Scientists warn about side effects of weak electrical stimulation of the brain

The girl uses the method of non-invasive micropolarization

When it comes to neurostimulators, most habitually stretches for a cup of coffee (caffeine), green tea (caffeine and thean) or a bar of dark chocolate (flavanols). More advanced users are aware of modern nootropics, including synthetic ones, which increase efficiency, concentration, improve working memory, speed up the processing of visual information, etc. Even more advanced know about the great effect that exercise gives .

However, science does not stand still. Recent advances in neurology can affect the brain without the help of chemicals at all, but directly. For several years, neurohackers and transhumanists have been experimenting with micropolarization (tDCS), a therapeutic method that allows improving the functional state of various brain regions with a small direct current (up to 1 mA or slightly more).
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The method of brain stimulation is very simple, non-invasive and is available for use even at home.

The equipment for micropolarization is also simple: a battery and two electrodes with sponges, which are soaked in salt water and applied to the place of the head where the corresponding part of the brain is located for stimulation. You can press the usual headbands that produce sports brands.


Commercial DC Stimulator Plus for electrical brain stimulation

On Reddit and other forums on the Internet, users share experiences and publish instructions on where to apply electrodes for the desired therapeutic effect (see poddit / r / tDCS / ).

Hacker enthusiasts claim that brain electrical stimulation will produce a better effect than nootropics. According to advanced experimenters, with proper application, the effect of micropolarization can be compared with modafinil intake, which is used inappropriately to enhance cognitive functions and eliminate drowsiness.

Scientists are not sure about the effectiveness of micropolarization. The fact is that the current strength of 1-2 milliamperes is not enough to activate neurons. Such weak stimulation can only bring them into a state of "readiness", that is, increase the likelihood of their activation and the installation of new connections. It is rather difficult to study this effect, although various studies have been conducted on the use of micropolarization for the treatment of depression , anxiety disorders , and the effects of stroke . Experiments in Australia have shown an improvement in the cognitive abilities of patients when solving mathematical problems during electrical brain stimulation. At the same time, this method is not an officially approved treatment for any disease or disorder. Officially, it is still considered an experimental treatment.


Solving math problems during electrical brain stimulation. Photo: Thomas Weickert, Neuroscience Research Australia

In addition, scientists note that, contrary to the generally accepted opinion in popular culture, the functional areas of the brain do not have a clear location. Each person has an individual map of the brain, with its own characteristics.

However, this does not stop experimenters who are “treated” at home and try to stimulate different areas of the brain, testing the effect on themselves: in which cases drowsiness disappears, in which the memory is supposedly improved.


Lisa Arnold placed the anode behind the left ear, presumably in the motor area of ​​the brain, and the cathode on the right hand, in order to cause a feeling of euphoria

In principle, to date, doctors have not objected to such experiments, because there was no clear evidence of the harmful effects of a weak current. Although a brain scan shows that some effect really exists, but scientists can not reliably predict how it will manifest, that is, how a particular person will react to a specific effect in a particular area of ​​the brain. This is a purely individual process, and so far laboratory tests give unpredictable results.

Previously, doctors had nothing against experiments, but now, nevertheless, objections have appeared. A group of scientists made an open letter published on July 7, 2016 in the scientific journal Annals of Neurology . Experts speak out against electrical stimulation of the brain at home, warning of possible side effects. They believe that short-term improvements in some cognitive abilities can manifest themselves at the expense of other abilities. Ultimately, it can harm the brain in the long run, they say.

Scientists mention that some negative side effects have already appeared: for example, possible weak skin burns in case of its increased sensitivity. Other side effects are not entirely clear, and this mystery even more alarming specialists. For example, there is evidence that the effect of brain stimulation manifests itself in different ways, depending on what the person is doing. The effect is different if a person reads a book, meditates, focuses his gaze at one point, does solves math problems, sleeps or plays computer games.

Apparently, even the time of day affects the effect of brain stimulation, for unknown reasons.

“We observed different kinds of response [to micropolarization of the brain],” says Rachel Wurzman from the laboratory of cognitive and neurological stimulation at the University of Pennsylvania, co-author of the open letter. Maybe every third person will have a braking effect on a certain type of stimulation. At the same time, another third may have the opposite effect, and the rest - no effect at all. All this extremely complicates the research of micropolarization. Scientists believe that care should be taken in such conditions.

“Neuronal networks in the brain interact with each other, so that changes in the activity of one network can affect others,” the authors of the open letter write. Stimulating one part of the brain can impair the performance of other areas of the brain. “For example, micropolarization can speed up the learning process, but this will occur due to the quality of processing of the acquired material, and vice versa, depending on the place of stimulation.”

Scientists admit that they have never conducted long-term studies of the effect of electrical stimulation on a daily basis for several months. In such experiments, they are inferior to the enthusiasts who set and continue to put such long-term experiments on themselves. But based on the available data, scientists suggest that micropolarization effects can last for at least six months.



Within six months, positive and / or negative effects will persist. In general, home neurohackers should understand the possible risks before connecting electrodes to a gray matter.