A cortical implant was a device used to interface directly with the mind of a humanoid. The Breen employed a type of cortical implant to probe the minds of prisoners, with unpleasant mental and physical side effects. These devices were used to interrogate Worf and Ezri Dax in late 2375. (DS9: "'Til Death Do Us Part") Tieran, former Autarch of the Ilari, used a cortical implant as part of a mechanism to transfer his consciousness into different host bodies to extend his life span. (VOY: "Warlord") The cortical implant in Borg drones may be the same device as the cortical node.