Scientific research that could be game changing

Fifteen electrodes were implanted in the patient’s brain, each one was stimulated in turn, and the responses of the others were measured.

The researchers noticed that every time they applied a strong electrical signal [0.2 millisecond pulse of 14 milliamperes (mA) at 0.25-second intervals for 3 to 10 seconds] to an electrode in a tiny area of the left brain, the patient lost consciousness. Specifically, there was a complete stop of “volitional behavior, unresponsiveness, and amnesia.” If the patient had been reading, she stopped reading, stared blankly, did not respond to any visual or auditory commands, and her breathing slowed. Sometimes, the loss of consciousness was “associated with scanty, perseverative, and incomprehensible verbal output consisting of one or two syllables, with a confused look on the face.” Furthermore, the patient had no memory of anything that was said or shown to her during the stimulation.

Given that stimulation to an area as close as 3 millimeters away had no such effect, a reduction of the applied current to 6 mA or less also did not show the effect, and the patient fully regained consciousness as soon as the stimulation stopped, the researchers concluded that the disruption of consciousness was related to electrical signals to that specific area of the brain. This was an extraordinary discovery. After more than 100 years of study of electrical stimulation to the human brain, no one had, until now, ever found a region that could switch off consciousness.