The Dangerous Joy of Dr. Sex and Other True Stories by Pagan Kennedy

cathode on her knee, to see whether they could use battery power to ease her out of her depression. They kept her brow area bathed in electricity for as many as eleven hours a
day, three treatments a week. She began to sleep soundly, no longer tormented by nightmares; she ate well; she prettied herself up; she found a boyfriend. She became, the researchers said, a “different person.”
    That year, she was just one of several dozen people wandering the halls of Summersdale Hospital with electrodes plastered to their foreheads and batteries on their lapels like boutonnieres. In an earlier study, Lippold and Redfearn had found that they could change the personalities of their subjects with electrical stimulation: positively charged electrodes on the forehead caused people to giggle and chat. Under the influence of negatively charged electrodes, people shut down, became silent and apathetic. Some of the patients had so enjoyed the positive electrodes that they asked for the “battery treatment” again. And so Lippold and Redfearn launched this new study; this time they would expose people—many of them severely depressed—to long sessions of electrical stimulation. The patients were allowed to go home with electrodes glued to their heads, the battery still buzzing. Almost half of them experienced miraculous recoveries. A shell-shocked World War II veteran compared the effects to a snoot of a whiskey—“I feel quite all right,” he crowed, after he’d been stimulated.

    In the decade that followed, other researchers tried to replicate these effects. They produced inconsistent results. Nowadays it’s clear why: researchers applied currents that were too small and glued electrodes to the wrong parts of the scalp. “They used some parameters of stimulation that we know now are not effective. They didn’t have the information that we have now,” according to Felipe Fregni, an instructor in Neurology at Harvard Medical School. Because the battery-powered electrodes seemed to be unreliable, the medical community lost interest in brain polarization.
    Then, in the 1980s, researchers found a much more powerful way to stimulate isolated buttons of the brain. Called repetitive transcranial magnetic stimulation (rTMS), the technique uses electromagnetic radiation—which can easily pass through the skull—to create localized electrical fields near the surface of the brain. The effects of rTMS are dramatic and reproducible. Place the machine’s wand on one part of the scalp and the patient will lose her ability to talk; move the wand to another spot and her leg will jerk.
    In essence, rTMS is a souped-up version of the old battery-and-electrodes treatment. But it also comes with greater risks: it can trigger seizures, an arm that won’t stop shaking or a patient who
slumps over in his chair. However, such side effects are rare, and rTMS has proven to be a powerful tool for mapping the brain and modulating brain activity; in the 1990s, researchers began using it (along with other new technologies) to draw blueprints of neural function. This new knowledge, in turn, meant that the battery treatment became relevant again—because now scientists could design a more effective tDCS machine. In the late 1990s, a team at the University of Göttingen enlarged the electrodes and covered them in sponges in order to allow more current to pass through the skull. They also created new protocols for placement of the electrodes, aiming them with greater accuracy at hotspots such as the motor cortex. Just a few years ago, these design changes began to pay off in studies that showed promising results: the new, improved battery treatment could quicken the tongue and the hand. It could make people smarter and faster, if only by a small margin. When German researchers trained the positive electrode on the motor cortex, their human subjects became significantly faster at learning to hit a