Direct Brain Stimulation, a Billion Dollar Invention? Not Yet.
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.
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.
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 foc.us, 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.
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.
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.
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.
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.
“Whether you want to smash a forehand like Federer, or just be an Xbox hero, there is a shocking short cut to getting the brain of an expert.
I’m close to tears behind my thin cover of sandbags as 20 screaming, masked men run towards me at full speed, strapped into suicide bomb vests and clutching rifles. For every one I manage to shoot dead, three new assailants pop up from nowhere. I’m clearly not shooting fast enough, and panic and incompetence are making me continually jam my rifle.
My salvation lies in the fact that my attackers are only a video, projected on screens to the front and sides. It’s the very simulation that trains US troops to take their first steps with a rifle, and everything about it has been engineered to feel like an overpowering assault. But I am failing miserably. In fact, I’m so demoralized that I’m tempted to put down the rifle and leave.
Then they put the electrodes on me.”
Full text of article here.
“Rapidly identifying the potentially threatening movements of other people and objects-biological motion perception and action understanding is critical to maintaining security in many civilian and military settings.
A key approach to improving threat detection in these environments is to sense when less than ideal conditions exist for the human observer, assess that condition relative to an expected standard, and if necessary use tools to augment human performance. Action perception is typically viewed as a relatively “primitive,” automatic function immune to top-down effects. However, recent research shows that attention is a top-down factor that has a critical influence on the identification of threat-related targets. In this paper, we show that detection of motion-based threats is attention sensitive when surveillance images are obscured by other movements, when they are visually degraded when other stimuli or tasks compete for attention, or when low-probability threats must be watched for over long periods of time-all features typical of operational security settings. Neuroimaging studies reveal that action understanding recruits a distributed network of brain regions, including the superior temporal cortex, intraparietal cortex, and inferior frontal cortex.
Within this network, attention modulates activation of the superior temporal sulcus (STS) and middle temporal gyrus. The dorsal frontoparietal network may provide the source of attention-modulation signals to action representation areas. Stimulation of this attention network should, therefore, enhance threat detection. We show that transcranial Direct Current Stimulation (tDCS) at 2 mA accelerates perceptual learning of participants performing a challenging threat-detection task. Together, cognitive, neuroimaging, and brain stimulation studies provide converging evidence for the critical role of attention in the detection and understanding of threat-related intentional actions.”
Full text of research paper here.
Objective: The authors evaluate the effectiveness of noninvasive brain stimulation, in particular, transcranial direct current stimulation (tDCS), for accelerating learning and enhancing human performance on complex tasks.
Background: Developing expertise in complex tasks typically requires extended training and practice. Neuroergonomics research has suggested new methods that can accelerate learning and boost human performance. TDCS is one such method. It involves the application of a weak DC current to the scalp and has the potential to modulate brain networks underlying the performance of a perceptual, cognitive, or motor task.
Method: Examples of tDCS studies of declarative and procedural learning are discussed. This mini-review focuses on studies employing complex simulations representative of surveillance and security operations, intelligence analysis, and procedural learning in complex monitoring.
Results: The evidence supports the view that tDCS can accelerate learning and enhance performance in a range of complex cognitive tasks. Initial findings also suggest that such benefits can be retained over time, but additional research is needed on training schedules and transfer of training.
Conclusion: Noninvasive brain stimulation can accelerate skill acquisition in complex tasks and may provide an alternative or addition to other training methods.
“In 2008, according to the Medical Expenditure Panel Survey (MEPS), about 100 million adults in the United States were affected by chronic pain, including joint pain or arthritis. For those who suffer pain, it limits their functional status and adversely impacts their quality of life. Pain is costly to the nation because it sometimes requires medical treatment. Pain also complicates medical care for other ailments, and it hinders one’s ability to work and function in society.
We estimated (1) the annual economic costs of pain in the United States and (2) the annual costs of treating patients with a primary diagnosis of pain.
We used the 2008 MEPS to compute the economic costs of pain in the United States. The analytic sample was restricted to adults, ages 18 years or older, who were civilians and noninstitutionalized. To compute the annual economic cost of pain, we defined persons with pain as those who reported having “severe pain,” “moderate pain,” “joint pain,” “arthritis,” or functional limitation that restricted their ability to work. To compute the cost of medical care for patients with a primary diagnosis of pain, we examined adults who were treated for headache, abdominal pain, chest pain, and back pain in 2008.
The annual economic costs of pain can be divided into two components: (1) the incremental costs of medical care due to pain, and (2) the indirect costs of pain due to lower economic productivity associated with lost wages, disability days, and fewer hours worked. We estimated the incremental and indirect costs using two-part models consisting of logistic regression models and generalized linear models. We also used different model specifications for sensitivity analysis and robustness. To compute the annual costs of medical treatment for patients with a primary diagnosis of pain, we summed the expenditures for medical encounters for headache, abdominal pain, chest pain, and back pain. We converted the cost estimates into 2010 dollars using the Medical Care Inflation Index of the Consumer Price Index (CPI) for medical costs and the General CPI for wages.
We found that the total incremental cost of health care due to pain ranged from $261 to $300 billion. The value of lost productivity is based on three estimates: days of work missed (ranging from $11.6 to $12.7 billion), hours of work lost (from $95.2 to $96.5 billion), and lower wages (from $190.6 to $226.3 billion). Thus, the total financial cost of pain to society, which combines the health care cost estimates and the three productivity estimates, ranges from $560 to $635 billion. All estimates are in 2010 dollars.
We found that the annual cost of pain was greater than the annual costs in 2010 dollars of heart disease ($309 billion), cancer ($243 billion), and diabetes ($188 billion) and nearly 30 percent higher than the combined cost of cancer and diabetes.”
Full text of research paper here.
“Living with chronic or long-term pain is a tremendous burden. But when you have chronic pain and depression, the burden gets even heavier.
Depression magnifies pain. It makes it more difficult to cope with everyday living. The good news is that chronic pain and depression are not inseparable. Effective medications and psychotherapy can help relieve the depression and make chronic pain more tolerable.”
Full text of webMD article here.
OBJECTIVE: To determine the current status for the association of chronic pain and depression and to review the evidence for whether depression is an antecedent or consequence of chronic pain (CP).
DESIGN: A computer and manual literature review yielded 191 studies that related to the pain-depression association. These reports were reviewed and sorted into seven categories relating to the topic of this paper. Eighty-three studies were then selected according to inclusion criteria and subjected to a structured review.
SETTING: Any medical treatment setting including pain treatment as inclusion criteria for the selection of studies.
PATIENTS: Any patients with any type of chronic pain.
RESULTS: The reviewed studies were consistent in indicating that there is a statistical relationship between chronic pain and depression. For the relationship between pain and depression, there was greater support for the consequence and scar hypotheses than the antecedent hypothesis.
CONCLUSIONS: Depression is more common in chronic pain patients (CPPs) than in healthy controls as a consequence of the presence of CP. At pain onset, predisposition to depression (the scar hypothesis) may increase the likelihood for the development of depression in some CPPS. Because of difficulties in measuring depression in the presence of CP, the reviewed studies should be interpreted with caution.
“Although much information still needs to be attained, imaging and other methods have begun to elucidate the neurobiological abnormalities associated with MDD. In particular, several prefrontal and limbic structures and their interconnected circuits have been implicated in effective regulation. Figure 2 These neuroanatomical areas include the ventromedial prefrontal cortex (VMPFC), lateral orbital prefrontal cortex (LOPFC), dorsolateral prefrontal cortex (DLPFC), anterior cingulated cortex (ACC), ventral striatum (including nucleus accumbens), amygdala and the hippocampus. Abnormalities in these areas have been shown in patients with MDD compared with healthy controls and thus suggest a foundation for the symptomatic expression of MDD.[24,25] However, these deviations may be obscured or not present at the individual patient level and thus, these findings cannot necessarily be considered pathognomic.”
“A primary aim in the neuroscientific study of depression is to identify the brain areas involved in the pathogenesis of symptoms. In this review, we describe evidence from studies employing various experimental approaches in humans (functional imaging, lesion method, and brain stimulation) that converge to implicate the ventromedial and dorsolateral sectors of the prefrontal cortex as critical neural substrates for depression, albeit with distinct functional contributions. The putative roles of ventromedial and dorsolateral prefrontal cortex in depression are discussed in light of the results.”
Full text of research paper here.
“BACKGROUND: So far, no comprehensive answer has emerged to the question of whether transcranial direct current stimulation (tDCS) can make a clinically useful contribution to the treatment of major depression. We aim to present a systematic review and meta-analysis of tDCS in the treatment of depression.
METHOD: Medline and Embase were searched for open-label and randomized controlled trials of tDCS in depression using the expressions (‘transcranial direct current stimulation’ or ‘tDCS’) and (‘depression’ or ‘depressed’). Study data were extracted with a standardized data sheet. For randomized controlled trials, effect size (Hedges’ g) was calculated and the relationships between study variables and effect size explored using meta-regression.
RESULTS: A total of 108 citations were screened and 10 studies included in the systematic review. Six randomized controlled trials were included in the meta-analysis, with a cumulative sample of 96 active and 80 sham tDCS courses. Active tDCS was found to be more effective than sham tDCS for the reduction of depression severity (Hedges’ g=0.743, 95% confidence interval 0.21-1.27), although study results differed more than expected by chance (Q=15.52, df=6, p=0.017, I2=61.35). Meta-regression did not reveal any significant correlations.
CONCLUSIONS: Our study was limited by the small number of studies included, which often had small sample size. Future studies should use larger, if possible representative, health service patient samples, and optimized protocols to evaluate the efficacy of tDCS in the treatment of depression further.”
“Major Depression Disorder (MDD) is usually accompanied by alterations of cortical activity and excitability, especially in prefrontal areas. These are reflections of dysfunction in a distributed cortico-subcortical, bihemispheric network. Therefore it is reasonable to hypothesize that altering this pathological state with techniques of brain stimulation may offer a therapeutic target. Besides repetitive transcranial magnetic stimulation, tonic stimulation with weak direct currents (tDCS) modulates cortical excitability for hours after the end of stimulation, thus, it is a promising non-invasive therapeutic option. Early studies from the 1960s suggested some efficacy of DC stimulation to reduce symptoms in depression, but mixed results and development of psychotropic drugs resulted in an early abandonment of this technique. In the last years, tDCS protocols have been optimized. Application of the newly developed stimulation protocols in patients with major depression has shown promise in few pilot studies. Further studies are needed to identify the optimal parameters of stimulation and the clinical and patient characteristics that may condition response to tDCS.”
“Transcranial direct current stimulation (tDCS) provides a non-invasive tool to elicit neuromodulation by delivering current through electrodes placed on the scalp. The present clinical paradigm uses two relatively large electrodes to inject current through the head resulting in electric fields that are broadly distributed over large regions of the brain. In this paper, we present a method that uses multiple small electrodes (i.e. 1.2 cm diameter) and systematically optimize the applied currents to achieve effective and targeted stimulation while ensuring safety of stimulation. We found a fundamental trade-off between achievable intensity (at the target) and focality, and algorithms to optimize both measures are presented. When compared with large pad-electrodes (approximated here by a set of small electrodes covering 25 cm(2)), the proposed approach achieves electric fields which exhibit simultaneously greater focality (80% improvement) and higher target intensity (98% improvement) at cortical targets using the same total current applied. These improvements illustrate the previously unrecognized and non-trivial dependence of the optimal electrode configuration on the desired electric field orientation and the maximum total current (due to safety). Similarly, by exploiting idiosyncratic details of brain anatomy, the optimization approach significantly improves upon prior un-optimized approaches using small electrodes. The analysis also reveals the optimal use of conventional bipolar montages: maximally intense tangential fields are attained with the two electrodes placed at a considerable distance from the target along the direction of the desired field; when radial fields are desired, the maximum-intensity configuration consists of an electrode placed directly over the target with a distant return electrode. To summarize, if a target location and stimulation orientation can be defined by the clinician, then the proposed technique is superior in terms of both focality and intensity as compared to previous solutions and is thus expected to translate into improved patient safety and increased clinical efficacy.”