Neuroscientist Sven Bestmann is standing behind me holding a pretzel-shaped coil of metal encased in plastic and connected to a machine the size of a small fridge. We're in his lab at University College London. 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's 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 doesn't 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 microvolts of electric current and sending it into the tiny portion of my brain under his hovering wand. The area he's chosen is responsible for co-ordinating the muscles that produce speech, hence my interrupted sentence. I'm amazed at how instantaneously the signal translates from electromagnetic click to distorted nonsense word.
But it's 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 United States, TMS is already in use for severe depression
, and although it hasn't 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's also some excitement about using stimulation to boost the function of the healthy brain.
Labels: brain, ECT, electro-stimulation, sven-bestmann, TMS