Androgens modulate neural networks of empathetic processes in female-to-male tanssexuals
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Androgens Modulate Neural Networks of Empathetic Processes in Female-to-Male Transsexuals Z. Ye 1 , R. Kopyciok 1 , B. Mohammadi 1,2 , U. M. Krämer 1 , C. Brunnlieb 1 , M. Heldmann 1 , A. Samii 2 , T. F. Münte 1 1 University of Lübeck, Germany 2 International Neuroscience Institute, Germany Univariate Analysis Performed with SPM8 on the basis of general linear model (p < 0.05 corrected at cluster level). • Brain responses to emotional cues in the medial prefrontal cortex (mPFC) and posterior superior temporal sulcus (pSTS) decreased during hormonal treatment. Network Analysis Performed with the Brain Connectivity Toolbox on the basis of graph theory • Each cerebral hemisphere was segmented into 45 regions according to the Automated Anatomical Labeling. • Correlations were computed for every possible pair of regions to construct the connectivity matrix. • The connectivity matrix was systematically threshold to generate 99 undirected binary matrix with costs from 0.01 to 0.99 at 0.01 intervals. • A small world network has both high global efficiency and high local efficiency. The brain network behaved like the small world network when cost = 0.12~0.23 (small-world regime). • Statistics were performed in the samll-world regime. Alpha levels were controlled with permutation (p < 0.05 corrected). • Left and right middle cingulate cortex (LMC/RMC), left middle temporal gyrus (LMT) and right superior temporal gyrus (RST) were regional hubs of which centrality did not change when androgen level changed. Acknowledgments Deutsche Forschungsgemeinschaft • DFG, SFB 779, TP A5 to TFM • KR 3691/1-1 to UMK German Federal Department of Research BMBF (to TFM). More info: [email protected] (Prof. Dr. T. F. Münte) Methods Transsexuals and hormonal treatment • Female-to-male transsexuals (n = 8, mean 28 years): Each was scanned twice, once before (pre-test) and once during hormonal therapy (post- test; 12months after the treatment began). • Hormone administration route and schedules were heterogeneous, as defined by the attending endocrinologist. Healthy controls: Females (n = 31, mean 24 years) and Males (n = 30, mean 27 years) Research Questions Women usually show higher sensitivity than men to emotional and social cues and are therefore better in showing empathy with others and in the deciphering of other’s intentions and mental states. These sex differences have been linked to hormonal levels. However, it remains unclear how hormones modulate neural mechanisms underlying empathic processes. Here we assess effects of chronic hormonal treatment in a group of female-to-male transsexuals before and during androgen therapy with functional magnetic resonance imaging (fMRI). We ask two questions. Q1: How is brain activity in response to emotional and/or social cues modulated during hormonal treatment in transsexuals (pre- vs. post- test)? ( Univariate analysis) Q2: How are neural networks of empathic processes modulated during hormonal treatment in transsexuals? Do same differences show up in healthy females vs. males? ( Graph theoretical analysis) Stimuli and task • Black-and-white drawings depicting emotionally negative or neural (Emot vs. Neut) social situations involving one or two persons (One vs. Two) • Participants watched the pictures during three sessions and completed a recognition after each session. Data acquisition • Collected on 3T Siemens scanner using EPI sequence, with 2000-ms TR, 30-ms TE and 80°flip angle. • 32 transversal slices; 192 mm*192 mm field of view; 3-mm thickness, 0.75-mm gap; 3 mm*3 mm in-plane resolution. • MPFC and pSTS responses to social cues also decreased during hormonal treatment. • Functional connections within frontal regions, those between frontal and temporal lobes, and those between frontal and striatal structures were stronger when androgen level was low (transsexuals before hormonal treatment and healthy females). • Functional connections within limbic system was stronger when androgen level was high (transsexuals after hormonal treatment and healthy males).
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Transcript of Androgens modulate neural networks of empathetic processes in female-to-male tanssexuals
Androgens Modulate Neural Networks of Empathetic Processes in Female-to-Male Transsexuals
Z. Ye1, R. Kopyciok1, B. Mohammadi1,2, U. M. Krämer1, C. Brunnlieb1, M. Heldmann1, A. Samii2, T. F. Münte1
1University of Lübeck, Germany 2International Neuroscience Institute, Germany
Univariate AnalysisPerformed with SPM8 on the basis of general linear model (p < 0.05
corrected at cluster level). • Brain responses to emotional cues in the medial prefrontal cortex
(mPFC) and posterior superior temporal sulcus (pSTS) decreased during hormonal treatment.
Network AnalysisPerformed with the Brain Connectivity Toolbox on the basis of graph
theory• Each cerebral hemisphere was segmented into 45 regions according to
the Automated Anatomical Labeling. • Correlations were computed for every possible pair of regions to
construct the connectivity matrix. • The connectivity matrix was systematically threshold to generate 99
undirected binary matrix with costs from 0.01 to 0.99 at 0.01 intervals.• A small world network has both high global efficiency and high local
efficiency. The brain network behaved like the small world network when cost = 0.12~0.23 (small-world regime).
• Statistics were performed in the samll-world regime. Alpha levels were controlled with permutation (p < 0.05 corrected).
• Left and right middle cingulate cortex (LMC/RMC), left middle temporal gyrus (LMT) and right superior temporal gyrus (RST) were regional hubs of which centrality did not change when androgen level changed.
AcknowledgmentsDeutsche Forschungsgemeinschaft• DFG, SFB 779, TP A5 to TFM• KR 3691/1-1 to UMKGerman Federal Department of
Research BMBF (to TFM).
More info: [email protected] (Prof. Dr. T. F. Münte)
MethodsTranssexuals and hormonal treatment• Female-to-male transsexuals (n = 8, mean 28 years): Each was scanned
twice, once before (pre-test) and once during hormonal therapy (post-test; 12months after the treatment began).
• Hormone administration route and schedules were heterogeneous, as defined by the attending endocrinologist.
Healthy controls: Females (n = 31, mean 24 years) and Males (n = 30, mean 27 years)
Research QuestionsWomen usually show higher sensitivity than men to emotional and social
cues and are therefore better in showing empathy with others and in the deciphering of other’s intentions and mental states. These sex differences have been linked to hormonal levels. However, it remains unclear how hormones modulate neural mechanisms underlying empathic processes. Here we assess effects of chronic hormonal treatment in a group of female-to-male transsexuals before and during androgen therapy with functional magnetic resonance imaging (fMRI). We ask two questions.
Q1: How is brain activity in response to emotional and/or social cues modulated during hormonal treatment in transsexuals (pre- vs. post-test)? (� Univariate analysis)
Q2: How are neural networks of empathic processes modulated during hormonal treatment in transsexuals? Do same differences show up in healthy females vs. males? (� Graph theoretical analysis)
Stimuli and task• Black-and-white drawings
depicting emotionally negative or neural (Emotvs. Neut) social situations involving one or two persons (One vs. Two)
• Participants watched the pictures during three sessions and completed a recognition after each session.
Data acquisition• Collected on 3T Siemens scanner using EPI sequence, with 2000-ms
TR, 30-ms TE and 80°flip angle.• 32 transversal slices; 192 mm*192 mm field of view; 3-mm thickness,
0.75-mm gap; 3 mm*3 mm in-plane resolution.
• MPFC and pSTS responses to social cues also decreased during hormonal treatment.
• Functional connections within frontal regions, those between frontal and temporal lobes, and those between frontal and striatal structures were stronger when androgen level was low (transsexuals before hormonal treatment and healthy females).
• Functional connections within limbic system was stronger when androgen level was high (transsexuals after hormonal treatment and healthy males).
