Early androgen exposure modulates spatial cognition in congenital adrenal hyperplasia (CAH)

Toward a Robust Definition of Sport Sex

Elite individual sports in which success depends on power, speed, or endurance are conventionally divided into male and female events using traditional binary definitions of sex. Male puberty creates durable physical advantages due to the 20- to 30-fold increase in circulating testosterone producing a sustained uplift in men's muscle, bone, hemoglobin, and cardiorespiratory function resulting from male puberty and sustained during men's lives. These male physical advantages provide strong justification for a separate protected category of female events allowing women to achieve the fame and fortune from success they would be denied if competing against men. Recent wider social acceptance of transgender individuals, together with the less recognized involvement of intersex individuals, challenge and threaten to defeat the sex classifications for elite individual female events. This can create unfair advantages if seeking inclusion into elite female events of unmodified male-bodied athletes with female gender identity who have gained the physical advantages of male puberty. Based on reproductive physiology, this paper proposes a working definition of sport sex based primarily on an individual's experience of male puberty and can be applied to transgender and various XY intersex conditions. Consistent with the multidimensionality of biological sex (chromosomal, genetic, hormonal, anatomical sex), this definition may be viewed as a multistrand cable whose overall strength survives when any single strand weakens or fails, rather than as a unidimensional chain whose strength is only as good as its weakest link.

Glucocorticoids and cognitive function: a walkthrough in endogenous and exogenous alterations

PURPOSE

The hypothalamic-pituitary-adrenal (HPA) axis exerts many actions on the central nervous system (CNS) aside from stress regulation. Glucocorticoids (GCs) play an important role in affecting several cognitive functions through the effects on both glucocorticoid (GR) and mineralocorticoid receptors (MR). In this review, we aim to unravel the spectrum of cognitive dysfunction secondary to derangement of circulating levels of endogenous and exogenous glucocorticoids.

METHODS

All relevant human prospective and retrospective studies published up to 2022 in PubMed reporting information on HPA disorders, GCs, and cognition were included.

RESULTS

Cognitive impairment is commonly found in GC-related disorders. The main brain areas affected are the hippocampus and pre-frontal cortex, with memory being the most affected domain. Disease duration, circadian rhythm disruption, circulating GCs levels, and unbalanced MR/GR activation are all risk factors for cognitive decline in these patients, albeit with conflicting data among different conditions. Lack of normalization of cognitive dysfunction after treatment is potentially attributable to GC-dependent structural brain alterations, which can persist even after long-term remission.

CONCLUSION

The recognition of cognitive deficits in patients with GC-related disorders is challenging, often delayed, or mistaken. Prompt recognition and treatment of underlying disease may be important to avoid a long-lasting impact on GC-sensitive areas of the brain. However, the resolution of hormonal imbalance is not always followed by complete recovery, suggesting irreversible adverse effects on the CNS, for which there are no specific treatments. Further studies are needed to find the mechanisms involved, which may eventually be targeted for treatment strategies.

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.

Endocrine-Disrupting Chemicals and Hippocampal Development: The Role of Estrogen and Androgen Signaling

Hormones are important regulators of key processes during fetal brain development. Thus, the developing brain is vulnerable to the action of chemicals that can interfere with endocrine signals. Epidemiological studies have pointed toward sexually dimorphic associations between neurodevelopmental outcomes, such as cognitive abilities, in children and prenatal exposure to endocrine-disrupting chemicals (EDCs). This points toward disruption of sex steroid signaling in the development of neural structures underlying cognitive functions, such as the hippocampus, an essential mediator of learning and memory processes. Indeed, during development, the hippocampus is subjected to the organizational effects of estrogens and androgens, which influence hippocampal cell proliferation, differentiation, dendritic growth, and synaptogenesis in the hippocampal fields of Cornu Ammonis and the dentate gyrus. These early organizational effects correlate with a sexual dimorphism in spatial cognition and are subject to exogenous chemical perturbations. This review summarizes the current knowledge about the organizational effects of estrogens and androgens on the developing hippocampus and the evidence for hippocampal-dependent learning and memory perturbations induced by developmental exposure to EDCs. We conclude that, while it is clear that sex hormone signaling plays a significant role during hippocampal development, a complete picture at the molecular and cellular levels would be needed to establish causative links between the endocrine modes of action exerted by EDCs and the adverse outcomes these chemicals can induce at the organism level.

Eye-Movements During Navigation in a Virtual Environment: Sex Differences and Relationship to Sex Hormones

Sex differences in spatial navigation have been related to different navigation strategies. For example, women are more likely to utilize local landmark-information in the environment compared to men. Furthermore, sex differences appear to be more pronounced when distances need to be judged in Euclidian terms and an allocentric representation of the environment is necessary. This suggests differential attentional processes during spatial navigation in men and women. However, eye-tracking studies on spatial navigation exploring these attentional processes are rare. The present study (39 men and 36 women) set out to investigate sex differences in eye-movements during spatial navigation in a 3D environment using virtual reality goggles. While we observed the expected sex differences in overall navigation performance, women did not benefit from the landmark-based instructions. Gaze fixations were in accordance with the preferred Euclidian strategy in men, but did not confirm the expected landmark-based strategy in women. However, high estradiol levels where related to an increased focus on landmark information. Surprisingly, women showed longer gaze distances than men, although the utilization of distal landmarks has been related to allocentric representations preferred by men. In fact, larger gaze distances related to slower navigation, even though previous studies suggest that the utilization of distal landmarks is beneficial for navigation. The findings are discussed with respect to the utility of virtual reality presentation for studies on sex differences in navigation. While virtual reality allows a full first-person immersion in the environment, proprioceptive and vestibular information is lacking.

Exploring the sex and gender correlates of cognitive sex differences

The correlates of cognitive sex differences are yet to be fully understood. Many biological and psychosocial factors modulate these cognitive abilities leading to mixed results in the scientific literature. The current study aims to explore the different parameters potentially influencing cognitive abilities acting in synergy. Sex and gender correlates of cognitive functioning were assessed in a sample of individuals ages 18 to 45 years (N = 87) from diverse sexual orientations. Sex hormones were assessed via saliva samples at four timepoints throughout the testing. Gender roles, sexual orientation and socio-demographics were measured via self-report questionnaires. Participants completed mental rotation and verbal fluency tasks. Men performed better than women at mental rotation, while no significant difference was found for verbal fluency. Significant positive associations were observed between estradiol and word fluency for the naturally cycling women compared to the women using oral contraception. While controlling for sex hormones, a significant interaction effect of sex by gender roles was identified for mental rotation among masculine women. These exploratory results suggest an effect principally driven by sex and sex hormones on cognitive performance that will need to be furthered with larger studies.

Berberine Improves Cognitive Impairment by Simultaneously Impacting Cerebral Blood Flow and β-Amyloid Accumulation in an APP/tau/PS1 Mouse Model of Alzheimer's Disease

Alzheimer's disease (AD) is accompanied by β-amyloid (Aβ), neurofibrillary tangles, and neuron cell death, and is one of the most commonly occurring diseases among the elderly. The pathology of AD is complex, involving Aβ overproduction and accumulation, tau hyperphosphorylation, and neuronal loss. In addition, chronic cerebral hypoperfusion (CCH) is ubiquitous in the AD patients and plans a pivotal role in triggering and exacerbating the pathophysiological progress of AD. The goal of this study was to investigate the neuroprotective properties of berberine (BBR) and the underlying mechanism. During the study, BBR was administrated to treat the triple-transgenic mouse model of Alzheimer's disease (3×Tg AD). To thoroughly evaluate the effects of the BBR administration, multiple manners were utilized, for instance, 3D arterial spin labeling technique, Morris water maze assay, immunofluorescence staining, TUNEL assay, laser speckle contrast imaging, western blotting, etc. The results showed that BBR ameliorated cognitive deficits in 3×Tg AD mice, reduced the Aβ accumulation, inhibited the apoptosis of neurons, promoted the formation of microvessels in the mouse brain by enhancing brain CD31, VEGF, N-cadherin, Ang-1. The new vessels promoted by BBR were observed to have a complete structure and perfect function, which in turn promoted the recovery of cerebral blood flow (CBF). In general, berberine is effective to 3×Tg AD mice, has a neuroprotective effect, and is a candidate drug for the multi-target prevention and treatment of AD.

Men, women and STEM: Why the differences and what should be done?

It is a well-known and widely lamented fact that men outnumber women in a number of fields in STEM (science, technology, engineering and maths). The most commonly discussed explanations for the gender gaps are discrimination and socialization, and the most common policy prescriptions target those ostensible causes. However, a great deal of evidence in the behavioural sciences suggests that discrimination and socialization are only part of the story. The purpose of this paper is to highlight other aspects of the story: aspects that are commonly overlooked or downplayed. More precisely, the paper has two main aims. The first is to examine the evidence that factors other than workplace discrimination contribute to the gender gaps in STEM. These include relatively large average sex differences in career and lifestyle preferences, and relatively small average differences in cognitive aptitudes – some favouring males, others favouring females – which are associated with progressively larger differences the further above the average one looks. The second aim is to examine the evidence suggesting that these sex differences are not purely a product of social factors but also have a substantial biological (i.e. inherited) component. A more complete picture of the causes of the unequal sex ratios in STEM may productively inform policy discussions.

Pubertal timing predicts adult psychosexuality: Evidence from typically developing adults and adults with isolated GnRH deficiency

Evidence suggests that psychosexuality in humans is modulated by both organizational effects of prenatal and peripubertal sex steroid hormones, and by activational effects of circulating hormones in adulthood. Experimental work in male rodents indicates that sensitivity to androgen-driven organization of sexual motivation decreases across the pubertal window, such that earlier puberty leads to greater sex-typicality. We test this hypothesis in typically developing men (n = 231) and women (n = 648), and in men (n = 72) and women (n = 32) with isolated GnRH deficiency (IGD), in whom the precise timing of peripubertal hormone exposure can be ascertained via the age at which hormone replacement therapy (HRT) was initiated. Psychosexuality was measured with the Sexual Desire Inventory-2 (SDI-2) and Sociosexual Orientation Inventory-Revised (SOI-R). In both sexes, earlier recalled absolute pubertal timing predicted higher psychosexuality in adulthood, although the magnitude of these associations varied with psychosexuality type and group (i.e., typically developing and IGD). Results were robust when controlling for circulating steroid hormones in typically developing participants. Age of initiation of HRT in men with IGD negatively predicted SOI-R. We discuss the clinical implications of our findings for conditions in which pubertal timing is medically altered.

Cognitive Function of Children and Adolescents With Congenital Adrenal Hyperplasia: Importance of Early Diagnosis

CONTEXT

Patients with classic congenital adrenal hyperplasia (CAH) are treated postnatally with lifelong glucocorticoid (GC) replacement therapy. Previous results on general cognitive ability in individuals with CAH have been conflicting.

OBJECTIVE

To evaluate long-term cognitive effects of GC replacement therapy and the impact of early diagnosis in children with CAH.

DESIGN AND SETTING

Observational study with patients from a single research institute.

PATIENTS

32 children with CAH (mean age 11.5 years) identified through the Swedish national neonatal screening program for CAH and 52 matched population controls (mean age 10.7 years). Eleven (6 female) children with CAH who were treated prenatally with dexamethasone (DEX), (CAH-DEX) (mean age 11.7 years).

INTERVENTION

GC replacement therapy, neonatal screening for CAH.

MEASURES

Cognitive abilities assessed with standardized neuropsychological tests (Wechsler scales, Span Board Test, Stroop Interference Test, NEPSY list learning).

RESULTS

Children with CAH (not prenatally treated) performed equally well as population controls on a series of tests assessing general intellectual ability and executive functions. No significant differences were observed in cognitive performance between patients with different genotypes (null, non-null). Patients with salt-wasting CAH performed poorer than patients with simple virilizing CAH in a test assessing visuo-spatial working memory (P = 0.039), although the performance was within the normal range for the population. Prenatally DEX-treated girls with CAH had lower verbal intellectual ability compared with CAH girls not exposed to prenatal treatment (P = 0.037).

CONCLUSION

Children and adolescents with CAH who were diagnosed early via a neonatal screening program and treated with hydrocortisone had normal psychometric intelligence and executive functions.

Sexual Orientation and Cognitive Ability: A Multivariate Meta-Analytic Follow-Up

A cross-sex shift model of human sexual orientation differences predicts that homosexual men should perform or score in the direction of heterosexual women, and homosexual women in the direction of heterosexual men, in behavioral domains such as cognition and personality. In order to test whether homosexual men and women's cognitive performance was closer to that of heterosexual men or that of heterosexual women (i.e., sex-atypical for their sex and closer to that of the opposite-sex), we conducted a multivariate meta-analysis based on data from our previous meta-analysis (Xu, Norton, & Rahman, 2017). A subset of this data was used and comprised 30 articles (and 2 unpublished datasets) and 244,434 participants. The multivariate meta-analysis revealed that homosexual men were sex-atypical in mental rotation (Hedges' g = -0.36) and the water level test (Hedges' g = -0.55). In mental rotation, homosexual men were in-between heterosexual men and women. There was no significant group difference on spatial location memory. Homosexual men were also sex-atypical on male-favoring spatial-related tasks (Hedges' g = -0.54), and female-favoring spatial-related tasks (Hedges' g = 0.38). Homosexual women tended to be sex-typical (similar to heterosexual women). There were no significant group differences on male-favoring "other" tasks or female-favoring verbal-related tasks. Heterosexual men and women differed significantly on female-favoring "other" tasks. These results support the cross-sex shift hypothesis which predicts that homosexual men perform in the direction of heterosexual women in sex differentiated cognitive domains. However, the type of task and cognitive domain tested is critical.

Ameliorative effect of Magnesium Isoglycyrrhizinate on hepatic encephalopathy by Epirubicin

BACKGROUND

The purpose of the present study was to evaluate the protective effect of Magnesium Isoglycyrrhizinate (MI) on Epirubicin (EPI)-induced hepatic encephalopathy (HE) and explore its underlying mechanism.

METHODS

Mice were divided randomly into groups for treatments as follows: control group, EPI group (Model group), EPI + MI (25, 50 mg/kg) group. Morris water maze test were conducted to evaluate the spatial learning and memory ability. The serum and hippocampus levels of oxidative stress or inflammation were uncovered with the detection of superoxide dismutase (SOD), malondialdehyde (MDA), and pro-inflammatory cytokines (IL-1β, IL-6, TNF-α).

RESULTS

As a result, treatment with MI effectively ameliorated the EPI-induced decline in the ability of spatial learning and memory. MI also significantly relieved the severity of oxidative stress or inflammation in serum and hippocampus, which was accompanied with regulating liver functional parameters. Western blot data demonstrated that administration of MI could regulate the redox-related expressions of Txnip, Trx, Nrf2, HO-1, p-IκB-α, p-NF-κB, Caspase-3, Caspase-9, Bax and Bcl-2 in EPI-stimulated hepatic encephalopathy (HE). And the potency of MI treatments on Nrf2, NF-κB expression was also confirmed with immunohistochemical analysis.

CONCLUSIONS

Taken together, the protective effect of Magnesium Isoglycyrrhizinate on EPI-induced hepatic encephalopathy might be mediated via the Txnip/Nrf2/NF-κB signaling pathway.

Gender-based eye movement differences in passive indoor picture viewing: An eye-tracking study

Male and female brains have different structures, which can make genders produce various eye- movement patterns. This study presents the results of an eye tracking experiment in which we analyzed the eye movements of 25 male and 20 female participants during passive indoor picture viewing. We examined eye-movement parameters, namely fixation duration, scan path length, number of saccades, spatial density, saccade amplitude, and the ratio of total fixation duration to total saccade duration so as to investigate gender differences in eye-movement patterns while indoor picture viewing. We found significant differences in eye-movement patterns between genders. The results of eye-movement analysis also indicated that females showed more explorative gaze behavior, indicated by larger saccade amplitudes, and by longer scan paths. Furthermore, owing to shorter ratio of fixation durations to saccade duration in females as compared to male, we speculate that females inspect the images faster than males. In addition, we classified the genders into two subgroups-males and females-based on their eye-movement parameters by using a support vector machine classifier achieving an accuracy of 70%. We have come to the result males and females - with same culture - see the environment differently. Our findings have profound implications for researches employing gaze-based models.

Cognitive functions in children with congenital adrenal hyperplasia

OBJECTIVE

There is controversy regarding cognitive function in patients with congenital adrenal hyperplasia (CAH). This study is aimed at the assessment of cognitive functions in children with CAH, and their relation to hydrocortisone (HC) therapy and testosterone levels.

SUBJECTS AND METHODS

Thirty children with CAH due to 21 hydroxylase deficiency were compared with twenty age- and sex-matched healthy controls. HC daily and cumulative doses were calculated, the socioeconomic standard was assessed, and free testosterone was measured. Cognitive function assessment was performed using the Wechsler Intelligence Scale - Revised for Children and Adults (WISC), the Benton Visual Retention Test, and the Wisconsin Card Sorting Test (WCST).

RESULTS

The mean age (SD) of patients was 10.22 (3.17) years [11 males (36.7%), 19 females (63.3%)]. Mean (SD) HC dose was 15.78 (4.36) mg/m 2 /day. Mean (SD) cumulative HC dose 44,689. 9 (26,892.02) mg. Patients had significantly lower scores in all domains of the WISC test, performed significantly worse in some components of the Benton Visual Retention Test, as well as in the Wisconsin Card Sorting Test. There was no significant difference in cognitive performance when patients were subdivided according to daily HC dose (< 10, 10 - 15, > 15 mg/m 2 /day). A positive correlation existed between cumulative HC dose and worse results of the Benton test. No correlation existed between free testosterone and any of the three tests.

CONCLUSION

Patients with CAH are at risk of some cognitive impairment. Hydrocortisone therapy may be implicated. This study highlights the need to assess cognitive functions in CAH.

Cognitive abilities in women with complete androgen insensitivity syndrome and women with gonadal dysgenesis

BACKGROUND

Many questions regarding the mechanisms behind sex differences in cognitive abilities are still unanswered. On a group level, men typically outperform women on certain spatial tasks, whereas women perform better on certain tests of memory and verbal ability. The prevailing theories concerning the biological predispositions for these and other differences in behaviour and brain function focus on early and prolonged exposure to sex hormones. There is, however, evidence of direct effects of sex chromosomes on sex-typical behaviour in other species.

OBJECTIVES

To study the influence of sex hormones and sex chromosomes on cognition in women with Complete androgen insensitivity (CAIS) and Gonadal dysgenesis (GD).

METHODS

Eighteen women with CAIS, 6 women with 46,XYGD, and 7 women with 46,XXGD were compared with age-matched male and female controls on tests of spatial and verbal abilities, memory functions, and emotion recognition.

RESULTS

Women with CAIS, XYGD, and XXGD performed similar to female controls on cognitive tasks. However, on a test of emotion recognition, women with XXGD outperformed the other groups, whereas women with CAIS and XYGD performed similar to male controls.

CONCLUSION

Our results support theories of androgen effects on cognitive abilities and suggest that factors related to sex chromosomes may influence emotion recognition. Implications of an atypical sex hormone situation and sex chromosome variation are discussed.

Gene expression and DNA methylation changes in the hypothalamus and hippocampus of adult rats developmentally exposed to bisphenol A or ethinyl estradiol: a CLARITY-BPA consortium study

Bisphenol A (BPA), an endocrine disrupting chemical (EDC), is a ubiquitous pollutant. As part of the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA), we sought to determine whether exposure of Sprague-Dawley rats to 2,500 μg/kg/day BPA (BPA) or 0.5 μg/kg/day ethinyl estradiol (EE) from gestational day 6 through postnatal day 21 induces behavior-relevant gene expression and DNA methylation changes in hippocampus and hypothalamus at adulthood. RNA and DNA were isolated from both regions. Expression of ten genes (Dnmt1, Dnmt3a, Dnmt3b, Esr1, Esr2, Avp, Ar, Oxt, Otr, and Bdnf) presumably altered by early-life BPA/EE exposure was examined. Three genes (Bdnf, Dnmt3b, and Esr1) were studied for DNA methylation changes in their putative 5' promoter regions. Molecular changes in hippocampus were correlated to prior Barnes maze performance, including sniffing correct holes, distance traveled, and velocity. Exposure to BPA and/or EE disrupted patterns of sexually dimorphic gene expression/promoter DNA methylation observed in hippocampus and hypothalamus of controls. In the hippocampus of female offspring, BPA exposure resulted in hypermethylation of the putative 5' promoter region of Bdnf, while EE exposure induced hypomethylation. Bdnf methylation was weakly associated with Bdnf expression in hippocampi of female rats. Hippocampal Bdnf expression in females showed a weak negative association with sniffing correct hole in Barnes maze. Hippocampal expression of Avp, Esr2, Oxt, and Otr was strongly associated with velocity of control rats in Barnes maze. Findings suggest BPA exposure induced non-EE-like gene expression and epigenetic changes in adult rat hippocampi, a region involved in spatial navigation.

Hypothalamic transcriptomic alterations in male and female California mice (Peromyscus californicus) developmentally exposed to bisphenol A or ethinyl estradiol

Bisphenol A (BPA) is an endocrine‐disrupting chemical (EDC) prevalent in many household items. Rodent models and human epidemiological studies have linked this chemical to neurobehavior impairments. In California mice, developmental exposure to BPA results in sociosexual disorders at adulthood, including communication and biparental care deficits, behaviors that are primarily regulated by the hypothalamus. Thus, we sought to examine the transcriptomic profile in this brain region of juvenile male and female California mice offspring exposed from periconception through lactation to BPA or ethinyl estradiol (EE, estrogen present in birth control pills and considered a positive estrogen control for BPA studies). Two weeks prior to breeding, P₀ females were fed a control diet, or this diet supplemented with 50 mg BPA/kg feed weight or 0.1 ppb EE, and continued on the diets through lactation. At weaning, brains from male and female offspring were collected, hypothalamic RNA isolated, and RNA‐seq analysis performed. Results indicate that BPA and EE groups clustered separately from controls with BPA and EE exposure leading to unique set of signature gene profiles. Kcnd3 was downregulated in the hypothalamus of BPA‐ and EE‐exposed females, whereas Tbl2, Topors, Kif3a, and Phactr2 were upregulated in these groups. Comparison of transcripts differentially expressed in BPA and EE groups revealed significant enrichment of gene ontology terms associated with microtubule‐based processes. Current results show that perinatal exposure to BPA or EE can result in several transcriptomic alterations, including those associated with microtubule functions, in the hypothalamus of California mice. It remains to be determined whether these genes mediate BPA‐induced behavioral disruptions.

Evolutionary perspective on sex differences in the expression of neurological diseases

Sex-specific brain and cognitive deficits emerge with malnutrition, some infectious and neurodegenerative diseases, and often with prenatal or postnatal toxin exposure. These deficits are described in disparate literatures and are generally not linked to one another. Sexual selection may provide a unifying framework that integrates our understanding of these deficits and provides direction for future studies of sex-specific vulnerabilities. Sexually selected traits are those that have evolved to facilitate competition for reproductive resources or that influence mate choices, and are often larger and more complex than other traits. Critically, malnutrition, disease, chronic social stress, and exposure to man-made toxins compromise the development and expression of sexually selected traits more strongly than that of other traits. The fundamental mechanism underlying vulnerability might be the efficiency of mitochondrial energy capture and control of oxidative stress that in turn links these traits to current advances in neuroenergetics, stress endocrinology, and toxicology. The key idea is that the elaboration of these cognitive abilities, with more underlying gray matter or more extensive inter-modular white matter connections, makes them particularly sensitive to disruptions in mitochondrial functioning and oxidative stress. A framework of human sexually selected cognitive abilities and underlying brain systems is proposed and used to organize what is currently known about sex-specific vulnerabilities.

The Role of Fluoxetine in Activating Wnt/β-Catenin Signaling and Repressing β-Amyloid Production in an Alzheimer Mouse Model

Fluoxetine (FLX) is one of the selective serotonin reuptake inhibitors (SSRIs) antidepressants, which could be used to relieve depression and anxiety among AD patients. This study was designed to search for new mechanisms by which fluoxetine could activate Wnt/β-catenin signaling pathway and reduce amyloidosis in AD brain. Fluoxetine was administered via intragastric injection to APP/tau/PS1 mouse model of Alzheimer’s disease (3×Tg-AD) mice for 4 months. In the hippocampus of AD mouse model, there could be observed neuronal apoptosis, as well as an increase in Aβ (amyloid-β) production. Moreover, there is a strong association between down-regulation of Wnt/β-catenin signaling and the alteration of AD pathology. The activity of protein phosphatases of type 2A (PP2A) could be significantly enhanced by the treatment of fluoxetine. The activation of PP2A, caused by fluoxetine, could then play a positive role in raising the level of active β-catenin, and deliver a negative impact in GSK3β activity in the hippocampal tissue. Both the changes mentioned above would lead to the activation of Wnt/β-catenin signaling. Meanwhile, fluoxetine treatment would reduce APP cleavage and Aβ generation. It could also prevent apoptosis in 3×Tg-AD primary neuronal cell, and have protective effects on neuron synapse. These findings imply that Wnt/β-catenin signaling could be a potential target outcome for AD prevention, and fluoxetine has the potential to be a promising drug in both AD prevention and treatment.

Effects of sex and prenatal androgen manipulations on Onuf's nucleus of rhesus macaques

The role of gonadal steroids in sexual differentiation of the central nervous system (CNS) is well established in rodents, but no study to date has manipulated androgens prenatally and examined their effects on any CNS structure in a primate. Onuf's nucleus is a column of motoneurons in the sacral spinal cord that innervates the striated perineal muscles. This cell group is larger in males than in females of many species, due to androgens acting during a sensitive perinatal period. Here, we examined Onuf's nucleus in 21 adult rhesus monkeys, including control males and females, as well as males whose mothers had been treated with an anti-androgen or testosterone during gestation. We found a robust sex difference, with more motoneurons in control males than in females. The soma size of Onuf's nucleus motoneurons was also marginally larger in males. Treatment with the anti-androgen flutamide for 35-40 days during early gestation partially blocked masculinization of Onuf's nucleus: motoneuron number in flutamide-treated males was decreased relative to control and testosterone-treated males, but remained greater than in females, with no effect on cell size. A control motor nucleus that innervates foot muscles (Pes9) showed no difference in motoneuron number or size between control males and females. Prenatal testosterone treatment of males did not alter Onuf's nucleus motoneuron number, but did increase the size of both Onuf's and Pes9 motoneurons. Thus, prenatal androgen manipulations cause cellular-level changes in the primate CNS, which may underlie previously observed effects of these manipulations on behavior.

Maternal androgen excess and obesity induce sexually dimorphic anxiety-like behavior in the offspring

Maternal polycystic ovary syndrome (PCOS), a condition associated with hyperandrogenism, is suggested to increase anxiety-like behavior in the offspring. Because PCOS is closely linked to obesity, we investigated the impact of an adverse hormonal or metabolic maternal environment and offspring obesity on anxiety in the offspring. The obese PCOS phenotype was induced by chronic high-fat-high-sucrose (HFHS) consumption together with prenatal dihydrotestosterone exposure in mouse dams. Anxiety-like behavior was assessed in adult offspring with the elevated-plus maze and open-field tests. The influence of maternal androgens and maternal and offspring diet on genes implicated in anxiety were analyzed in the amygdala and hypothalamus with real-time PCR ( n = 47). Independent of diet, female offspring exposed to maternal androgens were more anxious and displayed up-regulation of adrenoceptor α 1B in the amygdala and up-regulation of hypothalamic corticotropin-releasing hormone ( Crh). By contrast, male offspring exposed to a HFHS maternal diet had increased anxiety-like behavior and showed up-regulation of epigenetic markers in the amygdala and up-regulation of hypothalamic Crh. Overall, there were substantial sex differences in gene expression in the brain. These findings provide novel insight into how maternal androgens and obesity exert sex-specific effects on behavior and gene expression in the offspring of a PCOS mouse model.-Manti, M., Fornes, R., Qi, X., Folmerz, E., Lindén Hirschberg, A., de Castro Barbosa, T., Maliqueo, M., Benrick, A., Stener-Victorin, E. Maternal androgen excess and obesity induce sexually dimorphic anxiety-like behavior in the offspring.

Uncovering neurodevelopmental windows of susceptibility to manganese exposure using dentine microspatial analyses

BACKGROUND

Associations between manganese (Mn) and neurodevelopment may depend on dose and exposure timing, but most studies cannot measure exposure variability over time well.

OBJECTIVE

We apply temporally informative tooth-matrix biomarkers to uncover windows of susceptibility in early life when Mn is associated with visual motor ability in childhood. We also explore effect modification by lead (Pb) and child sex.

METHODS

Participants were drawn from the ELEMENT (Early Life Exposures in MExico and NeuroToxicology) longitudinal birth cohort studies. We reconstructed dose and timing of prenatal and early postnatal Mn and Pb exposures for 138 children by analyzing deciduous teeth using laser ablation-inductively coupled plasma-mass spectrometry. Neurodevelopment was assessed between 6 and 16 years of age using the Wide Range Assessment of Visual Motor Abilities (WRAVMA). Mn associations with total WRAVMA scores and subscales were estimated with multivariable generalized additive mixed models. We examined Mn interactions with Pb and child sex in stratified models.

RESULTS

Levels of dentine Mn were highest in the second trimester and declined steeply over the prenatal period, with a slower rate of decline after birth. Mn was positively associated with visual spatial and total WRAVMA scores in the second trimester, among children with lower (< median) tooth Pb levels: one standard deviation (SD) increase in ln-transformed dentine Mn at 150 days before birth was associated with a 0.15 [95% CI: 0.04, 0.26] SD increase in total score. This positive association was not observed at high Pb levels. In contrast to the prenatal period, significant negative associations were found in the postnatal period from ~ 6 to 12 months of age, among boys only: one SD increase in ln-transformed dentine Mn was associated with a 0.11 [95% CI: - 0.001, - 0.22] to 0.16 [95% CI: - 0.04, - 0.28] SD decrease in visual spatial score.

CONCLUSIONS

Using tooth-matrix biomarkers with fine scale temporal profiles of exposure, we found discrete developmental windows in which Mn was associated with visual-spatial abilities. Our results suggest that Mn associations are driven in large part by exposure timing, with beneficial effects found for prenatal levels and toxic effects found for postnatal levels.

Beyond Pink and Blue: The Complexity of Early Androgen Effects on Gender Development

Why do girls and women differ from boys and men? Gender development is typically considered to result from socialization, but sex hormones present during sensitive periods of development, particularly prenatal androgens, play an important role. Data from natural experiments, especially from females with congenital adrenal hyperplasia, show the complexity of the effects of androgens on behavior: Prenatal androgens apparently have large effects on interests and engagement in gendered activities; moderate effects on spatial abilities; and relatively small or no effects on gender identity, gender cognitions, and gendered peer involvement. These differential effects provide an opportunity to move beyond identifying sources of variation in behavior to understanding developmental processes. These processes include links among gendered characteristics, psychological and neural mechanisms underlying development, and the joint effects of biological predispositions and social experiences.

Sex effects on spatial learning but not on spatial memory retrieval in healthy young adults

OBJECTIVES

Sex differences have been found in spatial learning and spatial memory, with several studies indicating that males outperform females. We tested in the virtual Morris Water Maze (vMWM) task, whether sex differences in spatial cognitive processes are attributable to differences in spatial learning or spatial memory retrieval in a large student sample.

METHODS

We tested 90 healthy students (45 women and 45 men) with a mean age of 23.5 years (SD=3.5). Spatial learning and spatial memory retrieval were measured by using the vMWM task, during which participants had to search a virtual pool for a hidden platform, facilitated by visual cues surrounding the pool. Several learning trials assessed spatial learning, while a separate probe trial assessed spatial memory retrieval.

RESULTS

We found a significant sex effect during spatial learning, with males showing shorter latency and shorter path length, as compared to females (all p<0.001). Yet, there was no significant sex effect in spatial memory retrieval (p=0.615). Furthermore, post-hoc analyses revealed significant sex differences in spatial search strategies (p<0.05), but no difference in the number of platform crossings (p=0.375).

CONCLUSION

Our results indicate that in healthy young adults, males show faster spatial learning in a virtual environment, as compared to females. Interestingly, we found no significant sex differences during spatial memory retrieval. Our study raises the question, whether men and women use different learning strategies, which nevertheless result in equal performances of spatial memory retrieval.

Sexual Orientation-Related Differences in Virtual Spatial Navigation and Spatial Search Strategies

Spatial abilities are generally hypothesized to differ between men and women, and people with different sexual orientations. According to the cross-sex shift hypothesis, gay men are hypothesized to perform in the direction of heterosexual women and lesbian women in the direction of heterosexual men on cognitive tests. This study investigated sexual orientation differences in spatial navigation and strategy during a virtual Morris water maze task (VMWM). Forty-four heterosexual men, 43 heterosexual women, 39 gay men, and 34 lesbian/bisexual women (aged 18-54 years) navigated a desktop VMWM and completed measures of intelligence, handedness, and childhood gender nonconformity (CGN). We quantified spatial learning (hidden platform trials), probe trial performance, and cued navigation (visible platform trials). Spatial strategies during hidden and probe trials were classified into visual scanning, landmark use, thigmotaxis/circling, and enfilading. In general, heterosexual men scored better than women and gay men on some spatial learning and probe trial measures and used more visual scan strategies. However, some differences disappeared after controlling for age and estimated IQ (e.g., in visual scanning heterosexual men differed from women but not gay men). Heterosexual women did not differ from lesbian/bisexual women. For both sexes, visual scanning predicted probe trial performance. More feminine CGN scores were associated with lower performance among men and greater performance among women on specific spatial learning or probe trial measures. These results provide mixed evidence for the cross-sex shift hypothesis of sexual orientation-related differences in spatial cognition.

Sex Differences and Menstrual Cycle Dependent Changes in Cognitive Strategies during Spatial Navigation and Verbal Fluency

Men typically outperform women in spatial navigation tasks, while the advantage of women in verbal fluency is more controversial. Sex differences in cognitive abilities have been related to sex-specific cognitive strategies on the one hand and sex hormone influences on the other hand. However, sex hormone and menstrual cycle influences on cognitive strategies have not been previously investigated. In the present study we assessed cognitive strategy use during spatial navigation and verbal fluency in 51 men and 49 women. In order to evaluate sex hormone influences, all participants completed two test sessions, which were time-locked to the early follicular (low estradiol and progesterone) and mid-luteal cycle phase (high estradiol and progesterone) in women. As hypothesized, men outperformed women in navigation, whereas women outperformed men in phonemic verbal fluency. Furthermore, women switched more often between categories in the phonemic fluency condition, compared to men, indicating sex-specific strategy use. Sex differences in strategy use during navigation did, however, not follow the expected pattern. Menstrual cycle phase, however, did modulate strategy use during navigation as expected, with improved performance with the landmark strategy in the luteal, compared to the follicular phase. No menstrual cycle effects were observed on clustering or switching during verbal fluency. This suggests a modulation of cognitive strategy use during spatial navigation, but not during verbal fluency, by relative hormone increases during the luteal phase of the menstrual cycle.

Berberine improves cognitive impairment by promoting autophagic clearance and inhibiting production of β-amyloid in APP/tau/PS1 mouse model of Alzheimer's disease

This study investigates the neuroprotective properties of berberine (a natural isoquinoline alkaloid isolated from the Rhizoma coptidis) and finds that berberine could promote β-amyloid (Aβ) clearance and inhibit Aβ production in the triple-transgenic mouse model of Alzheimer's disease (3×Tg-AD). During the study, berberine was first administrated to treat 3×Tg-AD mice and primary neurons. Morris water maze assay, western blotting, enzyme-linked immunosorbent assay (ELISA), immunofluorescence staining and histological analysis, transmission electron microscopic analysis were then used to evaluate the effects of the berberine administration. The result showed that berberine significantly improved 3×Tg-AD mice's spatial learning capacity and memory retention, promoted autophagy activity identified by the enhancement of brain LC3-II, beclin-1, hVps34, and Cathepsin-D levels as well as the reduction of brain P62 and Bcl-2 levels in AD mice, facilitated reduction of Aβ and APP levels, reduced Aβ plaque deposition in the hippocampus of AD mice, and inhibited b-site APP cleavage enzyme 1 (BACE1) expression. Similar results were also found in 3×Tg-AD primary hippocampal neurons: berbernine treatment decreased the levels of extracellular and intracellular Aβ1-42, increased the protein levels of LC3-II, beclin-1, hVps34, and Cathepsin-D, and decreased the levels of P62, Bcl-2, APP and BACE1 levels. In summary, berberine shows neuroprotective effects on 3×Tg-AD mice and may be a promising multitarget drug in the preventionand protection against AD.

Prenatal phthalate, triclosan, and bisphenol A exposures and child visual-spatial abilities

INTRODUCTION

During fetal development, sex steroids influence sexually dimorphic behaviors, such as visual-spatial abilities. Thus, endocrine disrupting chemicals that impact sex steroids during gestation may affect these behaviors.

OBJECTIVE

We investigated the relationship between prenatal urinary phthalate metabolite, triclosan, and BPA concentrations and visual-spatial abilities in a prospective cohort of 198 mother-child dyads.

METHODS

Data are from a prospective cohort in Cincinnati, OH (HOME Study). We measured nine phthalate metabolites, triclosan, and BPA in maternal urine samples collected at 16 and 26 weeks of gestation. We assessed children's visual-spatial abilities at 8 years of age using the Virtual Morris Water Maze (VMWM), a computerized version of the rodent Morris Water Maze. We quantified the covariate-adjusted change in the time or distance to complete the VMWM and time spent in the correct quadrant during a probe trial with an interquartile range increase in chemical concentrations using linear mixed models and linear regression, respectively.

RESULTS

Boys completed the VMWM faster (4.1s; 95% CI:-7.1, -1.2) and in less distance (1.4 units; 95% CI:-2.8, 0) than girls. Overall, children with higher mono-n-butyl (MnBP), mono-benzyl (MBzP), and mono-carboxypropyl phthalate concentrations completed the VMWM in less time and distance than children with lower concentrations. For example, children with higher MnBP concentrations completed the VMWM in 0.9 less distance units (95% CI:-1.8, -0.0). Child sex modified the association between MnBP and VMWM performance. In girls, higher MnBP concentrations were associated with longer time (1.7s; 95% CI: -0.7, 4.1) and shorter distance (-1.7 units; 95% CI: -2.8, -0.5), whereas in boys, it was associated with shorter time (-3.0s; 95% CI:-5.6, -0.4), but not distance (-0.1 units; 95% CI:1.4, 1.0). Other phthalate metabolites, triclosan, and BPA were not associated with VMWM performance, and sex did not consistently modify these associations.

CONCLUSIONS

In this cohort, greater prenatal urinary concentrations of some phthalate metabolites were associated with improved VMWM performance, particularly among boys. Future studies should confirm these findings and determine if phthalates affect other hormonally sensitive aspects of child neurobehavior.

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

BACKGROUND

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

METHODS

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

RESULTS

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

LIMITATIONS

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

CONCLUSION

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

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 contribution of the androgen receptor (AR) in human spatial learning and memory: A study in women with complete androgen insensitivity syndrome (CAIS)

Few studies have examined the impact of androgen insensitivity on human spatial learning and memory. In the present study, we tested 11 women with complete androgen insensitivity syndrome (CAIS), a rare genetic disorder characterized by complete absence of AR activity, and compared their performance against 20 comparison males and 19 comparison females on a virtual analog of the Morris Water Maze task. The results replicated a main sex effect showing that men relative to women were faster in finding the hidden platform and had reduced heading error. Furthermore, findings indicated that mean performance of women with CAIS was between control women and control men, though the differences were not statistically significant. Effect size estimates (and corresponding confidence intervals) of spatial learning trials showed little difference between women with CAIS and control women but CAIS women differed from men, but not women, on two variables, latency to find the platform and first-move latency. No differences between groups were present during visible platform trials or the probe trial, a measure of spatial memory. Moreover, groups also did not differ on estimates of IQ and variability of performance. The findings are discussed in relation to androgen insensitivity in human spatial learning and memory.

Reduced short term memory in congenital adrenal hyperplasia (CAH) and its relationship to spatial and quantitative performance

Girls and women with classical congenital adrenal hyperplasia (CAH) experience elevated androgens prenatally and show increased male-typical development for certain behaviors. Further, individuals with CAH receive glucocorticoid (GC) treatment postnatally, and this GC treatment could have negative cognitive consequences. We investigated two alternative hypotheses, that: (a) early androgen exposure in females with CAH masculinizes (improves) spatial perception and quantitative abilities at which males typically outperform females, or (b) CAH is associated with performance decrements in these domains, perhaps due to reduced short-term-memory (STM). Adolescent and adult individuals with CAH (40 female and 29 male) were compared with relative controls (29 female and 30 male) on spatial perception and quantitative abilities as well as on Digit Span (DS) to assess STM and on Vocabulary to assess general intelligence. Females with CAH did not perform better (more male-typical) on spatial perception or quantitative abilities than control females, failing to support the hypothesis of cognitive masculinization. Rather, in the sample as a whole individuals with CAH scored lower on spatial perception (p ≤ .009), a quantitative composite (p ≤ .036), and DS (p ≤ .001), despite no differences in general intelligence. Separate analyses of adolescent and adult participants suggested the spatial and quantitative effects might be present only in adult patients with CAH; however, reduced DS performance was found in patients with CAH regardless of age group. Separate regression analyses showed that DS predicted both spatial perception and quantitative performance (both p ≤ .001), when age, sex, and diagnosis status were controlled. Thus, reduced STM in CAH patients versus controls may have more general cognitive consequences, potentially reducing spatial perception and quantitative skills. Although hyponatremia or other aspects of salt-wasting crises or additional hormone abnormalities cannot be ruled out as potential contributors, elevated GCs appear to be the most likely contributor to reductions in STM. Additional efforts to monitor GC administration protocols may help achieve optimal cognitive outcomes. Educational intervention for individuals with CAH might also be useful.

Adrenal steroidogenesis and congenital adrenal hyperplasia

Adrenal steroidogenesis is a dynamic process, reliant on de novo synthesis from cholesterol, under the stimulation of ACTH and other regulators. The syntheses of mineralocorticoids (primarily aldosterone), glucocorticoids (primarily cortisol), and adrenal androgens (primarily dehydroepiandrosterone and its sulfate) occur in separate adrenal cortical zones, each expressing specific enzymes. Congenital adrenal hyperplasia (CAH) encompasses a group of autosomal-recessive enzymatic defects in cortisol biosynthesis. 21-Hydroxylase (21OHD) deficiency accounts for more than 90% of CAH cases and, when milder or nonclassic forms are included, 21OHD is one of the most common genetic diseases.

Spatial function in adolescents and young adults with congenital adrenal hyperplasia: clinical phenotype and implications for the androgen hypothesis

Females with the classic form of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency are said to perform better than unaffected female controls on tests of mental rotation or other visuospatial abilities, but findings are conflicting. We studied 31 adolescents and young adults with CAH and 19 unaffected sibling controls, who were given standardized spatial tests and tests of other sexually differentiated cognitive functions (verbal fluency, perceptual speed). The possible role of CAH subtype (salt-wasting or simple-virilizing) was evaluated. Only females with the more severe, salt-wasting form of CAH, but not females with the simple-virilizing form, performed significantly better than sex-matched sibling controls on measures of mental rotation. Subtype differences were not significant for verbal fluency or perceptual speed. Severity of prenatal genital virilization, but not postnatal age when medication was started, predicted accuracy on the Mental Rotations Test. Results are consistent with the possibility of an organizational effect of androgens in the central nervous system that impacts the development of spatial abilities. Implications for the timing of the hypothetical critical period are discussed.

Could androgens maintain specific domains of mental health in aging men by preserving hippocampal neurogenesis?

Interest surrounds the role of sex-hormones in regulating brain function outside of reproductive behaviour. Declining androgen production in aging males has been associated with cognitive impairment, depression and increased risk of developing Alzheimer's disease. Indication for testosterone replacement therapy is based on biochemically determined low circulating testosterone combined with manifest symptoms. However, which aspects of age-related cognitive decline are attributable to low circulating testosterone remain ambiguous. Studies examining cognition in aging men receiving testosterone replacement therapy have yielded equivocal results. The exact role of testosterone in maintaining cognitive function and the underlying neural mechanisms are largely unknown, though it would appear to be domain specific. Clarity in this area will provide clinical direction toward addressing an increasing healthcare burden of mental health decline coincident with increasing longevity. The premise that androgens contribute to maintaining aspects of mental health in aging men by preserving hippocampal neurogenesis will be used as a forum in this review to discuss current knowledge and the need for further studies to better define testosterone replacement strategies for aging male health.

DSDs: genetics, underlying pathologies and psychosexual differentiation

Mammalian sex determination is the unique process whereby a single organ, the bipotential gonad, undergoes a developmental switch that promotes its differentiation into either a testis or an ovary. Disruptions of this complex genetic process during human development can manifest as disorders of sex development (DSDs). Sex development can be divided into two distinct processes: sex determination, in which the bipotential gonads form either testes or ovaries, and sex differentiation, in which the fully formed testes or ovaries secrete local and hormonal factors to drive differentiation of internal and external genitals, as well as extragonadal tissues such as the brain. DSDs can arise from a number of genetic lesions, which manifest as a spectrum of gonadal (gonadal dysgenesis to ovotestis) and genital (mild hypospadias or clitoromegaly to ambiguous genitalia) phenotypes. The physical attributes and medical implications associated with DSDs confront families of affected newborns with decisions, such as gender of rearing or genital surgery, and additional concerns, such as uncertainty over the child's psychosexual development and personal wishes later in life. In this Review, we discuss the underlying genetics of human sex determination and focus on emerging data, genetic classification of DSDs and other considerations that surround gender development and identity in individuals with DSDs.

Estradiol and cognitive function: past, present and future

A historical perspective on estradiol's enhancement of cognitive function is presented, and research, primarily in animals, but also in humans, is reviewed. Data regarding the mechanisms underlying the enhancements are discussed. Newer studies showing rapid effects of estradiol on consolidation of memory through membrane interactions and activation of inter-cellular signaling pathways are reviewed as well as studies focused on traditional genomic mechanisms. Recent demonstrations of intra-neuronal estradiol synthesis and possible actions as a neurosteroid to promote memory are discussed. This information is applied to the critical issue of the current lack of effective hormonal (or other) treatments for cognitive decline associated with menopause and aging. Finally, the critical period hypothesis for estradiol effects is discussed along with novel strategies for hormone/drug development. Overall, the historical record documents that estradiol positively impacts some aspects of cognitive function, but effective therapeutic interventions using this hormone have yet to be realized.

Perinatal testosterone exposure and cerebral lateralisation in adult males: evidence for the callosal hypothesis

Two competing theories address the influence of foetal testosterone on cerebral laterality: one proposing exposure to high foetal testosterone concentrations is related to atypical lateralisation (Geschwind-Galaburda hypothesis), the other that high foetal testosterone concentrations exaggerate typical lateralisation (callosal hypothesis). The current study examined the relationship between cord testosterone concentrations and cerebral laterality for language and spatial memory in adulthood. Male participants with high (>0.15nmol) and low (<0.10nmol) cord testosterone levels were invited to take part in the study (n=18 in each group). Cerebral laterality was measured using functional Transcranial Doppler ultrasonography, while participants completed word generation and visual short-term memory tasks. Typical left lateralisation of language was more common in the high-testosterone group than in the low-testosterone group, χ(2)=4.50, df=1, p=034. Spatial memory laterality was unrelated to cord testosterone level. Our findings indicate that foetal testosterone exposure is related to language laterality in a direction that supports the callosal hypothesis.

Evidence of MAOA genotype involvement in spatial ability in males

Although the monoamine oxidase-A (MAOA) gene has been linked to spatial learning and memory in animal models, convincing evidence in humans is lacking. Performance on an ecologically-valid, virtual computer-based equivalent of the Morris Water Maze task was compared between 28 healthy males with the low MAOA transcriptional activity and 41 healthy age- and IQ-matched males with the high MAOA transcriptional activity. The results revealed consistently better performance (reduced heading error, shorter path length, and reduced failed trials) for the high MAOA activity individuals relative to the low activity individuals. By comparison, groups did not differ on pre-task variables or strategic measures such as first-move latency. The results provide novel evidence of MAOA gene involvement in human spatial navigation using a virtual analogue of the Morris Water Maze task.

The biological basis of human sexual orientation: is there a role for epigenetics?

Sexual orientation is one of the largest sex differences in humans. The vast majority of the population is heterosexual, that is, they are attracted to members of the opposite sex. However, a small but significant proportion of people are bisexual or homosexual and experience attraction to members of the same sex. The origins of the phenomenon have long been the subject of scientific study. In this chapter, we will review the evidence that sexual orientation has biological underpinnings and consider the involvement of epigenetic mechanisms. We will first discuss studies that show that sexual orientation has a genetic component. These studies show that sexual orientation is more concordant in monozygotic twins than in dizygotic ones and that male sexual orientation is linked to several regions of the genome. We will then highlight findings that suggest a link between sexual orientation and epigenetic mechanisms. In particular, we will consider the case of women with congenital adrenal hyperplasia (CAH). These women were exposed to high levels of testosterone in utero and have much higher rates of nonheterosexual orientation compared to non-CAH women. Studies in animal models strongly suggest that the long-term effects of hormonal exposure (such as those experienced by CAH women) are mediated by epigenetic mechanisms. We conclude by describing a hypothetical framework that unifies genetic and epigenetic explanations of sexual orientation and the continued challenges facing sexual orientation research.

Magnetic resonance imaging in paediatric psychoneuroendocrinology: a new frontier for understanding the impact of hormones on emotion and cognition

Mounting magnetic resonance imaging (MRI) research is characterising the neurobiological trajectories of healthy human brain development. In parallel, studies increasingly acknowledge the relevance of perturbations of these trajectories for adolescent and adult psychopathology. Although an influence of steroid hormones on mood and anxiety disorders has been demonstrated in adults, very little is known about how steroid hormones alter human brain development and contribute to adolescent psychopathology. This review focuses on recent evidence obtained from structural and functional MRI in children and adolescents with genetic endocrine disorders and with characteristic fluctuations in androgen or oestrogen levels (familial male precocious puberty, congenital adrenal hyperplasia, Klinefelter syndrome and Turner syndrome). It aims to highlight how neurobiological findings from these paediatric endocrine disorders can provide insight into the contribution of sex steroids with respect to the development of neurocircuitry involved in affective processing (amygdala, hippocampus) and cognitive control (prefrontal cortex, inferior frontal gyrus, striatum). In addition, findings from these populations may also provide important information on aberrant psychological processes relevant for the clinical care and management of these populations. Finally, the findings are discussed within the context of current frameworks in animal models, such as the organisational-activational hypothesis or the aromatisation hypothesis. The review ends with a discussion of open questions for future enquiry with the goal of integrating translational models with current knowledge of endocrine disorders and developmental studies in healthy populations.

The effect of PN-1, a Traditional Chinese Prescription, on the Learning and Memory in a Transgenic Mouse Model of Alzheimer's Disease

Traditional Chinese Medicine (TCM) is a complete medical system that has been practiced for more than 3000 years. Prescription number 1 (PN-1) consists of several Chinese medicines and is designed according to TCM theories to treat patients with neuropsychiatric disorders. The evidence of clinical practice suggests the benefit effects of PN-1 on cognitive deficits of dementia patients. We try to prove and explain this by using contemporary methodology and transgenic animal models of Alzheimer's disease (AD). The behavioral studies were developed to evaluate the memory of transgenic animals after intragastric administration of PN-1 for 3 months. Amyloid beta-protein (A β ) neuropathology was quantified using immunohistochemistry and ELISA. The western blotting was used to detect the levels of plasticity associated proteins. The safety of PN-1 on mice was also assessed through multiple parameters. Results showed that PN-1 could effectively relieve learning and memory impairment of transgenic animals. Possible mechanisms showed that PN-1 could significantly reduce plaque burden and A β levels and boost synaptic plasticity. Our observations showed that PN-1 could improve learning and memory ability through multiple mechanisms without detectable side effects on mice. We propose that PN-1 is a promising alternative treatment for AD in the future.

Peri-pubertal gonadotropin-releasing hormone analog treatment affects hippocampus gene expression without changing spatial orientation in young sheep

BACKGROUND

Normal brain maturation is the result of molecular changes that can be modulated by endocrine variables associated with brain plasticity and results in sex- and age specific changes in cognitive performance. Using a sheep model, we have previously shown that peri-pubertal pharmacological blockade of gonadotropin releasing hormone (GnRH) receptors results in increased sex-differences in cognitive executive function and emotional control. In this study we explore effects of this treatment regime on hippocampal gene expression and spatial orientation.

METHODS

The study was conducted with 30 same-sex twin lambs, half of which were treated with the GnRH analog (GnRHa) goserelin acetate every 4th week, beginning before puberty, until 50 weeks of age. Animals were tested in their spatial orientation ability at 48 weeks of age. Quantitative real time PCR analysis was conducted to examine effects of treatment on the expression of genes associated with synaptic plasticity and endocrine signaling.

RESULTS

GnRHa treatment was associated with significant sex- and hemisphere specific changes in mRNA expression for some of the genes studied. The treatment had no significant effect on spatial orientation. However, there was a tendency that females performed better than males in spatial orientation.

CONCLUSION

Our results indicate that GnRH directly and/or indirectly, is involved in the regulation of sex- and side-specific expression patterns of genes. Hence, these results should be considered when long-term peri-pubertal GnRHa treatment is used in children.

Akebia Saponin D attenuates amyloid β-induced cognitive deficits and inflammatory response in rats: involvement of Akt/NF-κB pathway

Neuroinflammatory responses caused by amyloid β(Aβ) play an important role in the pathogenesis of Alzheimer's disease (AD). Aβ is known to be directly responsible for the activation of glial cells and induction of apoptosis. Akebia Saponin D (ASD) is extracted from a traditional herbal medicine Dipsacus asper Wall, which has been shown to protect against ibotenic acid-induced cognitive deficits and cell death in rats. In this study, we investigated the in vivo protective effect of ASD on learning and memory impairment induced by bilateral intracerebroventricular injections of Aβ1-42 using Morris water and Y-maze task. Furthermore, the anti-inflammatory activity and neuroprotective effect of ASD was examined with methods of histochemistry and biochemistry. These data showed that oral gavage with ASD at doses of 30, 90 and 270 mg/kg for 4 weeks exerted an improved effect on cognitive impairment. Subsequently, the ASD inhibited the activation of glial cells and the expression of tumor necrosis factor (TNF)-α, interleukin-1 beta (IL-1β) and cyclooxygenase-2 (COX-2) in rat brain. Moreover, ASD afforded beneficial actions on inhibitions of Akt and IκB kinase (IKK) phosphorylations, as well as nuclear factor κB (NF-κB) activation induced by Aβ1-42. These results suggest that ASD may be a potential agent for suppressing both Alzheimer's disease-related neuroinflammation and memory system dysfunction.

Predictors of virtual radial arm maze performance in adolescent Italian children

BACKGROUND

Comparisons between animal and human neurotoxicology studies are a foundation of risk assessment, but are hindered by differences in measured behaviors. The radial arm maze (RAM), a rodent visuospatial learning and memory task, has a computerized version for use in children, which may help improve comparisons between animal and human studies.

OBJECTIVE

To describe the characteristics and correlates of the virtual radial arm maze (VRAM) in 255 children age 10-15 years from Italy.

METHODS

We administered the VRAM using a laptop computer and measured children's performance using the latency, distance, and working/reference memory errors during eight trials. Using generalized linear mixed models, we described VRAM performance in relation to demographic factors, child activities, and several standard neuropsychologic tests (Italian translations), including the Conners Parent Rating Scales-Short Version (CPRS), California Verbal Learning Test (CVLT), Wechsler Intelligence Scales for Children, finger tapping speed, reaction time, and motor skills.

RESULTS

Children's VRAM performance tended to improve between trials 1 and 6 and then plateaued between trials 6 and 8. Males finished the task 14 s faster (95% confidence interval [CI]: -20, -9) than females. Children who played 2+h of video games per day finished 16 s faster (CI: -26, -6) and with 34% (CI: 5, 54%) fewer working memory errors than children who reported not playing video games. Higher IQ and better CVLT scores were associated with better VRAM performance. Higher cognitive/inattention CPRS scores were associated with more working (11%; CI: 1, 22) and reference memory errors (7%; CI: 1, 12).

CONCLUSIONS

Consistent with animal studies, VRAM performance improved over the course of test trials and males performed better than females. Better VRAM performance was related to higher IQ, fewer inattentive behaviors, and better verbal memory. The VRAM may help to improve the integration and comparison between animal and epidemiological studies of environmental neurotoxicants.