Electropathic residue

From Memory Alpha, the free Star Trek reference.

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 22 non-medical agents, including pherazine, hyladatine, dardilium, chrysomite, and manzine, all of which can be scanned by ships' sensors. (TNG: "Violations")