1. Pheromones and cerebral electrical activity Tatu K, Molo MT, Perozzo P, Castelli L, Vighetti S CE.R.NE., Fondazione Carlo Molo, Torino, Italy

2. AIM OF THIS STUDY To examine cerebral electrical activity during the nasal administration of male and female pheromones in transsexuals and eterosexuals, during erotic visual stimulation

3. The vomeronasal organ (VNO)

4. The vomeronasal organ: connection with the hypothalamus The vomeronasal organ: connection with the hypothalamus

5. Subjects: –6 heterosexual male –6 heterosexual female –6 male-to-female (MtF) transsexuals VNO detected with an optical fibre probe Cerebral electrical activity recording (EEG): Brain Mapping technique 16 erotic pictures of naked people (8 man and 8 women) selected from the International Affective Picture System (Lang, 1999) were presented to each subject.

6. First session MtF Estratetraenol/Androstadienone Males Estratetraenol/placebo Females Androstadienone/placebo Second session Second session MtF the opposite Males the opposite Females the opposite

7. Results A specific software transformed all the numerical values recorded by each electrode into a spectrum of colours, thus creating a brain map A specific software transformed all the numerical values recorded by each electrode into a spectrum of colours, thus creating a brain map Statistical analysis showed significant differences in the two following conditions: 1. in the MtF group when comparing the androstadienone with the estratetraenol condition 2. between the MtF and the heterosexual women during the androstadienone condition.

8. Procedure Procedure MtF Estratetraenol Males Estratetraenol/placebo Females Androstadienone/placebo MtF Androstadienone Males the opposite Females the opposite Results 1) In the MtF subgroup comparing the Androstadienone to the Estratetraenol condition we found: major decrease in alpha rhythm (p=0.015) major increase in beta rhythm (p=0.001) with androstadienone = cerebral arousal

9. MTF Androstadienone VSEstratetraenol

10. Procedure Procedure MtF Estratetraenol Males Estratetraenol/placebo Females Androstadienone/placebo MtF Androstadienone Males the opposite Females the opposite Results 2) During the Androstadienone condition, comparing the MtF and the Female subgroups we found: major decrease in alpha rhythm (p=0.045) major increase in beta rhythm (p=0.045) in the MtF subgroup = cerebral arousal

11. Androstadienone MtF VS Heterosexual females MtF VS Heterosexual females

12. Procedure Procedure MtF Estratetraenol Males Estratetraenol/placebo Females Androstadienone/placebo MtF Androstadienone Males the opposite Females the opposite Results 3) No significant differences were found among the other conditions: between the MtF and the heterosexual males in the estratetraenol condition between the estratetraenol condition and placebo in the heterosexual males between the estratetraenol condition and placebo in the heterosexual males between the androstadienone condition and placebo in the heterosexual females between the androstadienone condition and placebo in the heterosexual females

13. Conclusion Our study highlights two important findings: 1.New evidence of biological differences between transsexuals and men 2.Transsexuals are more aroused than heterosexuals by erotic stimuli