Antonio Guillamón

Antonio Guillamón
National Distance Education University | UNED · Department of Psychobiology

MD. Ph. D.

About

154
Publications
37,562
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Introduction
Antonio Guillamón currently works at the Department of Psychobiology, National Distance Education University. Antonio does research in Biological Psychology, Behavioural Science and Developmental Psychology. The current project is on genetic and neural (MRI) bases of gender.
Additional affiliations
December 1982 - present
Universidad a Distancia de Madrid
Position
  • Professor Emeritus
October 1982 - present
National Distance Education University
Position
  • Professor (Full)
October 1973 - January 1976
University of Oxford
Position
  • PostDoc Position
Description
  • Sex and strain differences in learning behavior

Publications

Publications (154)
Article
Background Some transgender people desire a transition through gender-affirming hormone treatment (GAHT). To date, it is unknown how GAHT changes emotion perception in transgender people. Methods Thirty transgender men (TM), 30 cisgender men (CM), and 35 cisgender women (CW) underwent 3 Tesla functional magnetic resonance imaging (fMRI) while pass...
Article
Full-text available
How the brain represents gender identity is largely unknown, but some neural differences have recently been discovered. We used an intrinsic ignition framework to investigate whether there are gender differences in the propagation of neural activity across the whole‐brain and within resting‐state networks. Studying 29 trans men and 17 trans women w...
Chapter
Full-text available
Gender incongruence (GI) is defined as an individual's discontent with their assigned gender at birth and their identification with a gender other than that associated with their sex based on physical sex characteristics. The origin of GI appears to be multifactorial. From the extensive research that has been conducted over the past few years, four...
Conference Paper
Objectives Human beings have an intrinsic need to belong, a desire to be loved by the people close to them, and to be accepted by society at large. The outcome and purpose of these fundamental human needs are the desire to form long-lasting, if not lifelong, and meaningful personal attachments and create long-term relationships with others. However...
Article
Full-text available
Abstract Background Minority stress via discrimination, stigmatization, and exposure to violence can lead to development of mood and anxiety disorders and underlying neurobiochemical changes. To date, the neural and neurochemical correlates of emotion processing in transgender people (and their interaction) are unknown. Methods This study combined...
Article
Full-text available
Transgender men (TM) experience an incongruence between the female sex assigned when they were born and their self-perceived male identity. Some TM seek for a gender affirming hormone treatment (GAHT) to induce a somatic transition from female to male through continuous administration of testosterone. GAHT seems to be relatively safe. However, test...
Preprint
Full-text available
How the brain constructs gender identity is largely unknown, but some neural differences have recently been discovered. Here, we used an intrinsic-ignition framework to investigate if gender identity changes the propagation of the neural activity across the whole-brain network and within resting-state networks. Studying 29 transmen and 17 transwome...
Article
Full-text available
Large-scale brain network interactions have been described between trans- and cis -gender binary identities. However, a temporal perspective of the brain's spontaneous fluctuations is missing. We investigated the functional connectivity dynamics in transmen with gender incongruence and its relationship with interoceptive awareness. We describe four...
Article
Transgender men and women represent about 0.6 -1.1%% of the general population. Gender affirming hormone therapy (GAHT) helps ameliorate gender dysphoria and promote well-being. However, these treatments’ cardiovascular (CV) effects are difficult to evaluate due to the limited number of extensive longitudinal studies focused on CV outcomes in this...
Article
Full-text available
Introduction: The main objective was to carry out a global DNA methylation analysis in a population with gender incongruence before gender-affirming hormone treatment (GAHT), in comparison to a cisgender population. Methods: A global CpG (cytosine-phosphate-guanine) methylation analysis was performed on blood from 16 transgender people before GAHT...
Poster
Full-text available
Gender incongruence (ICD-11) is characterized by a marked and persistent incongruence between an individual’s experienced gender and the assigned sex at birth. Our main objective was to carry out a prospective global methylation analysis in a transgender population pre versus post six months of gender-affirming hormone treatment (GAHT), respect to...
Article
Full-text available
Much research has been conducted on sexual differences of the human brain to determine whether and to what extent a brain gender exists. Consequently, a variety of studies using different neuroimaging techniques attempted to identify the existence of a brain phenotype in people with gender dysphoria (GD). However, to date, brain sexual differences...
Conference Paper
Full-text available
In humans, sex and gender are not always concordant. Gender incongruence (ICD-11) is characterized ‘‘by a marked and persistent incongruence between an individual’s experienced gender and the assigned sex’’. Our main objective was to carry out a prospective global CpG methylation analysis in a transgender population pre vs. post six months of gende...
Article
Full-text available
Introduction Brain sexual differentiation results from the effects of sex steroids on the developing brain. The presumptive route for brain masculinization is the direct induction of gene expression via activation of the estrogen receptors α and β and the androgen receptor through their binding to ligands and to coactivators, regulating the transcr...
Article
Full-text available
Background In contrast to cisgender persons, transgender persons identify with a different gender than the one assigned at birth. Although research on the underlying neurobiology of transgender persons has been accumulating over the years, neuroimaging studies in this relatively rare population are often based on very small samples resulting in dis...
Article
Full-text available
n mammals, the gonads and the brain develop from bipotential organs that will differentiate into female or male organs, during a critical period of development. This process begins with the production of testosterone by the testes, which will be converted into estradiol in the brain, by the aromatase. While the end is defined by the moment when the...
Preprint
Full-text available
Large-scale brain network interactions have been described between trans- and cis -gender identities. However, a temporal perspective of the brain spontaneous fluctuations is missing. We investigated the functional connectivity dynamics in transmen with gender incongruence and its relationship with interoceptive awareness. We describe four states i...
Chapter
Full-text available
In mammals, sex differences in the adult brain are established very early in development, when the brain is still very immature. In the case of having inherited the SRY gene, during embryogenesis, testosterone secreted by the testes enters the brain and is converted to estradiol by the aromatase. Then the estradiol acts by binding to intracellular...
Article
Body feminization, as part of gender affirmation process of transgender women, decreases the volume of their cortical and subcortical brain structures. In this work, we implement a rat model of adult male feminization which reproduces the results in the human brain and allows for the longitudinal investigation of the underlying structural and metab...
Article
Full-text available
Background Brain sexual differentiation is a process that results from the effects of sex steroids on the developing brain. Evidence shows that epigenetics plays a main role in the formation of enduring brain sex differences and that the estrogen receptor α (ESR1) is one of the implicated genes. Aim To analyze whether the methylation of region III...
Article
Full-text available
Introduction Gender incongruence defines a state in which individuals feel discrepancy between the sex assigned at birth and their gender. Some of these people make a social transition from male to female (trans women) or from female to male (trans men). By contrast, the word cisgender describes a person whose gender identity is consistent with the...
Article
Full-text available
We provide T2*-weighted and T1-weighted images acquired on a 3T MRI scanner obtained from 17 transwomen and 29 transmen with gender incongruence; and 22 ciswomen and 19 cismen that identified themselves to the sex assigned at birth. Data from three different techniques that describe global and regional connectivity differences within functional res...
Article
Full-text available
Functional brain organization in transgender persons remains unclear. Our aims were to investigate global and regional connectivity differences within functional networks in transwomen and transmen with early-in-life onset gender incongruence; and to test the consistency of two available hypotheses that attempted to explain gender variants: (i) a n...
Poster
Full-text available
Transsexualism is characterized by a marked incongruence between one’s experienced gender and biological sex. Transsexuals are individuals who seek or have undergone a social transition from male-to-female (MtF) or from female-to-male (FtM). Since estrogens and androgens are involved in human cerebral dimorphism, we performed a genetic association...
Article
Full-text available
Background: Polymorphisms in sex steroid receptors have been associated with transsexualism. However, published replication studies have yielded inconsistent findings, possibly because of a limited sample size and/or the heterogeneity of the transsexual population with respect to the onset of dysphoria and sexual orientation. We assessed the role o...
Poster
Full-text available
Background: Gender Dysphoria (GD) is characterized by a marked incongruence between one’s experienced gender and biological sex (DSM-5). Transsexuals are individuals who have undergone a transition from male-to-female (MtF) or female-to-male (FtM). Cross-sex hormone therapy (CHT) is critical for phenotypical and psychological transition, however, t...
Poster
Full-text available
Background: Gender Dysphoria (GD) in DSM-5 is characterized by a marked incongruence between one’s experienced gender and biological sex. The etiology is complex, but some hypotheses suggest that GD arises from discrepant cerebral and genital sexual differentiation due to the interaction of hormone, genetic and environmental factors that contribute...
Conference Paper
Full-text available
Gender Dysphoria (GD) (DSM-5) is characterized by a marked incongruence between gender and biological sex (ICD-10). They have undergone a social transition from male-to-female (MtF) or female-to-male (FtM), and do not constitute a homogeneous group according to the onset of dysphoria and the sexual orientation (Blanchard 1989). DNA polymorphisms of...
Poster
Full-text available
INTRODUCCIÓN El tratamiento hormonal cruzado por cambio de sexo (THC) es crítico en la transición fenotípica y psicológica en adultos con Disforia de Género (DG). Pero el impacto que tiene el tratamiento en el patrón de metilación de los receptores esteroideos no se ha estudiado todavía en detalle. OBJETIVO Se examinó el nivel de metilación CpG del...
Article
Full-text available
Gender Dysphoria is characterized by a marked incongruence between the cerebral sex and biological sex. To investigate the possible influence of karyotype on the etiology of Gender Dysphoria we carried out the cytogenetic analysis of karyotypes in 444 male-to-females (MtFs) and 273 female-to-males (FtMs) that attended the Gender Identity Units of B...
Poster
Full-text available
Gender Dysphoria (GD) is commonly thought to arise from discrepant cerebral and gonadal sexual differentiation. Since testosterone and estradiol are known to be involved in brain masculinization, we hypothesized the interaction between the estrogen receptors ERα and ERβ, AR, CYP19A1, and CYP17A1 in GD. The aim of the investigation was the molecular...
Article
Androgenization in adult natal women, as in transsexual men (TM), affects brain cortical thickness and the volume of subcortical structures. In order to understand the mechanism underlying these changes we have developed an adult female rat model of androgenization. Magnetic resonance imaging and spectroscopy were used to monitor brain volume chang...
Article
Full-text available
Introduction: Gender dysphoria, a marked incongruence between one's experienced gender and biological sex, is commonly believed to arise from discrepant cerebral and genital sexual differentiation. With the discovery that estrogen receptor β is associated with female-to-male (FtM) but not with male-to-female (MtF) gender dysphoria, and given estro...
Conference Paper
Full-text available
La disforia de género (DG) en adolescentes o adultos (302.85) (DSM-V) se caracteriza por una marcada incongruencia entre el género y el sexo biológico. Su etiología es compleja pero cada día hay más evidencias de una base genética. Así se ha demostrado la implicación del receptor de estrógenos β (ERβ) en la DG en mujeres que se sienten varones (FtM...
Article
Full-text available
The present review focuses on the brain structure of male-to-female (MtF) and female-to-male (FtM) homosexual transsexuals before and after cross-sex hormone treatment as shown by in vivo neuroimaging techniques. Cortical thickness and diffusion tensor imaging studies suggest that the brain of MtFs presents complex mixtures of masculine, feminine,...
Article
Full-text available
Gender dysphoria is commonly thought to arise from discrepant cerebral and genital sexual differentiation. Increasing evidence supports the idea of genetic vulnerability. The purpose of this paper was to investigate whether the polymorphism CYP17-MspA1 rs743572 is associated with gender dysphoria. Fragments that included the rs743572 polymorphism w...
Article
Full-text available
Purpose of review: Research on the health of transgender and gender nonconforming people has been limited with most of the work focusing on transition-related care and HIV. The present review summarizes research to date on the overall development and quality of life of transgender and gender nonconforming adults, and makes recommendations for futu...
Article
The current review gives an overview of brain studies in transgender people. First, we describe studies into the aetiology of feelings of gender incongruence, primarily addressing the sexual differentiation hypothesis: does the brain of transgender individuals resemble that of their natal sex, or that of their experienced gender? Findings from neur...
Article
Full-text available
The A2 allele of the CYP17 MspA1 polymorphism has been linked to higher levels of serum testosterone, progesterone, and estradiol. To determine whether the CYP17 MspA1 polymorphism is associated with transsexualism. We analyzed 151 male-to-female (MtF), 142 female-to-male (FtM), 167 control male, and 168 control female individuals. Fragments that i...
Article
Full-text available
Transsexuals vary in the sacrifices that they make while transitioning to their cross-gender group. We suggest that one influence on the sacrifices they make is identity fusion. When people fuse with a group, a visceral and irrevocable feeling of oneness with the group develops. The personal self (the sense of "I" and "me") remains potent and combi...
Article
Full-text available
IntroductionAlthough there is literature on sexuality in gender dysphoria, few studies have been done prior to genital sex reassignment surgery (SRS).AimsTo evaluate the perception of sexual QoL in gender-dysphoric patients before genital SRS and the possible factors associated to this perception.Methods The final sample consisted of 67 male-to-fem...
Article
Full-text available
Introduction: The etiology of male-to-female (MtF) transsexualism is unknown. Both genetic and neurological factors may play an important role. Aim: To investigate the possible influence of the genetic factor on the etiology of MtF transsexualism. Methods: We carried out a cytogenetic and molecular analysis in 442 MtFs and 473 healthy, age- an...
Article
Full-text available
Untreated transsexuals have a brain cortical phenotype. Cross-sex hormone treatments are used to masculinize or feminize the bodies of female-to-male (FtMs) or male-to-female (MtFs) transsexuals, respectively. A longitudinal design was conducted to investigate the effects of treatments on brain cortical thickness (CTh) of FtMs and MtFs. This study...
Chapter
Full-text available
Transsexualism is a gender identity disorder with a multifactorial etiology. Neurodevelopmental processes and genetic factors seem to be implicated. The aim of this study was to investigate the association between the genotype and female-to-male (FtM) and male-to-female (MtF) transsexualism by performing a karyotype and molecular analysis of three...
Article
Full-text available
Transsexualism is a gender identity disorder with a multifactorial etiology. Neurodevelopmental processes and genetic factors seem to be implicated. The aim of this study was to investigate the possible influence of the sex hormone-related genes ERβ (estrogen receptor β), AR (androgen receptor), and CYP19A1 (aromatase) in the etiology of female-to-...
Article
Full-text available
In rodents as well as in many other mammalian and non-mammalian species, the arginine-vasopressin (AVP) system includes a parvocellular sexually dimorphic portion located within the bed nucleus of the stria terminalis (BST), the medial amygdaloid nucleus (MeA) and the lateral septum. In this system, males have more cells and denser projections than...
Article
The aim of this study was to evaluate personality in transsexuals. The Temperament and Character Inventory (TCI) profiles of 166 male-to-female (MF) and 88 female-to-male (FM) transsexuals were compared with those of a control group of males and females. MF and FM transsexuals scored significantly lower than males and females in RD4 (more independe...
Article
Full-text available
To evaluate the self-reported perceived quality of life (QoL) in transsexuals attending a Spanish gender identity unit before genital sex reassignment surgery, and to identify possible determinants that likely contribute to their QoL. A sample of 119 male-to-female (MF) and 74 female-to-male (FM) transsexuals were included in the study. The WHOQOL-...
Article
Full-text available
Sex differences in cortical thickness (CTh) have been extensively investigated but as yet there are no reports on CTh in transsexuals. Our aim was to determine whether the CTh pattern in transsexuals before hormonal treatment follows their biological sex or their gender identity. We performed brain magnetic resonance imaging on 94 subjects: 24 untr...
Article
Diffusion tensor imaging (DTI) can sensitively detect white matter sex differences and the effects of pharmacological treatments. Before cross-sex hormone treatment, the white matter microstructure of several brain bundles in female-to-male transsexuals (FtMs) differs from those in females but not from that in males. The purpose of this study was t...
Article
Full-text available
The aim of the study is to evaluate the usefulness of the Bem Sex Role Inventory (BSRI; Bem, 1974), an overall measurement of the cultural construct of masculinity and femininity, in the psychological assessment of Spanish transsexuals. Seventy male-to-female transsexuals (MF), 51 female-to-male transsexuals (FM), 77 control men, and 79 control wom...
Article
The aim of the present study was to evaluate the presence of symptoms of current social distress, anxiety and depression in transsexuals. We investigated a group of 187 transsexual patients attending a gender identity unit; 120 had undergone hormonal sex-reassignment (SR) treatment and 67 had not. We used the Social Anxiety and Distress Scale (SADS...
Article
Full-text available
Some gray and white matter regions of the brain are sexually dimorphic. The best MRI technique for identifying subtle differences in white matter is diffusion tensor imaging (DTI). The purpose of this paper is to investigate whether white matter patterns in female to male (FtM) transsexuals before commencing cross-sex hormone treatment are more sim...
Article
Diffusion tensor imaging (DTI) has been shown to be sensitive in detecting white matter differences between sexes. Before cross-sex hormone treatment female to male transsexuals (FtM) differ from females but not from males in several brain fibers. The purpose of this paper is to investigate whether white matter patterns in male to female (MtF) tran...