EEG responses to visual erotic stimuli in men with normal and paraphilic interests

Contingent negative variation and evoked potentials to visual erotic stimuli were recorded from 8 brain sites in a sample of 62 right-handed men aged 20-50, half of whom declared paraphilic interests and half claimed "normal" heterosexual interests. To quantify erotic preferences, a "variance quotient" (VQ) was calculated from scores on the Wilson Sex Fantasy Questionnaire using the formula VQ = Impersonal + Sadomasochistic fantasies/Intimate + Exploratory fantasies. Stimuli consisted of 57 paraphilic slides (depicting fetishistic and sadomasochistic themes), 57 heterosexual erotic slides (explicit pictures of nude women, coitus, and oral sex), and 57 neutral slides (landscapes and street scenes). The P600 response appeared to be the best indicator of erotic preferences, butthe locus of maximum arousal was different for paraphilic and heterosexual stimuli. The primary brain site for heterosexual arousal was P4 (right parietal), where there was a -.34 (p < .01) correlation between VQ and P600 (i.e., nonvariant males showed greater responses to normal erotic stimuli at this location). For paraphilic stimuli, there was a correlation of .26 (p < .05) between the VQ and P600 response at the F3 (left frontal) site (i.e., paraphilic men showed greater responses to paraphilic stimuli than normal men at this brain location). Dividing the sample into groups of 23 paraphilics and 23 heterosexual controls on the basis of their VQs showed that "normals" differentiated between stimulus types more at the P4 than paraphilics. Theoretical and clinical implications of these findings are discussed.