! It may even already be possible for some subset of folks using tDCS.

      You may be interested in the algernon argument – , which basically claims that any cognitive enhancement with a significant effect probably has a downside (because if the effect is large, why don’t our brains do it on their own). I’m really hoping that tDCS is the exception, but it’ll take more time until we can be certain.

      • Thanks for sharing– that Algernon argument is compelling. It’s got a lot of weight in biological/evolution circles. Plus, I really loved that book!

  4. I know a lot about a certain aspect of this. The problem with some of these electrical stim system is that it isn’t specific to the neurons that pinpoint those feelings, so you get cross over into other neurons. For example, people with seizures sometimes find relief from stimulation to the nerves in their necks, but that can effect their vocal function.

    Stay tuned though. Some folks at Stanford have ways to stimulate specific neurons without electrical stim so there is no cross over—really specific. Hunger, sleep, addictions, mood, and many other brain functions can be controlled with startling specificity. I’ve seen a mouse fall asleep with a press of a button, and another walk in circles. Humans are next.

    Yes, stay tuned. Mind control, serious mind control, is just a few years away. Weird, huh?

    • Yes exactly – current tDCS devices can effect up to 50% of the brain – not specific at all.

      I’ve heard of a technique which uses lasers to stimulate specific neurons. Is that what you’re talking about? Sounds really interesting!

  5. I had heard of tDCS before on a This American Life story, and I have to say.. it’s really tempting, but also terrifying. I can’t help but think that there must be some side effects to constantly stimulating your brain to enhance your performance. Of course, that’s just anecdotal. It’s definitely a promising technology, and I can’t wait to hear about your experiments with it!

    • There’s nothing wrong with waiting a few years until more research has been done and there’s better data on long-term safety 🙂

  6. i came across this page while looking into tdcs as i have the FOC.US one mentioned in this article and can say without a doubt it has improved my depression that ive had for years trying every kind of DIY treatment via nootropics and other compounds. although made for gamers the placement for depression treatment is in the same spot as where the FOC.US headset electrodes sit. the only discomfort is a tingling stingy feeling once it kicks in and will usually do a 20 minute session while carrying on doing my everyday chore and simply take off and put away. i wish i knew of this earlier but already the benefits have come and best of all its something that does not feel artificial in that you still feel you but things are brighter life wise and im more talkative than before but dont feel if ive being taking something but im me if that makes any sense. would highly recommend at least trying it out if anyone has mood depressive symptoms it took for me around two weeks before i noticed that a change was occurring and it gets progressively better after that but dont expect a quick couple of zaps and it will work it wont it takes time for the neurons to start firing again as they should but the best £179 ive spent.

  7. Thank you for taking it from scary to academically interesting. There’s so much here I didn’t even know, and it goes a long way to furthering advancements in the technology. I had honestly never heard of this, only the application of electrical current being used for physical therapy purposes as with TENS machines. So naturally I assumed that current would be the same as the one stuck to the head… this has really opened up so much excitement about the possibilities here!

  8. I discovered binaural beats about 5 years ago in a program called Centerpointe. It was so great I started writing hypnosis MP3’s over binaural beats, and my brain has been thanking me ever since… but we always want more. I saw tCDS in a documentary, and thanks to your research I plan to test it sooner than later.

  9. I must admit that I had not heard of tDCS before but to me it does sound a bit scary.

    I agree with others and would rather wait for the technology to mature.

    It may be right for some people though, especially those with depression.

  10. I have heard of this treatment before and have always been intrigued. I think there is a long way to with controlled testing, but I’m going to keep an eye out in the future. Great post, very informative and well done for raising awareness.

  11. What an interesting and thought provoking look at the subject of Direct Brain Stimulation. The stuff of science fiction indeed and a little scary to think that we might experiment with our greatest resource – our minds. I think your pen-ultimate paragraph statement “we’re years or more away from seeing a reliable protocol” about sums up my concerns about this. Thanks for taking the time to pull together this research.

  12. Hey, Amit Interesting topic. “The future is here”. Thank you for diving deeper into this complex subject. Me and my audience would love to know more about your work using psychology to help people through our website let me know if you are available 🙂

  13. It is really very excellent,I find all articles was amazing.Awesome way to get exert tips from everyone,not only i like that post all peoples like that post.Because of all given information was wonderful and it’s very helpful for me.

  14. I know a lot about a certain aspect of this. The problem with some of these electrical stim system is that it isn’t specific to the neurons that pinpoint those feelings, so you get cross over into other neurons. For example, people with seizures sometimes find relief from stimulation to the nerves in their necks, but that can effect their vocal function.


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