M.Molo, L.Rolle, S. Vighetti, P Perozzo, M.Timpano, M.Molo, L.Rolle, S. Vighetti, P Perozzo, M.Timpano, M.Falcone, L. Castelli, D. Fontana M.Falcone, L. Castelli, D. Fontana

UNIVERSITAUNIVERSITA’’ DEGLI STUDI DI TORINO DEGLI STUDI DI TORINOA.S.O. S. Giovanni Battista – Molinette - TorinoA.S.O. S. Giovanni Battista – Molinette - Torino

Divisione Universitaria di Urologia II Divisione Universitaria di Urologia II Direttore Prof. D. FontanaDirettore Prof. D. Fontana

FONDAZIONE CARLO MOLO ONLIS FONDAZIONE CARLO MOLO ONLIS

NEUROPHYSIOLOGICAL NEUROPHYSIOLOGICAL POSTOPERATIVE VARIATIONS IN MtoF POSTOPERATIVE VARIATIONS IN MtoF

TRANSSEXUALSTRANSSEXUALS

Aim of the study…Aim of the study…

To investigate neurophysiological patterns, To investigate neurophysiological patterns, particularly the P300 wave, and to compare data particularly the P300 wave, and to compare data collected before and after Sex Reassignement collected before and after Sex Reassignement

SurgerySurgery

Animal studies have demonstrated the Animal studies have demonstrated the existence of sexual dimorphic brain areas existence of sexual dimorphic brain areas related to sexual behaviourrelated to sexual behaviour

Arnold 1976, Mac Lusky Arnold 1976, Mac Lusky 19811981

Dimorphic cerebral areas exist in humans Dimorphic cerebral areas exist in humans Hofman 1989, Allen 1990Hofman 1989, Allen 1990

INTRODUCTIONINTRODUCTION

• Numbers of neurons Numbers of neurons (Kruijver 2000)(Kruijver 2000)

• Type of neurons Type of neurons (Cooke 1999)(Cooke 1999)

Dimorphic areas have specific cellular patterns in Dimorphic areas have specific cellular patterns in terms of:terms of:

Men and women differ in processing cognitive and Men and women differ in processing cognitive and emotional informationemotional information

Emotions are characterised by:Emotions are characterised by:

• • valence (positive or negative)valence (positive or negative)

• • arousal ( high or low)arousal ( high or low)

Women have greater Women have greater answers to negative answers to negative emotional stimuli when emotional stimuli when compared with mencompared with men

Interstitial nucleus of anterior hypotalamusInterstitial nucleus of anterior hypotalamusBasal nucleus of stria terminalisBasal nucleus of stria terminalis

Preoptic area nucleusPreoptic area nucleusLocus ceruleusLocus ceruleus

AmygdalaAmygdala

Interstitial nucleus of anterior hypotalamusInterstitial nucleus of anterior hypotalamusBasal nucleus of stria terminalisBasal nucleus of stria terminalis

Preoptic area nucleusPreoptic area nucleusLocus ceruleusLocus ceruleus

AmygdalaAmygdala

Materials and methodsMaterials and methods

15 MtF transsexuals15 MtF transsexuals

60 slides from the IAPS: 20 positive, 20 negative 60 slides from the IAPS: 20 positive, 20 negative and 20 neutraland 20 neutral

Recording of the P300 evoked activity in Cz, Fz and Recording of the P300 evoked activity in Cz, Fz and Pz electrodesPz electrodes

Statistical analysis: t.test for pair samplesStatistical analysis: t.test for pair samples

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

• The visual related P300 is known to represent updating mechanism of task-relevant information and is influenced by the emotional characteristics of pictures Armehein 2004Armehein 2004

• Gender differences in the amplitude of the visual ERP have been reported in literature, reporting a major P300 amplitude in women than in men Geisler 1990, Deldin 1994Geisler 1990, Deldin 1994

P300 - ERP

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

ResultsResults

Positive stimuliPositive stimuli

Pre vs post p<0,01Pre vs post p<0,01

Positive stimuliPositive stimuli

Pre vs post p<0,01Pre vs post p<0,01

    Positive stimuli                

                       

MtoF pre     MtoF post

Latence Amplitude Area Latence Amplitude Area

Pz 342,4 4,7 95,7 Pz 361,4 6,73 104,4 p<0.01

Cz 342,4 2,9 89,7 Cz 363,9 4,1 99,8 p<0.01

Fz 340,6 1,8 71,1 Fz 359,3 2,7 84,9 p<0.01

ResultsResults

Negative stimuliNegative stimuli

Pre vs post p<0,01Pre vs post p<0,01

Negative stimuliNegative stimuli

Pre vs post p<0,01Pre vs post p<0,01

MtoF pre MtoF post

Latence Amplitude Area Latence Amplitude Area

Pz 349,8 3,0 117,9 Pz 371,7 5,3 128,5 p<0,01

Cz 351,2 3,4 119,0 Cz 386,5 6,2 133,3 p<0.01

Fz 354,9 2,9 91,2 Fz 376,5 5,2 107,6 p<0.01

ResultsResults

Neutral stimuliNeutral stimuli

Pre vs post p>0,05Pre vs post p>0,05

Neutral stimuliNeutral stimuli

Pre vs post p>0,05Pre vs post p>0,05

MtoF pre   MtoF post

Latence Amplitude Area Latence Amplitude Area

Pz 309,0 2,8 107,7 Pz 307,73 2,5 109,4 p>0,05

Cz 305,0 1,9 96,43 Cz 304,9 2,4 95,9 p>0,05

Fz 307,4 1,4 63,5 Fz 306,6 1,3 62,6 p>0,05

                       

ResultsResults

• Results evidenced a statistically significant post-Results evidenced a statistically significant post-surgery increase (pre vs. post-surgery period) in surgery increase (pre vs. post-surgery period) in P300 values for the negative and the positive P300 values for the negative and the positive slides, while no difference was found for the slides, while no difference was found for the neutral slidesneutral slides

• P300 values were higher in latency, area and P300 values were higher in latency, area and amplitude for positive or negative valence pictures amplitude for positive or negative valence pictures in post-SRS recording.in post-SRS recording.

• These differences were higher under the Cz These differences were higher under the Cz electrodeelectrode

ResultsResultsP300 AMPLITUDE (Cz electrode)P300 AMPLITUDE (Cz electrode)

DiscussionDiscussion

In post SRS recording P300 values were higher in In post SRS recording P300 values were higher in latency, area and amplitude for slides of positive latency, area and amplitude for slides of positive and negative valenceand negative valence

P300 feautures in post-SRS recording were even P300 feautures in post-SRS recording were even more similiar to women controls more similiar to women controls our results seem our results seem to confirm that MtF transsexuals show a to confirm that MtF transsexuals show a neurophysiological pattern similar to subjects of the neurophysiological pattern similar to subjects of the sex they would like to besex they would like to be

This results seem to confirm that SRS have a This results seem to confirm that SRS have a feminizing effect on the brain of MtF transexualsfeminizing effect on the brain of MtF transexuals