Electropathic residue is a reading that can be present in humanoid brains. It characterizes Iresine Syndrome when accompanied by depressed histamine counts; when unaccompanied by such counts and localized in the thalamus, it can indicate Ullian telepathic memory invasion. It can also be caused by some twenty-two non-medical agents, including ferrazene, hylanatine, dardilion, chrysimite, and manzene, all of which can be scanned by ships' sensors. (TNG: "Violations")