Lightly edited extract from the paper, for anyone curious about the method: BrainNet relies on two well-known technologies: Electroencephalography (EEG) for no

Lightly edited extract from the paper, for anyone curious about the method: BrainNet relies on two well-known technologies: Electroencephalography (EEG) for non-invasively recording brain signals from scalp and transcranial magnetic stimulation (TMS) for non-invasively stimulating the visual cortex. The Senders convey their decisions of "rotate" or "do not rotate" by controlling a horizontally moving cursor using steady-state visually-evoked potentials (SSVEPs): to convey a "rotate" decision, Senders focused their attention on a "Yes" LED light flashing at 17 Hz placed on one side of their computer screen; to convey a "do not rotate" decision, they focused on the “No” LED light flashing at 15 Hz placed on the other side. The direction of movement of the cursor was determined by comparing the EEG power at 17 Hz versus 15 Hz, with a higher power at 17 Hz over that at 15 Hz moving the cursor towards the side near the “Yes” light, and vice versa for the "No" light. A "rotate" ("do not rotate") decision was made when the cursor hit the "YES" ("NO") side of the screen. In trials where the cursor did not reach either side of the screen due to trial time elapsing, the decision closest to the last location of the cursor was chosen as the subject’s decision. The decisions of the two Senders were sent to the Receiver’s computer through a TCP/IP network and were further translated into single pulses of transcranial magentic stimulation (TMS) delivered to the occipital cortex of the Receiver. The intensity of the stimulation was set above or below the threshold at which the Receiver will perceive a flash of light known as a phosphene: a “Yes” response was translated to an intensity above the threshold, and “No” was translated to an intensity below the threshold. The Receiver made his/her decision based on whether a phosphene was perceived and this decision was conveyed to the game by the Receiver using the same SSVEP procedure used by both Senders.