1. Pheromones and Gender Identity:
A pilot study using cerebral electrical activity
Molo Mt, Cappai E, Castelli L, Perozzo P, Tomassoni C, 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)
Here is the VNO pit

4. The vomeronasal organ: connection with the hypothalamus

5. Subjects:
6 heterosexual male
6 heterosexual female
6 male-to-female (MtF) transsexuals
First session
MtF Estratetraenol/Androstadienone
Males Estratetraenol/placebo
Females Androstadienone/placebo
Second session
MtF the opposite
Males the opposite
Females the opposite

6. Results
A specific software transformed all the numerical values recorded by each electrode into a spectrum of colours, thus creating a brain map

7. 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

8. Androstadienone VS Estratetraenol
MTF
Androstadienone VS Estratetraenol
Example of a brain map referring to the frequency of β waves. The two coloured maps show the mean values of β frequency activation. As indicated in the column, the colour spectrum goes up from a lower value to a highier one, where the blu area represents a stronger activation.
The gray map shows the statistical difference between the two conditions. Data statistically significant with p<0.05 are in the red zone, left frontal region

9. 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

10. MtF VS Heterosexual females
Androstadienone
MtF VS Heterosexual females
A picture similar to the previous, but the major activation of MtF compared to women is bilaterally in frontal region.

11. 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 androstadienone condition and placebo in the heterosexual females

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