Smaller total and subregional cerebellar volumes in posttraumatic stress disorder: a mega-analysis by the ENIGMA-PGC PTSD workgroup.

Although the cerebellum contributes to higher-order cognitive and emotional functions relevant to posttraumatic stress disorder (PTSD), prior research on cerebellar volume in PTSD is scant, particularly when considering subregions that differentially map on to motor, cognitive, and affective functions. In a sample of 4215 adults (PTSD n = 1642; Control n = 2573) across 40 sites from the ENIGMA-PGC PTSD working group, we employed a new state-of-the-art deep-learning based approach for automatic cerebellar parcellation to obtain volumetric estimates for the total cerebellum and 28 subregions. Linear mixed effects models controlling for age, gender, intracranial volume, and site were used to compare cerebellum volumes in PTSD compared to healthy controls (88% trauma-exposed). PTSD was associated with significant grey and white matter reductions of the cerebellum. Compared to controls, people with PTSD demonstrated smaller total cerebellum volume, as well as reduced volume in subregions primarily within the posterior lobe (lobule VIIB, crus II), vermis (VI, VIII), flocculonodular lobe (lobule X), and corpus medullare (all p-FDR < 0.05). Effects of PTSD on volume were consistent, and generally more robust, when examining symptom severity rather than diagnostic status. These findings implicate regionally specific cerebellar volumetric differences in the pathophysiology of PTSD. The cerebellum appears to play an important role in higher-order cognitive and emotional processes, far beyond its historical association with vestibulomotor function. Further examination of the cerebellum in trauma-related psychopathology will help to clarify how cerebellar structure and function may disrupt cognitive and affective processes at the center of translational models for PTSD.

An influence of menopausal symptoms on mental health, emotion perception, and quality of life: a multi-faceted approach.

PURPOSE: The menopausal transition brings with it many physical, cognitive, and affective changes in a woman's life, impacting quality of life. Whereas prior work has examined impact on general mental health and cognitive function, research on basic affective processing during menopause remains scarce. METHODS: Using a median-split procedure, this pre-registered study examined the impact of stronger (N = 46 women) vs. milder (N = 47 women) menopausal symptoms using a behavioural task of subjective emotion perception (embody) and a passive eye tracking viewing task of emotional faces in addition to self-report questionnaires. After 3 months, participants completed the questionnaires again to examine whether objective measures of emotion perception (eye tracking) might predict mental health at follow-up. RESULTS: As anticipated, women with stronger vs. milder menopausal symptoms reported increased symptoms of anxiety, depression, stress, emotion regulation difficulties, and lower quality of life during both time points. While no evidence was found in the behavioural task, eye tracking data indicated blunted emotion perception in women with high menopausal symptoms, while women with low symptoms spent more time looking at happy faces relative to fearful or surprised faces. Although eye tracking or hormonal data did not predict mental health at follow-up, a higher estradiol/FSH ratio indicated a higher quality of life. CONCLUSIONS: This study documented an impact of the menopausal transition and strength of menopausal symptoms in particular on objective emotion perception as well as mental health and quality of life in women suffering from stronger vs. milder menopausal symptoms. Clinical implications are discussed.

Gender minority stress in transgender people: a major role for social network.

BACKGROUND: Gender minority individuals, on average, experience higher rates of mental health problems. Mounting work suggests that gender minority stress (GMS) contributes to mental health outcomes in transgender/gender-nonconforming individuals. AIM: We assessed whether GMS decreased in transgender people after initiating gender-affirming hormone therapy (GAHT), and we identified social predictors and hormonal associations for GMS at 2 time points. METHODS: GMS was surveyed through self-report questionnaires tapping into proximal and distal stressors and coping constructs following the minority stress framework. Eighty-five transgender persons wishing to undertake hormonal interventions were assessed prospectively at start of GAHT and after 7.7 ± 3.5 months (mean ± SD). Sixty-five cisgender persons served as a control group. OUTCOMES: (1) Proximal stressors were surveyed by the Beck Depression Inventory II, State-Trait Anxiety Inventory, Scale for Suicide Ideation, Suicidal Thoughts/Attempts, Stigma Consciousness Questionnaire, and Perceived Stress Scale; (2) distal stressors by the Everyday Discrimination Scale; and (3) coping constructs by the Resilience Scale, social network, social standing, and Marlowe Crowne Social Desirability Scale. RESULTS: Transgender people experienced higher rates of proximal stressors (Beck Depression Inventory II, State-Trait Anxiety Inventory, Scale for Suicide Ideation, Suicidal Thoughts/Attempts, Perceived Stress Scale) and had lower protective factors (social standing) prior to and during GAHT than cisgender people. Social network and resilience were lower in transgender people relative to cisgender peers only at baseline. Prospectively, decreasing trait anxiety was observed in transgender people. Social factors were adequate predictors of multiple GMS constructs. Specifically, a major role for social network emerged. As for hormonal associations, only serum estradiol levels in transgender women with GAHT were negatively associated with trait anxiety and suicidal thoughts/attempts but positively with resilience and social desirability. CLINICAL IMPLICATIONS: Stimulating a social environment supportive of diverse identities, particularly by investing in social networks as a resource for resilience, is likely to alleviate GMS. STRENGTHS AND LIMITATIONS: Longer duration of interventions with sex steroid treatment, with continued resilience-enhancing strategies, is needed to observe further alleviation of GMS in transgender persons. Also, objective and subjective GMS identification with heteronormative attitudes and beliefs should be surveyed for good measure when assessing GMS. CONCLUSION: Transgender people experienced more GMS throughout study visits than cisgender people did. With a relatively short period of GAHT, some significant changes in and predictors for experienced GMS emerged.

Minority Stress and the Effects on Emotion Processing in Transgender Men and Cisgender People: A Study Combining fMRI and 1H-MRS.

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 functional magnetic resonance imaging and magnetic resonance spectroscopy to uncover the effects of anxiety and perceived stress on the neural and neurochemical substrates, specifically choline, on emotion processing in transgender men. Thirty transgender men (TM), 30 cisgender men, and 35 cisgender women passively viewed angry, neutral, happy, and surprised faces in the functional magnetic resonance imaging scanner, underwent a magnetic resonance spectroscopy scan, and filled out mood- and anxiety-related questionnaires. RESULTS: As predicted, choline levels modulated the relationship between anxiety and stress symptoms and the neural response to angry and surprised (but not happy faces) in the amygdala. This was the case only for TM but not cisgender comparisons. More generally, neural responses in the left amygdala, left middle frontal gyrus, and medial frontal gyrus to emotional faces in TM resembled that of cisgender women. CONCLUSIONS: These results provide first evidence, to our knowledge, of a critical interaction between levels of analysis and that choline may influence neural processing of emotion in individuals prone to minority stress.

The Neuroanatomy of Transgender Identity: Mega-Analytic Findings From the ENIGMA Transgender Persons Working Group.

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 discrepant findings. AIM: To examine the neurobiology of transgender persons in a large sample. METHODS: Using a mega-analytic approach, structural MRI data of 803 non-hormonally treated transgender men (TM, n = 214, female assigned at birth with male gender identity), transgender women (TW, n = 172, male assigned at birth with female gender identity), cisgender men (CM, n = 221, male assigned at birth with male gender identity) and cisgender women (CW, n = 196, female assigned at birth with female gender identity) were analyzed. OUTCOMES: Structural brain measures, including grey matter volume, cortical surface area, and cortical thickness. RESULTS: Transgender persons differed significantly from cisgender persons with respect to (sub)cortical brain volumes and surface area, but not cortical thickness. Contrasting the 4 groups (TM, TW, CM, and CW), we observed a variety of patterns that not only depended on the direction of gender identity (towards male or towards female) but also on the brain measure as well as the brain region examined. CLINICAL TRANSLATION: The outcomes of this large-scale study may provide a normative framework that may become useful in clinical studies. STRENGTHS AND LIMITATIONS: While this is the largest study of MRI data in transgender persons to date, the analyses conducted were governed (and restricted) by the type of data collected across all participating sites. CONCLUSION: Rather than being merely shifted towards either end of the male-female spectrum, transgender persons seem to present with their own unique brain phenotype. Mueller SC, Guillamon A, Zubiaurre-Elorza L, et al. The Neuroanatomy of Transgender Identity: Mega-Analytic Findings From the ENIGMA Transgender Persons Working Group. J Sex Med 2021;18:1122-1129.

Working memory and emotional interpretation bias in a sample of Syrian refugee adolescents.

The number of adolescent refugees around the world has been continuously increasing over the past few years trying to escape war and terror, among other things. Such experience not only increases the risk for mental health problems including anxiety, depression, and post-traumatic stress disorder (PTSD), but also may have implications for socio-cognitive development. This study tested cognitive-affective processing in refugee adolescents who had escaped armed conflict in Syria and now resided in Istanbul, Turkey. Adolescents were split into a high trauma (n = 31, 12 girls, mean age = 11.70 years, SD = 1.15 years) and low trauma (n = 27, 14 girls, mean age = 11.07 years, SD = 1.39 years) symptom group using median split, and performed a working memory task with emotional distraction to assess cognitive control and a surprise faces task to assess emotional interpretation bias. The results indicated that high (vs. low) trauma symptom youth were ~ 20% worse correctly remembering the spatial location of a cue, although both groups performed at very low levels. However, this finding was not modulated by emotion. In addition, although all youths also had a ~ 20% bias toward interpreting ambiguous (surprise) faces as more negative, the high (vs. low) symptom youth were faster when allocating such a face to the positive (vs. negative) emotion category. The findings suggest the impact of war-related trauma on cognitive-affective processes essential to healthy development.

Brain network interactions in transgender individuals with gender incongruence.

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 neurodevelopmental cortical hypothesis that suggests the existence of different brain phenotypes based on structural MRI data and genes polymorphisms of sex hormone receptors; (ii) a functional-based hypothesis in relation to regions involved in the own body perception. T2*-weighted images in a 3-T MRI were obtained from 29 transmen and 17 transwomen as well as 22 cisgender women and 19 cisgender men. Resting-state independent component analysis, seed-to-seed functional network and graph theory analyses were performed. Transmen, transwomen, and cisgender women had decreased connectivity compared with cisgender men in superior parietal regions, as part of the salience (SN) and the executive control (ECN) networks. Transmen also had weaker connectivity compared with cisgender men between intra-SN regions and weaker inter-network connectivity between regions of the SN, the default mode network (DMN), the ECN and the sensorimotor network. Transwomen had lower small-worldness, modularity and clustering coefficient than cisgender men. There were no differences among transmen, transwomen, and ciswomen. Together these results underline the importance of the SN interacting with DMN, ECN, and sensorimotor networks in transmen, involving regions of the entire brain with a frontal predominance. Reduced global connectivity graph-theoretical measures were a characteristic of transwomen. It is proposed that the interaction between networks is a keystone in building a gendered self. Finally, our findings suggest that both proposed hypotheses are complementary in explaining brain differences between gender variants.

Neuroanatomy of transgender persons in a Non-Western population and improving reliability in clinical neuroimaging.

Although the neuroanatomy of transgender persons is slowly being charted, findings are presently discrepant. Moreover, the major body of work has focused on Western populations. One important factor is the issue of power and low signal-to-noise (SNR) ratio in neuroimaging studies of rare study populations including endocrine or neurological patient groups. The present study focused on the structural neuroanatomy of a Non-Western (Iranian) sample of 40 transgender men (TM), 40 transgender women (TW), 30 cisgender men (CM), and 30 cisgender women (CW), while assessing whether the reliability of findings across structural anatomical measures including gray matter volume (GMV), cortical surface area (CSA), and cortical thickness (CTh) could be increased by using two back-to-back within-session structural MRI scans. Overall, findings in transgender persons were more consistent with sex assigned at birth in GMV and CSA, while no group differences emerged for CTh. Repeated measures analysis also indicated that having a second scan increased SNR in all regions of interest, most notably bilateral frontal poles, pre- and postcentral gyri and putamina. The results suggest that a simple time and cost-effective measure to improve SNR in rare clinical populations with low prevalence rates is a second anatomical scan when structural MRI is of interest.

Neural and Hormonal Correlates of Sexual Arousal in Transgender Persons.

BACKGROUND: Whereas mounting work has begun to document the neural correlates underlying sexual arousal (SA) in humans, the associations between gender identity and the brain correlates of SA as well as their hormonal contributions remain unknown. AIM: This study investigated neural activation to sexual arousal in transgender and cisgender persons. METHODS: 20 transgender men and 19 transgender women (TW) already living in their identified gender were compared to 21 cisgender men (CM) and 19 cisgender women. Participants viewed erotic and neutral video clips while undergoing 3 Tesla magnetic resonance imaging. OUTCOMES: Group-specific brain activation, brain functional connectivity, and brain-hormone associations within the neurophenomenological model of sexual arousal (Stoleru et al, 2012). RESULTS: Consistent with the model, participants activated most of its components. However, between-group differences were mostly showing larger activation for CM relative to any of the other 3 groups. Moreover, functional connectivity analyses (psychophysiological interactions) indicated unique patterns for CM, cisgender women, and TW in how different components of SA communicated with one another. Finally, androgens in transgender men and estrogens in TW correlated negatively with parietal cortex and primary (sensori-) motor regions, respectively, while CM showed positive correlations of androgens with parietal cortex, somatosensory regions, and the insula. CLINICAL IMPLICATIONS: Data provide information on neurobiological changes in sexual arousal during treatment with gender-affirming hormone therapy. STRENGTHS & LIMITATIONS: Although a limitation is the lack of pretreatment data, the present study provides comprehensive information including brain activation, functional connectivity, and hormonal associations in a large sample. CONCLUSIONS: The results highlight a complex picture of the neural correlates of SA in gender identity and sex assigned at birth. Mueller SC, Wierckx K, T'Sjoen G. Neural and Hormonal Correlates of Sexual Arousal in Transgender Persons. J Sex Med 2020;17:2495-2507.

Defining the neural correlates of spontaneous theory of mind (ToM): An fMRI multi-study investigation.

There is a major debate in the theory of mind (ToM) field, concerning whether spontaneous and explicit ToM are based on the same or two distinct cognitive systems. While extensive research on the neural correlates of explicit ToM has demonstrated involvement of the temporo-parietal junction (TPJ) and the medial prefrontal cortex (mPFC), few studies investigated spontaneous ToM, leaving some open questions. Here, we implemented a multi-study approach by pooling data from three fMRI studies to obtain a larger sample to increase power and sensitivity to better define the neurocognitive mechanisms underlying spontaneous ToM. Participants watched videos in which an agent acquires a true or false belief about the location of a ball. Thus, the belief of the agent and that of the participant could either match or differ. Importantly, participants were never asked to consider the belief of the agent and were only instructed to press a button when they detected the presence of the ball after an occluder fell at the end of each video. By analysing the blood-oxygen level dependent signal during the belief formation phase for false versus true beliefs, we found a cluster of activation in the right, and to a lesser extent, left posterior parietal cortex spanning the TPJ, but no mPFC activation. Region of interest (ROI) analysis on bilateral TPJ and mPFC confirmed these results and added evidence to the asymmetry in laterality of the TPJ in spontaneous ToM. Interestingly, the whole brain analysis, supported by an overlap with brain maps, revealed maximum activation in areas involved in visuospatial working memory and attention switching functions, such as the supramarginal gyrus, the middle temporal gyrus, and the inferior frontal gyrus. By contrast, evidence for the presence of brain-behaviour correlations was mixed and there was no evidence for functional connectivity between the TPJ and mPFC. Taken together, these findings help clarifying the brain system supporting spontaneous ToM.

Emotion dysregulation, temperamental vulnerability, and parental depression in adolescents: Correspondence between physiological and informant-report measures.

Although numerous studies reveal altered respiratory sinus arrhythmia (RSA) among children, adolescents, and adults who exhibit emotion dysregulation, effects of temperamental vulnerability and parental mental health on RSA remain unclear. We evaluated the relationship among emotion regulation, RSA, and RSA reactivity in a pooled sample of 24 vulnerable and 31 resilient adolescents (mean age = 13.69 years; 60% girls), including associations with temperamental vulnerability and parental depressive symptoms. Participants watched a neutral film clip while their resting RSA was recorded, and then completed a reward and frustration task, using an affective Posner paradigm. Temperament and emotion regulation were assessed via self-report and parent report, and parents reported on their own depressive symptoms. Low resting RSA was associated with temperamental negative emotionality, whereas greater RSA reactivity to frustration was associated with maladaptive emotion regulation strategies. No significant relations were found between RSA and parental depressive symptoms. This study elucidates the role of RSA as a biomarker of individual differences in emotion dysregulation and temperamental vulnerability and stresses the importance of considering multiple units of analyses, as well as functional domains, when studying emotional responding and regulation in adolescents.

Neural correlates of ostracism in transgender persons living according to their gender identity: a potential risk marker for psychopathology?

BACKGROUND: Stigmatization in society carries a high risk for development of psychopathology. Transgender persons are at particularly high risk for such stigmatization and social rejection by others. However, the neural correlates of ostracism in this group have not been captured. METHOD: Twenty transgender men (TM, female-to-male) and 19 transgender women (TW, male-to-female) already living in their gender identity and 20 cisgender men (CM) and 20 cisgender women (CW) completed a cyberball task assessing both exclusion and re-inclusion during functional magnetic resonance imaging (fMRI). RESULTS: During psychosocial stress between-group differences were found in the dorsal and ventral anterior cingulate cortex (ACC) and the inferior frontal gyrus (IFG). Patterns were consistent with sex assigned at birth, i.e. CW showed greater activation in dorsal ACC and IFG relative to CM and TW. During re-inclusion, transgender persons showed greater ventral ACC activity relative to CW, possibly indicating persistent feelings of exclusion. Functional connectivity analyses supported these findings but showed a particularly altered functional connectivity between ACC and lateral prefrontal cortex in TM, which may suggest reduced emotional regulation to the ostracism experience in this group. Depressive symptoms or hormonal levels were not associated with these findings. CONCLUSION: The results bear implications for the role of social exclusion in development of mental health problems in socially marginalized groups.

Kynurenic acid is reduced in females and oral contraceptive users: Implications for depression.

The incidence of depression is approximately 2-fold greater in women than men but the biological mechanisms underlying this phenomenon remain unclear. One potential mechanism that has been understudied is immune function, which is modulated by sex hormones and differs considerably between males and females. The immune-regulating kynurenine pathway previously has been implicated in the pathogenesis of mood disorders. In particular, a decreased ratio of neuroprotective (kynurenic acid; KynA) to neurotoxic (3-hydroxykynurenine; 3HK and quinolinic acid; QA) kynurenine pathway metabolites has been reported in several mood disorder subtypes. Yet there is a paucity of research investigating sex differences in the kynurenine pathway in the context of depression. Similarly, oral contraceptive (OC) use has been shown to be a risk factor for depression but to our knowledge this epidemiological relationship has not been considered within the framework of immune dysfunction. Here, we compared the concentrations of c-reactive protein (CRP) and kynurenine pathway metabolites in a combined sample of subjects with major depressive disorder (MDD), bipolar disorder (BD), and healthy controls (HC) comprising 130 men and 350 women. CRP was measured in a CLIA-certified hospital laboratory. Kynurenine metabolites were quantified using high performance liquid chromatography with tandem mass spectrometry. Estradiol and progesterone were quantified with the Mesoscale Discovery (MSD) platform. After controlling for diagnosis, age, sex, BMI, analysis batch, and self-reported childhood trauma we found that women had significantly lower KynA/3HK and KynA/QA ratios than men, and that these results were driven by a decrease in KynA. There was no significant difference between males and females in the concentration of CRP. Further, women taking OC showed significantly higher levels of CRP and lower ratios of KynA/3HK and KynA/QA compared with women on no form of contraception. Moreover, among women using OC, progesterone concentrations were positively correlated with KynA, KynA/3HK, and KynA/QA. Although preliminary, our results indicate that on average, healthy women show the same pattern of kynurenine pathway metabolism as that observed in subjects with depression. This finding raises the possibility that a reduction in KynA concentrations in women may constitute a vulnerability factor that partly explains the higher incidence of depression in females. Further, the significant association between OC use and reduced KynA as well as increased CRP, could conceivably partially account for the epidemiological association between OC use and depression. Nonetheless, because of the cross-sectional nature of this study, these hypotheses need to be more rigorously tested with longitudinal designs and/or large epidemiological studies.

The impact of happy and angry faces on working memory in depressed adolescents.

Recent cognitive models suggest that the ability to control emotional information in working memory (WM) may be implicated in the etiology and maintenance of depression. However, few studies have examined the effects of processing relevant and irrelevant emotional stimuli on WM performance in depressed adolescents. In the current study, depressed adolescents (n = 27) and healthy adolescents (n = 49) completed two versions of an emotional n-back task: a low WM load (0-back) task and a high WM load (2-back) task. In the emotion-relevant condition participants were asked to attend to the emotional expression of an angry, happy, or neutral face, whereas in the emotion-irrelevant condition participants were asked to attend to the gender of the face. The results showed a WM improvement for happy faces in the emotion-relevant condition and a WM impairment for happy faces in the emotion-irrelevant condition for healthy adolescents but not for depressed adolescents. No biases toward angry faces were found. These results demonstrate that depressed adolescents do not show a preferential processing of angry faces but rather fail to show a positivity bias as seen in healthy adolescents. This supports the theoretical notion that a depressive disorder is characterized by a blunted reactivity toward positive information and may provide new insights into the underlying mechanisms of youth depression.

The Role of Interference and Inhibition Processes in Dysphoric Early Adolescents.

Cognitive theories emphasize the importance of attentional biases in the development and maintenance of depression. Noteworthy, recent studies indicate that depression-related biases only occur in later stages of attentional processing. This is consistent with the idea that attention is a multicomponent process, consisting of at least two mechanisms: selection and inhibition. Therefore, this study aims to investigate interference and inhibition toward angry and happy stimuli in dysphoric adolescents compared to nondysphoric adolescents. To examine interference and inhibition of emotional information in 21 dysphoric (17 girls) and 28 nondysphoric adolescents (17 girls), 10-16 years of age, a Negative Affective Priming task was used. In this task, a target has to be evaluated as positive or negative while ignoring a distractor. As expected, dysphoric adolescents showed both higher interference from and higher inhibition of angry stimuli relative to nondysphoric adolescents. In contrast, happy stimuli did not lead to interference and consequently did not have to be inhibited in either group. Finally, a positive relation was found between interference and the subsequent inhibition of emotional stimuli. These observations confirm the existence of a bias toward angry faces in dysphoric adolescents and indicate a higher inhibition of angry faces in dysphoric adolescents compared to nondysphoric adolescents. The obtained results are different from those of similar previous studies in depressed or dysphoric adults using sad faces or negatively valenced words and might reveal important emotion-specific or age-specific inhibitory biases.

Altered Working Memory Processing of Emotion in Adolescents with Dysphoric Symptomatology: An Eye Tracking Study.

It has been suggested that altered processing of emotion during cognitive control plays an important role in the etiology of depressive symptoms. The current study investigates the influence of emotional stimuli on working memory (WM) in adolescents with dysphoric symptomatology (DS). Twenty-five adolescents with DS and 40 adolescents with no dysphoric symptomatology (NDS) completed a memory-guided eye movement task. This task assessed the influence of irrelevant affective information on WM processes during high and low cognitive load. Latency analyses showed that, in the high load WM condition, negative distractors disturbed WM performance in adolescents with NDS, but not in adolescents with DS. Accuracy analyses revealed that adolescents with NDS had higher accuracy rates in the presence of positive distractors relative to negative and neutral distractors, and in comparison to adolescents with DS. The findings indicated altered WM performance in the context of emotional distractors in adolescents with DS and may contribute to theoretical knowledge and early prevention of youth depression.

A Structural Magnetic Resonance Imaging Study in Transgender Persons on Cross-Sex Hormone Therapy.

BACKGROUND: To date, research findings are inconsistent about whether the neuroanatomy in transgender persons resembles that of their natal sex or their gender identity. Moreover, few studies have examined the effects of long-term cross-sex hormonal treatment on neuroanatomy in this cohort. The purpose of the present study was to examine neuroanatomical differences in transgender persons after prolonged cross-sex hormone therapy. METHODS: Eighteen transgender men (female-to-male), 17 transgender women (male-to-female), 30 nontransgender men (natal men), and 27 nontransgender women (natal women) completed a high-resolution structural magnetic resonance imaging scan at 3 T. Eligibility criteria for transgender persons were gender-affirming surgery and at least 2 years of cross-sex hormone therapy. Exclusion criteria for nontransgender persons were presence of psychiatric or neurological disorders. RESULTS: The mean neuroanatomical volume for the amygdala, putamen, and corpus callosum differed between transgender women and natal women but not between transgender women and natal men. Differences between transgender men and natal men were found in several brain structures, including the medial temporal lobe structures and cerebellum. Differences between transgender men and natal women were found in the medial temporal lobe, nucleus accumbens, and 3rd ventricle. Sexual dimorphism between nontransgender men and women included larger cerebellar volumes and a smaller anterior corpus callosum in natal men than in natal women. The results remained stable after correcting for additional factors including age, total intracranial volume, anxiety, and depressive symptoms. CONCLUSIONS: Neuroanatomical differences were region specific between transgender persons and their natal sex as well as their gender identity, raising the possibility of a localized influence of sex hormones on neuroanatomy.

Pupil size directly modulates the feedforward response in human primary visual cortex independently of attention.

Controversy revolves around the question of whether psychological factors like attention and emotion can influence the initial feedforward response in primary visual cortex (V1). Although traditionally, the electrophysiological correlate of this response in humans (the C1 component) has been found to be unaltered by psychological influences, a number of recent studies have described attentional and emotional modulations. Yet, research into psychological effects on the feedforward V1 response has neglected possible direct contributions of concomitant pupil-size modulations, which are known to also occur under various conditions of attentional load and emotional state. Here we tested the hypothesis that such pupil-size differences themselves directly affect the feedforward V1 response. We report data from two complementary experiments, in which we used procedures that modulate pupil size without differences in attentional load or emotion while simultaneously recording pupil-size and EEG data. Our results confirm that pupil size indeed directly influences the feedforward V1 response, showing an inverse relationship between pupil size and early V1 activity. While it is unclear in how far this effect represents a functionally-relevant adaptation, it identifies pupil-size differences as an important modulating factor of the feedforward response of V1 and could hence represent a confounding variable in research investigating the neural influence of psychological factors on early visual processing.

Mineralocorticoid receptor stimulation effects on spatial memory in healthy young adults: A study using the virtual Morris Water Maze task.

OBJECTIVES: Stress hormones such as cortisol are known to influence a wide range of cognitive functions, including hippocampal based spatial memory. In the brain, cortisol acts via two different receptors: the glucocorticoid (GR) and the mineralocorticoid receptor (MR). As the MR has a high density in the hippocampus, we examined the effects of pharmacological MR stimulation on spatial memory. METHODS: Eighty healthy participants (40 women, 40 men, mean age=23.9years±SD=3.3) completed the virtual Morris Water Maze (vMWM) task to test spatial encoding and spatial memory retrieval after receiving 0.4mg fludrocortisone, a MR agonist, or placebo. RESULTS: There was no effect of MR stimulation on spatial encoding during the vMWM task. However, participants who received fludrocortisone exhibited improved spatial memory retrieval performance. There was neither a main effect of sex nor a sex-by-treatment interaction. CONCLUSION: In young healthy participants, MR stimulation improved hippocampal based spatial memory retrieval in a virtual Morris Water Maze task. Our study not only confirms the importance of MR function in spatial memory, but suggests beneficial effects of acute MR stimulation on spatial memory retrieval in humans.

The power of a smile: Stronger working memory effects for happy faces in adolescents compared to adults.

Theories of adolescent behaviour attribute increases in risk-taking and sensation-seeking in this age group to a heightened sensitivity to emotional stimuli on the one hand and a relatively immature cognitive control system on the other hand. However, little research has outlined to what extent relevant and irrelevant emotional stimuli bias the imbalance between affective processing and cognitive control. Thirty-three adolescents (19 females, aged 12-14) and 37 adults (18 females, aged 18-29) completed two attentional conditions of an emotional face working memory (WM) 0-back/2-back task. Participants were asked to attend to the emotional facial expression in the "relevant" emotion condition, and to the gender of the face in the "irrelevant" condition. The results revealed a WM improvement for happy faces in the relevant condition in both age groups, and an impairment for irrelevant happy faces in adolescents, but not adults. Furthermore, the difference between both attentional conditions for happy faces was larger in adolescents than adults. Results are discussed within the framework of theories of adolescent behaviour.