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Transcranial electrical stimulation - boosting the brain using batteries

Chung Yen Looi from Cohen Kadosh Lab preparing a participant for a brain stimulation and cognitive training session. Courtesy of Amy Hong
Chung Yen Looi from Cohen Kadosh Lab preparing a participant for a brain stimulation and cognitive training session. Courtesy of Amy Hong

Passing an electrical current through the brain can help some people learn maths faster or behave more altruistically.

The technique, known as transcranial electrical stimulation, involves attaching electrodes to a specific part of the skull so that an electrical current can be targeted to a predefined region of the brain, making it become more active.

‘In order to pass information, neurons need to fire and they need to get to a certain electrical threshold,’ said Dr Roi Cohen Kadosh from the University of Oxford, in the UK, whose research is part-funded by the European Research Council.

‘The electricity is able to change very mildly the thresholds of the neurons, then it increases the likelihood that the neurons will fire, so it basically increases the likelihood that this brain region is going to communicate with other brain regions.’

Unlike electroconvulsive therapy, where powerful electric charges are passed through the brain in order to induce seizures, transcranial electrical stimulation uses low-voltage current, which is applied painlessly to the brain in short sessions lasting around 20 minutes per day, over the course of a few days.

Transcranial stimulation only works if it is done alongside brain exercises. For example, the researchers devised a game where people must position a spacecraft between two planets based on the fractions they are given, while wearing a wireless stimulation device.

Dr Cohen Kadosh has shown that, by doing this, their maths ability is improved in the long term. He tested the people two months after the end of the study and showed that those who had received the stimulation still performed better than those who were given a pretend stimulation device.

‘We can improve skill learning, basic numerical skills, and higher ones such as arithmetic abilities,’ he said during a presentation at the EuroScience Open Forum (ESOF) this June in Copenhagen. ‘The effect can be long lasting.’

Social norms

Transcranial electrical stimulation has also been used to make people more likely to adhere to the rules of society.

‘By applying these kinds of currents we can change the way you interact with others … in particular how you comply with social norms,’ Professor Christian Ruff at ETH Zurich told the same seminar at ESOF.

‘It basically increases the likelihood that this brain region is going to communicate with other brain regions.’

Dr Roi Cohen Kadosh, University of Oxford

In experiments where people face the risk of punishment if they do not contribute money fairly to a game, his research showed that people who had received electrical stimulation to the part of the brain that governs fear of punishment gave money more fairly.

However, one of the main problems is that enhancing one part of the brain could have the effect of lowering the ability of another part of the brain.

‘There’s no free lunch,’ said Prof. Ruff. ‘Neuroenhancement also means neurodegeneration, because if you enhance the function of one brain system, other brain systems may find it harder to make themselves heard in this orchestra inside of our minds.’

It's one of the reasons why this research is so important - transcranial electrical stimulation kits are widely available on the internet, but at the moment they are unregulated. No one knows what the effect might be without proper testing, and the technology could affect the wrong part of the brain.

‘Even in numerical cognition, for example, if you take people with high numerical abilities and those with low numerical abilities, they would have different brain regions that are engaging in the same numerical tasks,’ said Dr Cohen Kadosh.

‘We are just at an early stage, I would not advise anyone to try this at home.’

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