In 2006, Liss Murphy was in thrall to what she calls a "sepsis of the soul" — an intractable and debilitating depression. She had hardly spoken in two years. She felt almost nothing; she was barely eating; she wanted to die.
No conventional treatments had helped. So when she heard that doctors at Massachusetts General Hospital, in Boston, had developed an experimental cure for severe depression that involved permanently implanting electrodes in the brain, she didn't hesitate. The procedure seemed like no big deal. "I never read the consent form," she says. "I just didn't care." This was her last shot, she thought. She half-hoped they would make a fatal mistake during the operation.
A few months later, on June 6th, 2006, Murphy lay in an operating room in the neurosurgery wing of Mass General. She looked hardly alive — her body emaciated from eating almost nothing, her skull shaved in preparation for the surgery. A shiny, donut-shaped CT scanner surrounded her head. The doctors began their work by drilling two dime-sized openings into her skull. Then they gingerly lowered tiny electrodes, about the width of the graphite in a pencil, into a region of her cerebral cortex known as the internal capsule. Once the electrodes were in place, the doctors asked her to interact with a computer simulation, with the holes in her skull still open. Before the surgery, they had used the CT scanner and a computerized navigation system (a kind of GPS for the brain surgeon) to map her brain and determine the precise spots where they would implant the electrodes.
Together with an electrical pulse generator — a boxy rectangle, like a small external hard drive — sewn into Murphy's chest cavity, the electrode would stimulate the region of her brain that the doctors believed to be responsible for her depression. The device, known as a deep-brain stimulator (DBS), is meant to regulate neural activity and bring the brain's patterns back to normalcy. A wire from the pulse generator snakes up to the electrode, carrying electricity, which the electrode then transmits to the brain.