The impact of resistance training on memory, gait and oxidative stress during periestropause in rats

Aging, especially in female, is complex, involving various factors such as reproductive sensitivity, cognitive and functional decline, and an imbalance in the redox system. This study aims to assess the effectiveness of long-term resistance training as a non-pharmacological strategy to mitigate the impairment of recognition memory, hippocampal redox state, and ambulation in aging female Wistar rats during the periestropause period. Thirty Wistar rats aged 17 months, in periestropause, were distributed into non-trained (NT) and resistance training (RT; stair climbing 3 times per week for 4 months) groups. Before (17 months) and after (21 months) of the RT period, the rats underwent tests for ambulation, elevated plus maze (EPM), open field, and object recognition. Biochemical and histological analyses were conducted on the hippocampus of these animals. Analysis of the results revealed that at 21 months, females in the NT group (21Mo/NT) exhibited a decreased in length (p=0.0458) and an increased in past width (p<0.0479) compared to their measurements at 17 months. However, after 4 months of RT, the female rats aged 21 months (21Mo/RT group) experienced changes in gait components, showing an increase in length (p<0.0008) and a decrease in stride width. Regarding memory, the object recognition test indicated potential cognitive improvement in 21Mo/RT animals, with significant interaction between intervention and age across all three stages of the test (total exploration time, p=0.0001; Test 1, p=0.0003; Test 2, p=0.0014). This response was notable compared to animals in the 21Mo/NT group, which showed a decline in memory capacity (p<0.01). The data showed a significant difference in relation to the age of the animals (p<0.01). The hippocampal redox state markers showed reduced lipid oxidative (p=0.028), catalase (p=0.022), and superoxide dismutase (p=0.0067) in the RT group compared to the NT group. Hippocampal cells from the 21Mo/RT group showed increased citrate synthase enzyme activity (p<0.05) and Nissl body staining (p<0.05). The results of this study demonstrate that RT performed during the periestropause phase leads to significant improvements in functional abilities, cognitive performance, and neuroplasticity in aging female rats.

Sex-dependent nonlinear Granger connectivity patterns of brain aging in healthy population

BACKGROUND

Brain aging is a complex process that involves functional alterations in multiple subnetworks and brain regions. However, most previous studies investigating aging-related functional connectivity (FC) changes using resting-state functional magnetic resonance images (rs-fMRIs) have primarily focused on the linear correlation between brain subnetworks, ignoring the nonlinear casual properties of fMRI signals.

METHODS

We introduced the neural Granger causality technique to investigate the sex-dependent nonlinear Granger connectivity (NGC) during aging on a publicly available dataset of 227 healthy participants acquired cross-sectionally in Leipzig, Germany.

RESULTS

Our findings indicate that brain aging may cause widespread declines in NGC at both regional and subnetwork scales. These findings exhibit high reproducibility across different network sparsities, demonstrating the efficacy of static and dynamic analysis strategies. Females exhibit greater heterogeneity and reduced stability in NGC compared to males during aging, especially the NGC between the visual network and other subnetworks. Besides, NGC strengths can well reflect the individual cognitive function, which may therefore work as a sensitive metric in cognition-related experiments for individual-scale or group-scale mechanism understanding.

CONCLUSION

These findings indicate that NGC analysis is a potent tool for identifying sex-dependent brain aging patterns. Our results offer valuable perspectives that could substantially enhance the understanding of sex differences in neurological diseases in the future, especially in degenerative disorders.

Impact of sex and hypoxia on brain region-specific expression of membrane androgen receptor AR45 in rats

Background

Sex differences in oxidative stress-associated cognitive decline are influenced by sex hormone levels. Notably, oxidative stress-associated neuronal cell death can be exacerbated through testosterone signaling via membrane androgen receptor AR45, which is complexed with G protein Gαq within plasma membrane-associated lipid rafts. The objective of this study was to elucidate the impact of sex on the expression of AR45 and Gαq in brain regions associated with cognitive function, specifically hippocampus subregions and entorhinal cortex. Additionally, we investigated whether chronic intermittent hypoxia (CIH), an oxidative stressor with sex-specific effects, would modulate AR45 and Gαq expression in these brain regions.

Methods

Adult male and female Sprague-Dawley rats were exposed to CIH or normoxia (room air) during their sleep phase for 14 days. We quantified AR45 and Gαq protein expression in various cognition-associated brain regions [dorsal hippocampal CA1, CA3, dentate gyrus (DG), and entorhinal cortex (ETC)] via western blotting. For comparisons, AR45 and Gαq protein expression were also assessed in brain regions outside the hippocampal-ETC circuit [thalamus (TH) and striatum (STR)].

Results

The highest AR45 levels were expressed in the hippocampal CA1 and DG while the lowest expression was observed in the extrahippocampal STR. The highest Gαq levels were expressed in the hippocampal-associated ETC while the lowest expression was observed in the extrahippocampal TH. Females expressed higher levels of AR45 in the hippocampal DG compared to males, while no sex differences in Gαq expression were observed regardless of brain region assessed. Moreover, there was no effect of CIH on AR45 or Gαq expression in any of the brain regions examined. AR45 expression was positively correlated with Gαq expression in the CA1, DG, ETC, TH, and STR in a sex-dependent manner.

Conclusion

Our findings reveal enrichment of AR45 and Gαq protein expression within the hippocampal-ETC circuit, which is vulnerable to oxidative stress and neurodegeneration during cognitive decline. Nonetheless, CIH does not modulate the expression of AR45 or Gαq. Importantly, there are sex differences in AR45 expression and its association with Gαq expression in various brain regions, which may underlie sex-specific differences in cognitive and motor function-associated declines with aging.

Parvalbumin interneuron mGlu5 receptors govern sex differences in prefrontal cortex physiology and binge drinking

Despite established sex differences in the prevalence and presentation of psychiatric disorders, little is known about the cellular and synaptic mechanisms that guide these differences under basal conditions. The proper function of the prefrontal cortex (PFC) is essential for the top-down regulation of motivated behaviors. The activity of the PFC is tightly controlled by parvalbumin-expressing interneurons (PV-INs), a key subpopulation of fast-spiking GABAergic cells that regulate cortical excitability through direct innervations onto the perisomatic regions of nearby pyramidal cells. Recent rodent studies have identified notable sex differences in PV-IN activity and adaptations to experiences such as binge drinking. Here, we investigated the cellular and molecular mechanisms that underlie sex-specific regulation of PFC PV-IN function. Using whole-cell patch-clamp electrophysiology and selective pharmacology, we report that PV-INs from female mice are more excitable than those from males. Moreover, we find that mGlu1 and mGlu5 metabotropic glutamate receptors regulate cell excitability, excitatory drive, and endocannabinoid signaling at PFC PV-INs in a sex-dependent manner. Genetic deletion of mGlu5 receptors from PV-expressing cells abrogates all sex differences observed in PV-IN membrane and synaptic physiology. Lastly, we report that female, but not male, PV-mGlu5-/- mice exhibit decreased voluntary drinking on an intermittent access schedule, which could be related to changes in ethanol's stimulant properties. Importantly, these studies identify mGlu1 and mGlu5 receptors as candidate signaling molecules involved in sex differences in PV-IN activity and behaviors relevant to alcohol use.

Mental illness and cardiovascular health: observational and polygenic score analyses in a population-based cohort study

BACKGROUND

Individuals with serious mental illness have a markedly shorter life expectancy. A major contributor to premature death is cardiovascular disease (CVD). We investigated associations of (genetic liability for) depressive disorder, bipolar disorder and schizophrenia with a range of CVD traits and examined to what degree these were driven by important confounders.

METHODS

We included participants of the Dutch Lifelines cohort (N = 147 337) with information on self-reported lifetime diagnosis of depressive disorder, bipolar disorder, or schizophrenia and CVD traits. Employing linear mixed-effects models, we examined associations between mental illness diagnoses and CVD, correcting for psychotropic medication, demographic and lifestyle factors. In a subsample (N = 73 965), we repeated these analyses using polygenic scores (PGSs) for the three mental illnesses.

RESULTS

There was strong evidence that depressive disorder diagnosis is associated with increased arrhythmia and atherosclerosis risk and lower heart rate variability, even after confounder adjustment. Positive associations were also found for the depression PGSs with arrhythmia and atherosclerosis. Bipolar disorder was associated with a higher risk of nearly all CVD traits, though most diminished after adjustment. The bipolar disorder PGSs did not show any associations. While the schizophrenia PGSs was associated with increased arrhythmia risk and lower heart rate variability, schizophrenia diagnosis was not. All mental illness diagnoses were associated with lower blood pressure and a lower risk of hypertension.

CONCLUSIONS

Our study shows widespread associations of (genetic liability to) mental illness (primarily depressive disorder) with CVD, even after confounder adjustment. Future research should focus on clarifying potential causal pathways between mental illness and CVD.

Parvalbumin interneuron mGlu5 receptors govern sex differences in prefrontal cortex physiology and binge drinking

Despite established sex differences in the prevalence and presentation of psychiatric disorders, little is known about the cellular and synaptic mechanisms that guide these differences under basal conditions. Proper function of the prefrontal cortex (PFC) is essential for the top-down regulation of motivated behaviors. Activity of the PFC is tightly controlled by parvalbumin-expressing interneurons (PV-INs), a key subpopulation of fast-spiking GABAergic cells that regulate cortical excitability through direct innervations onto the perisomatic regions of nearby pyramidal cells. Recent rodent studies have identified notable sex differences in PV-IN activity and adaptations to experiences such as binge drinking. Here, we investigated the cellular and molecular mechanisms that underlie sex-specific regulation of PFC PV-IN function. Using whole-cell patch clamp electrophysiology and selective pharmacology, we report that PV-INs from female mice are more excitable than those from males. Moreover, we find that mGlu1 and mGlu5 metabotropic glutamate receptors regulate cell excitability, excitatory drive, and endocannabinoid signaling at PFC PV-INs in a sex-dependent manner. Genetic deletion of mGlu5 receptors from PV-expressing cells abrogates all sex differences observed in PV-IN membrane and synaptic physiology. Lastly, we report that female, but not male, PV-mGlu5-/- mice exhibit decreased voluntary drinking on an intermittent access schedule, which could be related to changes in ethanol's stimulant properties. Importantly, these studies identify mGlu1 and mGlu5 receptors as candidate signaling molecules involved in sex differences in PV-IN activity and behaviors relevant for alcohol use.

Deep learning models reveal replicable, generalizable, and behaviorally relevant sex differences in human functional brain organization

Sex plays a crucial role in human brain development, aging, and the manifestation of psychiatric and neurological disorders. However, our understanding of sex differences in human functional brain organization and their behavioral consequences has been hindered by inconsistent findings and a lack of replication. Here, we address these challenges using a spatiotemporal deep neural network (stDNN) model to uncover latent functional brain dynamics that distinguish male and female brains. Our stDNN model accurately differentiated male and female brains, demonstrating consistently high cross-validation accuracy (>90%), replicability, and generalizability across multisession data from the same individuals and three independent cohorts (N ~ 1,500 young adults aged 20 to 35). Explainable AI (XAI) analysis revealed that brain features associated with the default mode network, striatum, and limbic network consistently exhibited significant sex differences (effect sizes > 1.5) across sessions and independent cohorts. Furthermore, XAI-derived brain features accurately predicted sex-specific cognitive profiles, a finding that was also independently replicated. Our results demonstrate that sex differences in functional brain dynamics are not only highly replicable and generalizable but also behaviorally relevant, challenging the notion of a continuum in male-female brain organization. Our findings underscore the crucial role of sex as a biological determinant in human brain organization, have significant implications for developing personalized sex-specific biomarkers in psychiatric and neurological disorders, and provide innovative AI-based computational tools for future research.

Exploring sex differences: insights into gene expression, neuroanatomy, neurochemistry, cognition, and pathology

Increased knowledge about sex differences is important for development of individualized treatments against many diseases as well as understanding behavioral and pathological differences. This review summarizes sex chromosome effects on gene expression, epigenetics, and hormones in relation to the brain. We explore neuroanatomy, neurochemistry, cognition, and brain pathology aiming to explain the current state of the art. While some domains exhibit strong differences, others reveal subtle differences whose overall significance warrants clarification. We hope that the current review increases awareness and serves as a basis for the planning of future studies that consider both sexes equally regarding similarities and differences.

Different cortical connectivities in human females and males relate to differences in strength and body composition, reward and emotional systems, and memory

Sex differences in human brain structure and function are important, partly because they are likely to be relevant to the male-female differences in behavior and in mental health. To analyse sex differences in cortical function, functional connectivity was measured in 36,531 participants (53% female) in the UK Biobank (mean age 69) using the Human Connectome Project multimodal parcellation atlas with 360 well-specified cortical regions. Most of the functional connectivities were lower in females (Bonferroni corrected), with the mean Cohen's d =  - 0.18. Removing these as covariates reduced the difference of functional connectivities for females-males from d =  - 0.18 to - 0.06. The lower functional connectivities in females were especially of somatosensory/premotor regions including the insula, opercular cortex, paracentral lobule and mid-cingulate cortex, and were correlated with lower maximum workload (r = 0.17), and with higher whole body fat mass (r =  - 0.17). But some functional connectivities were higher in females, involving especially the ventromedial prefrontal cortex and posterior cingulate cortex, and these were correlated with higher liking for some rewards such as sweet foods, higher happiness/subjective well-being, and with better memory-related functions. The main findings were replicated in 1000 individuals (532 females, mean age 29) from the Human Connectome Project. This investigation shows the cortical systems with different functional connectivity between females and males, and also provides for the first time a foundation for understanding the implications for behavior of these differences between females and males.

Comprehensive analysis of sex differences in the function and ultrastructure of hippocampal presynaptic terminals

Sex differences in the brain, encompassing variations in specific brain structures, size, cognitive function, and synaptic connections, have been identified across numerous species. While previous research has explored sex differences in postsynaptic structures, synaptic plasticity, and hippocampus-dependent functions, the hippocampal presynaptic terminals remain largely uninvestigated. The hippocampus is a critical structure responsible for multiple brain functions. This study examined presynaptic differences in cultured hippocampal neurons derived from male and female mice using a combination of biochemical assays, functional analyses measuring exocytosis and endocytosis of synaptic vesicle proteins, ultrastructural analyses via electron microscopy, and presynaptic Ca2+-specific optical probes. Our findings revealed that female neurons exhibited a higher number of synaptic vesicles at presynaptic terminals compared to male neurons. However, no significant differences were observed in presynaptic protein expression, presynaptic terminal ultrastructure, synaptic vesicle exocytosis and endocytosis, or presynaptic Ca2+ alterations between male and female neurons.

Sex/gender differences in cognitive abilities

Sex/gender differences in cognitive sciences are riddled by conflicting perspectives. At the center of debates are clinical, social, and political perspectives. Front and center, evolutionary and biological perspectives have often focused on 'nature' arguments, while feminist and constructivist views have often focused on 'nurture arguments regarding cognitive sex differences. In the current narrative review, we provide a comprehensive overview regarding the origins and historical advancement of these debates while providing a summary of the results in the field of sexually polymorphic cognition. In so doing, we attempt to highlight the importance of using transdisciplinary perspectives which help bridge disciplines together to provide a refined understanding the specific factors that drive sex differences a gender diversity in cognitive abilities. To summarize, biological sex (e.g., birth-assigned sex, sex hormones), socio-cultural gender (gender identity, gender roles), and sexual orientation each uniquely shape the cognitive abilities reviewed. To date, however, few studies integrate these sex and gender factors together to better understand individual differences in cognitive functioning. This has potential benefits if a broader understanding of sex and gender factors are systematically measured when researching and treating numerous conditions where cognition is altered.

Mental health outcomes in parents of children with a cancer diagnosis in Sweden: A nationwide cohort study

BACKGROUND

The diagnosis of paediatric cancer is a crisis for the parents who are the primary caregivers of the affected child. A comprehensive assessment of the longitudinal impact of childhood cancer on parental mental health and the potential sex differences between the parents is lacking. Thus, we aimed to explore the subsequent short- and long-term mental health outcomes among the parents of children with cancer and examine whether the outcomes vary between the mother and father.

METHODS

By combining several Swedish registers, parents of a child (ages 0-14 years) with a cancer diagnosis between Jan 1, 2006, and Dec 31, 2016 were identified. For each parent of children with cancer, up to five mothers or fathers of cancer-free children were randomly selected and matched, respectively. Hospital contacts for any mental health disorders between 5 years before and 7 years after the diagnosis of childhood cancer were retrieved. An interrupted time series negative binomial regression was performed to assess the short- and long-term impact of a childhood cancer diagnosis on the parents' subsequent mental health outcomes.

FINDINGS

16,199 mothers (2852 with a child with cancer and 13,347 without) and 15,708 fathers (2769 with a child with cancer and 12,939 without) were included in this study. Compared with mothers of children without cancer, mothers of children with cancer had higher risks of mental health disorders in the first year after diagnosis (rate ratio [RR] and 95% Confidence Interval [CI], 1.17 (1.03-1.32)), and notably, the adverse impact became more severe over time (RR and 95% CI, 1.36 (1.07-1.74), in the seventh year). For fathers of children with cancer, the risk of mental health disorders was continuously higher compared to matched comparisons (RR and 95% CI, 1.31 (1.01-1.71)).

INTERPRETATION

Our findings suggested that parental mental health was affected continuously by a diagnosis of childhood cancer in their children. In particular, the mother's mental health was affected more severely. Customised psychological services or interventions are highly needed for the parents of children with cancer.

FUNDING

Swedish Research Council, Allmänna Sjukhusets i Malmö Stiftelsen för bekämpande av cancer, Swedish Heart-Lung Foundation, ALF funding from Region Skåne and China Scholarship Council.

Metacognition and the effect of incentive motivation in two compulsive disorders: Gambling disorder and obsessive-compulsive disorder

AIMS

Compulsivity is a common phenotype among psychiatric disorders, such as obsessive-compulsive disorder (OCD) and gambling disorder (GD). Deficiencies in metacognition, such as the inability to estimate one's performance via confidence judgments could contribute to pathological decision-making. Earlier research has shown that patients with OCD exhibit underconfidence, while patients with GD exhibit overconfidence. Moreover, it is known that motivational states (e.g. monetary incentives) influence metacognition, with gain (respectively loss) prospects increasing (respectively decreasing) confidence. Here, we reasoned that OCD and GD symptoms might correspond to an exacerbation of this interaction between metacognition and motivation.

METHODS

We hypothesized GD's overconfidence to be exaggerated during gain prospects, while OCD's underconfidence to be worsened in loss context, which we expected to see represented in ventromedial prefrontal cortex (VMPFC) blood-oxygen-level-dependent activity. We tested those hypotheses in a task-based functional magnetic resonance imaging (fMRI) design (27 patients with GD, 28 patients with OCD, 55 controls). The trial is registered in the Dutch Trial Register (NL6171).

RESULTS

We showed increased confidence for patients with GD versus patients with OCD, which could partly be explained by sex and IQ. Although our primary analyses did not support the hypothesized interaction between incentives and groups, exploratory analyses did show increased confidence in patients with GD specifically in gain context. fMRI analyses confirmed a central role for VMPFC in the processing of confidence and incentives, but no differences between the groups.

CONCLUSION

Patients with OCD and those with GD reside at opposite ends of the confidence spectrum, while no interaction with incentives was found, nor group differences in neuronal processing of confidence.

HU-910, a CB2 receptor agonist, reverses behavioral changes in pharmacological rodent models for schizophrenia

Despite attenuating the positive symptoms, drugs currently used to treat schizophrenia frequently do not improve the negative symptoms and cognitive impairments. In addition, they show low tolerability, which has been associated with high rates of treatment discontinuation. Recent evidence suggests that the endocannabinoid system may be a target for schizophrenia treatment. The CB2 receptor modulates dopaminergic neurotransmission, which is abnormally enhanced in schizophrenia patients. Here, we aimed to evaluate whether HU-910, a selective CB2 receptor agonist, would reverse schizophrenia-related behavioral changes observed after the acute injections of amphetamine or the N-methyl-d-aspartate receptor (NMDAR) antagonist MK-801. We also investigated the effects of HU-910 in the memory impairment caused by repeated MK-801 administration. Finally, we tested whether HU-910 would produce the cannabinoid tetrad (catalepsy, hypolocomotion, hypothermia, and antinociception). In male C57BL/6 mice, the acute treatment with HU-910 (30 mg/kg) prevented the hyperlocomotion induced by acute MK-801. This effect was blocked by the CB2 receptor antagonist AM630 (1 mg/kg). On the contrary, HU-910 did not prevent the increased locomotor activity caused by acute amphetamine. The acute treatment with HU-910 (3, 10, and 30 mg/kg) also attenuated the impairments in the prepulse inhibition test induced by acute MK-801 and amphetamine. The repeated treatment with HU-910 attenuated the cognitive impairment caused by chronic administration of MK-801 in the novel object recognition test. Furthermore, HU-910 did not produce the cannabinoid tetrad. These results indicate that HU-910 produced antipsychotic-like effects and support further research on the potential therapeutic properties of this compound to treat schizophrenia.

Comparison of the Clinical and Treatment Characteristics of Patients Undergoing Electroconvulsive Therapy for Catatonia Indication in the Context of Gender

The aim of this study was to compare in the context of gender both clinical diagnosis and disease-related differences and electroconvulsive therapy (ECT)-related differences in data and efficacy in hospitalized patients with catatonic signs and symptoms. Data from 106 patients who received ECT with catatonia indication were retrospectively analyzed. Clinical data of male (n = 58) and female (n = 48) patients were compared. Hospitalization documents and outpatient files, sociodemographic and clinical data form, Clinical Global Improvement scores used by the ECT unit in the follow-up of patients who received ECT were used in the study. It was seen that the mean age of women at the onset of ECT was higher than in men and the presence of prolonged seizures was more common than men. In men, it was found out that the average number of sessions with the onset of clinical response to treatment was higher than the average of women. The distribution of diagnoses by gender showed that the presence of schizophrenia diagnosis in men and of bipolar disorder in women were significantly more frequent compared to the opposite sex. It was found out that there were no significant differences between genders in terms of response rate to ECT. Our study is important for being the first study in the literature investigating the gender differences in ECT used for catatonia. However, gender is not a distinctive factor in the effectiveness of treatment, there are some important differences between male and female patients showing signs and symptoms of catatonia and undergoing ECT.

An analysis of neuroscience and psychiatry papers published from 2009 and 2019 outlines opportunities for increasing discovery of sex differences

Sex differences exist in many neurological and psychiatric diseases, but these have not always been addressed adequately in research. In order to address this, it is necessary to consider how sex is incorporated into the design (e.g. using a balanced design) and into the analyses (e.g. using sex as a covariate) in the published literature. We surveyed papers published in 2009 and 2019 across six journals in neuroscience and psychiatry. In this sample, we find a 30% increase in the percentage of papers reporting studies that included both sexes in 2019 compared with 2009. Despite this increase, in 2019 only 19% of papers in the sample reported using an optimal design for discovery of possible sex differences, and only 5% of the papers reported studies that analysed sex as a discovery variable. We conclude that progress to date has not been sufficient to address the importance of sex differences in research for discovery and therapeutic potential for neurological and psychiatric disease.

Sex differences occur in many neurological and psychiatric diseases, and yet research is not always designed optimally to identify these. Here the authors perform a study of how sex was incorporated into the design and analyses of papers published six journals in neuroscience and psychiatry in 2009 compared with 2019.

A neural circuit perspective on brain aromatase

This review explores the role of aromatase in the brain as illuminated by a set of conserved network-level connections identified in several vertebrate taxa. Aromatase-expressing neurons are neurochemically heterogeneous but the brain regions in which they are found are highly-conserved across the vertebrate lineage. During development, aromatase neurons have a prominent role in sexual differentiation of the brain and resultant sex differences in behavior and human brain diseases. Drawing on literature primarily from birds and rodents, we delineate brain regions that express aromatase and that are strongly interconnected, and suggest that, in many species, aromatase expression essentially defines the Social Behavior Network. Moreover, in several cases the inputs to and outputs from this core Social Behavior Network also express aromatase. Recent advances in molecular and genetic tools for neuroscience now enable in-depth and taxonomically diverse studies of the function of aromatase at the neural circuit level.

Studying the relationship between clinical features and mental health among late-onset myasthenia gravis patients

BACKGROUND

Mental disorders are common comorbidities among individuals with neurological diseases, and the prevalence of depressive and anxiety-related symptoms in newly referred patients at neurology outpatient clinics is high. There have been few studies on the mental health of patients with late-onset myasthenia gravis (MG).

AIM

To examine the relationship between clinical features and the mental health symptoms within late-onset MG patients.

METHODS

A total of 105 patients diagnosed with MG were recruited consecutively from a neuromuscular outpatient clinic between December 2020 and February 2021. Patients were classified into two groups: early-onset MG (age at onset < 50 years, n = 63) and late-onset MG (age at onset ≥ 50 years, n = 42). Social demographic data and information about marital status, education level, clinical symptoms, serum antibody levels, and therapies used were collected for all participants. Participants were also evaluated using the Myasthenia Gravis Composite scale, the Myasthenia Gravis Activities of Daily Living scale, the Myasthenia Gravis Quality of Life 15 (MG-QOL-15) questionnaire, the 17-item version of the Hamilton Depression Rating Scale (HAM-D) and the Hamilton Anxiety Rating Scale (HAM-A). The relationship between clinical features and mental health in late-onset MG patients was examined using multivariate logistic regression analyses.

RESULTS

Late-onset MG patients were more prone to dyspnea, had higher levels of serum anti-acetylcholine receptor antibodies, and higher total scores on the MG-QOL-15, HAM-D, and HAM-A questionnaires, than early-onset MG patients had (P < 0.05). Among those with late-onset MG, female patients had higher total HAM-D and HAM-A scores than male patients had (P < 0.05). High scores on the QOL-15 questionnaire were associated with higher incidences of anxiety and depression, and the association was found to be independent after adjusting for confounding risk factors. In the late-onset subgroup, the areas under the receiver operating characteristic curves for the MG-QOL-15 score-based diagnostic accuracy for anxiety and depression state were 0.816 (P = 0.001) and 0.983 (P < 0.001), respectively.

CONCLUSION

Higher MG-QOL-15 scores were a risk factor for anxiety and depression in late-onset MG, and women with late-onset MG were more likely to have anxiety and depression than men were.

Sex-dependent features of social behavior differ between distinct laboratory mouse strains and their mixed offspring

The survival of individuals of gregarious species depends on their social interactions. In humans, atypical social behavior is a hallmark of several psychopathological conditions, many of which have sex-specific manifestations. Various laboratory mouse strains are used to reveal the mechanisms mediating typical and atypical social behavior in mammals. Here, we used three social discrimination tests to characterize social behavior in males and females of three widely used laboratory mouse strains (C57BL/6J, BALB/c, and ICR). We found marked sex- and strain-specific differences in the behavior exhibited by subjects, in a test-dependent manner. Interestingly, some characteristics were strain-dependent, while others were sex-dependent. We then crossbred C57BL/6J and BALB/c mice and found that offspring of such crossbreeding exhibit social behavior which differs from both parental strains and depends on the specific combination of parental strains. Thus, social behavior of laboratory mice is sex- and strain-specific and depends on both genetic and environmental factors.

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Social investigation behavior of laboratory mice is highly strain- and sex-specific

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Some behavioral aspects are either strain- or sex-specific, but not both

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Mixed offspring of distinct strains behave differently from both parental strains

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The behavior of mixed offspring depends on the specific combination of parents

Cerebral perfusion in depression: Relationship to sex, dehydroepiandrosterone sulfate and depression severity

BACKGROUND

Major depressive disorder (MDD) is a leading cause of disease burden and shows a marked sexual dimorphism. Previous studies reported changes in cerebral perfusion in MDD, an association between perfusion and dehydroepiandrosterone sulfate (DHEAS) levels, and large sex differences in perfusion. This study examines whether perfusion and DHEAS might mediate the link between sex and depressive symptoms in a large, unmedicated community sample.

METHODS

The sample included 203 healthy volunteers and 79 individuals with past or current MDD. Depression severity was assessed with the Hamilton Depression Scale (HAM-D) and Montgomery-Asberg Depression Rating Scale (MADRS). 3 T MRI perfusion data were collected with a pseudocontinuous arterial spin labelling sequence and DHEAS was measured in serum by LC-MS/MS.

RESULTS

Large sex differences in perfusion were observed (p < 0.001). Perfusion was negatively correlated with DHEAS (r = -0.23, p < 0.01, n = 250) and with depression severity (HAM-D: r = -0.17, p = 0.01, n = 242; partial Spearman correlation, controlling for age and sex), but not with anxiety. A significant sex*perfusion interaction on depression severity was observed. In women, perfusion showed more pronounced negative correlations with depressive symptoms, with absent or, in the case of the MADRS, opposite effects observed in men. A mediation analysis identified DHEAS and perfusion as mediating variables influencing the link between sex and the HAM-D score.

CONCLUSION

Perfusion was linked to depression severity, with the strongest effects observed in women. Perfusion and the neurosteroid DHEAS appear to mediate the link between sex and HAM-D scores, suggesting that inter-individual differences in perfusion and DHEAS levels may contribute to the sexual dimorphism in depression.

Functional and behavioral effects of de novo mutations in calcium-related genes in patients with bipolar disorder

Bipolar disorder is a common mental illness occurring in approximately 1% of individuals and exhibits lifetime prevalence. Although genetic factors are known to contribute to this disorder, the genetic architecture has not yet been completely clarified. Our initial trio-based exome sequencing study of bipolar disorder showed enrichment of de novo, loss-of-function (LOF) or protein-altering mutations in a combined group with bipolar I and schizoaffective disorders, and the identified de novo mutations were enriched in calcium-related genes. These findings suggested a role for de novo mutations in bipolar disorder. The validity of these statistical associations can be demonstrated if the functional impact of the mutations on cellular function and behavior are identified. In this study, we focused on two de novo LOF mutations in calcium-related genes, EHD1 and MACF1, found in patients with bipolar disorder. We first showed that the EHD1 mutation resulted in a truncated protein with diminished effect on neurite outgrowth and inhibited endocytosis. Next, we used CRISPR/Cas9 to establish two knock-in mouse lines to model the in vivo effects of these mutations. We performed behavioral screening using IntelliCage and long-term wheel running analysis. Ehd1 mutant mice showed higher activity in the light phase. Macf1 mutant mice showed diminished attention and persistence to rewards. These behavioral alterations were similar to the phenotypes in previously proposed animal models of bipolar disorder. These findings endorse the possible role of de novo mutations as a component of the genetic architecture of bipolar disorder which was suggested by the statistical evidence.

The Subcortical-Allocortical- Neocortical continuum for the Emergence and Morphological Heterogeneity of Pyramidal Neurons in the Human Brain

Human cortical and subcortical areas integrate emotion, memory, and cognition when interpreting various environmental stimuli for the elaboration of complex, evolved social behaviors. Pyramidal neurons occur in developed phylogenetic areas advancing along with the allocortex to represent 70-85% of the neocortical gray matter. Here, we illustrate and discuss morphological features of heterogeneous spiny pyramidal neurons emerging from specific amygdaloid nuclei, in CA3 and CA1 hippocampal regions, and in neocortical layers II/III and V of the anterolateral temporal lobe in humans. Three-dimensional images of Golgi-impregnated neurons were obtained using an algorithm for the visualization of the cell body, dendritic length, branching pattern, and pleomorphic dendritic spines, which are specialized plastic postsynaptic units for most excitatory inputs. We demonstrate the emergence and development of human pyramidal neurons in the cortical and basomedial (but not the medial, MeA) nuclei of the amygdala with cells showing a triangular cell body shape, basal branched dendrites, and a short apical shaft with proximal ramifications as "pyramidal-like" neurons. Basomedial neurons also have a long and distally ramified apical dendrite not oriented to the pial surface. These neurons are at the beginning of the allocortex and the limbic lobe. "Pyramidal-like" to "classic" pyramidal neurons with laminar organization advance from the CA3 to the CA1 hippocampal regions. These cells have basal and apical dendrites with specific receptive synaptic domains and several spines. Neocortical pyramidal neurons in layers II/III and V display heterogeneous dendritic branching patterns adapted to the space available and the afferent inputs of each brain area. Dendritic spines vary in their distribution, density, shapes, and sizes (classified as stubby/wide, thin, mushroom-like, ramified, transitional forms, "atypical" or complex forms, such as thorny excrescences in the MeA and CA3 hippocampal region). Spines were found isolated or intermingled, with evident particularities (e.g., an extraordinary density in long, deep CA1 pyramidal neurons), and some showing a spinule. We describe spiny pyramidal neurons considerably improving the connectional and processing complexity of the brain circuits. On the other hand, these cells have some vulnerabilities, as found in neurodegenerative Alzheimer's disease and in temporal lobe epilepsy.

Gender-specific approach in psychiatric diseases: Because sex matters

In both animals and human beings, males and females differ in their genetic background and hormonally driven behaviour and show sex-related differences in brain activity and response to internal and external stimuli. Gender-specific medicine has been a neglected dimension of medicine for long time, and only in the last three decades it is receiving the due scientific and clinical attention. Research has recently begun to identify factors that could provide a neurobiological basis for gender-based differences in health and disease and to point to gonadal hormones as important determinants of male-female differences. Animal studies have been of great help in understanding factors contributing to sex-dependent differences and sex hormones action. Here we review and discuss evidence provided by clinical and animal studies in the last two decades showing gender (in humans) and sex (in animals) differences in selected psychiatric disorders, namely eating disorders (anorexia nervosa, bulimia nervosa, binge eating disorder), schizophrenia, mood disorders (anxiety, depression, obsessive-compulsive disorder) and neurodevelopmental disorders (autism spectrum disorders, attention-deficit/hyperactivity disorder).

Biological sex, not reproductive cycle, influences peripheral blood immune cell prevalence in mice

KEY POINTS

Traditionally the female sex, compared with the male sex, has been perceived as having greater variability in many physiological traits, including within the immune system. We investigated effects of biological sex and the female reproductive cycle on numbers of circulating leukocytes in C57BL/6J mice. We show that biological sex, but not female reproductive cyclicity, has a significant effect on peripheral blood immune cell prevalence and variability, and that sex differences were not consistent amongst common inbred laboratory mouse strains. We found that male C57BL/6J mice, compared with female mice, have greater variability in peripheral blood immunophenotype, and that this was influenced by body weight. We created summary tables for researchers to facilitate experiment planning and sample size calculations for peripheral immune cells that consider the effects of biological sex.

ABSTRACT

Immunophenotyping (i.e. quantifying the number and types of circulating leukocytes) is used to characterize immune changes during health and disease, and in response to pharmacological and other interventions. Despite the importance of biological sex in immune function, there is considerable uncertainty amongst researchers as to the extent to which biological sex or the female reproductive cycle influence blood immunophenotype. We quantified circulating leukocytes by multicolour flow cytometry in young C57BL/6J mice and assessed the effects of the reproductive cycle, biological sex, and other experimental and biological factors on data variability. We found that there are no significant effects of the female reproductive cycle on the prevalence of peripheral blood B cells, NK cells, CD4⁺ T cells, CD8⁺ T cells, monocytes, or neutrophils. Immunophenotype composition and variability do not significantly change between stages of the female reproductive cycle. There are, however, sex-specific differences in immune cell prevalence, with fewer monocytes, neutrophils, and NK cells in female mice. Surprisingly, immunophenotype is more variable in male mice, and weight is a significant contributing factor. We provide tools for researchers to perform a priori sample size calculations for two-group and factorial analyses. We show that immunophenotype varies between inbred mouse strains, and that using equal sample sizes of male and female mice is not always appropriate for within-sex evaluations of immune cell populations in peripheral blood.

Maternal pineal melatonin in gestation and lactation physiology, and in fetal development and programming

Pregnancy and lactation are reproductive processes that rely on physiological adaptations that should be timely and adequately triggered to guarantee both maternal and fetal health. Pineal melatonin is a hormone that presents daily and seasonal variations that synchronizes the organism's physiology to the different demands across time through its specific mechanisms and ways of action. The reproductive system is a notable target for melatonin as it actively participates on reproductive physiology and regulates the hypothalamus-pituitary-gonads axis, influencing gonadotropins and sexual hormones synthesis and release. For its antioxidant properties, melatonin is also vital for the oocytes and spermatozoa quality and viability, and for blastocyst development. Maternal pineal melatonin blood levels increase during pregnancy and triggers the maternal physiological alterations in energy metabolism both during pregnancy and lactation to cope with the energy demands of both periods and to promote adequate mammary gland development. Moreover, maternal melatonin freely crosses the placenta and is the only source of this hormone to the fetus. It importantly times the conceptus physiology and influences its development and programing of several functions that depend on neural and brain development, ultimately priming adult behavior and energy and glucose metabolism. The present review aims to explain the above listed melatonin functions, including the potential alterations observed in the progeny gestated under maternal chronodisruption and/or hypomelatoninemia.

Sex Differences in the Development of the Rodent Corticolimbic System

In recent years, a growing body of research has shown sex differences in the prevalence and symptomatology of psychopathologies, such as depression, anxiety, and fear-related disorders, all of which show high incidence rates in early life. This has highlighted the importance of including female subjects in animal studies, as well as delineating sex differences in neural processing across development. Of particular interest is the corticolimbic system, comprising the hippocampus, amygdala, and medial prefrontal cortex. In rodents, these corticolimbic regions undergo dynamic changes in early life, and disruption to their normative development is believed to underlie the age and sex-dependent effects of stress on affective processing. In this review, we consolidate research on sex differences in the hippocampus, amygdala, and medial prefrontal cortex across early development. First, we briefly introduce current principles on sexual differentiation of the rodent brain. We then showcase corticolimbic regional sex differences in volume, morphology, synaptic organization, cell proliferation, microglia, and GABAergic signaling, and explain how these differences are influenced by perinatal and pubertal gonadal hormones. In compiling this research, we outline evidence of what and when sex differences emerge in the developing corticolimbic system, and illustrate how temporal dynamics of its maturational trajectory may differ in male and female rodents. This will help provide insight into potential neural mechanisms underlying sex-specific critical windows for stress susceptibility and behavioral emergence.

Association between EFHD2 gene polymorphisms and schizophrenia among the Han population in northern China

Objective

Schizophrenia is a severe neurodevelopmental disorder with a complex genetic and environmental etiology. The gene encoding EF-hand domain-containing protein D2 (EFHD2) may be a genetic risk locus for schizophrenia.

Methods

We genotyped four EFHD2 single-nucleotide polymorphisms (281 schizophrenia cases [SCZ], 321 controls) from northern Chinese Han individuals using Sanger sequencing and polymerase chain reaction-restriction fragment length polymorphism analysis. Differences existed in genotype, allele, and haplotype frequency distributions between SCZ and control groups.

Results

The rs2473357 genotype and allele frequency distributions differed between SCZ and controls; however, this difference disappeared after Bonferroni correction. Differences in rs2473357 genotype and allele frequency distributions between SCZ and controls were more pronounced in men than in women. The G allele increased schizophrenia risk (odds ratio = 1.807, 95% confidence interval = 1.164–2.803). Among six haplotypes (G–, A–, G-insC, A-C, G-C, and G-T), the G– haplotype frequency distribution differed between SCZ and controls in women; the A-C and G-C haplotype frequency distributions differed between SCZ and controls in men.

Conclusions

EFHD2 may be involved in schizophrenia. Sex differences in EFHD2 genotype and allele frequency distributions existed among schizophrenia patients. Further research is needed to determine the role of EFHD2 in schizophrenia.

Pet ownership in utero and in childhood decreases the effects of environmental tobacco smoke exposure on hypertension in children: A large population based cohort study

BACKGROUND

Little is known about whether exposure to pets influences the association between hypertension and environmental tobacco smoke (ETS). The current study aims to examine the interaction of pet ownership on ETS exposure and the development of hypertension in children.

METHODS

From 2012 to 2013, a total of 9354 children, 5 to 17 years of age, were recruited from 62 schools in seven northeastern cities. BP in children was measured and hypertension was defined as an average diastolic blood pressure (DBP) or systolic blood pressure (SBP) at or above the 95th percentile for that child's age, sex, and height. Pet ownership in three different time periods (in utero, past 2 years, and currently) and ETS exposure data were collected from parents via a questionnaire. Two-level regressions were used for the data analyses.

RESULTS

The data show consistent, significant interactions between exposure to pets and effects from ETS. Children who were not exposed to pets experienced stronger effects from ETS on hypertension when compared to those exposed to pets, and the protective effect of pet ownership became stronger with a greater number of pets in the home. Exposure to in utero ETS was associated with hypertension [adjusted odds ratio (aOR) = 1.32, 95% confidence interval (CI): 1.13-1.54] only for those children without pet exposure in utero but not for those with pets (aOR = 0.75; 95% CI: 0.49-1.15) (p_interaction < 0.05). Moreover, household dog ownership was related to significantly lower effects of current ETS on hypertension (aOR = 0.80, 95% CI: 0.61-1.05) compared with children without dogs (aOR = 1.26, 95% CI: 1.11-1.44) (p_interaction = 0.001). Interaction associations between ETS and pet ownership were more robust for girls than for boys and for younger than older children.

CONCLUSION

This study indicates an inverse relationship between pet ownership and ETS, potentially pointing to pet ownership as protecting against the development of hypertension in children.

Neuroprotective and neurotoxic outcomes of androgens and estrogens in an oxidative stress environment

BACKGROUND

The role of sex hormones on cellular function is unclear. Studies show androgens and estrogens are protective in the CNS, whereas other studies found no effects or damaging effects. Furthermore, sex differences have been observed in multiple oxidative stress-associated CNS disorders, such as Alzheimer's disease, depression, and Parkinson's disease. The goal of this study is to examine the relationship between sex hormones (i.e., androgens and estrogens) and oxidative stress on cell viability.

METHODS

N27 and PC12 neuronal and C6 glial phenotypic cell lines were used. N27 cells are female rat derived, whereas PC12 cells and C6 cells are male rat derived. These cells express estrogen receptors and the membrane-associated androgen receptor variant, AR45, but not the full-length androgen receptor. N27, PC12, and C6 cells were exposed to sex hormones either before or after an oxidative stressor to examine neuroprotective and neurotoxic properties, respectively. Estrogen receptor and androgen receptor inhibitors were used to determine the mechanisms mediating hormone-oxidative stress interactions on cell viability. Since the presence of AR45 in the human brain tissue was unknown, we examined the postmortem brain tissue from men and women for AR45 protein expression.

RESULTS

Neither androgens nor estrogens were protective against subsequent oxidative stress insults in glial cells. However, these hormones exhibited neuroprotective properties in neuronal N27 and PC12 cells via the estrogen receptor. Interestingly, a window of opportunity exists for sex hormone neuroprotection, wherein temporary hormone deprivation blocked neuroprotection by sex hormones. However, if sex hormones are applied following an oxidative stressor, they exacerbated oxidative stress-induced cell loss in neuronal and glial cells.

CONCLUSIONS

Sex hormone action on cell viability is dependent on the cellular environment. In healthy neuronal cells, sex hormones are protective against oxidative stress insults via the estrogen receptor, regardless of sex chromosome complement (XX, XY). However, in unhealthy (e.g., high oxidative stress) cells, sex hormones exacerbated oxidative stress-induced cell loss, regardless of cell type or sex chromosome complement. The non-genomic AR45 receptor, which is present in humans, mediated androgen's damaging effects, but it is unknown which receptor mediated estrogen's damaging effects. These differential effects of sex hormones that are dependent on the cellular environment, receptor profile, and cell type may mediate the observed sex differences in oxidative stress-associated CNS disorders.

Region-specific Effects of Maternal Separation on Perineuronal Net and Parvalbumin-expressing Interneuron Formation in Male and Female Rats

Early life experiences play a vital role in contributing to healthy brain development. Adverse experiences have a lasting impact on the prefrontal cortex (PFC) and basolateral amygdala (BLA), brain regions associated with emotion regulation. Early life adversity via maternal separation (MS) has sex-specific effects on expression of parvalbumin (PV), which is expressed in fast-spiking GABAergic interneurons that are preferentially enwrapped by perineuronal nets (PNNs). Importantly, PNN formation coincides with the closure of developmental critical periods and regulates PV-expressing interneuron activity. Since aberrant PNN organization has been reported following adverse experiences in adolescent and adult rats, we investigated the impact of adversity early in life in the form of MS on the developing brain. Rat pups were separated from their dams for 4 h per day from postnatal day (P) 2-20. Tissue sections from juvenile (P20), adolescent (P40), and early adult (P70) animals containing the PFC and BLA were fluorescently stained to visualize Wisteria floribunda agglutinin+ PNNs and PV-expressing interneurons, and density and intensity was quantified. Our results confirm past reports that PFC PNNs form gradually throughout development; however, PNN density plateaus in adolescence, while intensity continues to increase into adulthood. Importantly, MS delays PNN formation in the prelimbic PFC and results in sex-specific aberrations in PNN structural integrity that do not appear until adulthood. The present findings reveal sex-, age-, and region-specific effects of early life adversity on PNN and PV maturation, implicating neuroplastic alterations following early life adversity that may be associated with sex differences in psychopathology and resilience.

Suicide risk in people living with AIDS/HIV: the effect of childhood trauma is mediated by mental disorders and social vulnerability

Suicide is an important problem in people living with HIV/AIDS (PLWHA). The importance of mental disorders and social vulnerability on suicidal behaviors is described in the literature; however, the impact of childhood traumatic events in this scenario is not clear. The aim of this study was to verify the mediation effect of mental disorder comorbidities and social vulnerability in association with childhood trauma intensity and suicide risk level. This cross-sectional study of HIV-positive outpatients was conducted in a specialized care service in the city of Pelotas in Southern Brazil. Sociodemographic data and HIV-related information were collected and the Childhood Trauma Questionnaire was applied. A total of 364 patients underwent psychiatric evaluation using MINI Plus including module C of suicide risk severity. Suicide risk was present in 39.3% of the sample. The relation between childhood traumatic events and the level of suicide risk is mediated by mental disorder comorbidities and socioeconomic vulnerability. Specific psychosocial interventions in PLWHA should consider the potential role of abusive traumatic experiences in the current mental health conditions and suicidal behaviors.

Curcumin: Novel Treatment in Neonatal Hypoxic-Ischemic Brain Injury

Hypoxic-ischemic encephalopathy (HIE) is a major cause of mortality and morbidity in neonates, with an estimated global incidence of 3/1,000 live births. HIE brain damage is associated with an inflammatory response and oxidative stress, resulting in the activation of cell death pathways. At present, therapeutic hypothermia is the only clinically approved treatment available for HIE. This approach, however, is only partially effective. Therefore, there is an unmet clinical need for the development of novel therapeutic interventions for the treatment of HIE. Curcumin is an antioxidant reactive oxygen species scavenger, with reported anti-tumor and anti-inflammatory activity. Curcumin has been shown to attenuate mitochondrial dysfunction, stabilize the cell membrane, stimulate proliferation, and reduce injury severity in adult models of spinal cord injury, cancer, and cardiovascular disease. The role of curcumin in neonatal HIE has not been widely studied due to its low bioavailability and limited aqueous solubility. The aim of this study was to investigate the effect of curcumin treatment in neonatal HIE, including time of administration and dose-dependent effects. Our results indicate that curcumin administration prior to HIE in neonatal mice elevated cell and tissue loss, as well as glial activation compared to HI alone. However, immediate post-treatment with curcumin was significantly neuroprotective, reducing grey and white matter tissue loss, TUNEL+ cell death, microglia activation, reactive astrogliosis, and iNOS oxidative stress when compared to vehicle-treated littermates. This effect was dose-dependent, with 200 μg/g body weight as the optimal dose-regimen, and was maintained when curcumin treatment was delayed by 60 or 120 min post-HI. Cell proliferation measurements showed no changes between curcumin and HI alone, suggesting that the protective effects of curcumin on the neonatal brain following HI are most likely due to curcumin’s anti-inflammatory and antioxidant properties, as seen in the reduced glial and iNOS activity. In conclusion, this study suggests curcumin as a potent neuroprotective agent with potential for the treatment of HIE. The delayed application of curcumin further increases its clinical relevance.

Sex Differences in the Adult Human Brain: Evidence from 5216 UK Biobank Participants

Sex differences in the human brain are of interest for many reasons: for example, there are sex differences in the observed prevalence of psychiatric disorders and in some psychological traits that brain differences might help to explain. We report the largest single-sample study of structural and functional sex differences in the human brain (2750 female, 2466 male participants; mean age 61.7 years, range 44-77 years). Males had higher raw volumes, raw surface areas, and white matter fractional anisotropy; females had higher raw cortical thickness and higher white matter tract complexity. There was considerable distributional overlap between the sexes. Subregional differences were not fully attributable to differences in total volume, total surface area, mean cortical thickness, or height. There was generally greater male variance across the raw structural measures. Functional connectome organization showed stronger connectivity for males in unimodal sensorimotor cortices, and stronger connectivity for females in the default mode network. This large-scale study provides a foundation for attempts to understand the causes and consequences of sex differences in adult brain structure and function.

Dissecting the syndrome of schizophrenia: Associations between symptomatology and hormone levels in women with schizophrenia

Despite many studies implicating reproductive hormones in the development and outcome of schizophrenia, few have characterised the association between symptomatology and hormonal trajectories. To understand the influence of hormones on schizophrenia symptoms, serum steroids (estradiol, progesterone, follicular stimulating hormone (FSH), luteinising hormone (LH), and dehydroepiandrosterone (DHEA)) and psychopathology (The positive-and-negative-syndrome-scale(PANSS)) and depression (Montgomery-Asberg-Depression-Rating Scale(MADRS)) were collected across 12-weeks in 45 women (mean age 46) diagnosed with schizophrenia. To account for potential heterogeneity, Group-based-trajectory-modelling of psychopathology was used to identify distinct subgroups of individuals following a similar pattern of association between symptom score and hormone levels over-time. Two trajectories were identified for PANSS: one subgroup with lower symptom severity was associated with FSH, DHEA, LH, and another high severity subgroup associated with LH. Two trajectories were identified for MADRS: 'depressed' (associated with FSH), and non-depressed. The result delineates subpopulations with unique psychopathology and hormone associations that support the hypothesis that reproductive hormones play a role in the pathophysiology of schizophrenia, and that heterogeneity may exist in hormonal sensitivities in the schizophrenia population. Stratification of subjects according to biological phenotype may help improve existing treatments through personalised-medicine strategies. The endocrine system may be one such biological mechanism to continue dissecting the syndrome.

Sex differences in limbic network and risk-taking propensity in healthy individuals

Little is known about the structural neural substrates that may contribute to sex differences in risk-taking propensity (RTP). A close association between risk-seeking behavior and the emotional-regulation network led us to hypothesize that the sex differences in RTP would be associated with sex differences in brain morphometry of the limbic network (LN). We collected RTP scores using the bubble sheet version of the evaluation of risk (EVAR) scale and neuroanatomical data from 57 healthy individuals (29 males). The EVAR scale included sub-scales measuring recklessness/impulsivity, self-confidence, and need for control (NFC). We observed significant sex differences in NFC showing greater desire for control and dominance in males than females (multivariate analysis of covariance, MANCOVAN: p = .01). Morphometry analysis showed that it was only the right LN, which showed significant sex differences in normalized surface area, normalized cortical volume, and adjusted mean curvature index (females > males) at p < .01 (MANCOVAN, corrected for multiple comparisons). Correlation analysis showed that greater curvature of the right LN was significantly associated with lower desire for control in high-risk events (r = -.31, p = .02 at 95% CI of [-0.53, -0.05]). Our findings suggest that the normalized cortical measures could indicate specific sex differences in brain morphometry, particularly within the LN. The curvature index was the only differentiating factor for greater/lower propensity for risk-taking behavior in overall sample. Therefore, the LN and the curvature measures could be key biomarkers, which play an important role in predicting risk-taking behavior.

Structural plasticity of the hippocampus in response to estrogens in female rodents

It is well established that estrogens affect neuroplasticity in a number of brain regions. In particular, estrogens modulate and mediate spine and synapse formation as well as neurogenesis in the hippocampal formation. In this review, we discuss current research exploring the effects of estrogens on dendritic spine plasticity and neurogenesis with a focus on the modulating factors of sex, age, and pregnancy. Hormone levels, including those of estrogens, fluctuate widely across the lifespan from early life to puberty, through adulthood and into old age, as well as with pregnancy and parturition. Dendritic spine formation and modulation are altered both by rapid (likely non-genomic) and classical (genomic) actions of estrogens and have been suggested to play a role in the effects of estrogens on learning and memory. Neurogenesis in the hippocampus is influenced by age, the estrous cycle, pregnancy, and parity in female rodents. Furthermore, sex differences exist in hippocampal cellular and molecular responses to estrogens and are briefly discussed throughout. Understanding how structural plasticity in the hippocampus is affected by estrogens and how these effects can influence function and be influenced by other factors, such as experience and sex, is critical and can inform future treatments in conditions involving the hippocampus.

ADGRL3 rs6551665 as a Common Vulnerability Factor Underlying Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder

Neurodevelopmental disorders are prevalent, frequently occur in comorbidity and share substantial genetic correlation. Previous evidence has suggested a role for the ADGRL3 gene in Attention-Deficit/Hyperactivity Disorder (ADHD) susceptibility in several samples. Considering ADGRL3 functionality in central nervous system development and its previous association with neurodevelopmental disorders, we aimed to assess ADGRL3 influence in early-onset ADHD (before 7 years of age) and Autism Spectrum Disorder (ASD). The sample comprises 187 men diagnosed with early-onset ADHD, 135 boys diagnosed with ASD and 468 male blood donors. We tested the association of an ADGRL3 variant (rs6551665) with both early-onset ADHD and ASD susceptibility. We observed significant associations between ADGRL3-rs6551665 on ADHD and ASD susceptibilities; we found that G-carriers were at increased risk of ADHD and ASD, in accordance with previous studies. The overall evidence from the literature, corroborated by our results, suggests that ADGRL3 might be involved in brain development, and genetic modifications related to it might be part of a shared vulnerability factor associated with the underlying neurobiology of neurodevelopmental disorders such as ADHD and ASD.

Sex-dependent regulation of social reward by oxytocin: an inverted U hypothesis

The rewarding properties of social interactions are essential for the expression of social behavior and the development of adaptive social relationships. Here, we review sex differences in social reward, and more specifically, how oxytocin (OT) acts in the mesolimbic dopamine system (MDS) to mediate the rewarding properties of social interactions in a sex-dependent manner. Evidence from rodents and humans suggests that same-sex social interactions may be more rewarding in females than in males. We propose that there is an inverted U relationship between OT dose, social reward, and neural activity within structures of the MDS in both males and females, and that this dose-response relationship is initiated at lower doses in females than males. As a result, depending on the dose of OT administered, OT could reduce social reward in females, while enhancing it in males. Sex differences in the neural mechanisms regulating social reward may contribute to sex differences in the incidence of a large number of psychiatric and neurodevelopmental disorders. This review addresses the potential significance of a sex-dependent inverted U dose-response function for OT's effects on social reward and in the development of gender-specific therapies for these disorders.

Sex Differences in Aging and Associated Biomarkers

Aging is a natural process defined by the gradual, time-dependent decline of biological and behavioural functions, for which individuals of the same chronological age show variability. The capacity of biological systems to continuously adjust for optimal functioning despite ever changing environments is essential for healthy aging, and variability in these adaptive homeostatic mechanisms may reflect such heterogeneity in the aging process. With an ever-increasing aging population, interest in biomarkers of aging is growing. Although no universally accepted definition of biomarkers of healthy aging exists, mediators of homeostasis are consistently used as measures of the aging process. As important sex differences are known to underlie many of these systems, it is imperative to consider that this may reflect, to some extent, the sex differences observed in aging and age-related disease states. This chapter aims to outline sex differences in key homeostatic domains thought to be associated with the pathophysiology of aging, often proposed as biomarkers of aging and age-related disease states. This includes considering sex-based differences and hormonal status with regards to the gonadal and adrenal endocrine systems and immune function.

Sex differences in hippocampal cognition and neurogenesis

Sex differences are reported in hippocampal plasticity, cognition, and in a number of disorders that target the integrity of the hippocampus. For example, meta-analyses reveal that males outperform females on hippocampus-dependent tasks in rodents and in humans, furthermore women are more likely to experience greater cognitive decline in Alzheimer's disease and depression, both diseases characterized by hippocampal dysfunction. The hippocampus is a highly plastic structure, important for processing higher order information and is sensitive to the environmental factors such as stress. The structure retains the ability to produce new neurons and this process plays an important role in pattern separation, proactive interference, and cognitive flexibility. Intriguingly, there are prominent sex differences in the level of neurogenesis and the activation of new neurons in response to hippocampus-dependent cognitive tasks in rodents. However, sex differences in spatial performance can be nuanced as animal studies have demonstrated that there are task, and strategy choice dependent sex differences in performance, as well as sex differences in the subregions of the hippocampus influenced by learning. This review discusses sex differences in pattern separation, pattern completion, spatial learning, and links between adult neurogenesis and these cognitive functions of the hippocampus. We emphasize the importance of including both sexes when studying genomic, cellular, and structural mechanisms of the hippocampal function.

Sex differences in psychiatric disorders: what we can learn from sex chromosome aneuploidies

The study of sexual dimorphism in psychiatric and neurodevelopmental disorders is challenging due to the complex interplay of diverse biological, psychological, and social factors. Males are more susceptible to neurodevelopmental disorders including intellectual disability, autism spectrum disorder, and attention-deficit activity disorder. Conversely, after puberty, females are more prone to major depressive disorder and anxiety disorders compared to males. One major biological factor contributing to sex differences is the sex chromosomes. First, the X and Y chromosomes have unique and specific genetic effects as well as downstream gonadal effects. Second, males have one X chromosome and one Y chromosome, while females have two X chromosomes. Thus, sex chromosome constitution also differs between the sexes. Due to this complexity, determining genetic and downstream biological influences on sexual dimorphism in humans is challenging. Sex chromosome aneuploidies, such as Turner syndrome (X0) and Klinefelter syndrome (XXY), are common genetic conditions in humans. The study of individuals with sex chromosome aneuploidies provides a promising framework for studying sexual dimorphism in neurodevelopmental and psychiatric disorders. Here we will review and contrast four syndromes caused by variation in the number of sex chromosomes: Turner syndrome, Klinefelter syndrome, XYY syndrome, and XXX syndrome. Overall we describe an increased rate of attention-deficit hyperactivity disorder and autism spectrum disorder, along with the increased rates of major depressive disorder and anxiety disorders in one or more of these conditions. In addition to contributing unique insights about sexual dimorphism in neuropsychiatric disorders, awareness of the increased risk of neurodevelopmental and psychiatric disorders in sex chromosome aneuploidies can inform appropriate management of these common genetic disorders.

Effects of sex and menstrual cycle phase on cardiac response and alpha- amylase levels in psychosocial stress

The impact of sex and the menstrual cycle phase on the autonomic response to psychosocial stress remains controversial. This study explored autonomic nervous system activity through salivary alpha-amylase, heart rate, and heart rate variability responses to the Trier Social Stress Test (TSST) in healthy young people. The sample was composed of 25 men, 26 women in the luteal phase, and 25 women in the follicular phase, from 18 to 25 years of age. Participants were exposed to the TSST or a control condition. The results indicate that women in their follicular phase showed a blunted alpha-amylase response to stress compared to men and women in the luteal phase. In addition, men showed higher sympatho-vagal activity in the stress condition compared to the two groups of women. These results confirm that sex and the menstrual cycle phase are potential modulators of autonomic nervous system reactivity to psychosocial stress.

Is smaller worse? New insights about associations of PM1 and respiratory health in children and adolescents

BACKGROUND AND OBJECTIVES

Little is known about PM₁ effects on respiratory health, relative to larger size fractions (PM_2.5). To address this literature gap, we assessed associations between PM₁ exposure and asthmatic symptoms in Chinese children and adolescents, compared with PM_2.5.

METHODS

A total of 59,754 children, aged 2-17 years, were recruited from 94 kindergartens, elementary and middle schools in the Seven Northeast Cities (SNEC) study, during 2012-2013. We obtained information on asthma and asthma-related symptoms including wheeze, persistent phlegm, and persistent cough using a standardized questionnaire developed by the American Thoracic Society. PM₁ and PM_2.5 concentrations were estimated using a spatial statistical model matched to the children's geocoded home addresses. To examine the associations, mixed models with school/kindergarten as random intercept were used, controlling for covariates.

RESULTS

Odds ratios (ORs) of doctor-diagnosed asthma associated with a 10-μg/m³ increase for PM₁ and PM_2.5 were 1.56 (95% CI: 1.46-1.66) and 1.50 (1.41-1.59), respectively, and similar pattern were observed for other outcomes. Interaction analyses indicated that boys and the individuals with an allergic predisposition may be vulnerable subgroups. For example, among children with allergic predisposition, the ORs for doctor diagnosed asthma per 10 μg/m³ increase in PM₁ was 1.71 (95% CI: 1.60-1.83), which was stronger than in their counterparts (1.46; 1.37-1.56) (p_{for interaction} < 0.05).

CONCLUSIONS

This study indicated that long-term exposure to PM₁ may increase the risk of asthma and asthma-related symptoms, especially among boys and those with allergic predisposition. Furthermore, these positive associations for PM₁ were very similar to those for PM_2.5.

Polymorphisms in the human serotonin receptor 1B (HTR1B) gene are associated with schizophrenia: a case control study

BACKGROUND

Schizophrenia is associated with multiple neurotransmitter disorders, including serotonin (5-hydroxytryptamine, 5-HT). The neuromodulatory action of serotonin on brain function largely depends on the action of specific subtypes of serotonin receptors. The serotonin receptor 1B (HTR1B) gene has been proposed to play putative roles in the development of multiple emotional and psychiatric disorders.

METHODS

To study the relationship of HTR1B polymorphisms and schizophrenia, gene information was drawn from a cohort of 310 schizophrenic patients (152 men and 158 women) and 313 healthy controls (153 men and 160 women) of northern Han Chinese descent. The χ2 test was used to compare allele and genotype distributions between case and control groups. The haplotype and linkage equilibrium were also assessed in two group comparisons.

RESULTS

We detected 14 SNPs. Male patients were observed to have higher frequencies of the A-allele and AA+AG genotype at rs1778258 than female patients (p = 0.012 and p = 0.015, respectively). Both the A-allele and AA+AG genotype were associated with schizophrenia risk (OR = 1.986 and OR = 2.061, respectively), although the statistical significance of the genotype was lost after Bonferroni correction. Linkage analysis showed that rs17273700, rs11568817, rs9361234 and rs58138557 polymorphisms exhibit strong linkage disequilibrium (LD). In addition, schizophrenic patients show stronger linkage between 11,568,817 and rs130058 than healthy controls.

CONCLUSIONS

HTR1B polymorphisms are associated with schizophrenia in the northern Han Chinese population, which provides an etiological reference for schizophrenia.

The Intersection of Sex Differences, Tobacco Use, and Inflammation: Implications for Psychiatric Disorders

PURPOSE OF REVIEW

Tobacco use, sex differences, and psychiatric disorders are associated with altered immune function. There are also sex differences in tobacco use and psychiatric disorders. This review summarizes findings from the small, but growing literature examining sex differences in the effects of tobacco use on inflammation and the implications for psychiatric disorders.

RECENT FINDINGS

We identified four studies that tested the interaction between sex and tobacco/nicotine on inflammation. Although males and females generally exhibited differential tobacco-induced immune responses, the pattern varied depending on the sample (rodents vs. humans) and the method to evaluate inflammation. Evidence suggests that sex modulates the effects of tobacco smoke on inflammation. Many inflammation markers associated with sex differences and tobacco use are related to psychiatric disorders. We propose a model in which sex, tobacco use, and inflammation interact to increase risk for psychiatric disorders. Future studies are needed to examine the mechanisms that explain this relationship.

Principal component analysis identifies differential gender-specific dietary patterns that may be linked to mental distress in human adults

Independent reports describe the structural differences between the human male and female brains and the differential gender-susceptibility to mood disorders. Nutrition is one of the modifiable risk factors that has been reported to impact brain chemistry and affect mental health. Objectives: To study dietary patterns in adult men and women in relation to mental distress. Another aim was to develop evidence-based prototypes using System Dynamic Modeling methodology to better describe our findings. Methods: An anonymous internet-based survey was sent through social media platforms to different social and professional networks. Multivariate analyses were used for data mining. Data were stratified by gender and further by tertiles to capture the latent variables within the patterns of interest. Results: Mental distress in men associated with a consumption of a Western-like diet. In women, mental wellbeing associated with a Mediterranean-like diet and lifestyle. No other patterns in both genders were linked to mental distress. Based on the generated prototypes, men are more likely to experience mental wellbeing until nutritional deficiencies arise. However, women are less likely to experience mental wellbeing until a balanced diet and a healthy lifestyle are followed. In men, dietary deficiencies may have a profound effect on the limbic system; whereas dietary sufficiency in women may potentiate the mesocortical regulation of the limbic system. Discussion and conclusion: Our results may explain the several reports in the literature that women are at a greater risk for mental distress when compared to men and emphasize the role of a nutrient-dense diet in mental wellbeing.

Sex-Dependent Effects of the Histone Deacetylase Inhibitor, Sodium Valproate, on Reversal Learning After Developmental Arsenic Exposure

Several studies have demonstrated that exposure to arsenic in drinking water adversely affects brain development and cognitive function in adulthood. While the mechanism by which arsenic induces adverse neurological outcomes remains elusive, studies suggest a link between reduced levels of histone acetylation and impaired performance on a variety of behavioral tasks following arsenic exposure. Using our developmental arsenic exposure (DAE) paradigm, we have previously reported reduced histone acetylation and associated histone acetyltransferase enzyme expression in the frontal cortex of C57BL/6J adult male mice, with no changes observed in the female frontal cortex. In the present study, we sought to determine if DAE produced sex-dependent deficits in frontal cortical executive function using the Y-maze acquisition and reversal learning tasks, which are specific for assessing cognitive flexibility. Further, we tested whether the administration of valproic acid, a class I-IIa histone deacetylase inhibitor, was able to mitigate behavioral and biochemical changes resulting from DAE. As anticipated, DAE inhibited acquisition and reversal learning performance in adult male, but not female, mice. Valproate treatment for 2 weeks restored reversal performance in the male arsenic-exposed offspring, while not affecting female performance. Protein levels of HDACs 1, 2, and 5 were elevated following behavioral assessment but only in DAE male mice; restoration of appropriate HDAC levels occurred after valproate treatment and was concurrent with improved behavioral performance, particularly during reversal learning. Female frontal cortical levels of HDAC enzymes were not impacted by DAE or valproate treatment. Finally, mRNA expression levels of brain-derived neurotrophic factor, Bdnf, which has been implicated in the control of frontal cortical flexibility and is regulated by HDAC5, were elevated in DAE male mice and restored to normal levels following HDACi treatment. Levels of mRNA encoding glutamate receptor ionotropic NMDA type subunits, which have been linked to cognitive flexibility, were not related to the reversal learning deficit in the DAE mice and were not altered by HDACi treatments. These findings demonstrate that DAE alters frontal cortical HDAC levels and Bdnf expression in males, but not females, and that these molecular changes are associated with sex-dependent differences in cognitive flexibility in a reversal-learning task.

Estradiol and the Development of the Cerebral Cortex: An Unexpected Role?

The cerebral cortex undergoes rapid folding in an "inside-outside" manner during embryonic development resulting in the establishment of six discrete cortical layers. This unique cytoarchitecture occurs via the coordinated processes of neurogenesis and cell migration. In addition, these processes are fine-tuned by a number of extracellular cues, which exert their effects by regulating intracellular signaling pathways. Interestingly, multiple brain regions have been shown to develop in a sexually dimorphic manner. In many cases, estrogens have been demonstrated to play an integral role in mediating these sexual dimorphisms in both males and females. Indeed, 17β-estradiol, the main biologically active estrogen, plays a critical organizational role during early brain development and has been shown to be pivotal in the sexually dimorphic development and regulation of the neural circuitry underlying sex-typical and socio-aggressive behaviors in males and females. However, whether and how estrogens, and 17β-estradiol in particular, regulate the development of the cerebral cortex is less well understood. In this review, we outline the evidence that estrogens are not only present but are engaged and regulate molecular machinery required for the fine-tuning of processes central to the cortex. We discuss how estrogens are thought to regulate the function of key molecular players and signaling pathways involved in corticogenesis, and where possible, highlight if these processes are sexually dimorphic. Collectively, we hope this review highlights the need to consider how estrogens may influence the development of brain regions directly involved in the sex-typical and socio-aggressive behaviors as well as development of sexually dimorphic regions such as the cerebral cortex.

Neuroanatomical morphometric characterization of sex differences in youth using statistical learning

Exploring neuroanatomical sex differences using a multivariate statistical learning approach can yield insights that cannot be derived with univariate analysis. While gross differences in total brain volume are well-established, uncovering the more subtle, regional sex-related differences in neuroanatomy requires a multivariate approach that can accurately model spatial complexity as well as the interactions between neuroanatomical features. Here, we developed a multivariate statistical learning model using a support vector machine (SVM) classifier to predict sex from MRI-derived regional neuroanatomical features from a single-site study of 967 healthy youth from the Philadelphia Neurodevelopmental Cohort (PNC). Then, we validated the multivariate model on an independent dataset of 682 healthy youth from the multi-site Pediatric Imaging, Neurocognition and Genetics (PING) cohort study. The trained model exhibited an 83% cross-validated prediction accuracy, and correctly predicted the sex of 77% of the subjects from the independent multi-site dataset. Results showed that cortical thickness of the middle occipital lobes and the angular gyri are major predictors of sex. Results also demonstrated the inferential benefits of going beyond classical regression approaches to capture the interactions among brain features in order to better characterize sex differences in male and female youths. We also identified specific cortical morphological measures and parcellation techniques, such as cortical thickness as derived from the Destrieux atlas, that are better able to discriminate between males and females in comparison to other brain atlases (Desikan-Killiany, Brodmann and subcortical atlases).

More than a feeling: A unified view of stress measurement for population science

Stress can influence health throughout the lifespan, yet there is little agreement about what types and aspects of stress matter most for human health and disease. This is in part because "stress" is not a monolithic concept but rather, an emergent process that involves interactions between individual and environmental factors, historical and current events, allostatic states, and psychological and physiological reactivity. Many of these processes alone have been labeled as "stress." Stress science would be further advanced if researchers adopted a common conceptual model that incorporates epidemiological, affective, and psychophysiological perspectives, with more precise language for describing stress measures. We articulate an integrative working model, highlighting how stressor exposures across the life course influence habitual responding and stress reactivity, and how health behaviors interact with stress. We offer a Stress Typology articulating timescales for stress measurement - acute, event-based, daily, and chronic - and more precise language for dimensions of stress measurement.