Electrifying brain circuits could treat neurological and psychiatric symptoms not because it causes neurons to fire but it creates an environment that makes it more or less likely for neurons to fire, researchers have found.
Rather than taking medication, a growing number of people who suffer from chronic pain, epilepsy and drug cravings are zapping their skulls - using transcranial direct current stimulation (tDCS) - in the hope that a weak electric current will jolt them back to health.
“Although this therapy is taking off at the grassroots level and in academia (with an exponential increase in publications), evidence that tDCS does what is being promised is not conclusive,” said the study’s senior author Danny J J Wang, professor of neurology at Mark and Mary Stevens Neuroimaging and Informatics Institute, University of Southern California in the US.
In this study, published in the journal Scientific Reports, the researchers developed an MRI method whereby the magnetic fields induced by tDCS currents can be visualised in living humans.
“Scientists don’t yet understand the mechanisms at work, which prevents the FDA from regulating the therapy. Our study is the first step to experimentally map the tDCS currents in the brain and to provide solid data so researchers can develop science-based treatment,” Wang noted.
People in antiquity used electric fish to zap away headaches, but tDCS, as it is now known, was introduced in 2000, said study lead author Mayank Jog, a graduate student conducting research at the David Geffen School of Medicine at University of California, Los Angeles.
“Since then, this noninvasive, easy-to-use, low-cost technology has been shown to improve cognition as well as treat clinical symptoms,” Jog said.
The study is a technological breakthrough, study co-author Maron Bikson, professor at The City College of New York, noted.
“You cannot characterise what you cannot see, so this is a pivotal step in the development of tDCS technology,” Bikson said.
The researchers validated their MRI algorithm with a phantom, where the current path and induced magnetic field was known.
Then they tested the method using simple biological tissue - a human calf. Finally, they repeated the process on the scalp of 12 healthy volunteers.
After 20 to 30 minutes in a scanner, the new algorithm produced an image of the magnetic field tDCS created.