The brain as a network cable: Transmission of a modulated optical signal between two computers via the human brain

Abstract

The SSVEP response is used to transmit information in a unidirectional through-brain non-cognitive (entirely passive) communication channel. This, in effect, is connecting two otherwise disconnected computers through the brain, allowing us to consider the bandwidth of SSVEP encoding. The system uses green LEDs driven by a square wave to stimulate SSVEPs with EEG measurements being recorded by an EMOTIV EPOC. The stimulation and detection of SSVEPs is at the base of the channel - upon which a communication stack is implemented, allowing for character strings to be transmitted between an independent sender and receiver. The system was tested on four subjects, the best BER performance being achieved when using a PSDA detector on the O1 electrode with a 7,4 Hamming code being used as the FEC. A practical ITR of 25.6 bits/min was achieved. A prefix based transmission protocol was developed which allows the receiver to determine when a message is being sent and also allows the receiver to synchronise with the sender without the need for a secondary connection. The developed protocol correctly determined that a message was being sent across the channel 90% of the time with an average absolute synchronisation error of 0.397 s between sender and receiver.

Keywords

• Brain
• Communication channel
• EMOTIV
• SSVEP
• Transmission protocol