(covers information from several alternate timelines)
A synaptic interface was a process whereby a pilot could establish a direct link between their mind and the controls of a vessel, allowing for reduced response time and precision maneuvering. Invented by the USS Voyager's EMH in 2392, the process required the use of a synaptic transceiver implanted in the cerebral cortex, and a neural interface installed in the vessel to be piloted.
In 2404, Admiral Kathryn Janeway utilized a shuttle equipped with such an interface to travel back in time to the year 2378, on a mission to alter history and return the USS Voyager to the Alpha Quadrant sixteen years early. Later, the admiral utilized the interface to communicate with the Borg Queen, as part of her plot to destroy the Collective. (VOY: "Endgame")