Doctor Electric: A Handy Electromagnetic Gadget Stimulates the Brain

Credit: Hugh D'Andrade

Imagine you have a headache. Or you're too fried to face a busy workload. Rather than taking aspirin or coffee, you put a small device the size of an iPod to the back of your head and push a button to revitalize your brain. Sound futuristic? It may not be many years away.

Scientists have scrutinized the human brain for thousands of years, but with the use of electricity and magnets, medical researchers are getting closer to identifying the areas -- and creating the tools -- that stimulate and repair the mysterious organ.

Eric Wassermann, a neurologist and chief of the Brain Stimulation Unit at the National Institute of Neurological Disorders and Stroke [1] (NINDS), has come closest to creating an inexpensive, painless "thinking cap." The device runs on electrical currents, known as transcranial direct current stimulation. His studies have shown that tDCS can boost verbal skills in healthy people by as much as 20 percent.

In one study, volunteers were asked to recall and say as many words that begin with a particular letter as possible, then passed a tiny (2-milliamp) current through electrodes attached to their foreheads. The volunteers were quizzed again using a different letter with the current on and were able to come up with 20 percent more words. The only side effect so far has been itching or tingling on the scalp.

Wassermann can't pinpoint exactly what is happening, but he thinks tDCS lets the prefrontal cortex, the brain part associated with verbal memory, transmit signals more easily. Any function associated with a specific region of the cerebral cortex (the outer edges of the brain) is potentially within tDCS's reach. The goal is to make the targeted area work more effectively, like giving it a small cup of coffee.

"It doesn't cause neurons to fire on their own -- it needs to have some drive on them to do so," says Wassermann. "It's a little like treating specific nerve cells locally with a drug, so it could be a very helpful way of boosting brain function in people with brain disorders and injuries."

Even though he is focusing on tDCS for more heavy-duty problems like head injuries and dementia, Wassermann does not rule out a thinking cap that any healthy person could use to boost brainpower with the flick of a switch. The device is already simple and easy to make, he says. "Anyone with the know-how could go to an electronics store, buy the components, and build one. It's simply a 9-volt battery, a couple of wires, and some pieces of wet sponge. The question now is, what part of the brain do you stimulate, and how can it actually help you? That's what we're still trying to learn."

Neurologists are also using electricity to try to treat various brain disorders, from Parkinson's disease to headaches. As early as 45 BC, a Roman court physician named Scribonius Largus noted that the application of live torpedo fish, a type of electric ray, to patients' foreheads cured headaches. Greek physician and philosopher Galen noted the same findings a century later.

The modern version of Largus's and Galen's fish involves magnetic pulses in an up-and-coming treatment known as transcranial magnetic stimulation. Techniques are still being refined, but researchers know that by placing a TMS device on different areas of the head, they can make fingers twitch or freeze speech in mid-sentence. Doctors treating depression aim the magnets at the prefrontal cortex, while those treating migraine headaches go toward the nerve centers in the back of the head.

"There's evidence that migraines start with electrical hyperexcitability in the brain's cortex," says Yousef Mohammad, a neurologist at the Ohio State University Medical Center, who has found evidence that a TMS device placed against the back of the head can prevent migraine pain. "Our theory is that if we can break that with two pulses of an electromagnetic field, we can abort a headache before it starts." Mohammad is working with a medical company to research a portable TMS device the size of a hair dryer, and recently launched a bigger study nationwide.

Wassermann has also tested TMS by using himself as a guinea pig. He had a fellow researcher target his brain's speech centers by zapping him while speaking, which stopped him in mid-sentence -- a feeling he calls "indescribable."

So next time you feel frazzled or foggy, think of strapping on a catchy-looking gadget and gently jolting your way to rejuvenation. Now, that's an electrifying thought.

Vanessa Richardson is a freelance writer in San Francisco.