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Manzouri A, Savic I. Possible Neurobiological Underpinnings of Homosexuality and Gender Dysphoria. Cereb Cortex 2019; 29:2084-2101. [PMID: 30084980 PMCID: PMC6677918 DOI: 10.1093/cercor/bhy090] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/13/2018] [Accepted: 04/03/2018] [Indexed: 01/13/2023] Open
Abstract
Although frequently discussed in terms of sex dimorphism, the neurobiology of sexual orientation and identity is unknown. We report multimodal magnetic resonance imaging data, including cortical thickness (Cth), subcortical volumes, and resting state functional magnetic resonance imaging, from 27 transgender women (TrW), 40 transgender men (TrM), and 80 heterosexual (40 men) and 60 homosexual cisgender controls (30 men). These data show that whereas homosexuality is linked to cerebral sex dimorphism, gender dysphoria primarily involves cerebral networks mediating self-body perception. Among the homosexual cisgender controls, weaker sex dimorphism was found in white matter connections and a partly reversed sex dimorphism in Cth. Similar patterns were detected in transgender persons compared with heterosexual cisgender controls, but the significant clusters disappeared when adding homosexual controls, and correcting for sexual orientation. Instead, both TrW and TrM displayed singular features, showing greater Cth as well as weaker structural and functional connections in the anterior cingulate-precuneus and right occipito-parietal cortex, regions known to process own body perception in the context of self.
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Affiliation(s)
- A Manzouri
- Department of Women’s and Children’s Health, Karolinska Institute and University Hospital, Stockholm, Sweden
| | - I Savic
- Department of Women’s and Children’s Health, Karolinska Institute and University Hospital, Stockholm, Sweden
- Department of Neurology, University of California Los Angeles, Los Angeles, CA, USA
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Manzouri A, Savic I. Cerebral sex dimorphism and sexual orientation. Hum Brain Mapp 2018; 39:1175-1186. [PMID: 29227002 PMCID: PMC6866632 DOI: 10.1002/hbm.23908] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 11/29/2017] [Accepted: 11/29/2017] [Indexed: 11/08/2022] Open
Abstract
The neurobiology of sexual orientation is frequently discussed in terms of cerebral sex dimorphism (defining both functional and structural sex differences). Yet, the information about possible cerebral differences between sex-matched homo and heterosexual persons is limited, particularly among women. In this multimodal MRI study, we addressed these issues by investigating possible cerebral differences between homo and heterosexual persons, and by asking whether there is any sex difference in this aspect. Measurements of cortical thickness (Cth), subcortical volumes, and functional and structural resting-state connections among 40 heterosexual males (HeM) and 40 heterosexual females (HeF) were compared with those of 30 homosexual males (HoM) and 30 homosexual females (HoF). Congruent with previous reports, sex differences were detected in heterosexual controls with regard to fractional anisotropy (FA), Cth, and several subcortical volumes. Homosexual groups did not display any sex differences in FA values. Furthermore, their functional connectivity was significantly less pronounced in the mesial prefrontal and precuneus regions. In these two particular regions, HoM also displayed thicker cerebral cortex than other groups, whereas HoF did not differ from HeF. In addition, in HoM the parietal Cth showed "sex-reversed" values, not observed in HoF. Homosexual orientation seems associated with a less pronounced sexual differentiation of white matter tracts and a less pronounced functional connectivity of the self-referential networks compared to heterosexual orientation. Analyses of Cth suggest that male and female homosexuality are not simple analogues of each other and that differences from heterosexual controls are more pronounced in HoM.
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Affiliation(s)
- Amirhossein Manzouri
- Department of Women's and Children's Health, and Neurology ClinicKarolinska Institutet and HospitalStickholmSE‐171 76Sweden
| | - Ivanka Savic
- Department of Women's and Children's Health, and Neurology ClinicKarolinska Institutet and HospitalStickholmSE‐171 76Sweden
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Pound N, Lawson DW, Toma AM, Richmond S, Zhurov AI, Penton-Voak IS. Facial fluctuating asymmetry is not associated with childhood ill-health in a large British cohort study. Proc Biol Sci 2014; 281:20141639. [PMID: 25122232 PMCID: PMC4150332 DOI: 10.1098/rspb.2014.1639] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 07/22/2014] [Indexed: 11/16/2022] Open
Abstract
The idea that symmetry in facial traits is associated with attractiveness because it reliably indicates good physiological health, particularly to potential sexual partners, has generated an extensive literature on the evolution of human mate choice. However, large-scale tests of this hypothesis using direct or longitudinal assessments of physiological health are lacking. Here, we investigate relationships between facial fluctuating asymmetry (FA) and detailed individual health histories in a sample (n = 4732) derived from a large longitudinal study (Avon Longitudinal Study of Parents and Children) in South West England. Facial FA was assessed using geometric morphometric analysis of facial landmark configurations derived from three-dimensional facial scans taken at 15 years of age. Facial FA was not associated with longitudinal measures of childhood health. However, there was a very small negative association between facial FA and IQ that remained significant after correcting for a positive allometric relationship between FA and face size. Overall, this study does not support the idea that facial symmetry acts as a reliable cue to physiological health. Consequently, if preferences for facial symmetry do represent an evolved adaptation, then they probably function not to provide marginal fitness benefits by choosing between relatively healthy individuals on the basis of small differences in FA, but rather evolved to motivate avoidance of markers of substantial developmental disturbance and significant pathology.
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Affiliation(s)
- Nicholas Pound
- Division of Psychology, Department of Life Sciences, Brunel University, London UB8 3PH, UK
| | - David W Lawson
- Department of Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - Arshed M Toma
- Applied Clinical Research and Public Health, Orthodontic Department, School of Dentistry, Cardiff University, Cardiff, UK
| | - Stephen Richmond
- Applied Clinical Research and Public Health, Orthodontic Department, School of Dentistry, Cardiff University, Cardiff, UK
| | - Alexei I Zhurov
- Applied Clinical Research and Public Health, Orthodontic Department, School of Dentistry, Cardiff University, Cardiff, UK
| | - Ian S Penton-Voak
- School of Experimental Psychology, University of Bristol, Bristol, UK
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Nováková L, Varella Valentová J, Havlíček J. Olfactory performance is predicted by individual sex-atypicality, but not sexual orientation. PLoS One 2013; 8:e80234. [PMID: 24244657 PMCID: PMC3820642 DOI: 10.1371/journal.pone.0080234] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 10/01/2013] [Indexed: 11/19/2022] Open
Abstract
Many previous studies have reported robust sex differences in olfactory perception. However, both men and women can be expected to vary in the degree to which they exhibit olfactory performance considered typical of their own or the opposite sex. Sex-atypicality is often described in terms of childhood gender nonconformity, which, however, is not a perfect correlate of non-heterosexual orientation. Here we explored intrasexual variability in psychophysical olfactory performance in a sample of 156 individuals (83 non-heterosexual) and found the lowest odor identification scores in heterosexual men. However, when childhood gender nonconformity was entered in the model along with sexual orientation, better odor identification scores were exhibited by gender-nonconforming men, and greater olfactory sensitivity by gender-conforming women, irrespective of their sexual orientation. Thus, sex-atypicality, but not sexual orientation predicts olfactory performance, and we propose that this might not be limited to olfaction, but represent a more general phenomenon.
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Affiliation(s)
- Lenka Nováková
- Department of Anthropology, Faculty of Humanities, Charles University, Prague, Czech Republic, United States of America
- * E-mail:
| | - Jaroslava Varella Valentová
- Centre for Theoretical Study, Charles University and the Academy of Sciences of the CzechRepublic, Prague, Czech Republic, United States of America
| | - Jan Havlíček
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic, United States of America
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Hu S, Xu D, Peterson B, Wang Q, He X, Hu J, Xu X, Wei N, Long D, Huang M, Zhou W, Xu W, Zhang M, Xu Y. Association of cerebral networks in resting state with sexual preference of homosexual men: a study of regional homogeneity and functional connectivity. PLoS One 2013; 8:e59426. [PMID: 23555670 PMCID: PMC3605412 DOI: 10.1371/journal.pone.0059426] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Accepted: 02/14/2013] [Indexed: 11/25/2022] Open
Abstract
Recent imaging studies have shown that brain morphology and neural activity during sexual arousal differ between homosexual and heterosexual men. However, functional differences in neural networks at the resting state is unknown. The study is to characterize the association of homosexual preference with measures of regional homogeneity and functional connectivity in the resting state. Participants were 26 healthy homosexual men and 26 age-matched healthy heterosexual men in whom we collected echo planar magnetic resonance imaging data in the resting state. The sexual orientation was evaluated using the Kinsey Scale. We first assessed group differences in regional homogeneity and then, taking the identified differences as seed regions, we compared groups in measures of functional connectivity from those seeds. The behavioral significances of the differences in regional homogeneity and functional connectivity were assessed by examining their associations with Kinsey Scores. Homosexual participants showed significantly reduced regional homogeneity in the left inferior occipital gyrus, right middle occipital gyrus, right superior occipital gyrus, left cuneus, right precuneus, and increased regional homogeneity in rectal gyrus, bilateral midbrain, and left temporal lobe. Regional homogeneity correlated positively with Kinsey scores in the left inferior occipital gyrus. The homosexual group also showed reduced functional connectivity between left middle temporal gyrus, left supra-marginal gyrus, right cuneus and the seed region, i.e. left inferior occipital gyrus. Additionly, the connection between the left inferior occipital gyrus and right thalamus correlated positively with Kinsey scores. These differences in regional homogeneity and functional connectivity may contribute to a better understanding of the neural basis of male sexual orientation.
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Affiliation(s)
- Shaohua Hu
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Dongrong Xu
- MRI Unit, Department of Psychiatry, Columbia University and New York State Psychiatric Institute, New York, New York, United States of America
| | - Bradley Peterson
- MRI Unit, Department of Psychiatry, Columbia University and New York State Psychiatric Institute, New York, New York, United States of America
| | - Qidong Wang
- Department of Radiology, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Xiaofu He
- MRI Unit, Department of Psychiatry, Columbia University and New York State Psychiatric Institute, New York, New York, United States of America
| | - Jianbo Hu
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Xiaojun Xu
- Department of Radiology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Ning Wei
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Dan Long
- Department of Radiology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Manli Huang
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Weihua Zhou
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Weijuan Xu
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Minming Zhang
- Department of Radiology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Yi Xu
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
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Gangestad SW, Thornhill R, Garver-Apgar CE. Men's facial masculinity predicts changes in their female partners' sexual interests across the ovulatory cycle, whereas men's intelligence does not. EVOL HUM BEHAV 2010. [DOI: 10.1016/j.evolhumbehav.2010.06.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Banks GC, Batchelor JH, McDaniel MA. Smarter people are (a bit) more symmetrical: A meta-analysis of the relationship between intelligence and fluctuating asymmetry. INTELLIGENCE 2010. [DOI: 10.1016/j.intell.2010.04.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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DenBoer JW, Hough S. The Role of Clinical Neuropsychology in the Study of Sexuality and Disability. SEXUALITY AND DISABILITY 2010. [DOI: 10.1007/s11195-010-9163-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Perilloux HK, Webster GD, Gaulin SJC. Signals of Genetic Quality and Maternal Investment Capacity: The Dynamic Effects of Fluctuating Asymmetry and Waist-to-Hip Ratio on Men’s Ratings of Women’s Attractiveness. SOCIAL PSYCHOLOGICAL AND PERSONALITY SCIENCE 2010. [DOI: 10.1177/1948550609349514] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Fluctuating asymmetry (FA) and waist-to-hip ratio (WHR) are frequently studied physical attractiveness variables in social and evolutionary psychology. FA represents deviations in bilateral symmetry—differences between left and right body parts. WHR is the ratio of the smallest part of the waist to the largest part of the hips. Although FA and WHR are important mate preference criteria, research has not examined their joint influence on attraction. Thus, 140 heterosexual male undergraduates ranked—and 118 rated—the attractiveness of 10 photographs of rear-facing nude women. Women’s FA and WHR were negatively related to attractiveness separately, after controlling for each other and after controlling for body mass index (BMI). An FA × WHR interaction emerged, such that men’s preferences for lower WHRs increased as FA decreased, even after controlling for BMI. FA and WHR affected attractiveness in ways consistent with the information they carry and its likely effects on offspring quality.
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Johnson W, Segal NL, Bouchard TJ. Fluctuating asymmetry and general intelligence: No genetic or phenotypic association. INTELLIGENCE 2008. [DOI: 10.1016/j.intell.2007.07.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Møller AP. A review of developmental instability, parasitism and disease. INFECTION GENETICS AND EVOLUTION 2006; 6:133-40. [PMID: 16269271 DOI: 10.1016/j.meegid.2005.03.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Revised: 03/18/2005] [Accepted: 03/21/2005] [Indexed: 01/22/2023]
Abstract
Developmental instability is reflected in imprecise development caused by perturbations of the developmental process, while developmental stability reflects the ability to avoid or reduce such perturbations by developmental means. Developmental instability has been hypothesized to reflect overall individual condition, and asymmetric or otherwise aberrant individuals have thus been predicted to be particularly severely affected by disease and parasitism. An extensive review of the literature on animals, including humans, revealed consistent relationships between increased bilateral asymmetry and elevated risk of parasitism. Parasitism, including parasitism of mothers, is a cause of asymmetry as shown by a number of experiments, and asymmetric individuals are differentially susceptible to a range of different parasites. Extensive studies of humans have shown that asymmetric individuals also suffer disproportionately from a range of different diseases including mental diseases. Studies of transgenic organisms have now demonstrated that single genes associated with disease is a sufficient cause of increased asymmetry. A number of studies have also shown that activation of the immune system causes increased asymmetry in developing individuals, and that asymmetry and immunity show negative covariation. These findings may have important implications for the study of susceptibility of hosts to infectious disease.
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Affiliation(s)
- Anders Pape Møller
- Laboratoire de Parasitologie Evolutive, CNRS UMR 7103, Université Pierre et Marie Curie, Bât. A, 7ème étage, 7 quai St. Bernard, Case 237, F-75252 Paris Cedex 05, France.
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