Neuroscientist Sven Bestmann is standing behind me holding a pretzel-shaped piece of metal connected to a machine the size of a small fridge. We are in his lab at University College London (UCL). He tells me to hold my hand in front of my face and relax the muscles as he brings the metal coil up to my skull. With a click, the coil emits an electromagnetic pulse into my brain. Involuntarily, my fingers and wrist twitch.
“Ooh! I wasn’t expecting that!”
“It does feel a bit weird, doesn’t it?” Sven says reassuringly. He has done this many times and he and his colleagues often pilot studies on themselves.
Next, he brings the coil further forward on my head and asks me to speak. I choose a nice long word and start repeating it. In come the clicks — and I get stuck halfway through.
It does not hurt at all and the clicks are quiet through my precautionary cotton wool earplugs — and yet the effect is startling. Sven is generating just a few volts of electric current and sending it into the tiny portion of my brain under his hovering wand. The area he has chosen is responsible for co-ordinating the muscles that produce speech, hence my interrupted sentence. I am amazed at how instantaneously the signal translates from electromagnetic click to distorted nonsense word.
However, it is no mere party trick. This is a well-used research technique called transcranial magnetic stimulation (TMS). Bestmann, for example, uses it to study the regions of the brain that control movement.
Even more electrifying, stimulation techniques such as TMS may yet prove to be an effective therapy for all kinds of disorders of brain and mind. In the US, TMS is already in use for severe depression, and although it has not made its clinical debut here yet, some researchers think it might one day be able to treat not only depression, but obsessive-compulsive disorder, tinnitus, even Alzheimer’s disease. There is also some excitement about using stimulation to boost the function of the healthy brain.
Zapping the brain in the hope of treating its ailments is not a new idea. For decades, doctors have treated — and still treat — severe depression with electroconvulsive therapy (ECT), which involves passing an electric current through the brain for long enough to provoke a seizure. It is still not clear exactly how it works — the thinking is that the fit “resets” some of the brain’s circuits and stirs up its chemicals.
The practice has been made infamous in media portrayals: A violent and exaggerated form of shock therapy appeared in Ken Kesey’s book and film One Flew Over the Cuckoo’s Nest, where Jack Nicholson’s character, McMurphy, is “treated” after he causes an upset among the patients.
“Electrical stimulation got a very bad press,” says Heidi Johansen-Berg, a neuroscientist at the University of Oxford.
Modern-day ECT is much less troubling, but still rarely used. It is usually performed under anesthetic and reserved for people for whom drugs and other therapies have not worked. According to the most recent statistics available from the Royal College of Psychiatrists, 1,300 patients received ECT in the UK in 2006, down from 2,400 in 1999.
The popularity of ECT might be waning, but now a new suite of techniques is coaxing brain stimulation back into fashion, partly because drug treatments have failed to provide a panacea and partly, Johansen-Berg says, because in terms of the rehabilitation that many brain disorders need, “there’s so little out there.”