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Characteristics of brain activity in GID
people Molo M.T., Vighetti S., Rizzi L., Castelli
L., Cantafio P., Cappai E. CE.R.NE - Via della
Rocca 24 bis, Turin (Italy) - www.cerne.it -
e-mail mtmolo_at_attglobal.net
INTRODUCTION Nowadays transsexuals still suffer a
social discrimination due to their gender
identity. A major understanding of the phenomena
should help to overcome the prejudices. Our
studies investigate the psychophysiological
response to emotions, starting from the
difference between male and female,
scientifically demonstrated. Emotions take an
important role in cortical functioning because
they are relevant in every activity of our mind.
But scientists do not agree about definitions and
measures of them different are the emotions
supposed to be fundamental, different are
questionnaires used in order to evaluate them.
Affective states are usually investigated by
heart rate, skin conductance and facial
electrophysiological response. But their origin
seems to be in a subcortical area of the brain
called limbic system involving the amygdale, the
anterior cingulated and the orbital-frontal
cortex. Moreover, some studies support the idea
that greater left frontal activity is associated
with positive emotions and/or approach
motivation, and that greater right frontal
activity is associated with negative emotions
and/or withdrawal motivation (Harmon-Jones E,
2003). There are no studies in literature
dealing with the brain electrophysiological
response of transsexuals to emotional
stimuli. The aim of the present study is to
investigate the brain electrophysiological
response to different visual stimuli in
transsexuals compared to a control group.
RESULTS The results were analysed by a
statistical package for the brain
electrophysiological activity offered by the
Mizar Syrius. We considered as within-subject
factor the type of slide (positive vs negative)
and as between-subjects factor the group (male vs
female vs FtM vs MtF ). We considered the alpha
rhythm as indicative of attention. We also took
into account the theta rhythm as indicative of a
subcortical brain activity.
METHODS Twenty-four transsexuals (12 male to
female- MtF - and 12 female to male - MtF), some
of them in hormonal therapy, were enrolled in the
study. The control group consisted of 12
heterosexual women and 12 heterosexual men
matched for age and educational level. Twenty
positive and twenty negative slides were chosen
from the International Affective Picture System
(IAPS). Each picture was presented for 6 seconds
followed by a blank screen for other 6
seconds. Brain electrophysiological activity was
measured by Mizar Syrius according to the
International 10/20 System
About the alpha rhythm, the results were the
following
The female group was more activated than the
male during the negative slides  
The MtF were more activated than the FtM
during the presentation  
The female group was also more activated than the
FtM during both the positive and the negative
ones
Positive slide
Negative slide
Female group
Male group
MtF group
FtM group
Female group
FtM group
Female group
FtM group
About theta rhythm, we found that
The MtF were more activated than the FtM during
the negative ones
The female group was more activated than the male
during the positive slides
The MtF were more activated than the male during
both the positive and the negative slides
Positive slide
Negative slide
Female group
Male group
FtM group
MtF group
MtF group
Male group
MtF group
Male group
We didnt find any significant difference in the
other comparisons between the groups. Moreover,
the valence (positive or negative) of the visual
stimuli didnt reproduce the cerebral
asymmetrical (left or right) configuration found
in other studies.
DISCUSSION Our study evidences a major activation
of the brain alpha and theta rythms in the female
compared to the other groups (male, MtF, FtM).
The males are less sensitive to visual stimuli
with different affective valence (negative and
positive). The transsexuals put themselves
between the male and the female group and the FtM
seem to be more activated than the MtF. So, the
transsexuals seem to follow the same affective
trend of the heterosexuals their brain activity
was similar to the sex they would like to be.
This finding supports the idea that transsexuals
dont feel the emotions as we can expect thinking
about their gender identity. This is in
accordance with the previous studies about the
autonomic responses during the slide presentation
(Molo M., 2003 ). We agree that affective states
arent always correlated with gender identity in
transsexuals as it happens in some people not
suffering from this disorder.
REFERENCES Harmon-Jones E. Clarifying the emotive
functions of asymmetrical frontal cortical
activity. Psychophysiology, 200340838-48. Lang,
P.J., Bradley, M.M., Cuthbert,B.N. International
affective picture system (IAPS) Instrucion
manual and affective ratings. Technical
ReportA-4, The Center.For Research in
Psychophysiology, University of Florida,
1999. Molo M., Vighetti S., Castelli L., Cappai
E., Perozzo P., Neurophysiological correlates to
emotional stimuli in transsexuals. XVI Congresso
Mondiale Word Association for Sexology, WAS,
Cuba, 10-14 marzo 2003