Figure 6.

A schematic illustration of how real-time data access can be implemented. This example depicts the approached developed within the FieldTrip package working in conjunction with an MEG system. The MEG system acquisition software (Acq) writes data to a limited capacity memory segment set up on the acquisition computer (shared memory segment), which is the manufacturer-specific online interface. An external, manufacturer-independent buffer (FieldTrip buffer) is set up on the same or a different computer. An agent (acq2ft) continually monitors the shared memory segment for new data and copies them to the external buffer as soon as these become available. Once the data is in the external buffer they can be accessed and analyzed in Matlab for the purposes of the BCI. Crucially, the rapid copying of new data as soon as they become available to an external buffer deems the reverse-engineering of the MEG system data writing process superfluous.