Positron Emission Tomography and sexual arousal in a sadist and two controls

Positron Emission Tomography (PT) scans of the brain were compared in a sexual sadist and two community controls. The participants heard either an erotic audiotape or a sexually neutral tape while penile circumference was monitored. Results showed reliable penile differences between erotic and neutral stimuli. PT results showed that the right hemisphere of the brain was more activated than the left during both types of stimuli but the pattern of activation was not distinct. The erotic stimuli produced greater activation levels but in the same areas of the brain as neutral stimuli. The deep limbic structures of the brain were not especially activated as expected. The sadist differed from the controls in showing more bilateral activation during both types of stimuli but, here too, the same brain sites were activated. Suggestions for future study are discussed.