Well... it's not exactly that simple. Wadsworth Center research scientist Gerwin Schalk presented a video to the conference, showing a man playing Doom using a joystick to move his character, but actually using his mind to fire his weapon. Schalk explained that the man, who suffers from epilepsy, had electrodes implanted directly on the surface of his brain, and these were used to interpret his thought commands.
You can watch the entire presentation below, but be warned, it's like attending a university lecture. Skip through to the 10-minute mark to see the Doom brain-machine in action:
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The researchers have also used the technology to play the old-school shoot 'em up Galaga. Test subjects successfully managed to move their spaceships left and right using nothing but their thought patterns.