Effects of cross-sex hormones on cerebral activation during language and mental rotation: An fMRI study in transsexuals

Subjective Experiences of Pregnancy, Delivery, and Nursing in Transgender Men and Non-Binary Individuals: A Qualitative Analysis of Gender and Mental Health Concerns

Studies of how gender-diverse individuals experience pregnancy, childbirth, and nursing remain few, mainly focus on the US and contain scarce information about mental health concerns peri-partum. This hinders informed reproductive health decisions and counseling. We used in-depth interviews to examine how gestational gender-diverse individuals in Sweden experience the process of planning and undergoing pregnancy, delivery, and nursing. In total, 12 participants, identifying on the masculine side of the gender spectrum or as non-binary, who had attended Swedish antenatal care and delivered a live birth, were included in the study. Data were analyzed using qualitative thematic content analysis. The analysis resulted in one overarching theme: sustaining gender congruence during pregnancy and three main categories: (1) considering pregnancy; (2) undergoing pregnancy and childbirth; and (3) postnatal reflections. The association between childbearing and being regarded as female permeated narratives. Participants renegotiated the feminine connotations of pregnancy, accessed gender-affirming treatment, and concealed their pregnancy to safeguard their gender congruence. Mis-gendering and breast enlargement triggered gender dysphoria. Social judgment, loneliness, information shortages, hormonal influence and cessation of testosterone increased gender dysphoria and strained their mental health. Depression exacerbated gender dysphoria and made it harder to claim one's gender identity. Dissociation was used to handle a feminized body, vaginal delivery, and nursing. Pregnancy was easier to envision and handle after masculinizing gender-affirming treatments. The results deepen the understanding of gender dysphoria and may be used to inform reproductive counseling and healthcare development. Research outcomes on mental health concerns provide a basis for further research.

The influence of sex steroid treatment on insular connectivity in gender dysphoria

BACKGROUND

Sex-specific differences in brain connectivity were found in various neuroimaging studies, though little is known about sex steroid effects on insular functioning. Based on well-characterized sex differences in emotion regulation, interoception and higher-level cognition, gender-dysphoric individuals receiving gender-affirming hormone therapy represent an interesting cohort to investigate how sex hormones might influence insular connectivity and related brain functions.

METHODS

To analyze the potential effect of sex steroids on insular connectivity at rest, 11 transgender women, 14 transgender men, 20 cisgender women, and 11 cisgender men were recruited. All participants underwent two magnetic resonance imaging sessions involving resting-state acquisitions separated by a median time period of 4.5 months and also completed the Bermond-Vorst alexithymia questionnaire at the initial and final examination. Between scans, transgender subjects received gender-affirming hormone therapy.

RESULTS

A seed based functional connectivity analysis revealed a significant 2-way interaction effect of group-by-time between right insula, cingulum, left middle frontal gyrus and left angular gyrus. Post-hoc tests demonstrated an increase in connectivity for transgender women when compared to cisgender men. Furthermore, spectral dynamic causal modelling showed reduced effective connectivity from the posterior cingulum and left angular gyrus to the left middle frontal gyrus as well as from the right insula to the left middle frontal gyrus. Alexithymia changes were found after gender-affirming hormone therapy for transgender women in both fantasizing and identifying.

CONCLUSION

These findings suggest a considerable influence of estrogen administration and androgen suppression on brain networks implicated in interoception, own-body perception and higher-level cognition.

Gender-affirming hormonal treatment changes neural processing of emotions in trans men: An fMRI study

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 passively viewing emotional faces (happy, angry, surprised faces) at two timepoints (T0 and T1). At T0 all participants were hormone-naïve, while TM immediately commenced testosterone supplementation at T0. The second scanning session (T1) occurred after 6-10 months of GAHT in TM. All 3 groups completed both T0 and T1 RESULTS: GAHT in TM shifted the neural profile whilst processing emotions from a sex-assigned at birth pattern at T0 (similar to CW) to a consistent with gender identity pattern at T1 (similar to CM). Overall, the brain patterns stayed the same for the cis people at T0 and T1.

CONCLUSIONS

These findings document the impact of hormone treatment, and testosterone supplementation specifically, on emotion perception in TM.

A new angle on mental rotation ability in transgender men: Modulation by ovarian milieu

Organizational/activational theory posits that transgender individuals should perform in the direction of their gender, not their sex, on cognitive tasks that show sex differences-the largest of which are observed on visuospatial tasks. Yet, tests of this hypothesis have been mixed for transgender men (TM). One possible reason is that performance shifts associated with the hormonal milieu at testing have not been fully considered in TM. Although "activating" influences, like gender-affirming hormone therapy (GAHT), are well-characterized in this population, endogenous ones, like ovarian cycling, have gone unaddressed. To provide a more complete picture of hormonal activation, we explored an influence of ovarian milieu on visuospatial performance of TM, and its potential contributions toward effects of sex and GAHT. We administered two male-favoring mental rotation tests (MRTs), and a sex-neutral control task to 22 TM naïve to GAHT (TM-), 29 TM receiving GAHT (TM+), and cisgender men (CM; n = 24) and women (CW; n = 43), testing cycling men (TM-) and women (CW) in either early follicular phase (Follicular) or midluteal phase (Luteal). On MRTs, performance of TM- varied across the menstrual cycle, and matched that of menstrual phase-matched CW. Additionally, cycling individuals in Follicular performed as strongly as TM+ and CM, all of whom performed above individuals in Luteal. Effects did not extend to a verbal control task, on which TM+ performed below others. Rather than conforming to static categories that suggest sex- or gender-typical organization of cognitive circuits, our findings support dynamic shifts in visuospatial ability of TM, and illustrate the need to consider activating effects of hormones beyond GAHT.

Effects of testosterone administration on fMRI responses to executive function, aggressive behavior, and emotion processing tasks during severe exercise- and diet-induced energy deficit

BACKGROUND

Clinical administration of testosterone is widely used due to a variety of claimed physical and cognitive benefits. Testosterone administration is associated with enhanced brain and cognitive function, as well as mood, in energy-balanced males, although such relationships are controversial. However, the effects of testosterone administration on the brains of energy-deficient males, whose testosterone concentrations are likely to be well below normal, have not been investigated.

METHODS

This study collected functional magnetic resonance imaging (fMRI) data from 50 non-obese young men before (PRE) and shortly after (POST) 28 days of severe exercise-and-diet-induced energy deficit during which testosterone (200 mg testosterone enanthate per week in sesame oil, TEST) or placebo (sesame seed oil only, PLA) were administered. Scans were also collected after a post-energy-deficit weight regain period (REC). Participants completed five fMRI tasks that assessed aspects of: 1) executive function (Attention Network Task or ANT; Multi-Source Interference Task or MSIT; AXE Continuous Processing Task or AXCPT); 2) aggressive behavior (Provoked Aggression Task or AGG); and 3) latent emotion processing (Emotional Face Processing or EMO).

RESULTS

Changes over time in task-related fMRI activation in a priori defined task-critical brain regions during performance of 2 out of 5 tasks were significantly different between TEST and PLA, with TEST showing greater levels of activation during ANT in the right anterior cingulate gyrus at POST and during MSIT in several brain regions at REC. Changes over time in objective task performance were not statistically significant; testosterone-treated volunteers had greater self-reported anger during AGG at POST.

CONCLUSIONS

Testosterone administration can alter some aspects of brain function during severe energy deficit and increase levels of anger.

Neuroimaging gender dysphoria: a novel psychobiological model

Gender identity development is complex and involves several key processes. Transgender people experience incongruence between their biological and identified gender. This incongruence can cause significant impairment in overall functioning and lead to gender dysphoria (GD). The pathophysiology of GD is complex and is poorly understood. A PubMed search based on predetermined eligibility criteria was conducted to review neuropsychiatric articles focused on neurological, biological and neuroimaging aspects of gender development, transgender identity and GD. The information obtained from the literature was then used to formulize a GD model. Distinct gray matter volume and brain activation and connectivity differences were found in individuals with GD compared to controls, suggesting a neurobiological basis of GD; which leads to the concept of brain gender. Individuals with GD encounter a recurrent conflict between their brain gender and the societal feedback; which causes recurrent and ongoing cognitive dissonance, finally leading to GD and functional connectivity and activation changes in the transgender brain. GD has neurobiological basis, but it is closely associated with the individuals' interaction with the external world, their self-perception and the feedback received in return. We propose a novel model where the development of GD includes cognitive dissonance, involving anterior cingulate cortex and ventral striatum as the key brain structures. This model can be used to generate testable hypotheses using behavioral and neuroimaging techniques to understand the neuropsychobiology of GD.

Sex difference or hormonal difference in mental rotation? The influence of ovarian milieu

Sex differences in visuospatial cognition have long been reported, with men being advantaged on the Mental Rotations Test (MRT). The data, however, are variable, and sensitive to design parameters. When men and women are compared directly, with women in different hormonal milieus combined, there seem to be sex differences. When women alone are studied, taking into account different ovarian steroid concentrations and treatments, MRT performance varies with these changes. Indeed, several reports describe better performance among women with reduced estrogens. To better understand whether the sex difference in MRT persists once hormonal status is considered, we recruited reproductive age adults designated male and female at birth (MAB, FAB), and administered the Vandenberg-Kuse (V/K) MRT-comparing performance among MAB (n = 169) and FAB (n = 219). For FAB combined, we found a sex difference with MAB performing better than FAB. However, when FAB were analyzed by current menstrual cycle phase (Early Follicular (EF), Periovulatory (PO), Midluteal (ML)) or by hormone therapy (transmasculine testosterone administration (TM+), oral contraceptive (OC) ingestion prior to (OC+) or after cognitive testing (OC-)), low-estradiol groups (EF, OC-, TM+) performed as strongly as MAB, and had better MRT than cycling FAB in high-estradiol menstrual cycle phases (PO, ML). On a verbal memory control task, neither a sex difference nor a low estrogen advantage was detected, although performance varied with hormonal milieu. Our findings support a dynamic model of spatial performance and suggest that both MAB and FAB perform strongly on MRT, contingent on hormonal status.

Gender-affirming hormone treatment - A unique approach to study the effects of sex hormones on brain structure and function

Investigating the effects of the gender-affirming hormone treatment of transgender people using neuroimaging provides a unique opportunity to study the impact of high dosages of sex hormones on human brain structure and function. This line of research is of relevance from a basic neuroscientific as well as from a psychiatric viewpoint. Prevalence rates, etiopathology, and disease course of many psychiatric disorders exhibit sex differences which are linked to differences in sex hormone levels. Here, we review recent neuroimaging studies from others and our group that investigate the effects of gender-affirming hormone treatment in a longitudinal design utilizing structural and functional magnetic resonance imaging and positron emission tomography. Studies point to a general anabolic and anticatabolic effect of testosterone on grey and white matter structure, whereas estradiol and antiandrogen treatment seems to have partly opposite effects. Moreover, preliminary research indicates that gender-affirming hormone treatment influences serotonergic neurotransmission, a finding that is especially interesting for psychiatry. A clear picture of a hormonal influence on brain activity has yet to emerge. In conclusion, the available evidence reviewed here clearly indicates that sex hormone applications influence brain structure and function in the adult human brain.

Testosterone effects on functional amygdala lateralization: A study in adolescent transgender boys and cisgender boys and girls

The influence of testosterone on the development of human brain lateralization has been subject of debate for a long time, partly because studies investigating this are necessarily mostly correlational. In the present study we used a quasi-experimental approach by assessing functional brain lateralization in trans boys (female sex assigned at birth, diagnosed with Gender Dysphoria, n = 21) before and after testosterone treatment, and compared these results to the functional lateralization of age-matched control groups of cisgender boys (n = 20) and girls (n = 21) around 16 years of age. The lateralization index of the amygdala was determined with functional magnetic resonance imaging (fMRI) during an emotional face matching task with angry and fearful faces, as the literature indicates that boys show more activation in the right amygdala than girls during the perception of emotional faces. As expected, the lateralization index in trans boys shifted towards the right amygdala after testosterone treatment, and the cumulative dose of testosterone treatment correlated significantly with amygdala lateralization after treatment. However, we did not find any significant group differences in lateralization and endogenous testosterone concentrations predicted rightward amygdala lateralization only in the cis boys, but not in cis girls or trans boys. These inconsistencies may be due to sex differences in sensitivity to testosterone or its metabolites, which would be a worthwhile course for future studies.

Sex differences in early communication development: behavioral and neurobiological indicators of more vulnerable communication system development in boys

Perhaps due to different roles they have had in social groups during evolution, men and women differ in their verbal abilities. These differences are also (if not even more) present in children, both in the course of typical and pathological development. Beside the fact that girls have a well-documented advantage in early language development, almost all developmental disorders primarily affecting communication, speech, and language skills are more frequent in boys. The sex-related difference in the prevalence of these disorders is especially pronounced in autism spectrum disorder (1 girl for each 4-5 boys is affected). The aim of this review is to present the sex differences in typical communication and language development and in the prevalence of communication-related neurodevelopmental disorders. Also, a special focus is put on data from the field of neuroscience that might provide insight into the neurobiological mechanisms that can add to the understanding of this phenomenon. We argue that the functional organization of the female brain gives women an inherent advantage in the acquisition of communication and language system over men.

The effect of testosterone therapy on personality traits of trans men: a controlled prospective study in Germany and Switzerland

Gender dysphoria in transgender men is generally treated with exogenous testosterone administration aiming to suppress secondary female sex characteristics and achieve masculinization. However, the effect of testosterone on the personality of transgender men remains largely unknown. Therefore, we conducted a controlled study with 23 trans men (M = 27.2 years, Range = 18-51 years), recruited from internet-groups, medical and psychiatric services in Switzerland and Germany versus 27 cisgender women matched by age as control group. Data were collected prior to hormone therapy (HT), three and six months after the first treatment. Non-pathological personality traits (Big Five) were measured with the revised NEO-Personality-Inventory (NEO-PI-R). The greatest changes in the Big Five and its subdimensions occurred within the first three months. Interaction effects showed a significant decrease in the dimension Neuroticism (p < 0.01) - with the most relevant decline in its facet Depression - conversely, Extraversion (p < 0.001) increased, in particular, within its facets of Assertiveness (p < 0.01) and Warmth (p < 0.01). Expectedly, personality traits were stable in the control group. An overall decrease in interpersonal stress-related traits and a substantial increase in enhanced social-interaction traits and personal well-being occurred. These results enable medical services to ensure that informed-consent prior to HT is evidence-based with respect to potential changes in personality and may reduce concerns of trans men and their significant others regarding increased aggressiveness.

What has sex got to do with it? The role of hormones in the transgender brain

Sex differences and hormonal effects in presumed cisgender individuals have been well-studied and support the concept of a mosaic of both male and female "characteristics" in any given brain. Gonadal steroid increases and fluctuations during peri-puberty and across the reproductive lifespan influence the brain structure and function programmed by testosterone and estradiol exposures in utero. While it is becoming increasingly common for transgender and gender non-binary individuals to block their transition to puberty and/or use gender-affirming hormone therapy (GAHT) to obtain their desired gender phenotype, little is known about the impact of these manipulations on brain structure and function. Using sex differences and the effects of reproductive hormones in cisgender individuals as the backdrop, we summarize here the existing nascent neuroimaging and behavioral literature focusing on potential brain and cognitive differences in transgender individuals at baseline and after GAHT. Research in this area has the potential to inform our understanding of the developmental origins of gender identity and sex difference in response to gonadal steroid manipulations, but care is needed in our research questions and methods to not further stigmatize sex and gender minorities.

Gender incongruence and the brain - Behavioral and neural correlates of voice gender perception in transgender people

The phenomenon of gender incongruence is hypothesized to arise from a discrepant sexual development of the brain and the genitals, contingent on genetic and hormonal mechanisms. We aimed at visualizing transgender identity on a neurobiological level, assuming a higher functional similarity to individuals of the aspired rather than assigned sex. Implementing a gender perception paradigm featuring male and female voice stimuli, behavioral and functional imaging data of transmen were compared to men and women, and to transwomen, respectively. Men had decreased activation in response to voices of the other sex in regions across the frontoparietal and insular cortex, while the activation patterns of women and transmen were characterized by little or no differentiation between male and female voices. Further, transmen had a comparatively high discrimination performance for ambiguous male voices, possibly reflecting a high sensitivity for voices of the aspired sex. Comparing transmen and transwomen yielded only few differences in the processing of male compared to female voices. In the insula, we observed a pattern similar to that of men and women, the neural responses of the transgender group being in accordance with their gender identity rather than assigned sex. Notwithstanding the similarities found dependent on biological sex, the findings support the hypothesis of gender incongruence being a condition in which neural processing modes are partly incongruent with one's assigned sex.

Cognitive Impacts of Estrogen Treatment in Androgen-Deprived Males: What Needs to be Resolved

Background:

Many prostate cancer (PCa) patients are on androgen deprivation therapy (ADT) as part of their cancer treatments but ADT may lead to cognitive impairments. ADT depletes men of both androgen and estrogen. Whether estradiol supplementation can improve cognitive impairments in patients on ADT is understudied.

Objective:

To summarize data on the effects of estradiol treatment on cognitive function of androgen-deprived genetic male populations (PCa patients and male-to-female transsexuals) and castrated male animals.

Method:

Publications were identified by a literature search on PubMed and Google Scholar.

Results:

While some studies showed that estradiol improves cognitive function (most notably, spatial ability) for castrated rats, what remains uninvestigated are: 1) whether estradiol can improve cognition after long-term androgen deprivation, 2) how estradiol affects memory retention, and 3) how early vs. delayed estradiol treatment after castration influences cognition. For androgen-deprived genetic males, estradiol treatment may improve some cognitive functions (e.g., verbal and visual memory), but the findings are not consistent due to large variability in the study design between studies.

Conclusion:

Future studies are required to determine the best estradiol treatment protocol to maximize cognitive benefits for androgen-deprived genetic males. Tests that assess comparable cognitive domains in human and rodents are needed. What particularly under-investigated is how the effects of estradiol on cognitive ability intersect with other parameters; sleep, depression and physical fatigue. Such studies have clinical implications to improve the quality of life for both PCa patients on ADT as well as for male-to-female transsexuals.

Male-to-female gender dysphoria: Gender-specific differences in resting-state networks

INTRODUCTION

Recent research found gender-related differences in resting-state functional connectivity (rs-FC) measured by functional magnetic resonance imaging (fMRI). To the best of our knowledge, there are no studies examining the differences in rs-FC between men, women, and individuals who report a discrepancy between their anatomical sex and their gender identity, i.e. gender dysphoria (GD).

METHODS

To address this important issue, we present the first fMRI study systematically investigating the differences in typical resting-state networks (RSNs) and hormonal treatment effects in 26 male-to-female GD individuals (MtFs) compared with 19 men and 20 women.

RESULTS

Differences between male and female control groups were found only in the auditory RSN, whereas differences between both control groups and MtFs were found in the auditory and fronto-parietal RSNs, including both primary sensory areas (e.g. calcarine gyrus) and higher order cognitive areas such as the middle and posterior cingulate and dorsomedial prefrontal cortex. Overall, differences in MtFs compared with men and women were more pronounced before cross-sex hormonal treatment. Interestingly, rs-FC between MtFs and women did not differ significantly after treatment. When comparing hormonally untreated and treated MtFs, we found differences in connectivity of the calcarine gyrus and thalamus in the context of the auditory network, as well as the inferior frontal gyrus in context of the fronto-parietal network.

CONCLUSION

Our results provide first evidence that MtFs exhibit patterns of rs-FC which are different from both their assigned and their aspired gender, indicating an intermediate position between the two sexes. We suggest that the present study constitutes a starting point for future research designed to clarify whether the brains of individuals with GD are more similar to their assigned or their aspired gender.

Male-typical visuospatial functioning in gynephilic girls with gender dysphoria - organizational and activational effects of testosterone

BACKGROUND

Sex differences in performance and regional brain activity during mental rotation have been reported repeatedly and reflect organizational and activational effects of sex hormones. We investigated whether adolescent girls with gender dysphoria (GD), before and after 10 months of testosterone treatment, showed male-typical brain activity during a mental rotation task (MRT).

METHODS

Girls with GD underwent fMRI while performing the MRT twice: when receiving medication to suppress their endogenous sex hormones before onset of testosterone treatment, and 10 months later during testosterone treatment. Two age-matched control groups participated twice as well.

RESULTS

We included 21 girls with GD, 20 male controls and 21 female controls in our study. In the absence of any group differences in performance, control girls showed significantly increased activation in frontal brain areas compared with control boys (p_FWE = 0.012). Girls with GD before testosterone treatment differed significantly in frontal brain activation from the control girls (p_FWE = 0.034), suggesting a masculinization of brain structures associated with visuospatial cognitive functions. After 10 months of testosterone treatment, girls with GD, similar to the control boys, showed increases in brain activation in areas implicated in mental rotation.

LIMITATIONS

Since all girls with GD identified as gynephilic, their resemblance in spatial cognition with the control boys, who were also gynephilic, may have been related to their shared sexual orientation rather than their shared gender identity. We did not account for menstrual cycle phase or contraceptive use in our analyses.

CONCLUSION

Our findings suggest atypical sexual differentiation of the brain in natal girls with GD and provide new evidence for organizational and activational effects of testosterone on visuospatial cognitive functioning.

A Review of the Status of Brain Structure Research in Transsexualism

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, and demasculinized regions, while FtMs show feminine, masculine, and defeminized regions. Consequently, the specific brain phenotypes proposed for MtFs and FtMs differ from those of both heterosexual males and females. These phenotypes have theoretical implications for brain intersexuality, asymmetry, and body perception in transsexuals as well as for Blanchard's hypothesis on sexual orientation in homosexual MtFs. Falling within the aegis of the neurohormonal theory of sex differences, we hypothesize that cortical differences between homosexual MtFs and FtMs and male and female controls are due to differently timed cortical thinning in different regions for each group. Cross-sex hormone studies have reported marked effects of the treatment on MtF and FtM brains. Their results are used to discuss the early postmortem histological studies of the MtF brain.

Adult development and quality of life of transgender and gender nonconforming people

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 future research.

RECENT FINDINGS

Pervasive stigma and discrimination attached to gender nonconformity affect the health of transgender people across the lifespan, particularly when it comes to mental health and well-being. Despite the related challenges, transgender and gender nonconforming people may develop resilience over time. Social support and affirmation of gender identity play herein a critical role. Although there is a growing awareness of diversity in gender identity and expression among this population, a comprehensive understanding of biopsychosocial development beyond the gender binary and beyond transition is lacking.

SUMMARY

Greater visibility of transgender people in society has revealed the need to understand and promote their health and quality of life broadly, including but not limited to gender dysphoria and HIV. This means addressing their needs in context of their families and communities, sexual and reproductive health, and successful aging. Research is needed to better understand what factors are associated with resilience and how it can be effectively promoted.

Serum brain-derived neurotrophic factor (BDNF) is not regulated by testosterone in transmen

Brain morphology significantly differs between the sexes. It has been shown before that some of these differences are attributable to the sex-specific hormonal milieu. Brain-derived neurotrophic factor (BDNF) is involved in myriads of neuroplastic processes and shows a sexual dimorphism. Transsexual persons may serve as a model to study sex steroid-mediated effects on brain plasticity. We have recently demonstrated that serum levels of BDNF are reduced in transwomen following 12 months of cross-sex hormone treatment. We now wanted to look at the effects of testosterone treatment on BDNF in transmen. In contrast to our initial hypothesis, BDNF levels did not significantly change, despite dramatic changes in the sex-hormonal milieu. Our data indicate that testosterone does not seem to play a major role in the regulation of BDNF in females.

Emotional and cognitive functional imaging of estrogen and progesterone effects in the female human brain: a systematic review

Ovarian hormones are pivotal for the physiological maintenance of the brain function as well as its response to environmental stimuli. There is mounting evidence attesting the relevance of endogenous ovarian hormones as well as exogenous estradiol and progesterone for emotional and cognitive processing. The present review systematically summarized current knowledge on sex steroid hormonal modulation of neural substrates of emotion and cognition revealed by functional magnetic resonance imaging (fMRI). Twenty-four studies of healthy naturally cycling and combined oral contraceptives (COC) user women, or women undergoing experimental manipulations, during their reproductive age, were included. Furthermore, six studies of premenstrual dysphoric disorder (PMDD), a hormonally based mood disorder, and three of gender dysphoria (GD), which provides an intriguing opportunity to examine the effect of high-dose cross-sex hormone therapy (CSHT) on brain functioning, were included. Globally, low (early follicular and the entire follicular phase for estrogen and progesterone, respectively) and high (COC, CSHT, late follicular and luteal phase for estrogen; COC, mid- and late-luteal phase for progesterone) hormonal milieu diversely affected the response of several brain regions including the amygdala, anterior cingulate cortex, and inferior frontal gyrus, but their functional recruitment across groups and domains was scattered. The constellation of findings provides initial evidence of the influence of sex steroid hormones on cortical and subcortical regions implicated in emotional and cognitive processing. Further well-powered and multimodal neuroimaging studies will be needed to identify the neural mechanism of functional brain alterations induced by sex steroid hormones.

More than just two sexes: the neural correlates of voice gender perception in gender dysphoria

Gender dysphoria (also known as “transsexualism”) is characterized as a discrepancy between anatomical sex and gender identity. Research points towards neurobiological influences. Due to the sexually dimorphic characteristics of the human voice, voice gender perception provides a biologically relevant function, e.g. in the context of mating selection. There is evidence for a better recognition of voices of the opposite sex and a differentiation of the sexes in its underlying functional cerebral correlates, namely the prefrontal and middle temporal areas. This fMRI study investigated the neural correlates of voice gender perception in 32 male-to-female gender dysphoric individuals (MtFs) compared to 20 non-gender dysphoric men and 19 non-gender dysphoric women. Participants indicated the sex of 240 voice stimuli modified in semitone steps in the direction to the other gender. Compared to men and women, MtFs showed differences in a neural network including the medial prefrontal gyrus, the insula, and the precuneus when responding to male vs. female voices. With increased voice morphing men recruited more prefrontal areas compared to women and MtFs, while MtFs revealed a pattern more similar to women. On a behavioral and neuronal level, our results support the feeling of MtFs reporting they cannot identify with their assigned sex.

Brain signature characterizing the body-brain-mind axis of transsexuals

Individuals with gender identity disorder (GID), who are commonly referred to as transsexuals (TXs), are afflicted by negative psychosocial stressors. Central to the psychological complex of TXs is the conviction of belonging to the opposite sex. Neuroanatomical and functional brain imaging studies have demonstrated that the GID is associated with brain alterations. In this study, we found that TXs identify, when viewing male-female couples in erotic or non-erotic (“neutral”) interactions, with the couple member of the desired gender in both situations. By means of functional magnetic resonance imaging, we found that the TXs, as opposed to controls (CONs), displayed an increased functional connectivity between the ventral tegmental area, which is associated with dimorphic genital representation, and anterior cingulate cortex subregions, which play a key role in social exclusion, conflict monitoring and punishment adjustment. The neural connectivity pattern suggests a brain signature of the psychosocial distress for the gender-sex incongruity of TXs.

Testosterone in the brain: neuroimaging findings and the potential role for neuropsychopharmacology

Testosterone plays a substantial role in a number of physiological processes in the brain. It is able to modulate the expression of certain genes by binding to androgen receptors. Acting via neurotransmitter receptors, testosterone shows the potential to mediate a non-genomic so-called "neuroactive effect". Various neurotransmitter systems are also influenced by the aromatized form of testosterone, estradiol. The following article summarizes the findings of preclinical and clinical neuroimaging studies including structural and functional magnetic resonance imaging (MRI/fMRI), voxel based morphometry (VBM), as well as pharmacological fMRI (phfMRI) and positron emission tomography (PET) regarding the effects of testosterone on the human brain. The impact of testosterone on the pathogenesis of psychiatric disorders and on sex-related prevalence differences have been supported by a wide range of clinical studies. An antidepressant effect of testosterone can be implicitly explained by its effects on the limbic system--especially amygdala, a major target in the treatment of depression--solidly demonstrated by a large body of neuroimaging findings.

Effects of androgenization on the white matter microstructure of female-to-male transsexuals. A diffusion tensor imaging study

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 to investigate whether cross-sex hormone treatment (androgenization) affects the brain white matter microstructure. Using a Siemens 3 T Trio Tim Magneton, DTI was performed twice, before and during cross-sex hormonal treatment with testosterone in 15 FtMs scanned. Fractional anisotropy (FA) was analyzed on white matter of the whole brain, and the latter was spatially analyzed using Tract-Based Spatial Statistics. Before each scan the subjects were assessed for serum testosterone, sex hormone binding globulin level (SHBG), and their free testosterone index. After at least seven months of cross-gender hormonal treatment, FA values increased in the right superior longitudinal fasciculus (SLF) and the right corticospinal tract (CST) in FtMs compared to their pre-treatment values. Hierarchical regression analyses showed that the increments in the FA values in the SLF and CST are predicted by the free testosterone index before hormonal treatment. All these observations suggest that testosterone treatment changes white matter microstructure in FtMs.

The microstructure of white matter in male to female transsexuals before cross-sex hormonal treatment. A DTI study

BACKGROUND

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) transsexuals before commencing cross-sex hormone treatment are also more similar to those of their biological sex or whether they are more similar to those of their gender identity.

METHOD

DTI was performed in 18 MtF transsexuals and 19 male and 19 female controls scanned with a 3 T Trio Tim Magneton. Fractional anisotropy (FA) was performed on white matter of the whole brain, which was spatially analyzed using Tract-Based Spatial Statistics.

RESULTS

MtF transsexuals differed from both male and female controls bilaterally in the superior longitudinal fasciculus, the right anterior cingulum, the right forceps minor, and the right corticospinal tract.

CONCLUSIONS

Our results show that the white matter microstructure pattern in untreated MtF transsexuals falls halfway between the pattern of male and female controls. The nature of these differences suggests that some fasciculi do not complete the masculinization process in MtF transsexuals during brain development.

White matter microstructure in female to male transsexuals before cross-sex hormonal treatment. A diffusion tensor imaging study

BACKGROUND

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 similar to that of their biological sex or to that of their gender identity.

METHOD

DTI was performed in 18 FtM transsexuals and 24 male and 19 female heterosexual controls scanned with a 3 T Trio Tim Magneton. Fractional anisotropy (FA) was performed on white matter fibers of the whole brain, which was spatially analyzed using Tract-Based Spatial Statistics.

RESULTS

In controls, males have significantly higher FA values than females in the medial and posterior parts of the right superior longitudinal fasciculus (SLF), the forceps minor, and the corticospinal tract. Compared to control females, FtM showed higher FA values in posterior part of the right SLF, the forceps minor and corticospinal tract. Compared to control males, FtM showed only lower FA values in the corticospinal tract.

CONCLUSIONS

Our results show that the white matter microstructure pattern in untreated FtM transsexuals is closer to the pattern of subjects who share their gender identity (males) than those who share their biological sex (females). Our results provide evidence for an inherent difference in the brain structure of FtM transsexuals.

Cortical activation during mental rotation in male-to-female and female-to-male transsexuals under hormonal treatment

There is strong evidence of sex differences in mental rotation tasks. Transsexualism is an extreme gender identity disorder in which individuals seek cross-gender treatment to change their sex. The aim of our study was to investigate if male-to-female (MF) and female-to-male (FM) transsexuals receiving cross-sex hormonal treatment have different patterns of cortical activation during a three-dimensional (3D) mental rotation task. An fMRI study was performed using a 3-T scan in a sample of 18 MF and 19 FM under chronic cross-sex hormonal treatment. Twenty-three males and 19 females served as controls. The general pattern of cerebral activation seen while visualizing the rotated and non-rotated figures was similar for all four groups showing strong occipito-parieto-frontal brain activation. However, compared to control males, the activation of MF transsexuals during the task was lower in the superior parietal lobe. Compared to control females, MF transsexuals showed higher activation in orbital and right dorsolateral prefrontal regions and lower activation in the left prefrontal gyrus. FM transsexuals did not differ from either the MF transsexual or control groups. Regression analyses between cerebral activation and the number of months of hormonal treatment showed a significant negative correlation in parietal, occipital and temporal regions in the MF transsexuals. No significant correlations with time were seen in the FM transsexuals. In conclusion, although we did not find a specific pattern of cerebral activation in the FM transsexuals, we have identified a specific pattern of cerebral activation during a mental 3D rotation task in MF transsexuals under cross-sex hormonal treatment that differed from control males in the parietal region and from control females in the orbital prefrontal region. The hypoactivation in MF transsexuals in the parietal region could be due to the hormonal treatment or could reflect a priori cerebral differences between MF transsexual and control subjects.

Sex-based differences in answering strategy and the influence of cross-sex hormones

We investigated whether sex differences in answering strategy occur in normal controls (C). Furthermore, it was tested whether these sex differences were subject to change over time, and whether they were associated with hormonal treatment at time points 2 and 3 in patients with Gender Identity Disorder (GID). Two subtests measuring arithmetic ability were used: arithmetic aptitude (AA) and arithmetic operations (AO). Both the controls (n = 29) and GID patients (n = 33) were tested at baseline (T1), three months (T2) and 12 months (T3) after the start of hormonal treatment in the GID group. A repeated measures analysis of variance showed no differences between C males and females, for T1 and T2. At T3, C males guessed more than C females. At baseline, GID males and C males left an equal number of items unanswered. However, when being retested, C males left fewer items unanswered than GID males. No difference was found between C females and GID females at any time point. Our results suggest that healthy adult males become more confident when they are retested, and seem to adjust their answering strategy accordingly. Moreover, hormonal treatment of healthy adult GID patients born male is associated with a lack of adjustment in answering strategy.

Changes in neuronal activation patterns in response to androgen deprivation therapy: a pilot study

BACKGROUND

A common treatment option for men with prostate cancer is androgen deprivation therapy (ADT). However, men undergoing ADT may experience physical side effects, changes in quality of life and sometimes psychiatric and cognitive side effects.

METHODS

In this study, hormone naïve patients without evidence of metastases with a rising PSA were treated with nine months of ADT. Functional magnetic resonance imaging (fMRI) of the brain during three visuospatial tasks was performed at baseline prior to treatment and after nine months of ADT in five subjects. Seven healthy control patients, underwent neuroimaging at the same time intervals.

RESULTS

ADT patients showed reduced, task-related BOLD-fMRI activation during treatment that was not observed in control subjects. Reduction in activation in right parietal-occipital regions from baseline was observed during recall of the spatial location of objects and mental rotation.

CONCLUSIONS

Findings, while preliminary, suggest that ADT reduces task-related neural activation in brain regions that are involved in mental rotation and accurate recall of spatial information.

Passing through the wall: on outings, exodus, angels, and the ark

Classicists have argued that angels in Christian theology were modeled on the eunuchs of antiquity; with angels providing the same services to the Lord in Heaven that eunuchs provided to emperors on Earth. I apply this idea toward understanding the cherubim on the ark in Exodus 25 and the death of Aaron's sons in Leviticus 10. I also suggest that the angel-eunuch analogy can help us understand the psychological impact of androgen deprivation therapy on modern prostate cancer patients. Appreciating this analogy can help prostate cancer patients accept and adapt to the changes they experience.

Cognitive mechanisms underlying disorganization of thought in a genetic syndrome (47,XXY)

Because of the risk for development of psychopathology such as psychotic symptoms, it has been suggested that studying men with the XXY karyotype may help in the search for underlying cognitive, neural and genetic mechanisms. The aim of this study was to identify cognitive mechanisms that may contribute to disorganization of thought in XXY men. A group of 24 XXY men and two non-clinical control groups (N=20, N=18) participated in the study. The level of disorganization of thought was measured using the Schizotypal Personality Questionnaire. We assessed IQ, lateralization of verbal information processing and executive functions including inhibition and mental flexibility. XXY men with high levels of disorganization showed more severe impairments in mental flexibility and inhibition as compared to non-clinical controls and other XXY men. This subgroup also showed a stronger reduction in lateralization of verbal information processing. IQ measures did not differentiate XXY men with high versus low levels of disorganization. These findings indicate that executive impairments in the domains of inhibition and mental flexibility might play a role in the increased vulnerability for disorganized thought in the XXY group. Reduced lateralization of verbal information processing points to non-optimal cerebral specialization in the XXY group, especially in XXY men with high levels of disorganization. This fits with deficits in brain functions most vulnerable to such maturational disruptions, i.e. executive dysfunctions. Our findings are in line with those reported for schizophrenia patients with thought disorder. We speculate that the underlying mechanisms of thought disorder probably are deficit specific rather than disorder specific.

Cognitive and mood changes in men undergoing intermittent combined androgen blockade for non-metastatic prostate cancer

PURPOSE

Men with prostate-specific antigen (PSA)-only relapse of prostate cancer after primary therapy are generally fully functional and asymptomatic with a life expectancy of up to 10 or more years. Androgen deprivation therapy (ADT) is a common treatment option. This study examined mood and cognitive changes in otherwise healthy men with prostate cancer prior to, during and after ADT.

EXPERIMENTAL DESIGN

Twenty hormone naïve, eugonadal prostate cancer patients without evidence of metastases and with a rising PSA were treated with intermittent ADT consisting of 9 months of complete androgen blockade (CAB) achieved with combined leuprolide and flutamide followed by an 'off treatment' period. Cognitive function tests and mood measures were administered at baseline, after 3 and 9 months of ADT and after 3 months of no treatment. Twenty healthy control patients without prostate cancer range matched for age and education were tested at the same time intervals.

RESULTS

ADT patients evidenced a significant decline in spatial reasoning, spatial abilities and working memory during treatment compared with baseline. No changes were noted for measures of verbal or spatial memory, selective attention or language. Significant changes in self-rated mood such as increased depression, tension, anxiety, fatigue and irritability were evident during treatment compared with baseline for ADT patients. No significant changes in either cognitive tests or mood measures were noted for the healthy control group.

CONCLUSIONS

These findings, suggest that 9 months of combined androgen blockade may result in some adverse changes in cognition and mood. However, many but not all of these changes can return to baseline after cessation of ADT.

Effects of an extra X chromosome on language lateralization: an fMRI study with Klinefelter men (47,XXY)

De novo occurring genetic variations provide an opportunity to study the effects of genes on structure and function of the brain. The presence of an extra X chromosome in men (XXY karyotype) has been associated with language deficits. Recently, schizophrenia spectrum traits have been observed in XXY men, which is of interest as language deficits are prominent in schizophrenia. One possible neural mechanism underlying these deficits is reduced hemispheric specialization for language. However, there has been no study of brain activity patterns during language processing in XXY men. Also, it remains unclear whether reduced language lateralization may be related to mental functioning in these men. We used functional Magnetic Resonance Imaging (fMRI) to study language lateralization in 15 XXY men as compared to 14 control men. We used a psychiatric interview and a schizotypy questionnaire to explore the relation between language lateralization and mental functioning in these men, with special interest in disorganization of thought and language. Compared to controls, the XXY group showed reduced hemispheric specialization for language, which was due to decreased functional asymmetry in the superior temporal gyrus (STG) and the supramarginal gyrus (part of Wernicke's area). Reduced lateralization in the STG correlated significantly with disorganization traits. These findings suggest the X chromosome may be involved in hemispheric specialization for language. Moreover, reduced hemispheric specialization for language processing in the superior temporal gyrus may have important consequences for mental functioning, as it was associated with disorganization of thought and language as seen in the schizophrenia spectrum.