B) The effects of GHB on neuronal networks and sexual arousal in healthy subjects - an fMRI study: The investigators performed a characterization of the putative prosexual effects of GHB (35 mg/kg vs. placebo p.o.) in 19 healthy participants. Questionnaires (VAS, SADI, GSQ) were used to assess subjective aspects. Brain reactivity towards erotic vs. neutral pictures of persons, as well as resting state connectivity and arterial spin labelling (ASL) was investigated with functional magnetic resonance imaging (fMRI).