Brain electrical stimulation: scientific research inspires biohackers
Over the past few years, scientific studies of brain electrical stimulation (tDCS) have demonstrated that it can improve many of the cognitive functions of healthy people: concentration , mathematical ability , reaction speed . In total, more than 10,000 healthy volunteers have participated in tDCS studies.
Following the scientists, biohackers began to be interested in technology - people who want to experience the results of scientific research on themselves. In the US, a whole community has already formed, using electricity to “pump” its brain. In addition, tDCS begin to be used by athletes, hoping that it can become a new and hard-to-detect doping.
Scientific research
')
Briefly about the main thing. TDCS - transcranial stimulation with direct current - came from medical research, where it is used in recovering from a stroke, to treat depression, migraine and neurodegenerative diseases. At the moment, there are at least 224 clinical trials of this technology in the world. However, research began to appear in the 2000s, demonstrating that tDCS can improve cognitive and motor functions in healthy people. Since that time, articles have already appeared a great many, some of which were described on geektimes . However, even in the last year, the piggy bank has been replenished with several particularly interesting works:
# 1 Accelerate math learning and improve memory
In 2016, a group of scientists from Harvard, Oxford and Tubingen University found that tDCS accelerates learning and improves verbal memory by more than 20%, and the effect was long-term and persisted for 2 months.
The experiment involved 20 healthy volunteers who were electrostimulated by the dorsolateral prefrontal cortex (DLPFC), a brain area responsible for learning (including mathematics). In the experiment, there was also a control group of people who imitated tDCS to eliminate the placebo effect.
Electrical stimulation was carried out with a current of 1 milliamper for 30 minutes a day for 2 days in a row. And during the procedure, all participants in the experiment solved mathematical tasks. It turned out that 2 days after the start of the experiment, subjects began to solve tasks with a smaller number of errors and 9% faster compared to the control group. In addition, their verbal working memory improved by a quarter!
To evaluate the long-term effects of stimulation, 2 months after the experiment was completed, the scientists tested again. It turned out that those who passed tDCS still showed much better results. And, interestingly, they solved tasks even faster than directly after tDCS. (After stimulation, the solution speed was 9% more than in the control group, and after 2 months - 20% more).
# 2 Less sleep
In the same 2016, a group of German scientists under the leadership of Michael Nietzsche and Christoph Niessen demonstrated that with the help of tDCS you can reduce the sleep time. And this is not accompanied by a decrease in the quality of sleep, nor by fatigue and drowsiness after waking up.
In the 5-day experiment 19 healthy people took part, each of whom was electrostimulated before bedtime. The impact was carried out on the neurons of the cortex, which are part of the cortico-talamic pathway of sleep and wakefulness regulation. It turned out that tDCS reduced sleep time by an average of 25 minutes (compared to how much they slept while simulating tDCS) and was accompanied by a long-term increase in the activity of the cerebral cortex.
What is important, the quality and structure of sleep (phase ratio) did not change due to electrical stimulation, and in the morning after the procedure, people felt no worse than usual.
â„–3 Increase concentration
And in 2015, a study was conducted demonstrating that tDCS can improve concentration.
During the attentiveness test, the subjects sat in front of the screen, on which appeared 5 arrows, one above the other. Sometimes all the arrows were directed in one direction, and sometimes the central arrow had the opposite direction.
The subjects for a few hundred milliseconds had to determine in which direction the central arrow was directed, and press the corresponding key. In some tasks a distracting signal also appeared in different areas of the screen.
It turned out that after the electrical stimulation of the parietal cortex, the volunteers gave an answer faster (in the task of spatial attention) than before tDCS. In the experiment, there was also a control group of people who imitated tDCS. However, after the “fake” stimulation, the speed of the assignment has not changed.
Electric dope?
In 2016, Nature magazine published an article stating that tDCS improves endurance, muscle strength, and coordination of movements among athletes.
This study was conducted by Californian developers from Halo Neuroscience in collaboration with the US Ski and Snowboard Association. The experiment involved 7 professional athletes involved in ski jumping. Some of them even belonged to the US Olympic team.
Athletes were divided into 2 groups: electrostimulation was carried out in 4 people, and imitated in 3 people. The experiment lasted 2 weeks, during which the athletes trained to perform jumps. And, as the company Halo reported, electrostimulation by 70% (!) Improved the strength of the jump and 80% better coordination of movements, compared with the control group.
Another tDCS study in 2016 was conducted by scientists from the University of Kent. They found that electrostimulation of the motor cortex suppresses the feeling of fatigue in athletes and increases endurance. The study involved 12 people who were also divided into 2 groups: some received neurostimulation, while others only thought they were receiving. Participants who were exposed to tDCS were ready to pedal for an average of two minutes longer and at the same time feel less exhausted.
All this is only preliminary data obtained from very small samples of people, but the results are impressive. Many companies are already adopting them, starting to develop devices to improve the training of athletes.
How it works? Mechanism of action
The main effect of tDCS on nerve tissue is considered to be the ability to cause “long-term potentiation” (LTP) and “long-term synapse depression” (LTD) - the processes underlying memory formation and learning. LTP is the restructuring of contacts between neurons, leading to increased synaptic transmission. And LTD, on the contrary, leads to a decrease in the strength of synapses.
Now scientists identify several mechanisms by which tDCS can influence LTP and LTD, the most studied of which is the change in the membrane potential of neurons. A positively charged electrode (“anode”) reduces the potential difference across the membranes of nerve cells, which leads to an increase in their excitability. A negatively charged electrode (“cathode”), on the contrary, increases the potential difference, reducing the probability of neuron excitation when an external signal is received. Thus, electrical stimulation by itself does not cause activation (excitation) of neurons, however, it changes their physiological state, making them more or, conversely, less prone to excitation.
Recently, however, studies have emerged that show that the mechanisms of action of tDCS are much more diverse. In 2016, Nature Communications magazine published an article stating that tDCS can affect neuroplasticity through the activation of auxiliary cells of the nervous tissue - glial cells. In another study of the same year, tDCS was found to alter the epigenetic regulation of the Bdnf gene. This gene encodes a neurotrophic factor of the brain, which is necessary for the formation of long-term memory. And under the action of tDCS, the cells began to produce a much larger amount of this factor.
To conduct tDCS electrodes are placed on certain areas of the brain, depending on what effects you need to get. For example, to improve motor learning, an anode is placed above the primary motor cortex. The location of the electrodes is critical for tDCS, since stimulation of different zones can lead to different results. TDCS allows you to locally increase the activity of the brain area above which the anode is located. However, studies are now emerging that demonstrate that the action of tDCS is more widespread and affects some other areas of the brain that are functionally related to the stimulated area.
It is worth noting that the effectiveness of tDCS varies greatly for different cognitive functions. For example, the effect on motor learning and mathematical ability is more significant than that on working memory .
Most tDCS studies use 1-2 milliampe current for 20 minutes. In order for the effect of tDCS to be significant, it is necessary to conduct electrical stimulation for several days in a row. Single tDCS sessions for most cognitive functions are ineffective .
Brain biohacking - to spend at home?
The results of scientific research, as well as the simplicity of the tDCS procedure, attracted the attention of biohackers who began to conduct electrical stimulation on their own. In the US, a community of people who are addicted to “home tDCS” has already emerged, which, according to estimates of the popular Reddit resource, includes at least 8,000 people.
In June 2015, Stanford University conducted a first detailed study of this community: their age, gender, occupation and education, as well as the goals with which they use tDCS.
It turned out that self-stimulation is carried out mainly by men (94%) at the age of 20-30. However, there are cases of tDCS use by older people - to compensate for cognitive impairment in old age.
TDCS is mainly used by people with a university degree (64%), 13% even have a PhD, MD or JD degree (Juris Doctor). 11% of users graduated from only 2 years of college, and 24% graduated from school or are still studying there. Apparently, the point here is that people learn about tDCS mainly from scientific research of tDCS or tDCS dedicated sites (which also mostly describe scientific research), which introduces a certain educational qualification.
There was no correlation between the use of tDCS and the financial situation of people. Electrostimulation with approximately the same frequency (21%) is carried out by both low-income people with annual incomes of up to $ 20,000 and by quite rich people who earn more than $ 90,000 a year.
Regarding the scope of tDCS users, they are mainly people engaged in professional activities and managers (37%), as well as students (20%). To a lesser extent, tDCS is used by officials (5%), office workers and people working in the sales sector (4%), in the service sector (4%). 6% of tDCS users are unemployed.
Conduct tDCS mainly to improve concentration, training and memory. However, there is also a “medical” use of electrostimulation, mainly from depression.
However, despite the fact that studies show the effectiveness of tDCS for some cognitive functions, as well as the sufficient security of this method, scientists are rather restrained in regard to home-use initiatives and caution against using them. This is primarily due to the fact that if in scientific laboratories the correctness of the performance of tDCS is strictly controlled, then biohackers may neglect safety rules.
So, for example, if tDCS is carried out more than the prescribed 20 minutes, it is possible to cause skin damage under the electrodes up to burns. In addition, undesirable effects can be obtained if the electrodes are placed carelessly or the cathode and anode are interchanged (in this case, it is even possible to deteriorate cognitive function instead of improving it). In addition, it remains unknown how tDCS will act in the event of its long-term and regular use.
Nevertheless, the number of people wishing to try the effect of electrical stimulation on them is only growing, and their experience can be easily read on the Internet. For example, journalist Sally Adi used tDCS during her rifle training:
“Those 20 minutes that I spent shooting at targets while the current passed through my brain were beautiful. I remember only that I felt as if I drank a mug of excellent coffee, but without any “coffee nervousness”. I had an absolutely clear head, I was no different from the usual myself, but was more collected. And calmer. I had no fear, no doubt. From now on, I seemed to be just waiting for the appearance of a new task in order to fulfill it. Having got rid of my own fear and self-doubt, I became a damn cool shooter. You have no idea how amazing it was to find out how strongly these feelings prevent me from carrying out everyday tasks, and in general, to live . ”
Opinion polls also show that impressions of electrical stimulation are generally positive. Almost half (44%) rate their experience as “successful” and “very successful”. Approximately 41% rated the effect of tDCS as “average” and 14% rated it as “unsuccessful”.
It must, however, be borne in mind that in the case of individual use of tDCS the placebo effect is not excluded. In addition, it is difficult to separate the improvement in cognitive function, which occurs simply as a result of multiple tasks, and due to electrical stimulation.
On the other hand, a tDCS user survey shows that many of them have side effects. Basically - it is burning and itching in the area of ​​attachment of the electrodes. Sometimes when using tDCS, headache, nervousness and fatigue can occur, however, rated as “very weak”.
To achieve a quantitative assessment of changes in cognitive performance, tDCS users often use the so-called brain simulators - Lumosity, Dual N-Back Game or Cambridge Brain Challenge. Neurobiologist Nikolai Kukushkin wrote a story about testing tDCS, including while playing Lumosity:
“... The most interesting thing happened when I began to experiment with the places of attachment of electrodes. The US military is not stimulated by the forehead, but by the right temple. When I tried this configuration, the difference became obvious. Not goosebumps ran through the body, but such a soft, warm shiver - this is what happens when you plunge into some process and you see nothing but this process. I took up Lumosity again. The memory did not particularly stand out, the attention slightly improved. But when I tried the speed game, there were no questions left.
In these games, you need to quickly make a simple decision, for example, whether the card shown matches the previous one. Yes - one key, no - the other. You need to respond as quickly as possible and avoid mistakes. From the first, I broke three records in three different games organized according to this principle. In all three cases, the previous records were several months old. It took me a few seconds to “merge” into the game, after which my fingers seemed to drum themselves, and the same trembling spread all over my body. I wanted to laugh ... "
In general, tDCS at home is not difficult. Many companies began to produce compact tDCS devices, for example, “ focus ”, “ thync ” and “ the brainstimulator ” in the USA, “ Brainstorm ” in Russia.
However, it should be borne in mind that tDCS is still an experimental technology, the long-term and ethical implications of which are not fully understood. And in the case of use - it requires very careful attention and careful observance of all rules of application.
Following the scientists, biohackers began to be interested in technology - people who want to experience the results of scientific research on themselves. In the US, a whole community has already formed, using electricity to “pump” its brain. In addition, tDCS begin to be used by athletes, hoping that it can become a new and hard-to-detect doping.
Scientific research
')
Briefly about the main thing. TDCS - transcranial stimulation with direct current - came from medical research, where it is used in recovering from a stroke, to treat depression, migraine and neurodegenerative diseases. At the moment, there are at least 224 clinical trials of this technology in the world. However, research began to appear in the 2000s, demonstrating that tDCS can improve cognitive and motor functions in healthy people. Since that time, articles have already appeared a great many, some of which were described on geektimes . However, even in the last year, the piggy bank has been replenished with several particularly interesting works:
# 1 Accelerate math learning and improve memory
In 2016, a group of scientists from Harvard, Oxford and Tubingen University found that tDCS accelerates learning and improves verbal memory by more than 20%, and the effect was long-term and persisted for 2 months.
The experiment involved 20 healthy volunteers who were electrostimulated by the dorsolateral prefrontal cortex (DLPFC), a brain area responsible for learning (including mathematics). In the experiment, there was also a control group of people who imitated tDCS to eliminate the placebo effect.
Electrical stimulation was carried out with a current of 1 milliamper for 30 minutes a day for 2 days in a row. And during the procedure, all participants in the experiment solved mathematical tasks. It turned out that 2 days after the start of the experiment, subjects began to solve tasks with a smaller number of errors and 9% faster compared to the control group. In addition, their verbal working memory improved by a quarter!
To evaluate the long-term effects of stimulation, 2 months after the experiment was completed, the scientists tested again. It turned out that those who passed tDCS still showed much better results. And, interestingly, they solved tasks even faster than directly after tDCS. (After stimulation, the solution speed was 9% more than in the control group, and after 2 months - 20% more).
# 2 Less sleep
In the same 2016, a group of German scientists under the leadership of Michael Nietzsche and Christoph Niessen demonstrated that with the help of tDCS you can reduce the sleep time. And this is not accompanied by a decrease in the quality of sleep, nor by fatigue and drowsiness after waking up.
In the 5-day experiment 19 healthy people took part, each of whom was electrostimulated before bedtime. The impact was carried out on the neurons of the cortex, which are part of the cortico-talamic pathway of sleep and wakefulness regulation. It turned out that tDCS reduced sleep time by an average of 25 minutes (compared to how much they slept while simulating tDCS) and was accompanied by a long-term increase in the activity of the cerebral cortex.
What is important, the quality and structure of sleep (phase ratio) did not change due to electrical stimulation, and in the morning after the procedure, people felt no worse than usual.
â„–3 Increase concentration
And in 2015, a study was conducted demonstrating that tDCS can improve concentration.
During the attentiveness test, the subjects sat in front of the screen, on which appeared 5 arrows, one above the other. Sometimes all the arrows were directed in one direction, and sometimes the central arrow had the opposite direction.
The subjects for a few hundred milliseconds had to determine in which direction the central arrow was directed, and press the corresponding key. In some tasks a distracting signal also appeared in different areas of the screen.
It turned out that after the electrical stimulation of the parietal cortex, the volunteers gave an answer faster (in the task of spatial attention) than before tDCS. In the experiment, there was also a control group of people who imitated tDCS. However, after the “fake” stimulation, the speed of the assignment has not changed.
Electric dope?
In 2016, Nature magazine published an article stating that tDCS improves endurance, muscle strength, and coordination of movements among athletes.
This study was conducted by Californian developers from Halo Neuroscience in collaboration with the US Ski and Snowboard Association. The experiment involved 7 professional athletes involved in ski jumping. Some of them even belonged to the US Olympic team.
Athletes were divided into 2 groups: electrostimulation was carried out in 4 people, and imitated in 3 people. The experiment lasted 2 weeks, during which the athletes trained to perform jumps. And, as the company Halo reported, electrostimulation by 70% (!) Improved the strength of the jump and 80% better coordination of movements, compared with the control group.
Another tDCS study in 2016 was conducted by scientists from the University of Kent. They found that electrostimulation of the motor cortex suppresses the feeling of fatigue in athletes and increases endurance. The study involved 12 people who were also divided into 2 groups: some received neurostimulation, while others only thought they were receiving. Participants who were exposed to tDCS were ready to pedal for an average of two minutes longer and at the same time feel less exhausted.
All this is only preliminary data obtained from very small samples of people, but the results are impressive. Many companies are already adopting them, starting to develop devices to improve the training of athletes.
How it works? Mechanism of action
The main effect of tDCS on nerve tissue is considered to be the ability to cause “long-term potentiation” (LTP) and “long-term synapse depression” (LTD) - the processes underlying memory formation and learning. LTP is the restructuring of contacts between neurons, leading to increased synaptic transmission. And LTD, on the contrary, leads to a decrease in the strength of synapses.
Now scientists identify several mechanisms by which tDCS can influence LTP and LTD, the most studied of which is the change in the membrane potential of neurons. A positively charged electrode (“anode”) reduces the potential difference across the membranes of nerve cells, which leads to an increase in their excitability. A negatively charged electrode (“cathode”), on the contrary, increases the potential difference, reducing the probability of neuron excitation when an external signal is received. Thus, electrical stimulation by itself does not cause activation (excitation) of neurons, however, it changes their physiological state, making them more or, conversely, less prone to excitation.
Recently, however, studies have emerged that show that the mechanisms of action of tDCS are much more diverse. In 2016, Nature Communications magazine published an article stating that tDCS can affect neuroplasticity through the activation of auxiliary cells of the nervous tissue - glial cells. In another study of the same year, tDCS was found to alter the epigenetic regulation of the Bdnf gene. This gene encodes a neurotrophic factor of the brain, which is necessary for the formation of long-term memory. And under the action of tDCS, the cells began to produce a much larger amount of this factor.
To conduct tDCS electrodes are placed on certain areas of the brain, depending on what effects you need to get. For example, to improve motor learning, an anode is placed above the primary motor cortex. The location of the electrodes is critical for tDCS, since stimulation of different zones can lead to different results. TDCS allows you to locally increase the activity of the brain area above which the anode is located. However, studies are now emerging that demonstrate that the action of tDCS is more widespread and affects some other areas of the brain that are functionally related to the stimulated area.
It is worth noting that the effectiveness of tDCS varies greatly for different cognitive functions. For example, the effect on motor learning and mathematical ability is more significant than that on working memory .
Most tDCS studies use 1-2 milliampe current for 20 minutes. In order for the effect of tDCS to be significant, it is necessary to conduct electrical stimulation for several days in a row. Single tDCS sessions for most cognitive functions are ineffective .
Brain biohacking - to spend at home?
The results of scientific research, as well as the simplicity of the tDCS procedure, attracted the attention of biohackers who began to conduct electrical stimulation on their own. In the US, a community of people who are addicted to “home tDCS” has already emerged, which, according to estimates of the popular Reddit resource, includes at least 8,000 people.
In June 2015, Stanford University conducted a first detailed study of this community: their age, gender, occupation and education, as well as the goals with which they use tDCS.
It turned out that self-stimulation is carried out mainly by men (94%) at the age of 20-30. However, there are cases of tDCS use by older people - to compensate for cognitive impairment in old age.
TDCS is mainly used by people with a university degree (64%), 13% even have a PhD, MD or JD degree (Juris Doctor). 11% of users graduated from only 2 years of college, and 24% graduated from school or are still studying there. Apparently, the point here is that people learn about tDCS mainly from scientific research of tDCS or tDCS dedicated sites (which also mostly describe scientific research), which introduces a certain educational qualification.
There was no correlation between the use of tDCS and the financial situation of people. Electrostimulation with approximately the same frequency (21%) is carried out by both low-income people with annual incomes of up to $ 20,000 and by quite rich people who earn more than $ 90,000 a year.
Regarding the scope of tDCS users, they are mainly people engaged in professional activities and managers (37%), as well as students (20%). To a lesser extent, tDCS is used by officials (5%), office workers and people working in the sales sector (4%), in the service sector (4%). 6% of tDCS users are unemployed.
Conduct tDCS mainly to improve concentration, training and memory. However, there is also a “medical” use of electrostimulation, mainly from depression.
However, despite the fact that studies show the effectiveness of tDCS for some cognitive functions, as well as the sufficient security of this method, scientists are rather restrained in regard to home-use initiatives and caution against using them. This is primarily due to the fact that if in scientific laboratories the correctness of the performance of tDCS is strictly controlled, then biohackers may neglect safety rules.
So, for example, if tDCS is carried out more than the prescribed 20 minutes, it is possible to cause skin damage under the electrodes up to burns. In addition, undesirable effects can be obtained if the electrodes are placed carelessly or the cathode and anode are interchanged (in this case, it is even possible to deteriorate cognitive function instead of improving it). In addition, it remains unknown how tDCS will act in the event of its long-term and regular use.
Nevertheless, the number of people wishing to try the effect of electrical stimulation on them is only growing, and their experience can be easily read on the Internet. For example, journalist Sally Adi used tDCS during her rifle training:
“Those 20 minutes that I spent shooting at targets while the current passed through my brain were beautiful. I remember only that I felt as if I drank a mug of excellent coffee, but without any “coffee nervousness”. I had an absolutely clear head, I was no different from the usual myself, but was more collected. And calmer. I had no fear, no doubt. From now on, I seemed to be just waiting for the appearance of a new task in order to fulfill it. Having got rid of my own fear and self-doubt, I became a damn cool shooter. You have no idea how amazing it was to find out how strongly these feelings prevent me from carrying out everyday tasks, and in general, to live . ”
Opinion polls also show that impressions of electrical stimulation are generally positive. Almost half (44%) rate their experience as “successful” and “very successful”. Approximately 41% rated the effect of tDCS as “average” and 14% rated it as “unsuccessful”.
It must, however, be borne in mind that in the case of individual use of tDCS the placebo effect is not excluded. In addition, it is difficult to separate the improvement in cognitive function, which occurs simply as a result of multiple tasks, and due to electrical stimulation.
On the other hand, a tDCS user survey shows that many of them have side effects. Basically - it is burning and itching in the area of ​​attachment of the electrodes. Sometimes when using tDCS, headache, nervousness and fatigue can occur, however, rated as “very weak”.
To achieve a quantitative assessment of changes in cognitive performance, tDCS users often use the so-called brain simulators - Lumosity, Dual N-Back Game or Cambridge Brain Challenge. Neurobiologist Nikolai Kukushkin wrote a story about testing tDCS, including while playing Lumosity:
“... The most interesting thing happened when I began to experiment with the places of attachment of electrodes. The US military is not stimulated by the forehead, but by the right temple. When I tried this configuration, the difference became obvious. Not goosebumps ran through the body, but such a soft, warm shiver - this is what happens when you plunge into some process and you see nothing but this process. I took up Lumosity again. The memory did not particularly stand out, the attention slightly improved. But when I tried the speed game, there were no questions left.
In these games, you need to quickly make a simple decision, for example, whether the card shown matches the previous one. Yes - one key, no - the other. You need to respond as quickly as possible and avoid mistakes. From the first, I broke three records in three different games organized according to this principle. In all three cases, the previous records were several months old. It took me a few seconds to “merge” into the game, after which my fingers seemed to drum themselves, and the same trembling spread all over my body. I wanted to laugh ... "
In general, tDCS at home is not difficult. Many companies began to produce compact tDCS devices, for example, “ focus ”, “ thync ” and “ the brainstimulator ” in the USA, “ Brainstorm ” in Russia.
However, it should be borne in mind that tDCS is still an experimental technology, the long-term and ethical implications of which are not fully understood. And in the case of use - it requires very careful attention and careful observance of all rules of application.
Source: https://habr.com/ru/post/372473/
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