(A) Schematic diagram of set-up. Brain signals from one participant (the “Sender”) were recorded using EEG. When imagined hand movements were detected by the computer, a “Fire” command was transmitted over the internet to the TMS machine, which caused an upward movement of the right hand of a second participant (the “Receiver”), resulting in a press by the hand on a touchpad. This press triggered the firing of the cannon in the game seen by the Sender. Red lines mark the part of the architecture that corresponds to the direct brain-to-brain interface. (B) Screen shot from the game. In 50% of the trials, the pirate ship on the right side (skull-and-bones) shoots a rocket (top center) towards a city on the left. The Sender engages in motor imagery to move the white cursor on the left to hit the blue circular target in order to fire the cannon (bottom center) and destroy the rocket before it reaches the city. In the other 50% of the trials, a supply airplane moves from the right to the left side of the screen (not shown). The Sender rests in this case and refrains from imagery in order to avoid hitting the target.