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UNIVERSITA ’ DEGLI STUDI DI TORINO A.S.O. S. Giovanni Battista – Molinette - Torino Divisione Universitaria di Urologia II Direttore Prof. D. Fontana FONDAZIONE CARLO MOLO ONLIS. NEUROPHYSIOLOGICAL POSTOPERATIVE VARIATIONS IN MtoF TRANSSEXUALS.
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UNIVERSITA’ DEGLI STUDI DI TORINO A.S.O. S. Giovanni Battista – Molinette - Torino Divisione Universitaria di Urologia II Direttore Prof. D. Fontana FONDAZIONE CARLO MOLO ONLIS NEUROPHYSIOLOGICAL POSTOPERATIVE VARIATIONS IN MtoF TRANSSEXUALS M.Molo, L.Rolle, S. Vighetti, P Perozzo, M.Timpano, M.Falcone, L. Castelli, D. Fontana
Aim of the study… To investigate neurophysiological patterns, particularly the P300 wave, and to compare data collected before and after Sex Reassignement Surgery
INTRODUCTION Animal studies have demonstrated the existence of sexual dimorphic brain areas related to sexual behaviour Arnold 1976, MacLusky 1981 Dimorphic cerebral areas exist in humans Hofman 1989, Allen 1990
Dimorphic areas have specific cellular patterns in terms of: • Numbersofneurons(Kruijver 2000) • Typeofneurons(Cooke 1999)
Men and women differ in processing cognitive and emotional information • Emotions are characterised by: • valence (positive or negative) • arousal ( high or low) Women have greater answers to negative emotional stimuli when compared with men
Interstitial nucleus of anterior hypotalamus Basal nucleus of stria terminalis Preoptic area nucleus Locus ceruleus Amygdala
Materials and methods • 15 MtFtranssexuals • 60 slides from the IAPS: 20 positive, 20 negative and 20 neutral • Recording of the P300 evokedactivity in Cz, Fz and Pz electrodes • Statistical analysis: t.test for pairsamples
P300 - ERP • P300 ERP is a positive deflection located 300 ms after the presentation of a stimulus • To be elicited the subject must concentrate on the visual stimulus • P300 amplitude is correlated to the subject’s attention
P300 - ERP • The visualrelated P300 isknown to representupdatingmechanism of task-relevant information and isinfluenced by the emotionalcharacteristics of picturesArmehein 2004 • Gender differences in the amplitude of the visual ERP havebeenreported in literature, reporting a major P300 amplitude in womenthan in men Geisler 1990, Deldin 1994
P300 – Parameters • Latence considers the time between the elicitation of the stimulus and the deflection on the EEG • Topography position on the cranic surface where is recorded the maximum amplitude of the electrode • Amplitude the amount of the deflection, starting from the basal status
Results Positive stimuli Pre vs post p<0,01
Positive stimuli Pre vs post p<0,01
Results Negative stimuli Pre vs post p<0,01
Negative stimuli Pre vs post p<0,01
Results Neutral stimuli Pre vs post p>0,05
Neutral stimuli Pre vs post p>0,05
Results • Results evidenced a statistically significant post-surgery increase (pre vs. post-surgery period) in P300 values for the negative and the positive slides, while no difference was found for the neutral slides • P300 values were higher in latency, area and amplitude for positive or negative valence pictures in post-SRS recording. • These differences were higher under the Cz electrode
Results P300 AMPLITUDE (Cz electrode)
Discussion • In post SRS recording P300 valueswerehigher in latency, area and amplitudeforslidesof positive and negative valence • P300 feautures in post-SRSrecordingwereeven more similiarto women controls ourresultsseemtoconfirmthatMtFtranssexuals show a neurophysiological pattern similartosubjectsof the sex theywouldliketobe • Thisresultsseemtoconfirmthat SRS have a feminizingeffect on the brainofMtFtransexuals