A Danish-Italian team of scientists has demonstrated that passing even weak electrical currents through the brain can trigger unexpected reactions.
All over the world, people with no medical background are experimenting with electrical brain stimulation:
They are attaching electrodes to their head and hook it up to the direct current in the hopes of improving their intellect, for instance in order to perform better when paying computer games. Or to use electricity to treat everything from depression to serious neurological conditions like Parkinson’s disease.
The equipment is often purchased online – or built at home based on instructions that are also easy to find in cyberspace. And this type of electrical home therapy – called transcranial stimulation, where you pass electricity through your scull and into your brain – is quite widespread, even in Denmark.
‘The equipment isn’t too expensive, so most people can afford it. But the reality is that there are many reasons to warn against playing electrician with your own brain. Without a medical background and without the right measuring equipment, you have no earthly chance of measuring what is happening in the brain when you send electricity through it. And therefore no way to control the dosage,’ explains Hartwig Siebner, neurologist and Lundbeck Foundation Professor of Precision Medicine at the University of Copenhagen.
Hartwig Siebner, and his colleagues in Italy, recently published a study of the effects of transcranial electrical brain stimulation. The study, which was published in the scientific journal Human Brain Mapping, demonstrates that it takes specialist equipment and specialist knowledge to determine what electrical stimulation of the brain can actually do.
Hartwig Siebner and his colleagues conducted the experiment, upon which the research article is based, in a highly controlled laboratory environment. The test subjects had electrodes attached to their heads and then the researchers subjected them to weak electrical shocks in the form of a DC current with a voltage of 2 milliamperes. Shortly thereafter, the brains of the text subjects were scanned with a highly sensitive MEG scanner that measures the electromagnetic fields in the brain. These fields reflect the activity in the brain.
The voltage of 2 milliamperes is standard for scientific experiments in transcranial stimulation, because this voltage is just enough to enter the brain without causing a prickling sensation or other discomfort.
‘Don’t do it’
When the Danish-Italian team of researchers scanned the brains of the test subjects, they discovered that the electricity had temporarily reduced brain activity in the auditory cortex – the part of the brain that processes sound.
In reality, there was a brief functional change in the auditory cortex, explains Professor Hartwig Siebner:
‘We detected the phenomenon in 13 out of 15 test subjects when we put them in the brain scanner and measured their reactions to a buzzing sound. But we don’t yet know why electrical stimulation causes this reaction.’
Although the temporary functional change in itself is thought to be harmless, it illustrates another important point, according to Hartwig Siebner:
‘It shows that science for the most part still doesn’t have a detailed understanding of what electricity actually does to the brain. And to the many do-it-yourself’ers out there who are buying stimulation equipment online or building it at home, our experiment sends a clear message: Don’t do it.’
Good treatment options
Many scientists are interested in the idea of performing positive manipulation of the signal pathways in the brain using electricity.
Professor Hartwig Siebner is one of them, and he feels certain that there is a great deal of potential in electrical stimulation of the brain, including for the treatment of certain psychiatric conditions.
But before the method can actually become a therapy option, it is necessary to scientifically ‘map’ exactly where in the brain the stimulation should occur in order to provoke a specific positive reaction.
This is knowledge that scientists do not have yet, according to Hartwig Siebner, who is also chairman of the Danish Parkinson’s Association and head of the Danish Research Centre for Magnetic Resonance:
‘This is so complex – and there are so many unknowns – that it makes transcranial self-treatment very problematic, in my opinion.’