It had been more than six hours since Joan Sikkema first laid her shaven head on the operating table, six hours since a 14-millimeter hole was drilled in her skull and a thin electrode inserted deep inside her brain. Now, swaddled in blankets in the cold operating room and wide awake, Joan (pronounced joe-ann) looked up at half a dozen physicians in surgical gowns, all of whom seemed to be shouting orders at her simultaneously.

"Put your hands out steady!" one said.