an electrode with three - dimensional capabilities for detection and control of brain state changes of a subject . the electrode includes a disk portion having an upper surface and a lower surface , and a shaft portion secured to and extending perpendicularly outwardly from the lower surface of the disk portion ; the shaft portion having an outer surface . the disk portion and shaft portion may include one or more recording or stimulating contact surfaces structured to operatively interact with the brain of a subject . insulating material isolates each of the recording or stimulating contact surfaces from each other . at least one conductor operatively and separately connect each of the recording or stimulating contact surfaces in communication with external apparatus . the disk portion and shaft portion are structured relative to each other to operatively provide support and anchoring for each other while providing three - dimensional capabilities for detection and control of brain state changes of a subject . modified embodiments include insertible / retractable electrode wires , both contained in channels and sheathed in axially displaceable cannulae ; activating mechanisms for inserting / retracting the electrode wires and / or cannulae ; and multiple shaft portions .