“…Thus Freud, as cited below, used the abbreviation Qη to signify some form of quantity (‘Quantität’)—either flowing through a neuron or between neurons, or a more static entity within a neuron 8. The meaning of the curious terms ‘cathexis’ and ‘cathected’ have their origins in Greek and were introduced by Strachey as a much debated translation, or mistranslation, of Freud's ‘Besetzung’ and ‘besetzen’ 18. Cathexis appears to have been used in a neurological rather than psychological sense,19 and Freud seems to have envisaged that neurons, by being cathected, were in Wollheim's term ‘filled with energy’20 (ie, Qη) .…”