Scientific ways to improve attention: nootropics, neural interfaces and electrostimulation
How to increase concentration? To do this, there are many household tips, for example, to use noise-canceling headphones, to develop the habit of working with the music of the same style, block sites that you most distract from, go to the alarm clock, play sports and put all the important things in the right places.
In this article, I tried to dig deeper and see what the experts in neuroscience know about concentration, as well as understand what methods of improving attention are proven in scientific studies, preferably in several double-blind and placebo-controlled ones. Without this, we, unfortunately, remain within the framework of personal opinions, individual characteristics and self-suggestion. First of all, I was interested in methods that allow not to break away from work or study, roughly speaking, those that can be used while sitting in front of a computer monitor.
Under the cat, the current state of neurobiological research in the field of concentration of attention is described and a comparative review of various pharmacological stimulants, nootropics and neurotechnologies for increasing concentration is given. Often these technologies are used without understanding how they work (and if they work at all), and I hope that after this review there will be less confusion.
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From the point of view of neuroscience, 3 different systems are introduced to describe attention. The first is responsible for vigilance, or "watchfulness." It keeps the cognitive system at a sufficient level of activity and prepares it for a quick response. The second “executive control” system specializes in higher-level processes, for example, the resolution of conflicts between different systems or the detection of errors. And the third system responsible for the “orientation” determines the source of the signal and speeds up its processing.
For the convenience of describing these systems, neuroscientists use the so-called “cocktail party effect” . “Alertness” occurs when, in a lively environment, a person hears a familiar name among the noise and conversations. “Orientation” occurs when it determines where and who speaks, and the system of “executive control” allows us not to be distracted by other voices and sounds at this time.
As it turned out, the functioning of these systems is associated with certain areas of the brain and a special set of neurotransmitters - substances that allow you to transmit a signal from one nerve cell to another. Perhaps, the description of attention mechanisms given below will be unnecessarily detailed, but without this, in my opinion, it is impossible to understand how certain nootropes and neurotechnologies that stimulate attention act on the brain.
The system of “alertness” is mainly responsible for the right hemisphere, frontal and parietal cortex zones. Damage to these areas in brain injuries leads to a loss of ability to maintain attention by force of will. In addition, neurons that are located throughout the brain (from the midbrain to the cerebral cortex), which use acetylcholine as a neurotransmitter, are involved in the work of the alertness system.
Visualization of the activity of the human cerebral cortex (fMRI method) during the performance of tasks requiring vigilance. Colored pixels (red, green, yellow) indicate the activation of areas of the right hemisphere, as compared to the left, as a result of various tests for attention. According to Shulman, 2010 .
The second attention system, which is responsible for the “orientation,” deals with the selection of the most important information from the variety of incoming stimuli. The occipital, temporal and primary motor cortex are the areas of the brain that process visual, auditory and tactile information.
Neurons that use the neurotransmitter acetylcholine and are involved in transmitting sensory information from the sense organs to the hemispheric cortex are also involved in the operation of this system. The transmission of sensory signals goes through the thalamus, a subcortical integrative center, which passes only a portion of the signals to the hemispheres, and the rest is either blocking or weakening.
In a state of concentration, the “orientational” attention system begins to significantly change the filtering of information coming from the senses.
The executive control system performs more complex operations to resolve conflicts between processes occurring in different areas of the brain. For her research in neuroscience, the so-called “conflict tasks” are used, in which distracting stimuli prevent the execution of tests. If you look at how the human brain works at this time, you can see that the areas of the frontal cortex of the cerebral hemispheres are activated : part of the anterior cingulate and prefrontal cortex:
FMRI of the human brain during the execution of "conflict tasks". Red and yellow highlighted activated areas of the cortex (anterior cingulate - A, prefrontal - C). According to Kerns, 2004 .
These areas are also associated with the dopaminergic system of the brain. They send their processes (axons) neurons of the midbrain, using dopamine as a neurotransmitter.
All scientific approaches to improving attention, which will be discussed below, are aimed at the biological paths described in this section. Psychostimulants and nootropics, in the first place, affect the transmission of neurotransmitters, and neurotechnologies (biofeedback training and brain electrical stimulation) non-invasively affect the work of certain areas of the cortex, optimizing their activity.
In scientific research, nootropics and neurotechnologies are the main ways to improve attention in both patients and in the case of healthy people. They began to actively explore more than 50 years ago, and interest in them arose almost simultaneously. In 1964, Belgian pharmacologists synthesized piracetam, in 1966 physiologist Daniel Albert found out that stimulation of the brain by microcurrents can change the excitability of neurons, and in 1968, American Joe Kamiya discovered that a person can arbitrarily change the parameters of his EEG (brain wave activity) during availability of feedback on its current values.
These approaches gradually began to penetrate into ordinary life: after 10 years, healthy people began to use nootropes on their own, and with a lag of several decades, neurotechnology was gaining popularity. Today's bihacking fashion only boosts this interest.
In this article, I decided to find out what scientific basis underlies these methods, and delve into existing scientific articles. Moreover, the search for effective ways to increase concentration is relevant for me too.
In the field of neurotechnologies, there are two main approaches to improving attention: reading information about the brain and demonstrating it to the user on the basis of biofeedback (BFB workout), and changing the activity of brain areas through electrical stimulation.
Cognitive exercises by the method of BFB are arranged as follows. A person performs a specific computer test, during which the functional state of his brain is determined with the help of EEG (electroencephalography). This information is processed and shown to the user on the screen. So he learns about the degree of his own concentration or, conversely, relaxation and corrects the execution of the task. Thanks to scientists, such a BOS interface has been called a “physiological mirror.”
The structure of the training in the method of biofeedback. The activity of certain areas of the brain is determined by EEG (or fMRI). Data is processed in real time and displayed to the subject. For example, the higher the level of the “thermometer”, the better the concentration of attention. Given this information, a person learns to control their states. By Scharnowski, Weiskopf, 2015
Medical studies of BFR training began in the 60s. Since that time, the technology has been used to treat ADHD (attention deficit hyperactivity disorder), autism , epilepsy , insomnia and depression . If you delve into neurobiology, then the principle of BFB training is based on the fact that a person’s cognitive states can be judged by the electrical activity of his brain. The EEG method allows you to register several types of electrical oscillations that have a clear connection with the relaxed or, conversely, concentrated state.
The alpha rhythm (fluctuations of 8–13 Hz) occurs when we close our eyes and begin to relax; beta rhythm (14–40 Hz) and sensorimotor rhythm are associated with wakefulness and focusing attention, and gamma rhythm (> 30 Hz) is observed at maximum concentration. Delta rhythm (1-4 Hz), on the contrary, is characteristic for sleep, and theta rhythm (4-8 Hz) - for the state of drowsiness.
Here is a typical example of an encephalogram. In this case, the person first lies with his eyes closed, and then opens them (red arrow):
Changes in brain wave activity after a person opens his eyes. The graph shows that the alpha rhythm (underlined in red) disappears at the time of opening the eyes (marked with a red arrow). By Uri Shaked, 2017 .
At disturbances of attention the strengthened theta rhythm in frontal lobes, and also disturbances of beta and sensorimotor rhythms are often observed . They are optimized and carried out with BOS-therapy, including the treatment of ADHD.
As for the use of BFR interfaces on healthy people, there are still few such studies - I managed to find only a few high-quality scientific works. At the same time, all of them demonstrate that BOS training has statistically significant but weak or moderate effectiveness.
In a recent study by Austrian scientists, daily BOS exercises improved the alertness and spatial attention of healthy volunteers. The training consisted in the fact that the subjects were shown a circle, the size of which increased as their concentration increased. And attention was assessed in standard tests that require turning the figure in the mind or in the Go / No-Go tests. The meaning of this task is that when receiving a “Go” signal (image of a green cross), a person must press a button as soon as possible, and in a situation of “No Go” (when a blue cross appears), there is no need to press, and should slow down the movement started (see figure below).
After 6 weeks of daily biofeedback training, the speed of each task increased by 17-18 ms (which was 5-6% improvement), and the accuracy of execution increased by 16% relative to placebo control.
Top left: BFB training to improve concentration. The size of the white circle increases with increasing concentration.
Top right: The test for spatial thinking. It is required to determine which of the lower figures is a rotated copy of the upper one.
Bottom: “Go / No-Go” test, which requires a quick response to a target stimulus (green cross) and no response to a distracting stimulus (blue cross). By Doppelmayr & Weber, 2011.
Several more studies were conducted on students of music schools. They confirmed the effectiveness of BFB training, showing that after 5 weeks of the experiment the level of concentration increases by several percent. Similar results were achieved in studies on 11-year-old children. Studies also demonstrate the painlessness and safety of the method.
With regard to the use in everyday life, the BOS-training a few years ago began to commercialize. Nowadays several user neurogadgets are being actively sold, for example, Muse Neurobatch and Emotiv Epoc . All are designed to train attention or relax.
From left to right: Muse Neyroobruc, Emotiv Epoc Neutro Helm, Visualization of brain activity with Emotiv Epoc.
The Muse neuroobrac measures the brain activity using 4 EEG electrodes, processes it and transmits relaxing or invigorating music to the user in headphones. In addition, information can be visualized on the smartphone screen. The Emotiv Epoc Neutro Helm works in a similar way, reading information about the brain through 14 electrodes. An additional advantage of these gadgets is an ever-increasing base of applications for training. If you are tired of using one application, you can switch to another.
Summarizing the information on the BFB interfaces, one can say that there is little scientific research, but they speak in favor of the effectiveness of the technology. However, we must bear in mind that it takes at least a month of daily training to make the improvement in attention noticeable. This is a long time and is incomparable with studies of nootropics or electrostimulation (see below), in which effects are often observed after one session. Well, one can not ignore the fact that there is a problem of “insensitivity” to neurocomputer interfaces , that is, BFB workouts do not work for a very significant percentage of people, according to various estimates, from 15 to 30%. And for them, BFR interfaces will become a waste of time and money.
So in general, in my opinion, the use of such neural interfaces is still rather pleasant entertainment than a truly effective way to improve attention.
Another non-invasive way to improve attention is transcranial direct current stimulation (tDCS). As in the case of the BOS-interfaces, it came from medicine, where it has been used for more than 30 years to treat depression , chronic pain , Alzheimer's disease and when recovering from a stroke . In Russia, it is also actively used - mainly for the treatment of developmental delays in children, and is considered to be a very effective treatment for ADHD. According to Russian medical centers , as a result of electrostimulation, 77% of children experience an improvement.
Studies of tDCS in healthy people began in the 2000s, and now there are already quite a lot of them. The first to use electrical stimulation were the US military — to speed up the training of infantrymen and pilots on video simulators. Recruits trained to detect hidden threats (bombs or shadows from snipers) in a virtual game and respond to them as quickly as possible. In these studies, tDCS of the frontal cortex increased the rate of human learning by more than 2 times, compared with placebo by imitation of tDCS, which by the measures of neurobiology is a very significant effect.
Excerpt from the report of the American defense agency DARPA. Stimulation of the right temporal region with a direct current of 2 milliamperes led to an increase in the accuracy of the test by a factor of 2.1 (Fig. Right - a red bar), compared with placebo control (blue bar).
Then, military studies have shown that electrical stimulation can improve the performance of people who suffer from lack of sleep. The experiments were conducted on employees of American military bases and then were repeated on military pilots . The improvement in productivity as a result of tDCS was long-term and persisted throughout the day (during which people were still sleep deprived). This, by the way, is about 2 times longer than in the case of using standard psychostimulants used to combat fatigue - amphetamines and modafinil.
Then electrical stimulation was investigated to improve other cognitive functions of healthy people, including concentration of attention , working memory , reaction, and motor learning . TDCS has been used by athletes of the American Olympic team for several years - ski jumpers and cyclists. Several scientific studies show that electrostimulation of the motor cortex can increase endurance , muscle strength , movement technique and sensory-motor adaptation .
As part of this review, I, unfortunately, have no opportunity to dwell on all the cognitive effects of tDCS in healthy people. However, I wrote several articles about them before, as I myself am a fan of this technology. Here I will try to penetrate deeper only into scientific articles on concentration of attention.
Using tDCS for military training on video simulators and during sports training.
As for the principles of electrical stimulation of the brain, the procedure is as follows. Two electrodes are attached to the scalp, through which a weak direct current of 1-2 milliamperes is supplied. The impact of the anode ("+" electrode) reduces the potential difference across the neuronal membrane, which makes them more sensitive to excitation. Impact on neurons by a cathode ("-" electrode) has the opposite effect .
With repeated use, anodic tDCS affects synaptic plasticity - changes the structure of contacts between nerve cells and increases the density of these contacts, which has a beneficial effect on the processes of memory and learning. On the scale of the whole brain tDCS leads to an increase in the activity of certain areas of the big hemispheres:
Increased brain activity in tDCS parietal cortex. The color highlighted areas of brain activation at tDCS (upper row), compared with placebo stimulation (lower row). During tDCS and placebo-tDCS, all subjects completed the attention tasks. By Callan, 2016.
In research , tDCS of the prefrontal cortex is commonly used to improve concentration. In 2017, an article by Austrian scientists published that stimulation of this zone affects attention and reaction in a blind, placebo-controlled scientific study. The study involved 87 healthy volunteers who trained for 4 days in a row to perform cognitive tests in neurostimulators. To eliminate the effect of self-hypnosis, some people imitated tDCS.
It turned out that electrostimulation increased the accuracy of assignments by 15%, and the reaction rate increased by 30% compared with the placebo group. I want to note that these are high efficacy rates, since in scientific studies the reaction acceleration is rarely observed by more than 10–15% (see below. Psychostimulants and nootropics).
Left: Visual attention test. It is necessary to find the letter “T” among the letters “L” as soon as possible. Centered: Reaction change as a result of using tDCS. The graph shows the reaction rate in the case of anode tDCS (red line); placebo tDCS (black line); cathodic (inhibitory) tDCS (blue line). Right: The location of the electrodes during the experiment. The anode (red electrode) is located in the region of the prefrontal cortex. By Filmer, 2017.
Electrical stimulation improves attention in more complex experiments. For example, in Sternberg's test - a complex task for working memory, selective attention and concentration (see the figure below). 10 minutes tDCS increased the speed of responses given by 100-140 milliseconds (which was about 10% improvement). And in a very recent study of British scientists, electrical stimulation improved executive attention by 15–18% (see figure below). Similar results were obtained in several experiments.
Left: Sternberg test. The subject is consistently demonstrated a set of number 1 of words / images / numbers. Then demonstrated ("distracting") set number 2 of the new words / images / numbers. And after a small delay, set number 3 is shown, and it is necessary to choose those words / images / numbers that were in set No. 1, but not in set No. 2. According to Brodziak, 2014.
Right: Test for executive attention (test for neural networks of attention, or Ant). Subjects need to determine the direction of the central fish / arrow (circled in red) as soon as possible and respond by pressing a key. By Yoshida, Burling, 2012.
Interestingly, in addition to concentration, electrical stimulation of the prefrontal cortex has a number of other cognitive effects. For example, it leads to an improvement in memory , speech activity and work productivity . In addition, to improve attention, they stimulate another area of ​​the brain - the right parietal cortex, which improves visual and spatial attention , as well as visual orientation .
As for side effects, in general, electrical stimulation is considered a safe method. For 20 years of its use, no dangerous side effects have been recorded. However, it can cause itching, burning and irritation of the skin under the electrodes, dizziness and headache. This conclusion was made by a systematic analysis of tDCS studies conducted since 1998.
Despite the fact that in the laboratory the tDCS procedure is considered safe, scientists are concerned that more and more people use electrical stimulation at home on their own, and warn against abuse of this method. First and foremost, scientists are concerned that biohackers may neglect the rules for conducting tDCS: instead of the prescribed 15-20 minutes, the procedure will stimulate itself much longer and carry out tDCS daily for months or even years, although this mode of exposure has not been studied and its consequences are unknown.
Indeed, in the past 5-6 years, electrostimulation has been coming into vogue with biohackers. But this fashion, however, almost does not go beyond California. The exact number of people using tDCS independently is unknown, but indirect estimates suggest that we are talking about tens of thousands of people. At one Reddit forum in the tDCS section there are more than 11,000 subscribers.
Biohackers using tDCS have already been the object of several studies themselves. All these works agree on the fact that electrostimulation is used mainly by men, most often from 30 to 45 years. 61% of users have completed higher education, while 16%, in addition to this, have a PhD degree. And 92% of these people at least sometimes read scientific articles.
Opinion polls show that the impression of electrostimulation is 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”.
Electrostimulation is conducted at home, primarily to improve concentration, learning, and memory. However, there is also a “medical” use of electrostimulation, mainly from depression. For about 5 years, there have been user tDCS devices on the market, they are produced by several companies in the USA ( Brain Stimulator , Brain Driver , Foc.us), Hong Kong ( Priormind ) and Russia ( Brainstorm Neurostimulator) ).
In general, studies of electrostimulation to improve the attention of healthy people are still being conducted, but the data obtained, in my opinion, is already enough to talk about its effectiveness. The advantage is that the technology acts non-invasively and locally and does not alter the biochemistry of the brain, has fewer side effects and does not cause dependence. This distinguishes it from psychostimulants and nootropics, which will be discussed below.
Now I turn to the most extensive section of this article - pharmacological stimulants. If neurotechnology began to be used by healthy people only in the last 5-6 years, then nootropics have been popular for several decades. They were also originally developed in psychiatry — for the treatment of mental disorders in Alzheimer's disease and schizophrenia, damage to the areas of the cerebral cortex and ADHD.
Subsequently, many drugs were tested on healthy people, primarily on those engaged in activities that require the mobilization of mental and physical resources - students, doctors, soldiers. It turned out that in this case, some of these substances can be effective. At various times, various stimulants were systematically used by soldiers of the French Foreign Legion, the US and Indian Air Force, the armed forces of Great Britain , and the astronauts on the ISS .
Other drugs have not been studied in healthy people, or have not been effective for them, but for some reason, they still became actively used by healthy people to improve their mental potential.So the definition of "fake" nootropics is one of the objectives of this review.
According to different estimates, nootropics are used by millions of people in different countries. A German study in 2015 found that 6.7% of respondents took nootropes their whole lives. University surveys showed that from 2% to 25% of students are keen on nootropics, with most of the articles talking about a figure of 10% -15%. A study conducted in a French college revealed that 67.4% of students have used at least one stimulant over the past year.
A cursory overview of information on forums and specialized sites shows that, as a rule, such drugs as nootropil, fenotropil, glycine, methylphenidate, modafinil, levodopa, and many others are used to improve attention. Actually, the task was to understand what works from this and what side effects there might be.
Methylphenidate (or Ritalin) is a psychostimulant that is widely used to treat ADHD in children. It contributes to the release of the neurotransmitter dopamine into the synaptic cleft - the area of ​​contact between nerve cells. This is due to the fact that methylphenidate blocks the reuptake of dopamine by neurons, acting on a mechanism similar to amphetamines. Amplification of dopamine output has a stimulating effect on neurons - they are more actively excited and transmit a nerve signal. At the level of the whole brain, this is accompanied by an increase in the activity of entire areas of the cortex.
For the treatment of ADHDMethylphenidate was approved back in 1955, and in the 1990s, due to the growing number of diagnoses of ADHD, it began to be prescribed very often. In the past two decades, not only patients but also ordinary people began to actively take methylphenidate. For example, students actively use it to prepare for exams, especially in Europe and the USA , much more often than other nootropics. However, scientific studies of the effects of methylphenidate on healthy people contain rather contradictory information, which is especially evident in terms of improving attention.
On the one hand, the intake of methylphenidate leads to an increase in the activity of the areas of the brain responsible for attention. For example, the areas of the anterior cingulate cortex and parietal area are activated:
Visualization of brain activity (fMRI) in response to methylphenidate intake in conjunction with performing attention tests. (A) Anterior cingulate cortex, (B) Right lower parietal lobe (C) Left lower cingulate lobe. According to Hester, 2012.
On the other hand, scientific papers, in which the effectiveness of methylphenidate was evaluated in specific tests for attention, are rather contradictory. A review of 60 studies in healthy people found that methylphenidate improved attention or vigilance in only 29% of the work. This means that for the rest of 71% of the studies, its effects were not statistically significant. Methylphenidate turned out to be much more effective for improving working memory or speed of information processing (a significant improvement in 65% and 48% of the studies, respectively).
However, it is worth noting that in the above-mentioned review, the effects of a single dose of methylphenidate were analyzed. It is possible that repeated use of the drug would have a more pronounced effect. In addition, in the studies presented in this review, different doses of the substance were used - from 5 to 45 mg. And the intake of small doses of the substance, he was often ineffective.
If you look at a study in which healthy volunteers used methylphenidate in a higher dose (45 mg of substance), it is clear that the drug significantly improved a number of indicators in various tests for attention, and the effect was quite significant. In tests for selective attention, the reaction rate increased by 10%, and the accuracy increased by 1.5 times, compared with the placebo control.
The response time (left) and the number of errors (right) in tasks for attention after taking various doses (from 0 to 45 mg) of methylphenidate. There is a decrease in response time (i.e. an increase in speed), as well as a decrease in the number of errors. According to Hermens, 2007.
A number of studies have been conducted on older people. However, the effect of methylphenidate on their cognitive functions (including attention) is much weaker than in young people and most often turns out to be insignificant.
Interestingly, methylphenidate also improves this aspect of attention, as the ability to quickly recognize faces. In tasks that require quickly and accurately determine the sex of a person in a photo, the use of the drug increased the accuracy of the tasks by a few percent.
The test for selective attention is the ability to recognize faces. First, an arrow appears on the screen indicating the direction. Then a photo of the face appears in the corresponding side of the screen, and the subject must determine his sex by quickly pressing the appropriate key. To distract attention from the opposite side of the screen, another face or distorted image is shown. By ter Huurne, 2015 .
Thus, some studies suggest a sufficiently high efficiency of methylphenidate to improve attention. However, it is worth noting that in scientific papers there is not yet a consensus on the optimal doses and mode of use of methylphenidate for healthy people. On the other hand, more convincing is the ability of methylphenidate to improve memoryand speed up information processing.
As for the side effects of methylphenidate, the most frequent effects are nervousness, anxiety and insomnia. Also, allergic reactions, anorexia, nausea, dizziness, headache, depression are often observed. In addition, methylphenidate may adversely affect the cardiovascular system, lead to a rapid increase in pressure, etc. Large doses may even contribute to the development of psychosis. It is also frustrating that it can cause addiction. Such side effects are quite a big drawback of the drug.
In addition, in Russia, methylphenidate is not for sale, as it is entered in the register of prohibited drugs. However, it can be purchased in most countries of Europe and the USA, where it is used in medicine for the correction of ADHD.
Reading the articles, unexpectedly for myself, I discovered that according to scientific research, nicotine is an effective stimulant of attention.
It is an agonist of nicotinic acetylcholine receptors (that is, acts on those neurons that are traditionally associated with attention) and contributes to the release of acetylcholine, dopamine, serotonin, glutamate and other neurotransmitters involved in human cognitive processes. Nicotine and other nicotine-like substances have long been used to combat cognitive impairment. Scientific articles demonstrate that nicotine relieves the symptoms of schizophrenia, ADHD, Alzheimer's, Parkinson's, and age-related neurodegeneration.
Nicotine got its name from the Latin name of tobacco, Nicotiana tabacum, which, in turn, was coined in honor of Jean Nico, the French ambassador to the Portuguese court, who in 1560 sent some tobacco to Queen Catherine de Medici, recommending it as a means of migraine. In nature, nicotine serves plants to protect against insects and is a poison. However, as you know, in small doses, poisons can even be beneficial.
Today, nicotine has become one of the most intensively studied drugs, and its effects on human cognitive abilities are confirmed in dozens of scientific studies. For example, meta-analysis41 double-blind, placebo-controlled studies in healthy people found that nicotine has significant positive effects on 6 indicators, including fine motor skills, vigor, attention, reaction rate, episodic and working memory.
In most of the studies described, nicotine was administered by an FDA approved method: using chewing gum or a transdermal patch. More often than not, a single dose of nicotine was enough to achieve the effect. Interestingly, nicotine also improved driving and flight control in computer simulators. It is important to note that these studies were conductedeither on non-smoking people, or on those smokers who did not have a shortage of tobacco. As a consequence, the authors conclude that the observed cognitive improvements could not be associated with relief, due to the resumption of smoking. This led the authors of the article to speculate that the improvement in cognitive function caused by nicotine is one of the reasons why people start smoking and cannot quit.
It should be noted that the effectiveness of nicotine is not only statistically significant, but often turns out to be very noticeable at the “everyday” level. For example, in tests for spatial attention, chewing gum with nicotine (at a dose of 2 mg) improved the reaction rateby 30%, compared with placebo control. It is more effective than most other nootropics, which, as a rule, improve this figure by a maximum of 15-20%. A 30% improvement was observed in only a few experiments using brain electrical stimulation (see above).
The mechanism of action of nicotine on a person’s cognitive functions is not fully understood. It may be associated with the activation of the prefrontal and parietal cortex, as well as the thalamus and hippocampus, the brain areas that provide memory and attention.
Left: Visualization of brain activity of people performing tasks on attention and working memory (by fMRI method). The top row of images shows the activity of the cerebral cortex when performing the simplest tasks (0-back), the bottom one shows the most complex tasks (3-back).
Right: Areas of the brain that are activated in people who took nicotine, compared with placebo, are highlighted. According to Kumari, 2003.
Other studies, by contrast, demonstrate that nicotine improves attention by inactivating certain neurons. In this regard, scientists have put forward the theory that nicotine synchronizes high-frequency activity of the brain, and its effects are associated with the simultaneous activation of some and inactivation of other regions.
Despite the positive effects of nicotine on attention, there is no doubt that it is still a much better solution for health to quit smoking or not to start. Studies have shown that not only smoking cigarettes, but also regular use of nicotine as part of chewing gums or patches, increases the risk of diseases of the cardiovascular, respiratory systems and the gastrointestinal tract. Nicotine can reduce the immune response, adversely affect reproductive function and increase the risk of cancer. In addition, its use is easily addictive.
Modafinil (Provigil, Vigil) - is perhaps one of the most popular nootropics among biohackers. It began to be used in France in the 70s to combat narcolepsy (a disease characterized by sudden bouts of drowsiness), since it has a strong stimulating effect on the nervous system. He is now approved in the United States for the treatment of sleep disorders associated with shift shifts, and is often prescribed by doctors for the "owl" syndrome. In addition, in a number of countries - in the USA, Canada, France, India - at various times it was used to increase the efficiency of military or even astronauts at space stations.
Modafinil has an affinity for the dopamine transporter, which makes it possible to block the reuptake of this neurotransmitter from the area of ​​synaptic contact between neurons. As a result, dopamine concentration increases in some areas of the brain. This mechanism is also characteristic of other psychostimulants, cocaine and amphetamine. However, unlike the latter, which lead to widespread activation of areas of the brain, modafinil more specifically increases the activity of zones associated with vigor:
FMRI of the human brain after taking modafinil. An increase in the activity of the zones of the cortex responsible for attention: the anterior cingulate cortex (A) and the lower part of the intra-small groove of the large brain (B). According to Esposito, 2013.
Modafinil has been studied for a long time to improve the performance of healthy people - first of all, in conditions of lack of sleep. The use of modafinil retained the performance of pilots who were deprived of sleep for 37 hours, and increased the accuracy of flight control by approximately 27%, compared with placebo, without any significant side effects. However, numerous scientific studies on healthy volunteers demonstrate that it can be effective for improving the attention and vigor of people who do not experience lack of sleep.
For example, a comprehensive meta-analysis of 45 scientific studies of modafinil found that a single dose (at a dose of 100 to 400 mg) of this drug by people who do not have a lack of sleep significantly improved their attention, increased vigilance and “alertness”.
However, a later meta-analysis revealed that although there are works in which modafinil improves attention, their number does not exceed half of the studies performed. Perhaps this is due to the fact that modafinil is more effective for improving more complex cognitive abilities. The same meta-analysis showed that in the case of complex tests (which, in addition to attention, require memory stress, ability to learn and languages), the effect of modafinil is more convincing.
The fact that modafinil has a complex effect on cognitive abilities is also confirmed by other works. In them, modafinil has proven effective for improving planning , decision-making and intelligence.
As for side effects, modafinil can cause insomnia, headache, dizziness, in rare cases serious mental disorders: psychosis and mania. Studies of modafinil have not confirmed the existence of any dependence and the presence of "withdrawal syndrome", which can be considered a plus of this drug. In general, it is believed that the side effects of modafinil are milder compared to other stimulants, such as methylphenidate, but can still be very severe.
Modafinil is relatively easy to buy abroad: in the United States and in Ukraine it costs between $ 30 and $ 60 per month. In Russia, it has been banned since 2012. At the same time, some stores of sports nutrition seem to sell it, positioning it as an energy drink, but I have not met with this.
Other effective nootropics and stimulants for improving attention, I have not found
If we talk about nootropics and stimulants that improve the attention of healthy people, at least in a few independent scientific studies, then that's all. However, below I decided to briefly describe also those substances that do not exactly improve concentration or are not investigated for these purposes. Hope this frees you from wasting time and money. Moreover, many of them are actively recommended to improve the attention of sellers of nootropics or "experts" in specialized forums.
If there are no substances in this list, it means that I couldn’t find any scientific research about their usefulness for attention.
Atomexin
Atomexin (Strattera, Tomoxetin, Attentin) is a drug used to improve attention in cognitive pathologies. Studies in China, Korea, and Mexico show that Atomexin really improves the attention of children suffering from ADHD, but no better than the methylphenidate described above. In addition, compared with methylphenidate, atomexin causes much more side effects, for example, 3 times more often vomiting, and 7 times more often drowsiness. But for healthy people atomexin was ineffective. In the 2017 study, methylphenidate significantly improved attention, and atomexin did not perform better than placebo. Other studies repeat these results.
In this regard, it must be borne in mind that if a drug improves cognitive function in patients with impaired conditions, this does not confirm that the substance will improve the mental abilities of healthy people. The effect is unpredictable and may well turn out to be even negative.
Mirtazapine
Mirtazapine (Remeron, Mirzaten, Mirtazonal) is a tetracyclic antidepressant. It is able to slightly improve vigilance and attention in patients with depression. However, when the effects of mirtazapine decided to double-check on healthy people , the attention of the subjects, on the contrary, was greatly reduced. In addition, according to subjective feelings, people began to feel less vigorous and satisfied. Deterioration in driving tests was also found in another 2017 study.
Levodopa
L-Dopa (Sinemet, Parcopa, Atamet, Stalevo, Madopar, Prolopa) is a well-known drug for the treatment of Parkinson's disease and dopamine dystonia. It is interesting that for opening the ability of levodopa to reduce the symptoms of Parkinson's disease, they even awarded the Nobel Prize in 2001. Now, levodopa is a very popular nootropic drug, and at profile forums it is actively advertised as a means for “accelerating mental reactions”. However, in scientific experiments on healthy people, its effects are again not confirmed. An analysis of 7 double-blind, placebo-controlled studies showed that levodopa does not improve attention and may even impair memory. In addition, Levodopa has many unpleasant side effects, including depression and seizures.
Donepezil
Donepezil (Aricept) is approved by the FDA for the treatment of dementia in Alzheimer's disease, however, among scientists, evaluations of the effectiveness of this drug vary. However, in 2011, it turned out to be the best-selling medicine for the treatment of this disease. Systematic analysis of the effects of donepezil for healthy people again did not confirm its effectiveness. In 3 out of 4 behavioral jobs, donesepil led to a slight, but statistically significant, deterioration in attention .
Piracetam and analogues
I can not write about piracetam, because it is still one of the most popular nootropics in Russia. However, in his case we are dealing with a drug whose effectiveness has not been proven not only in healthy people, but even for medical purposes. In most countries of the world, piracetam is not registered as a medicine. In Russia, it is nevertheless used in neurological practice, although it is considered "an outdated drug with unproven efficacy."
I read a systematic review of 2010 , which summarized more than 300 scientific articles - these are all studies of piracetam and its analogues (aniracetam, oxyracetam, pramiracetam, phenylpyracetam - “phenotropyl”, nebracetam, and many others). However, among them I counted only 3 (!) Studies on healthy people. In one work , it was shown that the analogue of piracetam (nebracetam) is ineffective in improving memory. And in the other two, oxiracetam and pramiracetam were tested on healthy volunteers, whose cognitive functions were previously impaired by the administration of scopolamine. In such experiments, both drugs actually slightly improved cognitive abilities, however, on this basis no conclusions can be drawn about their effectiveness for normal healthy people.
Moreover, this systematic analysis showed that piracetam and its analogues are incapable of leading to improvements in mental abilities in cognitive diseases.
Caffeine
And finally, caffeine, which is the most popular psychostimulant in history - and is used daily by tens of millions of people to increase vigor and fight fatigue. Until recently, I myself was sure that caffeine is an effective stimulant of vitality, I read relevant scientific articles, but I learned about the problems with its research only while writing this text.
The authors of the 2015 analytical review note that the positive effects of coffee on productivity are often found due to the incorrect design of scientific experiments. The fact is that most people (including those who participate in the trials) use coffee every day. And to conduct a typical scientific study, subjects are asked to abstain from drinking this drink for a day, which in itself causes a “withdrawal syndrome”, impairs attention and efficiency. (I think everyone regularly drinking this drink is familiar with the lack of coffee in the morning). Subjects are then given caffeine, which restores their condition, and their vigor is compared with those who still suffer from a lack of coffee.
If we conduct a study with a more correct design: in people who have not drunk coffee at least a few weeks before the experiment and have lost the habit of using it, then caffeine does not improve either their attentiveness or productivity (even in case of lack of sleep).
To my surprise, I almost did not find studies in which the effectiveness of the approaches described above (nootropics, BFB training, electrical stimulation) would be compared with each other.
There are only a few experiments that compare the effects of methylphenidate and modafinil. For example, studies on children with ADHD demonstrate that both drugs have approximately similar efficacy for improving attention. And work on healthy people shows that methylphenidate and modafinil approximately equally increase the speed of processing visual information.
But I found an interesting study in rats, in which methylphenidate, amphetamine, nicotine and caffeine were simultaneously compared. The results of this article seemed pretty funny to me. All drugs, except caffeine, increased accuracy and improved reaction rate in attention tests. However, unlike methylphenidate and amphetamine, nicotine also made animals nervous and impulsive. ( Similar effects of nicotine are observed in humans). Caffeine was ineffective , which also repeated experiments on humans.
In general, with regard to nootropics to improve attention, studies indicate the possible efficacy of modafinil, methylphenidate and nicotine. For each of them there are several scientific studies, where they increase the speed and accuracy of the tests in healthy volunteers. Often there is an improvement of more than 10-15%. The disadvantages of these drugs are their side effects, which manifest themselves individually and can be quite strong, including mental disorders and poor health. In addition, they can be addictive. And yet - modafinil and methylphenidate are not sold in Russia.
With regard to electrostimulation using the tDCS method, a certain amount of scientific evidence was accumulated about its ability to improve the attention of healthy people. Its efficiency varies on average from 10 to 20%, however in some tests it reaches 30% (as with nicotine). And unlike pharmacological nootropics, it has weaker side effects. So in general, although research continues to be conducted, the available results already look quite promising.
Well, BFR interfaces are an example of a completely painless and safe approach. However, in contrast to electrical stimulation and nootropics, in order to achieve the effect, it is required to conduct BFR-training for more than a month - and all this time daily perform certain computer tests. And this already requires high discipline and free time.
Of course, there are other ways to improve attention, such as exercise. Indeed, some scientific studies indicate that cognitive improvements occur immediately after an adrenaline rush. In addition, there are experiments in which it is demonstrated that attention even improves meditation of awareness. However, while I did not go into it. As I have already said, now I was interested only in those approaches, for the sake of which you do not need to be distracted from work and change your schedule.
And finally, I want to note that in this text I dealt with scientific approaches only in the area of ​​improving attention; if we talk about memory, speed of learning, intelligence, etc., then other nootropes and technologies are being explored to stimulate them in science. However, this requires separate consideration.
And this text may be able to help you save time (and not be distracted too much) if you yourself at some point would like to find ways to increase concentration.
In this article, I tried to dig deeper and see what the experts in neuroscience know about concentration, as well as understand what methods of improving attention are proven in scientific studies, preferably in several double-blind and placebo-controlled ones. Without this, we, unfortunately, remain within the framework of personal opinions, individual characteristics and self-suggestion. First of all, I was interested in methods that allow not to break away from work or study, roughly speaking, those that can be used while sitting in front of a computer monitor.
Under the cat, the current state of neurobiological research in the field of concentration of attention is described and a comparative review of various pharmacological stimulants, nootropics and neurotechnologies for increasing concentration is given. Often these technologies are used without understanding how they work (and if they work at all), and I hope that after this review there will be less confusion.
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Concentration: how does it work?
From the point of view of neuroscience, 3 different systems are introduced to describe attention. The first is responsible for vigilance, or "watchfulness." It keeps the cognitive system at a sufficient level of activity and prepares it for a quick response. The second “executive control” system specializes in higher-level processes, for example, the resolution of conflicts between different systems or the detection of errors. And the third system responsible for the “orientation” determines the source of the signal and speeds up its processing.
For the convenience of describing these systems, neuroscientists use the so-called “cocktail party effect” . “Alertness” occurs when, in a lively environment, a person hears a familiar name among the noise and conversations. “Orientation” occurs when it determines where and who speaks, and the system of “executive control” allows us not to be distracted by other voices and sounds at this time.
As it turned out, the functioning of these systems is associated with certain areas of the brain and a special set of neurotransmitters - substances that allow you to transmit a signal from one nerve cell to another. Perhaps, the description of attention mechanisms given below will be unnecessarily detailed, but without this, in my opinion, it is impossible to understand how certain nootropes and neurotechnologies that stimulate attention act on the brain.
The system of “alertness” is mainly responsible for the right hemisphere, frontal and parietal cortex zones. Damage to these areas in brain injuries leads to a loss of ability to maintain attention by force of will. In addition, neurons that are located throughout the brain (from the midbrain to the cerebral cortex), which use acetylcholine as a neurotransmitter, are involved in the work of the alertness system.
Visualization of the activity of the human cerebral cortex (fMRI method) during the performance of tasks requiring vigilance. Colored pixels (red, green, yellow) indicate the activation of areas of the right hemisphere, as compared to the left, as a result of various tests for attention. According to Shulman, 2010 .
The second attention system, which is responsible for the “orientation,” deals with the selection of the most important information from the variety of incoming stimuli. The occipital, temporal and primary motor cortex are the areas of the brain that process visual, auditory and tactile information.
Neurons that use the neurotransmitter acetylcholine and are involved in transmitting sensory information from the sense organs to the hemispheric cortex are also involved in the operation of this system. The transmission of sensory signals goes through the thalamus, a subcortical integrative center, which passes only a portion of the signals to the hemispheres, and the rest is either blocking or weakening.
In a state of concentration, the “orientational” attention system begins to significantly change the filtering of information coming from the senses.
The executive control system performs more complex operations to resolve conflicts between processes occurring in different areas of the brain. For her research in neuroscience, the so-called “conflict tasks” are used, in which distracting stimuli prevent the execution of tests. If you look at how the human brain works at this time, you can see that the areas of the frontal cortex of the cerebral hemispheres are activated : part of the anterior cingulate and prefrontal cortex:
FMRI of the human brain during the execution of "conflict tasks". Red and yellow highlighted activated areas of the cortex (anterior cingulate - A, prefrontal - C). According to Kerns, 2004 .
These areas are also associated with the dopaminergic system of the brain. They send their processes (axons) neurons of the midbrain, using dopamine as a neurotransmitter.
All scientific approaches to improving attention, which will be discussed below, are aimed at the biological paths described in this section. Psychostimulants and nootropics, in the first place, affect the transmission of neurotransmitters, and neurotechnologies (biofeedback training and brain electrical stimulation) non-invasively affect the work of certain areas of the cortex, optimizing their activity.
In scientific research, nootropics and neurotechnologies are the main ways to improve attention in both patients and in the case of healthy people. They began to actively explore more than 50 years ago, and interest in them arose almost simultaneously. In 1964, Belgian pharmacologists synthesized piracetam, in 1966 physiologist Daniel Albert found out that stimulation of the brain by microcurrents can change the excitability of neurons, and in 1968, American Joe Kamiya discovered that a person can arbitrarily change the parameters of his EEG (brain wave activity) during availability of feedback on its current values.
These approaches gradually began to penetrate into ordinary life: after 10 years, healthy people began to use nootropes on their own, and with a lag of several decades, neurotechnology was gaining popularity. Today's bihacking fashion only boosts this interest.
In this article, I decided to find out what scientific basis underlies these methods, and delve into existing scientific articles. Moreover, the search for effective ways to increase concentration is relevant for me too.
Neurotechnology to improve attention
Neural Interfaces
In the field of neurotechnologies, there are two main approaches to improving attention: reading information about the brain and demonstrating it to the user on the basis of biofeedback (BFB workout), and changing the activity of brain areas through electrical stimulation.
Cognitive exercises by the method of BFB are arranged as follows. A person performs a specific computer test, during which the functional state of his brain is determined with the help of EEG (electroencephalography). This information is processed and shown to the user on the screen. So he learns about the degree of his own concentration or, conversely, relaxation and corrects the execution of the task. Thanks to scientists, such a BOS interface has been called a “physiological mirror.”
The structure of the training in the method of biofeedback. The activity of certain areas of the brain is determined by EEG (or fMRI). Data is processed in real time and displayed to the subject. For example, the higher the level of the “thermometer”, the better the concentration of attention. Given this information, a person learns to control their states. By Scharnowski, Weiskopf, 2015
Medical studies of BFR training began in the 60s. Since that time, the technology has been used to treat ADHD (attention deficit hyperactivity disorder), autism , epilepsy , insomnia and depression . If you delve into neurobiology, then the principle of BFB training is based on the fact that a person’s cognitive states can be judged by the electrical activity of his brain. The EEG method allows you to register several types of electrical oscillations that have a clear connection with the relaxed or, conversely, concentrated state.
The alpha rhythm (fluctuations of 8–13 Hz) occurs when we close our eyes and begin to relax; beta rhythm (14–40 Hz) and sensorimotor rhythm are associated with wakefulness and focusing attention, and gamma rhythm (> 30 Hz) is observed at maximum concentration. Delta rhythm (1-4 Hz), on the contrary, is characteristic for sleep, and theta rhythm (4-8 Hz) - for the state of drowsiness.
Here is a typical example of an encephalogram. In this case, the person first lies with his eyes closed, and then opens them (red arrow):
Changes in brain wave activity after a person opens his eyes. The graph shows that the alpha rhythm (underlined in red) disappears at the time of opening the eyes (marked with a red arrow). By Uri Shaked, 2017 .
At disturbances of attention the strengthened theta rhythm in frontal lobes, and also disturbances of beta and sensorimotor rhythms are often observed . They are optimized and carried out with BOS-therapy, including the treatment of ADHD.
As for the use of BFR interfaces on healthy people, there are still few such studies - I managed to find only a few high-quality scientific works. At the same time, all of them demonstrate that BOS training has statistically significant but weak or moderate effectiveness.
In a recent study by Austrian scientists, daily BOS exercises improved the alertness and spatial attention of healthy volunteers. The training consisted in the fact that the subjects were shown a circle, the size of which increased as their concentration increased. And attention was assessed in standard tests that require turning the figure in the mind or in the Go / No-Go tests. The meaning of this task is that when receiving a “Go” signal (image of a green cross), a person must press a button as soon as possible, and in a situation of “No Go” (when a blue cross appears), there is no need to press, and should slow down the movement started (see figure below).
After 6 weeks of daily biofeedback training, the speed of each task increased by 17-18 ms (which was 5-6% improvement), and the accuracy of execution increased by 16% relative to placebo control.
Top left: BFB training to improve concentration. The size of the white circle increases with increasing concentration.
Top right: The test for spatial thinking. It is required to determine which of the lower figures is a rotated copy of the upper one.
Bottom: “Go / No-Go” test, which requires a quick response to a target stimulus (green cross) and no response to a distracting stimulus (blue cross). By Doppelmayr & Weber, 2011.
Several more studies were conducted on students of music schools. They confirmed the effectiveness of BFB training, showing that after 5 weeks of the experiment the level of concentration increases by several percent. Similar results were achieved in studies on 11-year-old children. Studies also demonstrate the painlessness and safety of the method.
With regard to the use in everyday life, the BOS-training a few years ago began to commercialize. Nowadays several user neurogadgets are being actively sold, for example, Muse Neurobatch and Emotiv Epoc . All are designed to train attention or relax.
From left to right: Muse Neyroobruc, Emotiv Epoc Neutro Helm, Visualization of brain activity with Emotiv Epoc.
The Muse neuroobrac measures the brain activity using 4 EEG electrodes, processes it and transmits relaxing or invigorating music to the user in headphones. In addition, information can be visualized on the smartphone screen. The Emotiv Epoc Neutro Helm works in a similar way, reading information about the brain through 14 electrodes. An additional advantage of these gadgets is an ever-increasing base of applications for training. If you are tired of using one application, you can switch to another.
Summarizing the information on the BFB interfaces, one can say that there is little scientific research, but they speak in favor of the effectiveness of the technology. However, we must bear in mind that it takes at least a month of daily training to make the improvement in attention noticeable. This is a long time and is incomparable with studies of nootropics or electrostimulation (see below), in which effects are often observed after one session. Well, one can not ignore the fact that there is a problem of “insensitivity” to neurocomputer interfaces , that is, BFB workouts do not work for a very significant percentage of people, according to various estimates, from 15 to 30%. And for them, BFR interfaces will become a waste of time and money.
So in general, in my opinion, the use of such neural interfaces is still rather pleasant entertainment than a truly effective way to improve attention.
Brain electrical stimulation
Another non-invasive way to improve attention is transcranial direct current stimulation (tDCS). As in the case of the BOS-interfaces, it came from medicine, where it has been used for more than 30 years to treat depression , chronic pain , Alzheimer's disease and when recovering from a stroke . In Russia, it is also actively used - mainly for the treatment of developmental delays in children, and is considered to be a very effective treatment for ADHD. According to Russian medical centers , as a result of electrostimulation, 77% of children experience an improvement.
Studies of tDCS in healthy people began in the 2000s, and now there are already quite a lot of them. The first to use electrical stimulation were the US military — to speed up the training of infantrymen and pilots on video simulators. Recruits trained to detect hidden threats (bombs or shadows from snipers) in a virtual game and respond to them as quickly as possible. In these studies, tDCS of the frontal cortex increased the rate of human learning by more than 2 times, compared with placebo by imitation of tDCS, which by the measures of neurobiology is a very significant effect.
Excerpt from the report of the American defense agency DARPA. Stimulation of the right temporal region with a direct current of 2 milliamperes led to an increase in the accuracy of the test by a factor of 2.1 (Fig. Right - a red bar), compared with placebo control (blue bar).
Then, military studies have shown that electrical stimulation can improve the performance of people who suffer from lack of sleep. The experiments were conducted on employees of American military bases and then were repeated on military pilots . The improvement in productivity as a result of tDCS was long-term and persisted throughout the day (during which people were still sleep deprived). This, by the way, is about 2 times longer than in the case of using standard psychostimulants used to combat fatigue - amphetamines and modafinil.
Then electrical stimulation was investigated to improve other cognitive functions of healthy people, including concentration of attention , working memory , reaction, and motor learning . TDCS has been used by athletes of the American Olympic team for several years - ski jumpers and cyclists. Several scientific studies show that electrostimulation of the motor cortex can increase endurance , muscle strength , movement technique and sensory-motor adaptation .
As part of this review, I, unfortunately, have no opportunity to dwell on all the cognitive effects of tDCS in healthy people. However, I wrote several articles about them before, as I myself am a fan of this technology. Here I will try to penetrate deeper only into scientific articles on concentration of attention.
Using tDCS for military training on video simulators and during sports training.
As for the principles of electrical stimulation of the brain, the procedure is as follows. Two electrodes are attached to the scalp, through which a weak direct current of 1-2 milliamperes is supplied. The impact of the anode ("+" electrode) reduces the potential difference across the neuronal membrane, which makes them more sensitive to excitation. Impact on neurons by a cathode ("-" electrode) has the opposite effect .
With repeated use, anodic tDCS affects synaptic plasticity - changes the structure of contacts between nerve cells and increases the density of these contacts, which has a beneficial effect on the processes of memory and learning. On the scale of the whole brain tDCS leads to an increase in the activity of certain areas of the big hemispheres:
Increased brain activity in tDCS parietal cortex. The color highlighted areas of brain activation at tDCS (upper row), compared with placebo stimulation (lower row). During tDCS and placebo-tDCS, all subjects completed the attention tasks. By Callan, 2016.
In research , tDCS of the prefrontal cortex is commonly used to improve concentration. In 2017, an article by Austrian scientists published that stimulation of this zone affects attention and reaction in a blind, placebo-controlled scientific study. The study involved 87 healthy volunteers who trained for 4 days in a row to perform cognitive tests in neurostimulators. To eliminate the effect of self-hypnosis, some people imitated tDCS.
It turned out that electrostimulation increased the accuracy of assignments by 15%, and the reaction rate increased by 30% compared with the placebo group. I want to note that these are high efficacy rates, since in scientific studies the reaction acceleration is rarely observed by more than 10–15% (see below. Psychostimulants and nootropics).
Left: Visual attention test. It is necessary to find the letter “T” among the letters “L” as soon as possible. Centered: Reaction change as a result of using tDCS. The graph shows the reaction rate in the case of anode tDCS (red line); placebo tDCS (black line); cathodic (inhibitory) tDCS (blue line). Right: The location of the electrodes during the experiment. The anode (red electrode) is located in the region of the prefrontal cortex. By Filmer, 2017.
Electrical stimulation improves attention in more complex experiments. For example, in Sternberg's test - a complex task for working memory, selective attention and concentration (see the figure below). 10 minutes tDCS increased the speed of responses given by 100-140 milliseconds (which was about 10% improvement). And in a very recent study of British scientists, electrical stimulation improved executive attention by 15–18% (see figure below). Similar results were obtained in several experiments.
Left: Sternberg test. The subject is consistently demonstrated a set of number 1 of words / images / numbers. Then demonstrated ("distracting") set number 2 of the new words / images / numbers. And after a small delay, set number 3 is shown, and it is necessary to choose those words / images / numbers that were in set No. 1, but not in set No. 2. According to Brodziak, 2014.
Right: Test for executive attention (test for neural networks of attention, or Ant). Subjects need to determine the direction of the central fish / arrow (circled in red) as soon as possible and respond by pressing a key. By Yoshida, Burling, 2012.
Interestingly, in addition to concentration, electrical stimulation of the prefrontal cortex has a number of other cognitive effects. For example, it leads to an improvement in memory , speech activity and work productivity . In addition, to improve attention, they stimulate another area of ​​the brain - the right parietal cortex, which improves visual and spatial attention , as well as visual orientation .
As for side effects, in general, electrical stimulation is considered a safe method. For 20 years of its use, no dangerous side effects have been recorded. However, it can cause itching, burning and irritation of the skin under the electrodes, dizziness and headache. This conclusion was made by a systematic analysis of tDCS studies conducted since 1998.
Despite the fact that in the laboratory the tDCS procedure is considered safe, scientists are concerned that more and more people use electrical stimulation at home on their own, and warn against abuse of this method. First and foremost, scientists are concerned that biohackers may neglect the rules for conducting tDCS: instead of the prescribed 15-20 minutes, the procedure will stimulate itself much longer and carry out tDCS daily for months or even years, although this mode of exposure has not been studied and its consequences are unknown.
Indeed, in the past 5-6 years, electrostimulation has been coming into vogue with biohackers. But this fashion, however, almost does not go beyond California. The exact number of people using tDCS independently is unknown, but indirect estimates suggest that we are talking about tens of thousands of people. At one Reddit forum in the tDCS section there are more than 11,000 subscribers.
Biohackers using tDCS have already been the object of several studies themselves. All these works agree on the fact that electrostimulation is used mainly by men, most often from 30 to 45 years. 61% of users have completed higher education, while 16%, in addition to this, have a PhD degree. And 92% of these people at least sometimes read scientific articles.
Opinion polls show that the impression of electrostimulation is 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”.
Electrostimulation is conducted at home, primarily to improve concentration, learning, and memory. However, there is also a “medical” use of electrostimulation, mainly from depression. For about 5 years, there have been user tDCS devices on the market, they are produced by several companies in the USA ( Brain Stimulator , Brain Driver , Foc.us), Hong Kong ( Priormind ) and Russia ( Brainstorm Neurostimulator) ).
In general, studies of electrostimulation to improve the attention of healthy people are still being conducted, but the data obtained, in my opinion, is already enough to talk about its effectiveness. The advantage is that the technology acts non-invasively and locally and does not alter the biochemistry of the brain, has fewer side effects and does not cause dependence. This distinguishes it from psychostimulants and nootropics, which will be discussed below.
Stimulants and nootropics to improve attention
Now I turn to the most extensive section of this article - pharmacological stimulants. If neurotechnology began to be used by healthy people only in the last 5-6 years, then nootropics have been popular for several decades. They were also originally developed in psychiatry — for the treatment of mental disorders in Alzheimer's disease and schizophrenia, damage to the areas of the cerebral cortex and ADHD.
Subsequently, many drugs were tested on healthy people, primarily on those engaged in activities that require the mobilization of mental and physical resources - students, doctors, soldiers. It turned out that in this case, some of these substances can be effective. At various times, various stimulants were systematically used by soldiers of the French Foreign Legion, the US and Indian Air Force, the armed forces of Great Britain , and the astronauts on the ISS .
Other drugs have not been studied in healthy people, or have not been effective for them, but for some reason, they still became actively used by healthy people to improve their mental potential.So the definition of "fake" nootropics is one of the objectives of this review.
According to different estimates, nootropics are used by millions of people in different countries. A German study in 2015 found that 6.7% of respondents took nootropes their whole lives. University surveys showed that from 2% to 25% of students are keen on nootropics, with most of the articles talking about a figure of 10% -15%. A study conducted in a French college revealed that 67.4% of students have used at least one stimulant over the past year.
A cursory overview of information on forums and specialized sites shows that, as a rule, such drugs as nootropil, fenotropil, glycine, methylphenidate, modafinil, levodopa, and many others are used to improve attention. Actually, the task was to understand what works from this and what side effects there might be.
Methylphenidate
Methylphenidate (or Ritalin) is a psychostimulant that is widely used to treat ADHD in children. It contributes to the release of the neurotransmitter dopamine into the synaptic cleft - the area of ​​contact between nerve cells. This is due to the fact that methylphenidate blocks the reuptake of dopamine by neurons, acting on a mechanism similar to amphetamines. Amplification of dopamine output has a stimulating effect on neurons - they are more actively excited and transmit a nerve signal. At the level of the whole brain, this is accompanied by an increase in the activity of entire areas of the cortex.
For the treatment of ADHDMethylphenidate was approved back in 1955, and in the 1990s, due to the growing number of diagnoses of ADHD, it began to be prescribed very often. In the past two decades, not only patients but also ordinary people began to actively take methylphenidate. For example, students actively use it to prepare for exams, especially in Europe and the USA , much more often than other nootropics. However, scientific studies of the effects of methylphenidate on healthy people contain rather contradictory information, which is especially evident in terms of improving attention.
On the one hand, the intake of methylphenidate leads to an increase in the activity of the areas of the brain responsible for attention. For example, the areas of the anterior cingulate cortex and parietal area are activated:
Visualization of brain activity (fMRI) in response to methylphenidate intake in conjunction with performing attention tests. (A) Anterior cingulate cortex, (B) Right lower parietal lobe (C) Left lower cingulate lobe. According to Hester, 2012.
On the other hand, scientific papers, in which the effectiveness of methylphenidate was evaluated in specific tests for attention, are rather contradictory. A review of 60 studies in healthy people found that methylphenidate improved attention or vigilance in only 29% of the work. This means that for the rest of 71% of the studies, its effects were not statistically significant. Methylphenidate turned out to be much more effective for improving working memory or speed of information processing (a significant improvement in 65% and 48% of the studies, respectively).
However, it is worth noting that in the above-mentioned review, the effects of a single dose of methylphenidate were analyzed. It is possible that repeated use of the drug would have a more pronounced effect. In addition, in the studies presented in this review, different doses of the substance were used - from 5 to 45 mg. And the intake of small doses of the substance, he was often ineffective.
If you look at a study in which healthy volunteers used methylphenidate in a higher dose (45 mg of substance), it is clear that the drug significantly improved a number of indicators in various tests for attention, and the effect was quite significant. In tests for selective attention, the reaction rate increased by 10%, and the accuracy increased by 1.5 times, compared with the placebo control.
The response time (left) and the number of errors (right) in tasks for attention after taking various doses (from 0 to 45 mg) of methylphenidate. There is a decrease in response time (i.e. an increase in speed), as well as a decrease in the number of errors. According to Hermens, 2007.
A number of studies have been conducted on older people. However, the effect of methylphenidate on their cognitive functions (including attention) is much weaker than in young people and most often turns out to be insignificant.
Interestingly, methylphenidate also improves this aspect of attention, as the ability to quickly recognize faces. In tasks that require quickly and accurately determine the sex of a person in a photo, the use of the drug increased the accuracy of the tasks by a few percent.
The test for selective attention is the ability to recognize faces. First, an arrow appears on the screen indicating the direction. Then a photo of the face appears in the corresponding side of the screen, and the subject must determine his sex by quickly pressing the appropriate key. To distract attention from the opposite side of the screen, another face or distorted image is shown. By ter Huurne, 2015 .
Thus, some studies suggest a sufficiently high efficiency of methylphenidate to improve attention. However, it is worth noting that in scientific papers there is not yet a consensus on the optimal doses and mode of use of methylphenidate for healthy people. On the other hand, more convincing is the ability of methylphenidate to improve memoryand speed up information processing.
As for the side effects of methylphenidate, the most frequent effects are nervousness, anxiety and insomnia. Also, allergic reactions, anorexia, nausea, dizziness, headache, depression are often observed. In addition, methylphenidate may adversely affect the cardiovascular system, lead to a rapid increase in pressure, etc. Large doses may even contribute to the development of psychosis. It is also frustrating that it can cause addiction. Such side effects are quite a big drawback of the drug.
In addition, in Russia, methylphenidate is not for sale, as it is entered in the register of prohibited drugs. However, it can be purchased in most countries of Europe and the USA, where it is used in medicine for the correction of ADHD.
Nicotine
Reading the articles, unexpectedly for myself, I discovered that according to scientific research, nicotine is an effective stimulant of attention.
It is an agonist of nicotinic acetylcholine receptors (that is, acts on those neurons that are traditionally associated with attention) and contributes to the release of acetylcholine, dopamine, serotonin, glutamate and other neurotransmitters involved in human cognitive processes. Nicotine and other nicotine-like substances have long been used to combat cognitive impairment. Scientific articles demonstrate that nicotine relieves the symptoms of schizophrenia, ADHD, Alzheimer's, Parkinson's, and age-related neurodegeneration.
Nicotine got its name from the Latin name of tobacco, Nicotiana tabacum, which, in turn, was coined in honor of Jean Nico, the French ambassador to the Portuguese court, who in 1560 sent some tobacco to Queen Catherine de Medici, recommending it as a means of migraine. In nature, nicotine serves plants to protect against insects and is a poison. However, as you know, in small doses, poisons can even be beneficial.
Today, nicotine has become one of the most intensively studied drugs, and its effects on human cognitive abilities are confirmed in dozens of scientific studies. For example, meta-analysis41 double-blind, placebo-controlled studies in healthy people found that nicotine has significant positive effects on 6 indicators, including fine motor skills, vigor, attention, reaction rate, episodic and working memory.
In most of the studies described, nicotine was administered by an FDA approved method: using chewing gum or a transdermal patch. More often than not, a single dose of nicotine was enough to achieve the effect. Interestingly, nicotine also improved driving and flight control in computer simulators. It is important to note that these studies were conductedeither on non-smoking people, or on those smokers who did not have a shortage of tobacco. As a consequence, the authors conclude that the observed cognitive improvements could not be associated with relief, due to the resumption of smoking. This led the authors of the article to speculate that the improvement in cognitive function caused by nicotine is one of the reasons why people start smoking and cannot quit.
It should be noted that the effectiveness of nicotine is not only statistically significant, but often turns out to be very noticeable at the “everyday” level. For example, in tests for spatial attention, chewing gum with nicotine (at a dose of 2 mg) improved the reaction rateby 30%, compared with placebo control. It is more effective than most other nootropics, which, as a rule, improve this figure by a maximum of 15-20%. A 30% improvement was observed in only a few experiments using brain electrical stimulation (see above).
The mechanism of action of nicotine on a person’s cognitive functions is not fully understood. It may be associated with the activation of the prefrontal and parietal cortex, as well as the thalamus and hippocampus, the brain areas that provide memory and attention.
Left: Visualization of brain activity of people performing tasks on attention and working memory (by fMRI method). The top row of images shows the activity of the cerebral cortex when performing the simplest tasks (0-back), the bottom one shows the most complex tasks (3-back).
Right: Areas of the brain that are activated in people who took nicotine, compared with placebo, are highlighted. According to Kumari, 2003.
Other studies, by contrast, demonstrate that nicotine improves attention by inactivating certain neurons. In this regard, scientists have put forward the theory that nicotine synchronizes high-frequency activity of the brain, and its effects are associated with the simultaneous activation of some and inactivation of other regions.
Despite the positive effects of nicotine on attention, there is no doubt that it is still a much better solution for health to quit smoking or not to start. Studies have shown that not only smoking cigarettes, but also regular use of nicotine as part of chewing gums or patches, increases the risk of diseases of the cardiovascular, respiratory systems and the gastrointestinal tract. Nicotine can reduce the immune response, adversely affect reproductive function and increase the risk of cancer. In addition, its use is easily addictive.
Modafinil
Modafinil (Provigil, Vigil) - is perhaps one of the most popular nootropics among biohackers. It began to be used in France in the 70s to combat narcolepsy (a disease characterized by sudden bouts of drowsiness), since it has a strong stimulating effect on the nervous system. He is now approved in the United States for the treatment of sleep disorders associated with shift shifts, and is often prescribed by doctors for the "owl" syndrome. In addition, in a number of countries - in the USA, Canada, France, India - at various times it was used to increase the efficiency of military or even astronauts at space stations.
Modafinil has an affinity for the dopamine transporter, which makes it possible to block the reuptake of this neurotransmitter from the area of ​​synaptic contact between neurons. As a result, dopamine concentration increases in some areas of the brain. This mechanism is also characteristic of other psychostimulants, cocaine and amphetamine. However, unlike the latter, which lead to widespread activation of areas of the brain, modafinil more specifically increases the activity of zones associated with vigor:
FMRI of the human brain after taking modafinil. An increase in the activity of the zones of the cortex responsible for attention: the anterior cingulate cortex (A) and the lower part of the intra-small groove of the large brain (B). According to Esposito, 2013.
Modafinil has been studied for a long time to improve the performance of healthy people - first of all, in conditions of lack of sleep. The use of modafinil retained the performance of pilots who were deprived of sleep for 37 hours, and increased the accuracy of flight control by approximately 27%, compared with placebo, without any significant side effects. However, numerous scientific studies on healthy volunteers demonstrate that it can be effective for improving the attention and vigor of people who do not experience lack of sleep.
For example, a comprehensive meta-analysis of 45 scientific studies of modafinil found that a single dose (at a dose of 100 to 400 mg) of this drug by people who do not have a lack of sleep significantly improved their attention, increased vigilance and “alertness”.
However, a later meta-analysis revealed that although there are works in which modafinil improves attention, their number does not exceed half of the studies performed. Perhaps this is due to the fact that modafinil is more effective for improving more complex cognitive abilities. The same meta-analysis showed that in the case of complex tests (which, in addition to attention, require memory stress, ability to learn and languages), the effect of modafinil is more convincing.
The fact that modafinil has a complex effect on cognitive abilities is also confirmed by other works. In them, modafinil has proven effective for improving planning , decision-making and intelligence.
As for side effects, modafinil can cause insomnia, headache, dizziness, in rare cases serious mental disorders: psychosis and mania. Studies of modafinil have not confirmed the existence of any dependence and the presence of "withdrawal syndrome", which can be considered a plus of this drug. In general, it is believed that the side effects of modafinil are milder compared to other stimulants, such as methylphenidate, but can still be very severe.
Modafinil is relatively easy to buy abroad: in the United States and in Ukraine it costs between $ 30 and $ 60 per month. In Russia, it has been banned since 2012. At the same time, some stores of sports nutrition seem to sell it, positioning it as an energy drink, but I have not met with this.
Other effective nootropics and stimulants for improving attention, I have not found
If we talk about nootropics and stimulants that improve the attention of healthy people, at least in a few independent scientific studies, then that's all. However, below I decided to briefly describe also those substances that do not exactly improve concentration or are not investigated for these purposes. Hope this frees you from wasting time and money. Moreover, many of them are actively recommended to improve the attention of sellers of nootropics or "experts" in specialized forums.
If there are no substances in this list, it means that I couldn’t find any scientific research about their usefulness for attention.
Ineffective (to improve attention), but popular nootropics
Atomexin
Atomexin (Strattera, Tomoxetin, Attentin) is a drug used to improve attention in cognitive pathologies. Studies in China, Korea, and Mexico show that Atomexin really improves the attention of children suffering from ADHD, but no better than the methylphenidate described above. In addition, compared with methylphenidate, atomexin causes much more side effects, for example, 3 times more often vomiting, and 7 times more often drowsiness. But for healthy people atomexin was ineffective. In the 2017 study, methylphenidate significantly improved attention, and atomexin did not perform better than placebo. Other studies repeat these results.
In this regard, it must be borne in mind that if a drug improves cognitive function in patients with impaired conditions, this does not confirm that the substance will improve the mental abilities of healthy people. The effect is unpredictable and may well turn out to be even negative.
Mirtazapine
Mirtazapine (Remeron, Mirzaten, Mirtazonal) is a tetracyclic antidepressant. It is able to slightly improve vigilance and attention in patients with depression. However, when the effects of mirtazapine decided to double-check on healthy people , the attention of the subjects, on the contrary, was greatly reduced. In addition, according to subjective feelings, people began to feel less vigorous and satisfied. Deterioration in driving tests was also found in another 2017 study.
Levodopa
L-Dopa (Sinemet, Parcopa, Atamet, Stalevo, Madopar, Prolopa) is a well-known drug for the treatment of Parkinson's disease and dopamine dystonia. It is interesting that for opening the ability of levodopa to reduce the symptoms of Parkinson's disease, they even awarded the Nobel Prize in 2001. Now, levodopa is a very popular nootropic drug, and at profile forums it is actively advertised as a means for “accelerating mental reactions”. However, in scientific experiments on healthy people, its effects are again not confirmed. An analysis of 7 double-blind, placebo-controlled studies showed that levodopa does not improve attention and may even impair memory. In addition, Levodopa has many unpleasant side effects, including depression and seizures.
Donepezil
Donepezil (Aricept) is approved by the FDA for the treatment of dementia in Alzheimer's disease, however, among scientists, evaluations of the effectiveness of this drug vary. However, in 2011, it turned out to be the best-selling medicine for the treatment of this disease. Systematic analysis of the effects of donepezil for healthy people again did not confirm its effectiveness. In 3 out of 4 behavioral jobs, donesepil led to a slight, but statistically significant, deterioration in attention .
Piracetam and analogues
I can not write about piracetam, because it is still one of the most popular nootropics in Russia. However, in his case we are dealing with a drug whose effectiveness has not been proven not only in healthy people, but even for medical purposes. In most countries of the world, piracetam is not registered as a medicine. In Russia, it is nevertheless used in neurological practice, although it is considered "an outdated drug with unproven efficacy."
I read a systematic review of 2010 , which summarized more than 300 scientific articles - these are all studies of piracetam and its analogues (aniracetam, oxyracetam, pramiracetam, phenylpyracetam - “phenotropyl”, nebracetam, and many others). However, among them I counted only 3 (!) Studies on healthy people. In one work , it was shown that the analogue of piracetam (nebracetam) is ineffective in improving memory. And in the other two, oxiracetam and pramiracetam were tested on healthy volunteers, whose cognitive functions were previously impaired by the administration of scopolamine. In such experiments, both drugs actually slightly improved cognitive abilities, however, on this basis no conclusions can be drawn about their effectiveness for normal healthy people.
Moreover, this systematic analysis showed that piracetam and its analogues are incapable of leading to improvements in mental abilities in cognitive diseases.
Caffeine
And finally, caffeine, which is the most popular psychostimulant in history - and is used daily by tens of millions of people to increase vigor and fight fatigue. Until recently, I myself was sure that caffeine is an effective stimulant of vitality, I read relevant scientific articles, but I learned about the problems with its research only while writing this text.
The authors of the 2015 analytical review note that the positive effects of coffee on productivity are often found due to the incorrect design of scientific experiments. The fact is that most people (including those who participate in the trials) use coffee every day. And to conduct a typical scientific study, subjects are asked to abstain from drinking this drink for a day, which in itself causes a “withdrawal syndrome”, impairs attention and efficiency. (I think everyone regularly drinking this drink is familiar with the lack of coffee in the morning). Subjects are then given caffeine, which restores their condition, and their vigor is compared with those who still suffer from a lack of coffee.
If we conduct a study with a more correct design: in people who have not drunk coffee at least a few weeks before the experiment and have lost the habit of using it, then caffeine does not improve either their attentiveness or productivity (even in case of lack of sleep).
What is more effective?
To my surprise, I almost did not find studies in which the effectiveness of the approaches described above (nootropics, BFB training, electrical stimulation) would be compared with each other.
There are only a few experiments that compare the effects of methylphenidate and modafinil. For example, studies on children with ADHD demonstrate that both drugs have approximately similar efficacy for improving attention. And work on healthy people shows that methylphenidate and modafinil approximately equally increase the speed of processing visual information.
But I found an interesting study in rats, in which methylphenidate, amphetamine, nicotine and caffeine were simultaneously compared. The results of this article seemed pretty funny to me. All drugs, except caffeine, increased accuracy and improved reaction rate in attention tests. However, unlike methylphenidate and amphetamine, nicotine also made animals nervous and impulsive. ( Similar effects of nicotine are observed in humans). Caffeine was ineffective , which also repeated experiments on humans.
In general, with regard to nootropics to improve attention, studies indicate the possible efficacy of modafinil, methylphenidate and nicotine. For each of them there are several scientific studies, where they increase the speed and accuracy of the tests in healthy volunteers. Often there is an improvement of more than 10-15%. The disadvantages of these drugs are their side effects, which manifest themselves individually and can be quite strong, including mental disorders and poor health. In addition, they can be addictive. And yet - modafinil and methylphenidate are not sold in Russia.
With regard to electrostimulation using the tDCS method, a certain amount of scientific evidence was accumulated about its ability to improve the attention of healthy people. Its efficiency varies on average from 10 to 20%, however in some tests it reaches 30% (as with nicotine). And unlike pharmacological nootropics, it has weaker side effects. So in general, although research continues to be conducted, the available results already look quite promising.
Well, BFR interfaces are an example of a completely painless and safe approach. However, in contrast to electrical stimulation and nootropics, in order to achieve the effect, it is required to conduct BFR-training for more than a month - and all this time daily perform certain computer tests. And this already requires high discipline and free time.
Of course, there are other ways to improve attention, such as exercise. Indeed, some scientific studies indicate that cognitive improvements occur immediately after an adrenaline rush. In addition, there are experiments in which it is demonstrated that attention even improves meditation of awareness. However, while I did not go into it. As I have already said, now I was interested only in those approaches, for the sake of which you do not need to be distracted from work and change your schedule.
And finally, I want to note that in this text I dealt with scientific approaches only in the area of ​​improving attention; if we talk about memory, speed of learning, intelligence, etc., then other nootropes and technologies are being explored to stimulate them in science. However, this requires separate consideration.
And this text may be able to help you save time (and not be distracted too much) if you yourself at some point would like to find ways to increase concentration.
Source: https://habr.com/ru/post/429998/
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