( Now a St. Louis-area teenage boy and a...)Teenager moves video icons just by imagination

The boy, a 14-year-old who suffers from epilepsy, is the first teenager to play a two-dimensional video game, Space Invaders, using only the signals from his brain to make movements.

Getting subjects to move objects using only their brains has implications toward someday building biomedical devices that can control artificial limbs, for instance, enabling the disabled to move a prosthetic arm or leg by thinking about it.

Many gamers think fondly of Atari's Space Invaders, one of the most popular breakthrough video games of the late '70s. The player controls the motions of a movable laser cannon that moves back and forth across the bottom of the video screen. Row upon row of video aliens march back and forth across the screen, slowly coming down from the top to the bottom of the screen. The objective is to prevent any one of the aliens from landing on the bottom of the screen, which ends the game. The player has an unlimited ammunition supply.

The aliens can shoot back at the player, who has to evade, moving left and right. There are lots of levels of play, reflecting the speed at which the aliens descend. The Washington University subject mastered the first two levels of play, using just his imagination.

Here's how:

The teenager, a patient at St. Louis Children's Hospital, had a grid atop his brain to record brain surface signals, a brain-machine interface technique that uses electrocorticographic (ECoG) activity - data taken invasively right from the brain surface. It is an alternative to a frequently used technique to study humans called electroencephalographic activity (EEG) - data taken non-invasively by electrodes outside the brain on the scalp. Engineers programmed the Atari software to interface
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Source:Washington University School of Medicine