Sep 1, 2014

The surprising health benefits of smoking cigarettes


I’ve been fumbling myself at the doorknob of addiction to cigarettes for my entire life, but my girlfriend is addicted. She’s smoked for years and I wanted to arm her with all the information I could find to help her objectively decide if and when she ought to quit. Below is a compendium of some of the more counter-intuitive findings . 

To be clear, I have no horse in this race whatsoever, but I’m also not a doctor and the information below is not medical advice (you should talk to a doctor before doing anything that could affect your health).

At the start I expected to find a damning litany of studies admonishing everyone to run, not walk, from smoking. What I found instead was quite surprising. It seems there are some benefits to smoking cigarettes and, for those at high-risk for particular diseases, even a net health benefit to smoking (especially if in the right amount and along with certain “harm-reduction” strategies).

To be sure, smoking kills an absurd amount of people every year and if it were up to me every tobacco executive who knew the dangers of smoking (but hid it, or otherwise intentionally deceived the public) would be in prison.  Most are acutely aware of the dangers of smoking, here are some of the interesting and surprising benefits associated with smoking.

Posted Image

I got a good laugh at the irony associate with the fact that the oldest woman (Jeanne Calment), in fact the longest living human ever in recorded history (she lived to be 122 years and 164 days old) was...you guessed it, a smoker since she was a teenager. That’s literally over a hundred years smoking:

I know, shocking. But the irony wouldn't be complete without her male counterpart:

The longest living man (Shigechiyo Izumi) in history, himself living to be a staggering 120 and 237 days old was...well, you get the idea; the dude was a lifelong smoker as well. 


Now they both look fairly busted to be sure, but how do you think you’ll look at 122 years old? Perhaps smoking is the only way you’ll find out. Eheh.




In the 70’s the government funded extensive research into the dangers of smoking. Their findings continue to confound in that the overall impact on longevity was far less pronounced than expected.  amsters who "smoked" daily lived 22% longer than their buzzkill non-smoking peers:

graph showing difference in survival rates between rats exposed to smoke and sham


There also appear to be a number of “harm reduction” techniques that work to offset the clear toxicity of cigarette smoking, these range from IV glutathione to resveratrol (as discussed in the following study):




Resveratrol Protects against Cigarette Smoke–Induced Oxidative Damage and Pulmonary Inflammation



Biodynamics of smoking cigarettes

Interestingly smoking is both a stimulant and depressant and Arousal is increased by the increase of norepinephrine.

Research suggests that, when smokers wish to achieve a stimulating effect, they take short quick puffs, which produce a low level of blood nicotine.  This stimulates nerve transmission. When they wish to relax, they take deep puffs, which produce a high level of blood nicotine, which depresses the passage of nerve impulses, producing a mild sedative effect. At low doses, nicotine potently enhances the actions of norepinephrine and dopamine in the brain, causing a drug effect typical of those of psychostimulants. At higher doses, nicotine enhances the effect of serotonin and opiate activity, producing a calming, pain-killing effect. Nicotine is unique in comparison to most drugs, as its profile changes from stimulant to sedative/pain killer in increasing dosages and use.

Pain is also reduced by the increases of acetylcholine and beta-endorphins.  Anxiety is reduced by the increase of beta-endorphins, and nicotine also extends the duration of positive effects of dopamine and increases sensitivity in brain reward systems.  Most cigarettes (in the smoke inhaled) contain 1 to 3 milligrams of nicotine.

Smoking appears to lowers risks from these and other diseases, cancers, and ailments.


Parkinson's disease

An association between smoking and a lower incidence of Parkinson's disease has been observed in a number of studies.  An analysis of longitudinal studies found a protective effect against Parkinson's disease for current and former smokers compared with those who had never smoked; the risk of Parkinson's disease was reduced by about half among everyday smokers (RR 0.51; 95% CI, 0.43–0.61) and this protective effect was more pronounced among current smokers, where the risk was about one-third that of never smokers (RR 0.35; 95% CI, 0.26–0.47). Similar findings of a protective effect for Parkinson's disease were also reported from a case–control study conducted in Japan.  

Nicotine is thought to be the chemical in tobacco smoke mostly likely to be implicated in this finding, but there may be other chemicals or compounds involved.  Based on data from 2004–05 we can derive theoretical estimates that about 97 deaths from Parkinson's disease are prevented by smoking in Australia annually.  Finally, recent research also suggests that nicotine can improve compromised semantic processing in Parkinson's disease, and also influence semantic processing in healthy older individuals.

A study has shown a protective effect of nicotine itself on neurons due to nicotine activation of α7-nAChR and the PI3K/Akt pathway which inhibits apoptosis-inducing factor release and mitochondrial translocation, cytochrome c release and caspase 3 activation.


Pre-eclampsia (hypertension in pregnancy)

This part below is probably of most interest to women considering pregnancy and worth considering:

Pre-eclampsia is a potentially serious condition in pregnancy in which the mother develops high blood pressure, fluid retention and abnormal kidney function. Smokers are less likely to develop pre-eclampsia than non-smokers; recent research points to the impact of smoking on the ratio of soluble fms-like tyrosine kinase-1 (sFlt-1) to placental growth factor (PlGF) as one possible pathway20, however the mechanism by which the observed protective effects occur remains poorly understood.

Nicotine reduces the chance of preeclampsia, and atopic disorders such as allergic asthma. A plausible mechanism of action in these cases may be nicotine acting as an anti-inflammatory agent, and interfering with the inflammation-related disease process, as nicotine has vasoconstrictive effects.

The teratogenic properties of nicotine has been investigated. According to a study of ca. 77,000 pregnant women in Denmark, women who used nicotine gum and patches during the early stages of pregnancy were found to face an increased risk of having babies with birth defects. The study showed that women who used nicotine-replacement therapy in the first 12 weeks of pregnancy had a 60% greater risk of having babies with birth defects compared to women who were non-smokers.

While 60% is a terrifying number, we should first think about what percent of 77,000 women had babies and weren't exposed to nicotine had babies w/ birth defects…that would be a very low number…it’s that number that you’d increase by 60%…still scary, but not terrifying.

Tobacco use among pregnant women has also been correlated to increased frequency of ADHD. Children born to mothers who used tobacco were two and a half times more likely to be diagnosed with ADHD. Froelich estimated that "exposure to higher levels of lead and prenatal tobacco each accounted for 500,000 additional cases of ADHD in U.S. children".

A study using Swedish birth registry data on more than 600,000 births examined the effects of snuff and cigarette smoking on pre-eclampsia risk and whether changes in tobacco habits during pregnancy affected the risk of developing term pre-eclampsia. Compared with non-tobacco users, light smokers experienced a one-third reduction in risk (OR 0.66; 95% CI, 0.61–0.71) and heavy smokers a halving of risk (OR 0.51; 95% CI, 0.44–0.58) with OR lower for term than preterm pre-eclampsia. The study found that tobacco combustion products rather than nicotine are the probable protective ingredients against pre-eclampsia in cigarette smoke and further concluded that it is smoking behavior in the middle or late rather than in the beginning of pregnancy that seems to have the greatest effect on the risk of pre-eclampsia.  The US Surgeon General has concluded that 'the decreased risk of pre-eclampsia among smokers compared with non-smokers does not outweigh the adverse outcomes that can result from prenatal smoking.  These conclusions are underscored by findings from a recent case–control study conducted in Canada where notwithstanding a (non-significant) reduction in the risk of pre-eclampsia, persistent smoking was also associated with a 10-fold increase in the risk of low birthweight (OR 10.2; 95% CI, 2.49–41.8) and a four-fold increase in the risk of preterm birth (OR 3.59; 95% CI, 1.06–12.1).


Liver disease

Those at risk for Primary Sclerosing Cholangitis “PSC” might want to drop their wheatgrass shots and pick up the closest cigarette.  Kidding of course.  In Norway, Denmark, and Sweden PSC is the main cause of liver transplants.  A new study there involving 500 PSC patients found that smoking cigarettes exerted significant protection from the disease:


Cognitive benefits

Here are some of the more pronounced dangers and benefits to human cognitive function associated with smoking:

Nicotine's mood-altering effects are different by report: in particular it is both a stimulant and a relaxant.  First causing a release of glucose from the liver and epinephrine(adrenaline) from the adrenal medulla, it causes stimulation. Users report feelings of relaxation, sharpness, calmness, and alertness.  Like any stimulant, it may very rarely cause the often uncomfortable neuropsychiatric effect of akathisia. By reducing the appetite and raising the metabolism, some smokers may lose weight as a consequence.

β-Carbolines (BCs), present in tobacco smoke, also exert an unexpected stimulatory effect on dopaminergic neurons and act as cognitive enhancers, elevating dopamine levels in the hippocampal formation, and increasing synaptic proliferation.

When a cigarette is smoked, nicotine-rich blood passes from the lungs to the brain within seven seconds and immediately stimulates the release of many chemical messengers such as acetylcholine, norepinephrine, epinephrine, vasopressin, histamine, arginine, serotonin, dopamine, autocrine agents, and beta-endorphin. This release of neurotransmitters and hormones is responsible for most of nicotine's effects.

Studies indicate that nicotine can be used to help adults suffering from autosomal dominant nocturnal frontal lobe epilepsy. The same areas that cause seizures in that form of epilepsy are responsible for processing nicotine in the brain.

Studies suggest a correlation between smoking and schizophrenia, with estimates near 75% for the proportion of schizophrenic patients who smoke. Although the nature of this association remains unclear, it has been argued that the increased level of smoking in schizophrenia may be due to a desire to self-medicate with nicotine.  Other research found that mildly dependent users got some benefit from nicotine, but not those who were highly dependent.

Research at Duke University Medical Center found that nicotine may improve the symptoms of depression.  Nicotine appears to improve ADHD symptoms. Some studies have focused on benefits of nicotine therapy in adults with ADHD.

While acute/initial nicotine intake causes activation of nicotine receptors, chronic low doses of nicotine use leads to desensitisation of nicotine receptors (due to the development of tolerance) and results in an antidepressant effect, with research showing low dose nicotine patches being an effective treatment of major depressive disorder in non-smokers.

Nicotine (in the form of chewing gum or a transdermal patch) has been explored as an experimental treatment for OCD. Small studies show some success, even in otherwise treatment-refractory cases.

A meta-analysis of research into the effects of nicotine and smoking on human performance found positive effects of nicotine or smoking on six domains: (i) fine motor, (ii) alerting attention-accuracy, (iii) response time (RT), (iv) orienting attention-RT, (v) short-term episodic memory-accuracy, and (vi) working memory-RT (effect size range = 0.16 to 0.44).  There is evidence that nicotine may stimulate immediate and sustained improvements in working memory, that nicotine replacement in smokers avoids cognitive impairment through direct pharmacological effects on brain neuronal activity, and that nicotine may improve prospective memory (the retrieval and implementation of a previously encoded intention).  

Interesting reference material:




Here is a link containing additional information that better explain the biomechanics of cigarettes, for good and ill as it were:

Nicotine biomechanics

In smaller doses (an average cigarette yields about 1 mg of absorbed nicotine), the substance acts as a stimulant in mammals, while high amounts (500–1000 mg) can be harmful.  This stimulant effect is likely a major contributing factor to the dependence-forming properties of tobacco smoking. According to the American Heart Association, nicotine addiction has historically been one of the hardest addictions to break, while the pharmacological and behavioral characteristics that determine tobacco addiction are similar to those determining addiction to heroin and cocaine. The nicotine content of popular American-brand cigarettes has slowly increased over the years, and one study found that there was an average increase of 1.78% per year between the years of 1998 and 2005. This was found for all major market categories of cigarettes.


Medical uses

Although population level effectiveness has not been demonstrated, the primary therapeutic use of nicotine is in treating nicotine dependence in order to eliminate smoking with the damage it does to health. Controlled levels of nicotine are given to patients through gums, dermal patches, lozenges, electronic/substitute cigarettes or nasal sprays in an effort to wean them off their dependence.

For instance, studies suggest that smokers require less frequent repeated revascularization after percutaneous coronary intervention(PCI).  Risk of ulcerative colitis has been frequently shown to be reduced by smokers on a dose-dependent basis; the effect is eliminated if the individual stops smoking. Smoking also appears to interfere with development of Kaposi's sarcoma in patients with HIV.

Tobacco smoke has been shown to contain compounds capable of inhibiting monoamine oxidase [this is mainly what Selegiline does], which is responsible for the degradation of dopamine in the human brain. When dopamine is broken down by MAO-B, neurotoxic by-products are formed, possibly contributing to Parkinson's and Alzheimers disease.

The relationship between smoking and inflammatory bowel disease has been firmly established, but remains a source of confusion among both patients and doctors. It is negatively associated with ulcerative colitis but positively associated with Crohn's disease. In addition, it has opposite influences on the clinical course of the two conditions with benefit in ulcerative colitis but a detrimental effect in Crohn's disease.



References:






Aug 15, 2014

Overclocking your brain with tDCS

So I’ve been looking forward to sharing my notes on tDCS, easily the most powerful, even life-changing of any cognitive enhancers I've yet used, but condensing the exponentially increasing trove of data on the subject proved a far more challenging undertaking than expected.

Traditional Cognitive Enhancers
Before reading on, please be advised that I have absolutely no financial stake in tDCS, nor do I have ties to anyone with a stake of any kind in tDCS technology.  Also, bear in mind I'm not a doctor either, so none of the following should be relied upon in making decisions about matters that may affect your personal health.  Please consult with your doctor before using any of the technology or methods described below. 

Now then, with that preamble out of the way, here’s a quick overview of this new and groundbreaking technology:

Novel DIY tDCS Headset
At the most basic, “tDCS” stands for transcranial direct current stimulation. Transcranial simply means that the direct current is passed across a region of your brain between two electrodes (the cathode and anode) to form a circuit within the body.  The constant, low-current delivered directly to the brain is a form of neurostimulation which primes the neurons in the target cortical system to fire faster (increasing their “action potential”).  The particular benefits of a tDCS session are dependent on where the tDCS electrodes are placed on the scalp and/or body (each unique placement of tDCS electrodes is known as a “montage”).

And there’s clearly a lot to be excited about when you consider the sheer breadth and variety of uses for which tDCS is proving useful.  The notes and links you'll find below will connect you to research and studies which demonstrate tDCS's utility when applied to accelerate learning, augment working memory, recover from brain trauma, and even in alleviating treatment resistant depression.

After having personally used transcranial direct current stimulation for going on two years now I can say, without reservation, that transcranial direct current stimulation has been the closest thing to a miracle I've yet tried.  In fact it's dramatically exceeded my expectations, becoming the most effective of all cognitive enhancers in my arsenal.  It's even proven beneficial in other meaningful ways that I never expected it could (which I describe in more detail below).

Transcranial direct current stimulation was originally developed to help patients with brain injuries recover from ischemia and neural insults brought about by strokes and other trauma. However, more recently tests on healthy adults have demonstrated that tDCS can markedly increase cognitive performance on a variety of tasks (again depending on the area of the brain being stimulated), diminish lethargy, and bring about feelings of well-being.

By contrast to many available cognitive enhancers, tDCS stands as one of the most thoroughly tested.  A good number of studies have demonstrated the technology particularly effective in learning language, speeding reaction time, augmenting mathematical ability and problem solving, increasing attention span, and  working memory, among others.  In some of the more interesting studies below you'll read about how tDCS has, in clinical trials, been proven to enhance overall learning speed by a factor of 230%!

Of note, even when the tDCS session is terminated the beneficial effects are proven to continue enhancing the subjects working memory ability to learn new skills. These effects have been proven to continue post-session for not less than 1-2 hours, perhaps even days.

Many experts continue to advise that you not try transcranial direct current stimulation at home, but the genie appears well out of the proverbial bottle on this one, accelerated by mass produced DIY tDCS devices like the Foc.us. And it’s no wonder, given the parade of amazing results that researchers have reported achieving on subjects in the lab. It seems like you can make people better at just about anything if you just put the electrodes in the right place. To name just a few of the findings:

  • Applying the electrodes to the prefrontal cortex can improve learning and increase your working memory. 
  • Stimulation of the parietal cortex can improve numerical reasoning.
  • Applying tDCS to the motor cortex can raise your threshold for pain and even make you more adept with your non-dominant hand. 
  • Position the electrodes above the posterior portion of the left perisylvian area (in right-handed people) and tDCS can facilitate rapid language acquisition. 


And the list goes on and on, from depression, to motor reflexes, to recovery from all sorts of ischemia and neural insults.  Very quickly we’re seeing a surge of interest in tDCS as it continues to outperform other choices in cognitive enhancers both in terms of efficacy and safety.  tDCS technology is increasingly being employed to significantly speed healing and restore functionality in stroke victims, and on the other end of the spectrum was recently deployed by every branch of the United States military to augment working memory and effectively train soldiers (sometimes twice as fast!) in skills that vary from flying fighter jets to firing sniper rifles! 



“The military has been looking at how to improve vigilance for the past 50 or 60 years,” said Andy McKinley, a civilian biomedical engineer who has been studying tDCS at the Air Force Research Laboratory at Wright-Patterson Air Force Base in Ohio.“At minimum we get a twofold improvement in how long a person can maintain performance. We’ve never seen that with anything else.”

A few studies claim results that are even more jaw-dropping. In Neuroscience Letters last year, Australian researchers reported applying tDCS to 33 people as they tried to solve the notoriously tricky “nine-dot” logic problem. Not one was able to crack it without stimulation, or with “sham” stimulation (in which electricity is applied only briefly to mimic the feeling of tDCS).  However, among those augmented with tDCS, a shocking 40 percent of that group solved it! 

Among cognitive enhancers tCDS certainly ranks among the least convenient, if not intimidating.  Many fear the sessions will be painful or unpleasant but hold in mind that 1 to 2 milliamperes (1mA - 2mA) is an incredibly low amount of electricity.  Wikipedia states that "A person can feel at least 5mA of direct current".  Among those who have used tDCS, the reported effects have seemed, in many instances, too good to be true.  Many subjects report a tickling or burning sensation from the electrodes, and some say they feel different when the current is flowing, with time seeming to pass quickly. But far from finding it painful, an editor at New Scientist who tried it out during a marksmanship test described tDCS as “the most powerful drug I’ve ever used in my life” and “a near-spiritual experience.”  The editor, Sally Adee, wrote:

“When a nice neuroscientist named Michael Weisend put the electrodes on me, what defined the experience was not feeling smarter or learning faster: The thing that made the earth drop out from under my feet was that for the first time in my life, everything in my head finally shut up. …  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.” 

Oh, and she nailed the target.



The Latest and Best tDCS Research and Devices.


Below you'll find a collection of some of my favorite articles, research, and devices using tDCS technology.

Transcranial Direct Current Stimulation articles:




tDCS devices for use at home










Here are my favorite two devices available for purchase by an ordinary consumer without medical supervision.  When cost is weighed in as a factor, I believe the Foc.us tDCS headset to be the best device on the market today:


BEST PRODUCT:

Foc.us tDCS headset

BEST PRODUCT FOR THE MONEY:


Additional tDCS manufacturers, suppliers, and DIY instruction sites:









Manufacturers and suppliers of tDCS parts or alternatives to tDCS:





Interesting product providers (various uses):




An example of a practicing tDCS clinic in Atlanta: 


Aug 14, 2014

Everything you want to know about tDCS


So I’ve been looking forward to sharing my notes on this life-changing technology known as Transcranial Direct-Current Stimulation, or "tDCS", for quite a while now, but condensing the exponentially increasing trove of data on the subject proved far harder to do than anticipated.

Alas, below you'll find my first attempt at a high-level summary of tDCS technology, as well a collection of what I found to be the most compelling information and scientific basis for its benefits:

Before you go further, please know that as incredible as what you're about to read sounds, every claim in the text to follow is supported by myriad clinical studies and objectively quantifiable scientific evidence.  I can say without reservation that it worked miraculously for me, and I now evangelize for the technology at every chance I get.

The framework for the tech I keep referencing has been around for 200 years.  Though it languished basically ignored (industry preferring the far more lucrative pharmaceutical means of addressing all that ails us); lately however tDCS has been gaining a great deal of attention and praise as an efficacious and safe alternative to drugs.

How does it work?  It's as simple as attaching one electrode to your scalp (above the part of the brain you want to stimulate), and another electrode either on somewhere innocuous like your shoulder (at a site on your scalp above an area of the brain you want to inhibit).  

The two electrodes form a circuit of sorts in the body.  Then you turn on the juice!  

Figuratively anyway.

In actuality you're only sending somewhere between 1 to 2 milliamperes of electricity through the brain, but the reported effects have seemed, in many instances, too good to be true.

Almost every expert who talks about tDCS will tell you, “Don’t try this at home.” But fact is, a lot of people are starting to do just that. And it’s no wonder, given the parade of amazing results that researchers have reported achieving on subjects in the lab. It seems like you can make people better at just about anything if you just put the electrodes in the right place. To name just a few of the findings:

  • Applying the electrodes to the prefrontal cortex can improve learning and increase your working memory. 
  • Stimulation of the parietal cortex can improve numerical reasoning.
  • Applying tDCS to the motor cortex can raise your threshold for pain and even make you more adept with your non-dominant hand. 
  • Position the electrodes (the different coordinates on the scalp and head where the electrodes are placed are known as a “montages”) above the posterior portion of the left perisylvian area (in right-handed people) and tDCS can facilitate rapid language acquisition. 


And the list goes on and on, from depression, to motor reflexes, to recovery from all sorts of ischemia and neural insults.  Very quickly we’re seeing a surge in tDCS interest and use across a wide spectrum of early adopters.  tDCS is increasingly being employed to significantly speed the healing and restore functionality in stroke victims, and on the other end of the spectrum was recently deployed by every branch of the United States military to effectively train soldiers (sometimes twice as fast!) in skills that vary from flying fighter jets to firing sniper rifles! 

“The military has been looking at how to improve vigilance for the past 50 or 60 years,” said Andy McKinley, a civilian biomedical engineer who has been studying tDCS at the Air Force Research Laboratory at Wright-Patterson Air Force Base in Ohio.“At minimum we get a twofold improvement in how long a person can maintain performance. We’ve never seen that with anything else.”

A few studies claim results that are even more jaw-dropping. In Neuroscience Letters last year, Australian researchers reported applying tDCS to 33 people as they tried to solve the notoriously tricky “nine-dot” logic problem. Not one was able to crack it without stimulation, or with “sham” stimulation (in which electricity is applied only briefly to mimic the feeling of tDCS).  However, among those augmented with tDCS,40 percent of that group solved it! 

You might suspect the procedure would be painful or unpleasant. Many subjects report a tickling or burning sensation from the electrodes, and some say they feel different when the current is flowing, with time seeming to pass quickly. But far from finding it painful, an editor at New Scientist who tried it out during a marksmanship test described tDCS as “the most powerful drug I’ve ever used in my life” and “a near-spiritual experience.”  The editor, Sally Adee, wrote:

“When a nice neuroscientist named Michael Weisend put the electrodes on me, what defined the experience was not feeling smarter or learning faster: The thing that made the earth drop out from under my feet was that for the first time in my life, everything in my head finally shut up. …  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.” 

Oh, and she nailed the target.

Here's a company that I bought my tDCS unit from:


Let me know if you have any questions further questions about this very interesting tech.  I'd be happy to help however I can.



Below you’ll find an extensive collection of additional notes and scientific basis I aggregated from various studies online, as well a peppering of some of my own thoughts and experiences with tDCS:

tDCS Notes:

To give its full name, tDCS stands for “transcranial direct current stimulation”. Transcranial simply means that the direct current (i.e. from a battery rather than the AC mains) is passed across a region of your brain. In the case of the Foc.us headset that I’ve been testing, the direct current passes between the cathode and anode, which are placed over your prefrontal cortex using a fixed-position montage that’s designed to have either an excitatory or inhibitory effect.

Different montages elicit different effects, one could position the tDCS system to improve mathematical reasoning, or when the anodes and cathodes of a tDCS system are positioned to activate cortical neuronal systems, neurons are primed to fire faster and elicit faster reaction times in the wearer.   

Even when the tDCS session is terminated the beneficial effects are proven to continue enhancing the subjects ability to learn new skills. These effects have been proven to continue post-session for not less than 1-2 hours.

Transcranial direct current stimulation (tDCS) is a form of neurostimulation which uses constant, low-current delivered directly to the brain through various vectors or “montages” (benefits to unique cognitive functions are dependent on where the tDCS electrodes are placed on the scalp).

tDCS was originally developed to help patients with brain injuries such as strokes. However, more recently tests on healthy adults have demonstrated that tDCS can increase cognitive performance on a variety of tasks, (again depending on the area of the brain being stimulated).

tDCS has thus far been utilized to enhance language and mathematical ability, attention span, problem solving, working memory, learning, and coordination.  In some of the more interesting studies below you'll learn that tDCS has enhanced a overall learning speed by a factor of 230%!

tDCS can modify brain behavior by inducing changes in its function. To better understand the effects of tDCS, study examines tDCS' impact on performance on working memory and underlying neural activity


Below is a collection of some of my favorite articles and information resources on tDCS:












"Anodal tDCS" may be overall better than "cathodal tDCS", though at least one study disputes that belief.



Excellent informational resource detailing proper use of tDCS technology as well as offering useful insights into tDCS montage locations (translated: instructions that show where to place anodes and cathodes to get certain benefits):



Here are my back-of-the-napkin ratings for each tDCS device available for purchase by an ordinary consumer.  These ratings don’t take price into consideration.  If they did, I believe the Foc.us tDCS headset to be the best device on the market today:


BEST PRODUCT:



2ND BEST PRODUCT:



3RD BEST PRODUCT:

The product used by Atlanta based clinic you can find at: 




Additional tDCS manufacturers, suppliers, and DIY instruction sites:



Manufacturers and suppliers of tDCS parts or alternatives to tDCS:






Interesting product providers (various uses):




Excellent tDCS article:



Anode and Cathode placement on scalp:  




Further definitions and articles:

A widely cited definition characterizes cognitive enhancement as “interventions in humans that aim to improve mental functioning beyond what is necessary to sustain or restore good health”


Abstract
The term “cognitive enhancement” usually characterizes interventions in humans that aim to improve mental functioning beyond what is necessary to sustain or restore good health. While the current bioethical debate mainly concentrates on pharmaceuticals, according to the given characterization, cognitive enhancement also by non-pharmacological means has to be regarded as enhancement proper. Here we summarize empirical data on approaches using nutrition, physical exercise, sleep, meditation, mnemonic strategies, computer training, and brain stimulation for enhancing cognitive capabilities. Several of these non-pharmacological enhancement strategies seem to be more efficacious compared to currently available pharmaceuticals usually coined as cognitive enhancers. While many ethical arguments of the cognitive enhancement debate apply to both pharmacological and non-pharmacological enhancers, some of them appear in new light when considered on the background of non-pharmacological enhancement.


How it works:

The physiological changes involve the modulation of spontaneous neuronal activity through polarity-specific shifts of the resting membrane potential in the direction of de- or hyperpolarisation. The direction of the change is governed by the direction of current flow, the spatial orientation of the neuron, the type of neuron and the total charge.



Abstract

The ability to detect errors during cognitive performance is compromised in older age and in a range of clinical populations. This study was designed to assess the effects of transcranial direct current stimulation (tDCS) on error awareness in healthy older human adults. tDCS was applied over DLPFC while subjects performed a computerized test of error awareness. The influence of current polarity (anodal vs cathodal) and electrode location (left vs right hemisphere) was tested in a series of separate single-blind, Sham-controlled crossover trials, each including 24 healthy older adults (age 65–86 years). Anodal tDCS over right DLPFC was associated with a significant increase in the proportion of performance errors that were consciously detected, and this result was recapitulated in a separate replication experiment. No such improvements were observed when the homologous contralateral area was stimulated. The present study provides novel evidence for a causal role of right DLPFC regions in subserving error awareness and marks an important step toward developing tDCS as a tool for remediating the performance-monitoring deficits that afflict a broad range of populations.


All known human societies have maintained social order by enforcing compliance with social norms. The biological mechanisms underlying norm compliance are, however, hardly understood. We show that the right lateral prefrontal cortex (rLPFC) is involved in both voluntary and sanction-induced norm compliance. Both types of compliance could be changed by varying the neural excitability of this brain region with transcranial direct current stimulation, but they were affected in opposite ways, suggesting that the stimulated region plays a fundamentally different role in voluntary and sanction-based compliance. Brain stimulation had a particularly strong effect on compliance in the context of socially constituted sanctions, whereas it left beliefs about what the norm prescribes and about subjectively expected sanctions unaffected. Our findings suggest that rLPFC activity is a key biological prerequisite for an evolutionarily and socially important aspect of human behavior. 



It's still so early, but this is very exciting:

Remarkably, MRI brain scans revealed clear structural changes in the brain as soon as five days after TDCS. Neurons in the cerebral cortex connect with one another to form circuits via massive bundles of nerve fibers (axons) buried deep below the brain's surface in "white matter tracts." The fiber bundles were found to be more robust and more highly organized after TDCS. No changes were seen on the opposite side of the brain that was not stimulated by the scalp electrodes. Amping Up Brain Function: Transcranial Stimulation Shows Promise in Speeding Up Learning



Amping Up Brain Function: Transcranial Stimulation Shows Promise in Speeding Up Learning Electrical stimulation of subjects' brains is found to accelerate learning in military and civilian subjects, although researchers are yet wary of drawing larger conclusions about the mechanism By R. Douglas Fields

Antidepressant drugs and psychotherapy are the first line treatments for depressive disorders. If efficacy is not satisfactory, supplementary biological treatment procedures can be used. Transcranial magnetic stimulation (TMS) has established itself as a possible new approach in the treatment of depressive disorders. The hypothesis is that stimulation of areas relevant to the pathophysiology of depressions will induce metabolic and biochemical processes—both in the stimulated areas and in associated subcortical regions—that have an anti-depressive effect. On the basis of this pathophysiological model, tDCS was investigated as another non-invasive method of brain stimulation. The approach is based on the physiological knowledge that anodal stimulation of nerve cells, i.e. stimulation with positive charge, causes a depolarization of the membrane potential in the underlying neurons, whereas a negative external charge from a cathode hyperpolarises a negative membrane potential.








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