Pubertal hormones organize the adolescent brain and behavior

Altered activity within the social behavior neural network in adolescent rats following prenatal alcohol exposure and/or early-life adversity

BACKGROUND

Social behavior relies on the dynamic, complex, and coordinated activity of a highly conserved "social behavior neural network," which includes the olfactory bulb (OB), piriform cortex (PCX), lateral septum, medial prefrontal cortex (mPFC), amygdala, paraventricular nucleus of the hypothalamus (PVN), and ventral hippocampus. Prenatal alcohol exposure (PAE) is known to disrupt social behavior development, leading to lifelong social functioning impairments. Individuals with PAE are at heightened risk of experiencing early-life adversity (ELA), which independently affects social behavior development; however, little is known about the combined effects of PAE and ELA on social behavior.

METHODS

We previously demonstrated that PAE and ELA impact social recognition memory throughout adolescence; here, we combine animal models of PAE and ELA to gain insight into both independent and interactive effects of these insults on social behavior network neural activity in both early and late adolescent male and female rats. We measured neural activity (c-fos mRNA expression) across the network following social recognition memory testing.

RESULTS

Our findings indicate that both PAE and ELA are associated with altered neural activity in regions supporting social recognition memory, notably the OB, PCX, mPFC, amygdala, and PVN. The direction of these effects and specific regions impacted vary by sex and age at assessment. Importantly, different brain areas exhibit distinct sensitivities to each type of insult, with PAE generally resulting in hypoactivity of the amygdala and ELA altering mPFC activity.

CONCLUSIONS

These data contribute to a more complete social neurobehavioral profile, accounting for both PAE and ELA, to support earlier diagnoses and interventions.

Testosterone and cortisol jointly mediate and modulate trust behavior in early adolescence

During early adolescence, individuals undergo significant changes in neuroendocrine systems, neurodevelopment, and social sensitivity. Placing trust in the appropriate person becomes especially crucial for adolescents, given their increased peer interaction and heightened susceptibility to peer influence during this period. Adolescents take social distance into account when making trust decisions. However, the biological and cognitive mechanisms involved in trust decision-making towards peers of different social distances remain unclear. The present study investigated the interactions among hormonal (basal cortisol and basal testosterone), cognitive (impulsivity and theory of mind), and contextual (friends and strange peers) factors underlying trust decision-making in a sample of 142 adolescents (45 % females, Mage = 12.32 years, SDage = 0.60). Using a balloon analog risk task, a cartoon story reasoning task, and a modified version of the trust game, we assessed adolescents' impulsivity, theory of mind, as well as trust investment and evaluation of return possibility towards their friends and strangers, separately. The results showed a unique hormonal-cognitive-contextual mechanism underlying trust investment, despite adolescents demonstrating a preference for trusting friends over strangers in both trust investment and trust evaluation. Cortisol predominantly influenced adolescents' general trust, directly and indirectly through impulsivity. Testosterone appeared to modulate the indirect effect of cortisol via impulsivity on general trust and impacted their strategic trust decisions through the theory of mind. These findings highlight the role of cortisol and testosterone in trust and its potential cognitive process and provide guidance for tailored interventions for promoting healthy social development.

Impact of adolescent high-fat diet and psychosocial stress on neuroendocrine stress responses and binge eating behavior in adult male Lewis rats

Childhood obesity is a multifactorial disease affecting >160 million adolescents worldwide. Adolescent exposure to obesogenic environments, characterized by access to high-fat diets and stress, precipitates maladaptive eating habits in adulthood such as binge eating. Evidence suggests a strong association between Western-like high-saturated fat (WD) food consumption and dysregulated hormone fluctuations. However, few studies have explored the long-term impact of adolescent WD and psychosocial stress on brain and behavior. This longitudinal study aimed to investigate the impact of adolescent exposure to an obesogenic diet on stress resiliency and increased susceptibility for binge-like eating behaviors. Adolescent male Lewis rats were given WD (41% fat; n = 40) or control diet (CD, 16% fat; n = 38) for 4 weeks before undergoing a stress protocol of predator exposure and social instability (CDE, WDE, CDU, WDU; n = 16/group). Subjects were provided intermittent WD access (24 h/week) to evaluate binge-like eating behavior in adulthood. Fecal corticosterone and testosterone were measured at four timepoints throughout adolescence and adulthood. WD rats exhibited increased body weight (p = 0.0217) and elevated testosterone in mid-adolescence (p = 0.0312) and blunted stress-induced corticosterone response in mid-late adolescence (CDE:WDE, p = 0.028). Adolescent hormone levels were negatively correlated with binging and explained the variability between adult rats expressing hyperphagic and hypophagic behaviors. These results demonstrate that exposure to WD in adolescence disrupts hormone fluctuations and stress responsivity, with effects persisting into adulthood. This underscores the importance of addressing obesogenic environments early to mitigate their lasting impact on hormone regulation and stress responsiveness.

Multimodal Measurement of Pubertal Development: Stage, Timing, Tempo, and Hormones

Using data from the Human Connectome Project in Development (N = 1304; ages 5-21 years; 50% male; 59% White, 17% Hispanic, 13% Black, 9% Asian), multiple measures (self-report, salivary hormones) and research designs (longitudinal, cross-sectional) were used to characterize age-related changes and sex differences in pubertal development. Both sexes exhibit a sigmoid trajectory of pubertal development; females show earlier pubertal timing and increased tempo ~9-13 years, while males show greater tempo ~14-18 years. All hormones increased with age, with sex differences in testosterone and DHEA levels and in testosterone rates of change. Higher testosterone and DHEA corresponded with earlier pubertal timing in both sexes. These findings characterize typical pubertal and hormonal development and inform best practices for handling puberty data.

The intersection and developmental trajectory of morning cortisol and testosterone in autistic and neurotypical youth

BACKGROUND

Behavioral endocrinology examines associations between hormone expression, such as testosterone and cortisol, and behavior; both of which have been implicated in autism spectrum disorder (ASD). The overarching aim of the study was to examine the intersection of sex-based (Male, Female), hormonal (testosterone, cortisol), diagnostic (ASD, typically developing, (TD)) and developmental (age, puberty) patterns over four years of a longitudinal study in a well-characterized sample of youth (spanning 10 to 17 years).

METHODS

In year 1 (Y1), participants included 140 autistic youth (36 females, 104 males) and 105 TD youth (46 females, 59 males.). For Y4, participants included 83 ASD and 77 TD youth. Immediate waking morning salivary samples were collected for hormone assay. Mixed effects and ordinary linear regression models were used, as well as mediation effects of hormones on behavior.

RESULTS

For cortisol, there was a significant diagnosis by sex by age interaction (X2 = 15.62, df = 3, p = 0.0014, S = 0.2446) showing that autistic females evidence higher morning cortisol that increased over developmental progression compared to TD females. Moreover, ASD males had stunted testosterone growth compared to TD males (Est = 0.1530, p = 0.0130). Regarding biobehavioral associations in year 1, diagnosis (X2 = 80.72, df = 1, p < 0.0001, S = 0.5704) and cortisol (X2 = 14.42, df = 3, p = 0.0024, S = 0.2159) were associated with social problems; however, there were no effects for testosterone on diagnosis or a mediation effect on social problems. There was a significant effect of diagnosis on CBCL Aggression score (X2 = 34.39, df = 1, p < 0.0001, S = 0.3692) independent of hormonal measurements.

LIMITATIONS

Despite the large sample, it was not fully representative based on race, ethnicity or intellectual profile. Attrition of the sample is also acknowledged especially between portions of Y2 and Y3 due to the COVID-19 pandemic. Finally, only the immediate morning salivary samples were used due to lower and undetectable concentration levels of testosterone in younger and female children.

CONCLUSIONS

Collectively, these findings underscore the need to elucidate the biobehavioral patterns that emerge during the complex adolescent transition for autistic youth to determine how they impact clinical and long-term outcomes. The unique hormonal trajectories may be related to differences in advanced pubertal progression and affective states found in autistic females.

The ventral premammillary nucleus at the interface of environmental cues and social behaviors

The survival of species heavily depends on social behaviors, which in turn rely on the ability to recognize conspecifics within an appropriate environmental context. These behaviors are regulated by the hypothalamus, which processes signals from both the external environment (such as food availability, photoperiod, and chemical cues from other animals) and the internal state (including sex, estrous cycle stage, nutritional status, and levels of stress). Understanding the brain circuits responsible for specific behaviors in experimental animals is a complex task given the intricate interactions between these factors and the diverse behavioral strategies employed by different species. In this review, we will critically evaluate recent studies focused on the ventral premammillary nucleus (PMv) and discuss findings that reveal the PMv as a key, yet sometimes overlooked, node in integrating external and internal environmental cues. We will examine its structural components, internal connectivity, humoral influences, and associated functions, demonstrating the PMv role in the neural regulation of neuroendocrine responses and social behaviors. While much of the existing research centers on rats and mice as model organisms, we will highlight relevant species differences and include a dedicated section for findings in other species.

Breaking family bonds: pair disruption alters female adolescent spatial neophobia but not other personality traits or corticosterone stress response in zebra finches (Taeniopygia guttata)

Adolescence is a sensitive period because it is associated with the ontogeny of key neurological, physiological and behavioural systems. These systems can be permanently altered by social disruption during adolescence and therefore impair an individual's ability to cope with its environment later in life. We tested whether pair disruption of captive zebra finches (Taeniopygia guttata) during emancipation affects the family social structure, with potential consequences for the nutritional status, personality and corticosterone stress response of juveniles. We experimentally manipulated the social environment of 22 families during emancipation by replacing fathers with unfamiliar males (experimental families) or leaving them unchanged (control families) and monitored the prevalence of affiliative, agonistic and sexual interactions between family members. We assessed offspring growth, timing of nutritional independence, body condition as well as five personality traits and the corticosterone stress response to isolation. While we observed more agonistic and sexual behaviours in experimental families, we also observed more affiliative behaviours between experimental siblings and more maternal provisioning of the experimental juveniles. Among all the traits we tested, we only found a sex-dependent effect of the experimental treatment on spatial neophobia, suggesting that pair disruption may have long-term consequences for females' ability to cope with new environments. However, our findings suggest overall that the emancipation phase is less sensitive to social environment in comparison to the prenatal and early postnatal periods and that nutritional and social buffers may mitigate the lasting impacts of pair disruption on adolescent behavioural and stress response profiles in altricial species such as the zebra finch.

The role of androgens on experimental pain sensitivity: a systemic review and meta-analysis

Animal studies have shown androgens, especially testosterone, may have an analgesic effect on nociceptive behavior. However, it is unclear if this effect is present in humans. This review and meta-analysis aim to summarize and synthesize the role of androgens on experimental pain sensitivity in humans. Studies were included if they examined the (1) relationships between androgens and experimental pain sensitivity, (2) group differences in androgen or pain levels, and (3) the effect of androgen interventions on experimental pain sensitivity. After a comprehensive search, 31 papers were identified. When possible, meta-analyses were performed. Most studies examined the impact of testosterone on experimental pain, and only a few studies focused on other androgens, such as dehydroepiandrosterone and dehydroepiandrosterone sulfate. Overall, the current data do not support the effect of androgens on experimental pain sensitivity in adult men and women with or without chronic pain. In addition, meta-analyses of Pearson correlations did not find relationships between testosterone levels and pain ratings of heat stimulus (3 studies, n = 93, Z correlation coefficient = -0.43, confidence intervals [-1.50, 0.64]) or electrical pain thresholds (4 studies, n = 147, Z correlation coefficient = 0.24, confidence intervals [-0.10, 0.58]). Moreover, contradicting results were found in intervention studies that increased or decreased testosterone levels. Thus, it is suggested that the role of testosterone on experimental pain sensitivity may be minor, even though there is a wide heterogeneity between studies. Future studies should examine the impact of other androgens and the interaction between testosterone and other hormones on experimental pain sensitivity.

The multiscale brain structural re-organization that occurs from childhood to adolescence correlates with cortical morphology maturation and functional specialization

From childhood to adolescence, the structural organization of the human brain undergoes dynamic and regionally heterogeneous changes across multiple scales, from synapses to macroscale white matter pathways. However, during this period, the developmental process of multiscale structural architecture, its association with cortical morphological changes, and its role in the maturation of functional organization remain largely unknown. Here, using two independent multimodal imaging developmental datasets aged 6-14 years, we investigated developmental process of multiscale cortical organization by constructing an in vivo multiscale structural connectome model incorporating white matter tractography, cortico-cortical proximity, and microstructural similarity. By employing the gradient mapping method, the principal gradient derived from the multiscale structural connectome effectively recapitulated the sensory-association axis. Our findings revealed a continuous expansion of the multiscale structural gradient space during development, characterized by enhanced differentiation between primary sensory and higher-order transmodal regions along the principal gradient. This age-related differentiation paralleled regionally heterogeneous changes in cortical morphology. Furthermore, the developmental changes in coupling between multiscale structural and functional connectivity were correlated with functional specialization refinement, as evidenced by changes in the participation coefficient. Notably, the differentiation of the principal multiscale structural gradient was associated with improved cognitive abilities, such as enhanced working memory and attention performance, and potentially underpinned by synaptic and hormone-related biological processes. These findings advance our understanding of the intricate maturation process of brain structural organization and its implications for cognitive performance.

Pubertal stress accelerates copulation in adult male rats: Mitigating effects of a high-calorie diet in adulthood

The pubertal phase involves significant brain reorganization, where external stressors and diet can profoundly influence long-term behavioral outcomes. In this study, we investigated the interaction between acute pubertal stress (via immune challenge) and a hypercaloric diet in adulthood on the copulatory sexual behavior of male Wistar rats. At postnatal day (PND) 35, pubertal males received a single injection of lipopolysaccharide (LPS, 1.5 mg/kg i.p.) or saline. All subjects were fed standard rat chow until postnatal week 14, during which copulatory sexual behavior was assessed from weeks 11 to 14. Then, from weeks 15 to 18, half of the animals in each group were switched to a hypercaloric cafeteria-type diet and the other half continued on standard chow, with sexual behavior of all males re-assessed during weeks 19 to 22 and under standard diet. Our results indicated that treatment with LPS during puberty accelerated copulation in adulthood, characterized by fewer mounts and intromissions per series, shorter latency to ejaculation and higher intromission ratio. Cafeteria diet alone increased mount and intromission frequency, but had no effect on ejaculations. Only intromission were affected by an interaction of treatment and diet. These findings show that LPS-induced immune stress during puberty acts as an early-life stressor with enduring consequences on copulatory timing in males, while a subchronic hypercaloric diet in adulthood may mitigate some of these effects.

Critical menarche age for late-life dementia and the role of education and socioeconomic status

Estrogen exposure during menstrual years has been associated with late-life neuroprotection. We explored the presence of an age-sensitive menarche window for cognition in old age and the impact of socioeconomic status and education. We compared neuropsychological performance of 1082 older women [MeanAGE = 72.69 (5.48)] with menarche in childhood, early-, mid-, and late-adolescence and dementia prevalence, severity, and type, including the effects of education and socioeconomic status. Adjusting for covariates, menarche at 11-14 years of age was associated with better memory, executive and global cognitive functioning in old age, and stronger positive effects of education and socioeconomic status on cognition than those with menarche at 15-17 years. We found a critical age window for the neuroprotective effects of estrogens during early adolescence, putting women with later menarche at higher risk for cognitive decline. Effects of socioeconomic status and education in adulthood should be a focus of future research.

Effects of a school-based physical activity intervention on mental health indicators in a sample of Brazilian adolescents: a cluster randomized controlled trial

PURPOSE

To test the effects of a physical activity intervention program on symptoms of mental disorders among adolescents.

METHODS

This study is a 12-week cluster randomized controlled trial. The sample consisted of 306 adolescents (45,8% male, age: 13,6 [0,72] years; 54.2% female, age: 13.5 [0.69] years), randomized into an intervention group (N = 165) and a control group (N = 141). The physical activity program involved sessions including muscle strengthening and cardiorespiratory exercises and lifestyle guidance. The mental health indicators analyzed were: anxiety, depression, sleep, and psychological well-being. Intervention effects were analyzed by generalized estimating equations.

RESULTS

After 12 weeks, no significant improvements were observed in the intervention group for sleep; anxiety; depression, and psychological well-being. In the subgroup analysis, significant group×time interactions were observed for adolescents who were classified with moderate symptoms of depression (mean difference: -0.97, p = 0.002) and anxiety (mean difference: -3.03, p = 0.01) with favorable effects for intervention group.

CONCLUSION

After the 12-week intervention period, it can be concluded that 12 weeks of school-based physical activity intervention significantly reduced symptoms of anxiety and depression in adolescents with moderate/severe symptoms. Furthermore, the intervention contributed to the maintenance of psychological well-being, since the control group showed a significant reduction in this mental health indicator.

Preconceptional brain structure and future conception: a prospective brain MRI study among 321 women

Brain structure may influence female fertility through its reciprocal relationship with the endocrine system, but this hypothesis is underexplored. This study investigated the association between preconceptional brain structure and the likelihood of conception in a prospective population-based neuroimaging cohort. Women intending to conceive within a year were recruited and structural brain MRI scans were collected from 321 participants between June 2019 and March 2021. During the 12-month follow-up, 185 women became pregnant, and 136 did not. Logistic regression was used to examine associations between global brain parameters and conception, adjusting for age, intracranial volume, BMI, prior STD diagnosis, ethnicity, education, household income, smoking, and alcohol use. Unadjusted analyses showed associations between conception and larger occipital lobe and nucleus accumbens volume, increased surface area across all lobes, and occipital cortical thickness, and conception. Adjusted analyses identified a positive association between nucleus accumbens volume and conception (OR = 1.50 (95% CI: 1.12, 1.99), p-value = 0.007). Sensitivity analyses linked caudate volume to conception, but no findings remained significant after correction for multiple comparisons. Further research is needed to understand the potential role of brain structure and function in conception, in relationship with general health and socioeconomic factors.

Cognitive performance in young adult women with a history of premature adrenarche

BACKGROUND

Girls with premature adrenarche (PA) mature earlier than peers and have been found to have greater symptom accounts reflecting anxiety compared to peers. It is not known, however, whether PA effects cognitive development. This longitudinal case-control cohort study aimed: (1) To investigate whether a history of PA leads to measurable changes in adulthood cognitive performance, and (2) to assess whether findings characteristic of PA girls predict adulthood cognitive performance.

METHODS

Twenty-seven girls with PA and 27 age-matched control girls were examined and followed from mid-childhood (mean age 7.2 years) until early adult age (18.5 years). Wechsler Adult Intelligence Scale, Fourth Edition scores were used as main outcome measure.

RESULTS

Allostatic load (AL) scores, which compile multisystem variables to reflect the overall wear and tear of the body from increased and prolonged stress, were higher in the PA group in both prepuberty and adulthood, but there were no differences in WAIS-IV results between the groups (full-scale IQ 92.7 vs. 97.5, p 0.376; no differences in separate indexes). Childhood androgen levels, glucose metabolism biomarkers, and AL scores failed to predict adulthood cognitive performance outcomes.

CONCLUSION

The study suggests that PA does not predispose to adverse adulthood outcomes of cognitive development.

IMPACT

The study suggests that a history of premature adrenarche (PA) does not affect cognitive performance in adult age. Childhood androgen levels and biomarkers of glucose metabolism failed to predict adulthood cognitive outcomes in this study. Allostatic load scores were elevated in the PA group both in childhood and adulthood but did not predict adulthood cognitive outcomes.

Alterations in white matter integrity and correlations with clinical characteristics in children with non-lesional temporal lobe epilepsy

PURPOSE

To complement the current research on altered white matter integrity in children with non-lesional temporal lobe epilepsy (NL-TLE), especially the correlation between diffusion metrics and clinical characteristics, so as to provide imaging evidence for clinical practice.

METHODS

Children with temporal lobe epilepsy and no lesions on magnetic resonance imaging (MRI) were retrospectively collected from 2016.01.01 to 2022.12.31, and typically developing children (TDC) with normal MRI were collected as control group. Tract-based spatial statistics (TBSS) was used to compare the fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) between the two groups. Twenty fiber bundles were used as regions of interest (ROIs) to extract and compare the diffusion metrics. Partial correlation analysis was performed to assess the association between diffusion parameters within ROIs and clinical characteristics.

RESULTS

TBSS and ROI analysis showed that FA values decreased and MD and RD values increased in the NL-TLE compared with the TDC, without significant differences in AD values. FA values in all ROIs increased with age, while the MD and RD values decreased in all ROIs, and the AD values decreased in most ROIs. Epilepsy duration was negatively correlated with FA values and positively correlated with MD and RD values in specific fibers. Frequency of seizures was negatively correlated with the FA values in a few trats. Full-scale intelligence quotient (FSIQ) was positively correlated with FA values and negatively with RD value in a few tracts.

CONCLUSION

Children with NL-TLE showed widespread alterations in white matter integrity, which were correlated with clinical characteristics.

Cross-trait multivariate GWAS confirms health implications of pubertal timing

Pubertal timing is highly variable and is associated with long-term health outcomes. Phenotypes associated with pubertal timing include age at menarche, age at voice break, age at first facial hair and growth spurt, and pubertal timing seems to have a shared genetic architecture between the sexes. However, puberty phenotypes have primarily been assessed separately, failing to account for shared genetics, which limits the reliability of the purported health implications. Here, we model the common genetic architecture for puberty timing using a multivariate GWAS, with an effective population of 514,750 European participants. We find 266 independent variants in 197 loci, including 18 novel variants. Transcriptomic, proteome imputation and fine-mapping analyses reveal genes causal for pubertal timing, including KDM4C, LEPR, CCNC, ACP1, and PCSK1. Linkage disequilibrium score regression and Mendelian randomisation analysis establish causal associations between earlier puberty and both accelerated ageing and the risk of developing cardiovascular disease and osteoporosis. We find that alanine aminotransferase, glycated haemoglobin, high-density lipoprotein cholesterol and Parabacteroides levels are mediators of these relationships, and establish that controlling oily fish and retinol intake may be beneficial for promoting healthy pubertal development.

Effects of early maternal care on anxiety and threat learning in adolescent nonhuman primates

Early life adverse experiences, including childhood maltreatment, are major risk factors for psychopathology, including anxiety disorders with dysregulated fear responses. Consistent with human studies, maltreatment by the mother (MALT) leads to increased emotional reactivity in rhesus monkey infants. Whether this persists and results in altered emotion regulation, due to enhanced fear learning or impaired utilization of safety signals as shown in human stress-related disorders, is unclear. Here we used a rhesus model of MALT to examine long-term effects on state anxiety and threat/safety learning in 25 adolescents, using a fear conditioning paradigm (AX+/BX-) with acoustic startle amplitude as the peripheral measure. The AX+/BX- paradigm measures baseline startle, fear-potentiated startle, threat/safety cue discrimination, startle attenuation by safety signals, and extinction. Baseline startle was higher in MALT animals, suggesting elevated state anxiety. No differences in threat learning, or threat/safety discrimination were detected. However, MALT animals showed generalized blunted responses to the conditioned threat cue, regardless of the safety cue presence in the transfer test, and took longer to extinguish spontaneously recovered threat. These findings suggest adverse caregiving experiences have long-term impacts on adolescent emotion regulation, including elevated state anxiety and blunted fear conditioning responses, consistent with reports in children with maltreatment exposure.

The connecting brain in context: How adolescent plasticity supports learning and development

Puberty initiates significant neurobiological changes that amplify adolescents' responsiveness to their environment, facilitating neural adaptation through processes like synaptic pruning, myelination, and neuronal reorganization. This heightened neuroplasticity, combined with their burgeoning social curiosity and appetite for risk, propels adolescents to explore diverse new environments and forge social bonds. Such exploration can accelerate experiential learning and the formation of social networks as adolescents prepare for adult independence. This review examines the complex interplay between adolescent neuroplasticity, environmental influences, and learning processes, synthesizing findings from recent studies that illustrate how factors such as social interactions, school environments, and neighborhood contexts influence both the transient activation and enduring organization of the developing brain. We advocate for incorporating social interaction into adolescent-tailored interventions, leveraging their social plasticity to optimize learning and development during this critical phase. Going forward, we discuss the importance of longitudinal studies that employ multimodal approaches to characterize the dynamic interactions between development and environment, highlighting recent advancements in quantifying environmental impacts in studies of developmental neuroscience. Ultimately, this paper provides an updated synopsis of adolescent neuroplasticity and the environment, underscoring the potential for environmental enrichment programs to support healthy brain development and resilience at this critical development stage.

The effects of anemia on the timing of pubertal onset in female rats

Attainment of vaginal patency is an endpoint for the onset of puberty in female animals in toxicity studies. It is widely acknowledged that certain substances with endocrine-modulating effects can influence the timing of puberty in female rats and that factors unrelated to endocrine mechanisms, such as malnutrition and stress, can also affect pubertal onset. Some epidemiological studies have also suggested a link between anemia and delay in pubertal onset in women, however, little is known regarding the relation between hematological changes and female pubertal onset in experimental animals. The purpose of this study was to examine the effects of anemia during the prepubertal period on pubertal onset and reproductive organs in female rats. In this study, anemia was induced by drawing a certain amount of blood from the jugular vein or by intraperitoneal administration of phenylhydrazine, a well-known inducer of hemolytic anemia. As a result, both treatment groups showed a transient anemia characterized by an approximately 20-35% decrease in hemoglobin levels compared to the control group. Anemia in these female rats produced no obvious changes in body weight on each postnatal day and had no effect on the weights and histopathology of reproductive organs after sexual differentiation, but the age at vaginal opening (VO) was delayed and the body weight at VO was higher than the same parameters in the control group. These results suggest that anemia in prepubertal females could cause a delay in pubertal onset.

Neuroanatomical alterations in young boys and adolescents with Klinefelter syndrome

Klinefelter syndrome (KS, 47,XXY) is a common sex chromosome aneuploidy in males that is characterized by pubertal developmental delays and a wide range of alterations in cognitive, social and emotional functioning. The neural bases of these behavioral symptoms, however, are unclear. A total of 130 boys and adolescents, including 67 males with KS (11.5 ± 2.8 years) and 63 typically developing (TD; control) males (10.6 ± 2.8 years) underwent MRI scanning and pubertal assessment. Group differences in regional gray matter volume was examined using voxel-based morphometry while controlling for age at scan and total gray matter volume. Thresholded statistical significance maps indicated widespread reductions in frontal and temporal and cerebellar gray matter in males with KS relative to TD males, as well as increases in parietal and occipital gray matter. Secondary analyses explored potential associations between GMV in these regions and pubertal development. Lower testicular volume was a significant predictor of reduced GMV in frontal, temporal and cerebellar subregions, even after accounting for group status (KS, TD). Taken together, these findings add support for a neuroanatomical phenotype of KS and provide initial evidence for a role of pubertal development in KS-associated differences in gray matter structure. Future studies that examine the influence of testosterone supplementation on GMV in males with KS are warranted.

The effect of ovariectomy, 17β-estradiol treatment, and progesterone treatment on dopaminergic regulation of prepulse inhibition in adult and adolescent female mice

The aim of the present study was to investigate the role of ovarian hormones on dopaminergic regulation of prepulse inhibition (PPI), a measure of sensorimotor gating deficient in schizophrenia and other psychiatric illnesses. Either in adulthood (11 weeks of age) or adolescence (5 weeks of age), female mice underwent ovariectomy (OVX) and were implanted with 17β-estradiol, progesterone, or a combination of these hormones. All mice were tested in adulthood for the acute effect of the dopamine receptor agonist, apomorphine, on PPI. Apomorphine treatment reduced PPI in intact mice and this effect was blocked after OVX in adulthood. A low dose implant of 17β-estradiol prevented this OVX effect and reinstated apomorphine-induced PPI disruption. Following adolescent OVX, the effect of apomorphine was not altered and it significantly reduced PPI in adulthood. A low dose implant of 17β-estradiol following adolescent OVX effect blocked apomorphine-induced PPI disruption in adulthood. Apomorphine had no effect on PPI in any of the mice treated with the high dose of 17β-estradiol or a combination of low-dose 17β-estradiol and progesterone, irrespective of treatment age, suggesting an antipsychotic action. Apomorphine tended to disrupt PPI in mice treated with progesterone only, irrespective of age of OVX. These results suggest that in adult mice, circulating 17β-estradiol and progesterone play an important role in dopaminergic regulation of PPI. This role may develop during adolescence as similar effects of OVX and ovarian hormones were not observed following interventions in 5-week old mice. Our results also confirm and extend previous evidence that 17β-estradiol may have antipsychotic properties.

Linking Adult Olfactory Neurogenesis to Social Reproductive Stimuli: Mechanisms and Functions

Over the last three decades, adult neurogenesis in mammals has been a central focus of neurobiological research, providing insights into brain plasticity and function. However, interest in this field has recently waned due to challenges in translating findings into regenerative applications and the ongoing debate about the persistence of this phenomenon in the adult human brain. Despite these hurdles, significant progress has been made in understanding how adult neurogenesis plays a critical role in the adaptation of brain circuits to environmental stimuli regulating key brain functions. This review focuses on the role of olfactory neurogenesis in the brain's response to social reproductive cues in rodents, highlighting its influence on animal behaviors critical for survival. We also address open questions and propose future directions to advance our understanding of the relationship between adult neurogenesis and reproductive function regulation.

Vasopressinergic sexual dimorphism: Sex chromosome complement and organizational hormonal effects

This study aimed to analyze the role of the sex chromosomes (SCC: XX/XY) and the interaction with organizational hormonal effects on Avp gene expression at the supraoptic (SON) and paraventricular nuclei (PVN) due to water deprivation, as well as on the vasopressinergic sexually dimorphic antidiuretic and pressor responses. For this purpose, we used gonadectomized (GDX) transgenic mice of the "four core genotypes" model, in which the effect of gonadal sex and SCC are dissociated. A significant interaction between treatment and SCC on Avp gene expression at the SON was observed. Regardless of sex, XX mice showed higher basal expression than those with XY; however after water deprivation no changes in mRNA Avp expression were observed in the XX group, while an increase for XY was reported. At the PVN an interaction of SCC, organizational hormonal, and treatment factors was observed, revealing an increase in Avp gene expression in the XY-GDX male DEP group. Although no SCC or organizational hormonal effects were observed on the demopressin-antidiuretic response and renal Avpr2 mRNA expression, an interplay of organizational hormonal and SCC factors in short and medium-term vasopressin-blood pressure regulation were reported. XX-GDX females showed a facilitated vasopressin-bradycardic baroreflex response when compared to the other genotypes. Furthermore, although vasopressin continuous infusion resulted initially in the expected increase in the percentage change in MAP in all genotypes, in XX-GDX male and female this increase was sustained until the 30-min infusion, while in XY-GDX male and in XY-GDX female mice a decrease in MAP was observed.

Impact of adolescent high-fat diet and psychosocial stress on neuroendocrine stress responses and binge eating behavior in adult male Lewis rats

Childhood obesity is a multifactorial disease affecting more than 160 million adolescents worldwide. Adolescent exposure to obesogenic environments, characterized by access to high-fat diets and stress, precipitates maladaptive eating habits in adulthood such as binge eating. Evidence suggests a strong association between Western-like high-saturated-fat (WD) food consumption and dysregulated hormone fluctuations. However, few studies have explored the long-term impact of adolescent WD and psychosocial stress on brain and behavior. This longitudinal study aimed to investigate the impact of adolescent exposure to an obesogenic diet on stress resiliency and increased susceptibility for binge-like eating behaviors. Adolescent male Lewis rats were given WD (41% fat; n=40) or control diet (CD, 16% fat; n=38) for 4 weeks before undergoing a stress paradigm of predator exposure and social instability (CDE, WDE, CDU, WDU; n=16/group). Subjects were provided intermittent WD access (24 h/week) to evaluate binge eating-like behavior in adulthood. Fecal corticosterone and testosterone were measured at four timepoints throughout adolescence and adulthood. WD rats exhibited increased body weight (p = 0.0217) and elevated testosterone in mid-adolescence (p=0.0312) and blunted stress-induced corticosterone response in mid-late adolescence (CDE:WDE, p=0.028). Adolescent hormone levels were negatively correlated with bingeing and explained the variability between adult rats expressing hyperphagic and hypophagic behaviors. These results demonstrate that exposure to WD in adolescence disrupts hormone fluctuations and stress responsivity, with effects persisting into adulthood. This underscores the importance of addressing obesogenic environments early to mitigate their lasting impact on hormone regulation and stress responsiveness.

Coming of age in war: Early life adversity, age at menarche, and mental health

Armed conflict and forced migration (ACFM) represent a set of extreme environments that are increasingly common for children and adolescents to experience. Adolescence may constitute a sensitive period (puberty and psychoneurological maturation) through which ACFM adversity leaves a lasting mark. Adolescence has become a focal point for analysis and intervention as it relates to the effects of early life adversity on puberty, linear growth, and mental health. Research in public health and psychological science suggests early life adversity (ELA) may accelerate puberty, heightening risks for mental health disorders. However, it is not well substantiated whether ACFM-derived adversities accelerate or delay relative pubertal timing. Secondly, ACFM provides salient context through which to probe the relationships between nutritional, psychosocial, and demographic changes and their respective impact on puberty and mental health. We conducted a narrative review which 1) examined constructions of early life adversity and their proposed influence on puberty 2) reviewed empirical findings (n = 29 studies, n = 36 samples) concerning effects of ACFM ELA on age at menarche and 3) discussed proposed relationships between early life adversity, puberty, and mental ill-health. Contrary to prior research, we found war-derived early life adversity was more consistently associated with pubertal delay than acceleration and may exert counterintuitive effects on mental health. We show that ELA cannot be operationalized in the same way across contexts and populations, especially in the presence of extreme forms of human stress and resilience. We further discuss the ethics of puberty research among conflict-affected youth.

Disorders of puberty and neurodevelopment: A shared etiology?

The neuroendocrine control of puberty and reproduction is fascinatingly complex, with up- and down-regulation of key reproductive hormones during fetal, infantile, and later childhood periods that determine the correct function of the hypothalamic-pituitary-gonadal axis and the timing of puberty. Neuronal development is a vital element of these processes, and multiple conditions of disordered puberty and reproduction have their etiology in abnormal neuronal migration or function. Although there are numerous documented cases across multiple conditions wherein patients have both neurodevelopmental disorders and pubertal abnormalities, this has mostly been described ad hoc and the associations are not clearly documented. In this review, we aim to describe the overlap between these two groups of conditions and to increase awareness to ensure that puberty and reproductive function are carefully monitored in patients with neurodevelopmental conditions, and vice versa. Moreover, this commonality can be explored for clues about the disease mechanisms in these patient groups and provide new avenues for therapeutic interventions for affected individuals.

Neural adaptation to changes in self-voice during puberty

The human voice is a potent social signal and a distinctive marker of individual identity. As individuals go through puberty, their voices undergo acoustic changes, setting them apart from others. In this article, we propose that hormonal fluctuations in conjunction with morphological vocal tract changes during puberty establish a sensitive developmental phase that affects the monitoring of the adolescent voice and, specifically, self-other distinction. Furthermore, the protracted maturation of brain regions responsible for voice processing, coupled with the dynamically evolving social environment of adolescents, likely disrupts a clear differentiation of the self-voice from others' voices. This socioneuroendocrine framework offers a holistic understanding of voice monitoring during adolescence.

Starting the pill during adolescence: Age of onset and duration of use influence morphology of the hippocampus and ventromedial prefrontal cortex

From adolescence, women become more likely to experience fear dysregulation. Oral contraceptives (OCs) can modulate the brain regions involved in fear processes. OCs are generally used for years and often initiated during adolescence, a sensitive period where certain brain regions involved in the fear circuitry are still undergoing important reorganization. It remains unknown whether OC use during adolescence may induce long-lasting changes in the fear circuitry. This study aimed to examine whether age of onset moderated the relationship between duration of use and fear-related brain structures. We collected structural MRI data in 98 healthy adult women (61 current users, 37 past users) and extracted grey matter volumes (GMV) and cortical thickness (CT) of key regions of the fear circuitry. Non-linear multiple regressions revealed interaction effects between age of onset and quadratic duration of use on GMV of the right hippocampus and right ventromedial prefrontal cortex (vmPFC). Among women who initiated OCs earlier in adolescence, a short duration of use was associated with smaller hippocampal GMV and thicker vmPFC compared to a longer duration of use. For both GMV and CT of the right vmPFC, women with an early OC onset had more grey matter at a short duration of use than those with a later onset. Our results suggest that OC use earlier in adolescence may induce lasting effects on structural correlates of fear learning and its regulation. These findings support further investigation into the timing of OC use to better comprehend how OCs could disrupt normal brain development processes.

An emerging role of STriatal-Enriched protein tyrosine Phosphatase in hyperexcitability-associated brain disorders

STriatal-Enriched protein tyrosine Phosphatase (STEP) is a brain-specific tyrosine phosphatase that is associated with numerous neurological and neuropsychiatric disorders. STEP dephosphorylates and inactivates various kinases and phosphatases critical for neuronal function and health including Fyn, Pyk2, ERK1/2, p38, and PTPα. Importantly, STEP dephosphorylates NMDA and AMPA receptors, two major glutamate receptors that mediate fast excitatory synaptic transmission. This STEP-mediated dephosphorylation leads to their internalization and inhibits both Hebbian synaptic potentiation and homeostatic synaptic scaling. Hence, STEP has been widely accepted to weaken excitatory synaptic strength. However, emerging evidence implicates a novel role of STEP in neuronal hyperexcitability and seizure disorders. Genetic deletion and pharmacological blockade of STEP reduces seizure susceptibility in acute seizure mouse models and audiogenic seizures in a mouse model of Fragile X syndrome. Pharmacologic inhibition of STEP also decreases hippocampal activity and neuronal intrinsic excitability. Here, we will highlight the divergent roles of STEP in excitatory synaptic transmission and neuronal intrinsic excitability, present the potential underlying mechanisms, and discuss their impact on STEP-associated neurologic and neuropsychiatric disorders.

Under the influence: exogenous testosterone influences men's cross-sex perceptions of sexual interest

The sexual misperception bias is a cognitive bias in which men tend to overestimate sexual interest from women, potentially shaped by evolutionary mating strategies. Testosterone, often linked to mating behaviors, might play a role in sustaining sexual overperceptions. To explore this possibility, we conducted a placebo-controlled study with 190 heterosexual men, administering either 11 mg of testosterone or a placebo. Participants interacted with an attractive female confederate, while naïve raters assessed the confederate's affiliative behaviors. Our findings suggest that exogenous testosterone did not broadly impact sexual overperception. However, we found that affiliative behavior from the confederate was positively correlated with perceived sexual interest among testosterone-treated, but not placebo-treated men. In addition, we found that this effect among testosterone-treated men was contingent on their self-perceived attractiveness. Specifically, the confederate's affiliative behaviors were positively correlated with perceived sexual interest, but only for testosterone-treated men with average or above average self-perceived attractiveness. Furthermore, our data revealed that men's tendency to project their own short-term and long-term mating interests increases as a function of self-perceived attractiveness, and this coupling is enhanced by testosterone for long-term interest. Taken together, these results suggest that testosterone may potentiate existing biases, particularly when sexual motivation is high, and bias perceptions of friendly behavior when engaging in cross-sex mindreading. This study adds to the understanding of the neuroendocrine bases of social cognition, suggesting that testosterone can affect men's perceptions of potential mates.

Acute Stress Affects the Relaxin/Insulin-Like Family Peptide Receptor 3 mRNA Expression in Brain of Pubertal Male Wistar Rats

The current literature suggests that relaxin-3/relaxin/insulin-like family peptide receptor 3 (RLN-3/RXFP-3) system is involved in the pathophysiology of affective disorders because the results of anatomical and pharmacological studies have shown that the RLN-3 signaling pathway plays a role in modulating the stress response, anxiety, arousal, depression-like behavior, and neuroendocrine homeostasis. The risk of developing mental illnesses in adulthood is increased by exposure to stress in early periods of life. The available data indicate that puberty is especially characterized by the development of the neural system and emotionality and is a "stress-sensitive" period. The presented study assessed the short-term changes in the expression of RLN-3 and RXFP-3 mRNA in the stress-dependent brain regions in male pubertal Wistar rats that had been subjected to acute stress. Three stressors were applied from 42 to 44 postnatal days (first day: a single forced swim; second day: stress on an elevated platform that was repeated three times; third day: restraint stress three times). Anxiety (open field, elevated plus maze test) and anhedonic-like behavior (sucrose preference test) were estimated during these tests. The corticosterone (CORT) levels and blood morphology were estimated. We found that the RXFP-3 mRNA expression decreased in the brainstem, whereas it increased in the hypothalamus 72 h after acute stress. These molecular changes were accompanied by the increased levels of CORT and anxiety-like behavior detected in the open field test that had been conducted earlier, that is, 24 h after the stress procedure. These findings shed new light on the neurochemical changes that are involved in the compensatory response to adverse events in pubertal male rats and support other data that suggest a regulatory interplay between the RLN-3 pathway and the hypothalamus-pituitary-adrenal axis activity in the mechanisms of anxiety-like behavior.

Using Organoids to Model Sex Differences in the Human Brain

Sex differences are widespread during neurodevelopment and play a role in neuropsychiatric conditions such as autism, which is more prevalent in males than females. In humans, males have been shown to have larger brain volumes than females with development of the hippocampus and amygdala showing prominent sex differences. Mechanistically, sex steroids and sex chromosomes drive these differences in brain development, which seem to peak during prenatal and pubertal stages. Animal models have played a crucial role in understanding sex differences, but the study of human sex differences requires an experimental model that can recapitulate complex genetic traits. To fill this gap, human induced pluripotent stem cell-derived brain organoids are now being used to study how complex genetic traits influence prenatal brain development. For example, brain organoids from individuals with autism and individuals with X chromosome-linked Rett syndrome and fragile X syndrome have revealed prenatal differences in cell proliferation, a measure of brain volume differences, and excitatory-inhibitory imbalances. Brain organoids have also revealed increased neurogenesis of excitatory neurons due to androgens. However, despite growing interest in using brain organoids, several key challenges remain that affect its validity as a model system. In this review, we discuss how sex steroids and the sex chromosomes each contribute to sex differences in brain development. Then, we examine the role of X chromosome inactivation as a factor that drives sex differences. Finally, we discuss the combined challenges of modeling X chromosome inactivation and limitations of brain organoids that need to be taken into consideration when studying sex differences.

Tamoxifen exerts direct and microglia-mediated effects preventing neuroinflammatory changes in the adult mouse hippocampal neurogenic niche

Tamoxifen-inducible systems are widely used in research to control Cre-mediated gene deletion in genetically modified animals. Beyond Cre activation, tamoxifen also exerts off-target effects, whose consequences are still poorly addressed. Here, we investigated the impact of tamoxifen on lipopolysaccharide (LPS)-induced neuroinflammatory responses, focusing on the neurogenic activity in the adult mouse dentate gyrus. We demonstrated that a four-day LPS treatment led to an increase in microglia, astrocytes and radial glial cells with concomitant reduction of newborn neurons. These effects were counteracted by a two-day tamoxifen pre-treatment. Through selective microglia depletion, we elucidated that both LPS and tamoxifen influenced astrogliogenesis via microglia mediated mechanisms, while the effects on neurogenesis persisted even in a microglia-depleted environment. Notably, changes in radial glial cells resulted from a combination of microglia-dependent and -independent mechanisms. Overall, our data reveal that tamoxifen treatment per se does not alter the balance between adult neurogenesis and astrogliogenesis but does modulate cellular responses to inflammatory stimuli exerting a protective role within the adult hippocampal neurogenic niche.

Gender diversity in autistic and neurotypical youth over adolescence and puberty: A longitudinal study

Recent research in autism spectrum disorder (ASD) has suggested a higher prevalence of gender diversity in individuals diagnosed with ASD. Adolescence is a critical period for the consolidation of gender identity, yet the extent to which the experience of gender diversity is stable over adolescence and puberty in autistic youth is poorly understood. The aim of the study was to examine the consistency of gender diversity using the gender diversity screening questionnaire for self- and parent-report of youth (GDSQ-S, GDSQ-P) over a four-year longitudinal study of pubertal development in youth with ASD (N = 140, 36 assigned-female-at birth (AFAB)) and typical development (TD, N = 104, 58 assigned-male-at-birth [AMAB]) and their parents. The extent to which diagnosis (ASD vs. TD), assigned sex (AFAB vs. AMAB) and developmental level (age, puberty) predict GDSQ trajectory over time was explored. There was a significant diagnosis by sex-assigned-at-birth by age interaction for GDSQ-S Gender Diversity, p = 0.002, showing higher scores in autistic AFAB youth over adolescence, and TD AFAB showing initially lower, then increasing levels over adolescence. For GDSQ-P, Gender Incongruence was significantly different between the groups, p = 0.032, showing higher incongruence for autistic AFAB around age 10, decreasing between age 12-14 before increasing again, while TD AFAB evidence the inverse trend. AMAB trends were stable. The significant diagnostic, developmental and sex-based differences indicate AFAB youth experience greater gender diversity that evolves over development. Findings suggest gender identity formation is nuanced and may be influenced by pubertal progression, hormonal patterns, and psychosocial factors. Results underscore the need for enhanced understanding of the unique, dynamic profiles of females-assigned-at-birth.

Regrettable Substitutes and the Brain: What Animal Models and Human Studies Tell Us about the Neurodevelopmental Effects of Bisphenol, Per- and Polyfluoroalkyl Substances, and Phthalate Replacements

In recent decades, emerging evidence has identified endocrine and neurologic health concerns related to exposure to endocrine-disrupting chemicals (EDCs), including bisphenol A (BPA), certain per- and polyfluoroalkyl compounds (PFASs), and phthalates. This has resulted in consumer pressure to remove these chemicals from the market, especially in food-contact materials and personal care products, driving their replacement with structurally or functionally similar substitutes. However, these "new-generation" chemicals may be just as or more harmful than their predecessors and some have not received adequate testing. This review discusses the research on early-life exposures to new-generation bisphenols, PFASs, and phthalates and their links to neurodevelopmental and behavioral alterations in zebrafish, rodents, and humans. As a whole, the evidence suggests that BPA alternatives, especially BPAF, and newer PFASs, such as GenX, can have significant effects on neurodevelopment. The need for further research, especially regarding phthalate replacements and bio-based alternatives, is briefly discussed.

GABA system as the cause and effect in early development

GABA is the primary inhibitory neurotransmitter in the adult brain and through its actions on GABAARs, it protects against excitotoxicity and seizure activity, ensures temporal fidelity of neurotransmission, and regulates concerted rhythmic activity of neuronal populations. In the developing brain, the development of GABAergic neurons precedes that of glutamatergic neurons and the GABA system serves as a guide and framework for the development of other brain systems. Despite this early start, the maturation of the GABA system also continues well into the early postnatal period. In this review, we organize evidence around two scenarios based on the essential and protracted nature of GABA system development: 1) disruptions in the development of the GABA system can lead to large scale disruptions in other developmental processes (i.e., GABA as the cause), 2) protracted maturation of this system makes it vulnerable to the effects of developmental insults (i.e., GABA as the effect). While ample evidence supports the importance of GABA/GABAAR system in both scenarios, large gaps in existing knowledge prevent strong mechanistic conclusions.

Sex-specific associations between co-exposure to multiple metals and externalizing symptoms in adolescence and young adulthood

Externalizing disorders, such as attention-deficit/hyperactivity disorder (ADHD), account for the majority of the child/adolescent referrals to mental health services and increase risk for later-life psychopathology. Although the expression of externalizing disorders is more common among males, few studies have addressed how sex modifies associations between metal exposure and adolescent externalizing symptoms. This study aimed to examine sex-specific associations between co-exposure to multiple metals and externalizing symptoms in adolescence and young adulthood. Among 150 adolescents and young adults (55% female, ages: 15-25 years) enrolled in the Public Health Impact of Metals Exposure (PHIME) study in Brescia, Italy, we measured five metals (manganese (Mn), lead (Pb), copper (Cu), chromium (Cr), nickel (Ni)) in four biological matrices (blood, urine, hair, and saliva). Externalizing symptoms were assessed using the Achenbach System of Empirically Based Assessment (ASEBA) Youth Self-Report (YSR) or Adult Self Report (ASR). Using generalized weighted quantile sum (WQS) regression, we investigated the moderating effect of sex (i.e., assigned at birth) on associations between the joint effect of exposure to the metal mixture and externalizing symptoms, adjusting for age and socioeconomic status. We observed that metal mixture exposure was differentially associated with aggressive behavior in males compared to females (β = -0.058, 95% CI [-0.126, -0.009]). In males, exposure was significantly associated with more externalizing problems, and aggressive and intrusive behaviors, driven by Pb, Cu and Cr. In females, exposure was not significantly associated with any externalizing symptoms. These findings suggest that the effect of metal exposure on externalizing symptoms differs in magnitude between the sexes, with males being more vulnerable to increased externalizing symptoms following metal exposure. Furthermore, our findings support the hypothesis that sex-specific vulnerabilities to mixed metal exposure during adolescence/young adulthood may play a role in sex disparities observed in mental health disorders, particularly those characterized by externalizing symptoms.

Neuronal E93 is required for adaptation to adult metabolism and behavior

OBJECTIVE

Metamorphosis is a transition from growth to reproduction, through which an animal adopts adult behavior and metabolism. Yet the neural mechanisms underlying the switch are unclear. Here we report that neuronal E93, a transcription factor essential for metamorphosis, regulates the adult metabolism, physiology, and behavior in Drosophila melanogaster.

METHODS

To find new neuronal regulators of metabolism, we performed a targeted RNAi-based screen of 70 Drosophila orthologs of the mammalian genes enriched in ventromedial hypothalamus (VMH). Once E93 was identified from the screen, we characterized changes in physiology and behavior when neuronal expression of E93 is knocked down. To identify the neurons where E93 acts, we performed an additional screen targeting subsets of neurons or endocrine cells.

RESULTS

E93 is required to control appetite, metabolism, exercise endurance, and circadian rhythms. The diverse phenotypes caused by pan-neuronal knockdown of E93, including obesity, exercise intolerance and circadian disruption, can all be phenocopied by knockdown of E93 specifically in either GABA or MIP neurons, suggesting these neurons are key sites of E93 action. Knockdown of the Ecdysone Receptor specifically in MIP neurons partially phenocopies the MIP neuron-specific knockdown of E93, suggesting the steroid signal coordinates adult metabolism via E93 and a neuropeptidergic signal. Finally, E93 expression in GABA and MIP neurons also serves as a key switch for the adaptation to adult behavior, as animals with reduced expression of E93 in the two subsets of neurons exhibit reduced reproductive activity.

CONCLUSIONS

Our study reveals that E93 is a new monogenic factor essential for metabolic, physiological, and behavioral adaptation from larval behavior to adult behavior.

The role of exogenous testosterone and social environment on the expression of sociosexuality and status-seeking behaviors in young Chilean men

Testosterone plays an important role as a social hormone. Current evidence suggests that testosterone is positively related to sociosexuality increasing the psychological attitudes toward investing in short-term versus long-term mating and promotes status-seeking behaviors both by dominance and prestige. In addition, the social environment may play an important role in the expression of mating effort through changes in sociosexuality and status-seeking behaviors. However, the causal relationships among the mentioned variables are still debated. We employed a double-blind, placebo-controlled within-individual design, in order to test and integrate the proposed causal relationships between testosterone and social environment over short-term and long-term mating orientation and dominant and prestigious status-seeking behaviors in a sample of 95 young Chilean men. We did not find evidence that the administration of exogenous testosterone increased short-term or decreased long-term mating orientation as expected. Moreover, exogenous testosterone did not affect either aggressive or cooperative behavior failing to support the social status hypothesis. We also did not find any relationship between short or long-term mating orientation with status-seeking behaviors. Finally, we found support for the effect of social environment on sociosexual attitudes but not over status-seeking behaviors. Thus, men reported higher levels of short-term mating orientation in the presence of a woman compared to a man and no differences were found for long-term mating orientation. We argue that sociosexuality may be expressed flexibly, but contextual factors such as the presence of women seem more important than changes in testosterone levels.

Mood variability during adolescent development and its relation to sleep and brain development

Mood swings, or mood variability, are associated with negative mental health outcomes. Since adolescence is a time when mood disorder onset peaks, mood variability during this time is of significant interest. Understanding biological factors that might be associated with mood variability, such as sleep and structural brain development, could elucidate the mechanisms underlying mood and anxiety disorders. Data from the longitudinal Leiden self-concept study (N = 191) over 5 yearly timepoints was used to study the association between sleep, brain structure, and mood variability in healthy adolescents aged 11-21 at baseline in this pre-registered study. Sleep was measured both objectively, using actigraphy, as well as subjectively, using a daily diary self-report. Negative mood variability was defined as day-to-day negative mood swings over a period of 5 days after an MRI scan. It was found that negative mood variability peaked in mid-adolescence in females while it linearly increased in males, and average negative mood showed a similar pattern. Sleep duration (subjective and objective) generally decreased throughout adolescence, with a larger decrease in males. Mood variability was not associated with sleep, but average negative mood was associated with lower self-reported energy. In addition, higher thickness in the dorsolateral prefrontal cortex (dlPFC) compared to same-age peers, suggesting a delayed thinning process, was associated with higher negative mood variability in early and mid-adolescence. Together, this study provides an insight into the development of mood variability and its association with brain structure.

Prenatal androgen exposure and sex-typical play behaviour: A meta-analysis of classic congenital adrenal hyperplasia studies

Thousands of non-human mammal experiments have demonstrated that early androgen exposure exerts long-lasting effects on neurobehavioural sexual differentiation. In humans, females with classic congenital adrenal hyperplasia (CAH) are exposed to unusually high concentrations of androgens prenatally, whereas prenatal concentrations of androgens in males with CAH are largely normal. The current meta-analysis included 20 independent samples and employed multi-level meta-analytic models. Consistently across all 7 male-typical and female-typical play outcomes, in the expected directions, the present study found significant and large average differences between control males and control females (gs = 0.83-2.78) as well as between females with CAH and control females (gs = 0.95-1.08), but differences between males with CAH and control males were mostly negligible and were non-significant for 6 of the 7 outcomes (gs = 0.04-0.27). These meta-analytic findings suggest that prenatal androgen exposure masculinises and defeminises play behaviour in humans. Broader implications in relation to sex chromosomes, brain development, oestrogens, socio-cognitive influences, other aspects of sex-related behavioural development, and gender nonconformity are discussed.

Brain network connectivity during peer evaluation in adolescent females: Associations with age, pubertal hormones, timing, and status

Despite copious data linking brain function with changes to social behavior and mental health, little is known about how puberty relates to brain functioning. We investigated the specificity of brain network connectivity associations with pubertal indices and age to inform neurodevelopmental models of adolescence. We examined how brain network connectivity during a peer evaluation fMRI task related to pubertal hormones (dehydroepiandrosterone and testosterone), pubertal timing and status, and age. Participants were 99 adolescents assigned female at birth aged 9-15 (M = 12.38, SD = 1.81) enriched for the presence of internalizing symptoms. Multivariate analysis revealed that within Salience, between Frontoparietal - Reward and Cinguloopercular - Reward network connectivity were associated with all measures of pubertal development and age. Specifically, Salience connectivity linked with age, pubertal hormones, and status, but not timing. In contrast, Frontoparietal - Reward connectivity was only associated with hormones. Finally, Cinguloopercular - Reward connectivity related to age and pubertal status, but not hormones or timing. These results provide evidence that the salience processing underlying peer evaluation is jointly influenced by various indices of puberty and age, while coordination between cognitive control and reward circuitry is related to pubertal hormones, pubertal status, and age in unique ways.

Pain mechanisms in the transgender individual: a review

Specific Aim

Provide an overview of the literature addressing major areas pertinent to pain in transgender persons and to identify areas of primary relevance for future research.

Methods

A team of scholars that have previously published on different areas of related research met periodically though zoom conferencing between April 2021 and February 2023 to discuss relevant literature with the goal of providing an overview on the incidence, phenotype, and mechanisms of pain in transgender patients. Review sections were written after gathering information from systematic literature searches of published or publicly available electronic literature to be compiled for publication as part of a topical series on gender and pain in the Frontiers in Pain Research.

Results

While transgender individuals represent a significant and increasingly visible component of the population, many researchers and clinicians are not well informed about the diversity in gender identity, physiology, hormonal status, and gender-affirming medical procedures utilized by transgender and other gender diverse patients. Transgender and cisgender people present with many of the same medical concerns, but research and treatment of these medical needs must reflect an appreciation of how differences in sex, gender, gender-affirming medical procedures, and minoritized status impact pain.

Conclusions

While significant advances have occurred in our appreciation of pain, the review indicates the need to support more targeted research on treatment and prevention of pain in transgender individuals. This is particularly relevant both for gender-affirming medical interventions and related medical care. Of particular importance is the need for large long-term follow-up studies to ascertain best practices for such procedures. A multi-disciplinary approach with personalized interventions is of particular importance to move forward.

Menarche, pubertal timing and the brain: female-specific patterns of brain maturation beyond age-related development

BACKGROUND

Puberty depicts a period of profound and multifactorial changes ranging from social to biological factors. While brain development in youths has been studied mostly from an age perspective, recent evidence suggests that pubertal measures may be more sensitive to study adolescent neurodevelopment, however, studies on pubertal timing in relation to brain development are still scarce.

METHODS

We investigated if pre- vs. post-menarche status can be classified using machine learning on cortical and subcortical structural magnetic resonance imaging (MRI) data from strictly age-matched adolescent females from the Adolescent Brain Cognitive Development (ABCD) cohort. For comparison of the identified menarche-related patterns to age-related patterns of neurodevelopment, we trained a brain age prediction model on data from the Philadelphia Neurodevelopmental Cohort and applied it to the same ABCD data, yielding differences between predicted and chronological age referred to as brain age gaps. We tested the sensitivity of both these frameworks to measures of pubertal maturation, specifically age at menarche and puberty status.

RESULTS

The machine learning model achieved moderate but statistically significant accuracy in the menarche classification task, yielding for each subject a class probability ranging from 0 (pre-) to 1 (post- menarche). Comparison to brain age predictions revealed shared and distinct patterns of neurodevelopment captured by both approaches. Continuous menarche class probabilities were positively associated with brain age gaps, but only the menarche class probabilities-not the brain age gaps-were associated with age at menarche.

CONCLUSIONS

This study demonstrates the use of a machine learning model to classify menarche status from structural MRI data while accounting for age-related neurodevelopment. Given its sensitivity towards measures of puberty timing, our work suggests that menarche class probabilities may be developed toward an objective brain-based marker of pubertal development.

Developmental remodeling repurposes larval neurons for sexual behaviors in adult Drosophila

Most larval neurons in Drosophila are repurposed during metamorphosis for functions in adult life, but their contribution to the neural circuits for sexually dimorphic behaviors is unknown. Here, we identify two interneurons in the nerve cord of adult Drosophila females that control ovipositor extrusion, a courtship rejection behavior performed by mated females. We show that these two neurons are present in the nerve cord of larvae as mature, sexually monomorphic interneurons. During pupal development, they acquire the expression of the sexual differentiation gene, doublesex; undergo doublesex-dependent programmed cell death in males; and are remodeled in females for functions in female mating behavior. Our results demonstrate that the neural circuits for courtship in Drosophila are built in part using neurons that are sexually reprogrammed from former sex-shared activities in larval life.

The Association among Hypothalamic Subnits, Gonadotropic and Sex Hormone Plasmas Levels in Alzheimer's Disease

This study investigates the sex-specific role of the Hypothalamic-Pituitary-Gonadal axis in Alzheimer's disease progression, utilizing ADNI1 data for 493 individuals, analyzing plasma levels of gonadotropic and sex hormones, and examining neurodegeneration-related brain structures. We assessed plasma levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), progesterone (P4), and testosterone (T), along with volumetric measures of the hippocampus, entorhinal cortex, and hypothalamic subunits, to explore their correlation with Alzheimer's disease markers across different cognitive statuses and sexes. Significant cognitive status effects were observed for all volumetric measures, with a distinct sex-by-cognitive status interaction for hypothalamic volume, indicating a decrease in males but not in females across cognitive impairment stages. Regression analyses showed specific hypothalamic subunit volume related to hormone levels, accounting for up to approximately 40% of the variance (p < 0.05). The findings highlight sex differences in neurodegeneration and hormonal regulation, suggesting potential for personalized treatments and advancing the understanding of Alzheimer's disease etiology.

Effects of testosterone enanthate on aggression, risk-taking, competition, mood, and other cognitive domains during 28 days of severe energy deprivation

RATIONALE

Behavioral effects of testosterone depend on dose, acute versus sustained formulation, duration of administration, personality, genetics, and endogenous levels of testosterone. There are also considerable differences between effects of endogenous and exogenous testosterone.

OBJECTIVES

This study was the secondary behavioral arm of a registered clinical trial designed to determine if testosterone protects against loss of lean body mass and lower-body muscle function induced by a severe energy deficit typical of sustained military operations.

METHODS

Behavioral effects of repeated doses of testosterone on healthy young men whose testosterone was reduced by severe energy deficit were examined. This was a double-blind, placebo-controlled, between-group study. Effects of four weekly intramuscular injections of testosterone enanthate (200 mg/week, N = 24) or matching placebo (N = 26) were evaluated. Determination of sample size was based on changes in lean body mass. Tasks assessing aggression, risk-taking, competition, social cognition, vigilance, memory, executive function, and mood were repeatedly administered.

RESULTS

During a period of artificially induced, low testosterone levels, consistent behavioral effects of administration of exogenous testosterone were not observed.

CONCLUSIONS

Exogeneous testosterone enanthate (200 mg/week) during severe energy restriction did not reliably alter the measures of cognition. Study limitations include the relatively small sample size compared to many studies of acute testosterone administration. The findings are specific to healthy males experiencing severe energy deficit and should not be generalized to effects of other doses, formulations, or acute administration of endogenous testosterone or studies conducted with larger samples using tests of cognitive function designed to detect specific effects of testosterone.

Multi-omic analysis of precocious puberty girls: pathway changes and metabolite validation

Objective

Precocious puberty (PP) is a prevalent endocrine disorder affecting the physical and mental wellbeing of children. Identifying the triggering factors of PP has become a central issue. This study seeks to investigate the metabolomic and transcriptomic alterations in PP.

Material and methods

First, 37 school-aged girls diagnosed with PP and 25 age-matched prepubertal control girls were recruited, and the fecal samples were collected for non-targeted metabolomic analysis to screen for differentially expressed metabolites (DEMs). Subsequently, an animal model of PP was constructed by danazol administration to neonatal female rats, and both fecal non-targeted metabolomics and serum next-generation transcriptomic sequencing were performed to screen DEMs and differentially expressed genes (DEGs) in PP. Moreover, the DEM co-existing in clinical and animal models was administrated to PP rats to explore the role of the target metabolite in PP.

Results

A total of 24 DEMs in PP clinical samples and 180 DEMs and 425 DEGs in PP animal samples were identified. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that these DEMs and DEGs were enriched in disease-associated pathways, including fatty acid synthesis, glycerolipid metabolism, pyrimidine metabolism, steroid hormone biosynthesis, progesterone-mediated oocyte maturation, and gonadotropin-releasing hormone (GnRH) signaling pathway, forming a tight DEM-DEG pathway regulatory network. Further DEM validation demonstrated that thymine supplementation delayed the opening of the vagina and development of PP in model rats.

Conclusion

This study reveals that the metabolomic and transcriptomic changes, along with enriched pathways, are implicated in PP based on clinical and animal analyses. The findings may provide new strategies and research avenues for PP treatment.

Glow up: does a professional photoshoot intervention affect self-esteem and emotions among adolescent psychiatric patients?-A longitudinal intervention study

Background

Today, online communication is shaped by a billion-dollar social media (SM) and social networking site (SNS) industry. Visual content consumed by children and adolescents has been shown to influence behavioral patterns, state emotions, and self-esteem (SE). In this study, we introduced a novel intervention creating visual content through a professional photoshoot and investigated its impact on state emotions and SE in child and adolescent psychiatric (CAP) patients.

Methods

Standardized and validated self-rating questionnaires were used to assess SE, state emotions, coping mechanisms, psychopathological symptoms, and internet use behavior at baseline. SE and state emotions were monitored at different time points around a professional photoshoot within 45 CAP patients (30 female patients; mean age, 15.1 years) using a longitudinal design.

Results

Within-subject repeated-measures ANOVA and bootstrapped paired-sample t-tests showed a significant fluctuation in state emotions and SE throughout the intervention. Spearman correlations and univariate logistic regressions revealed that internalizing symptomatology and maladaptive coping significantly worsened the outcome of the intervention on state emotions and SE in girls. Internet-related variables heightened the positive effect of the intervention in boys and lowered SE in girls during the intervention.

Conclusion

The photo intervention had various gender-specific effects. Boys did benefit from the intervention in terms of longitudinal outcome on positive state emotions (PE) and SE, even positively influenced by SNS and SM. Thus, it might be concluded that online social comparison was processed more beneficial in boys. In contrast, when working with visual content in girls, psychopathology and coping must be considered. Internet consumption in general, especially SM and SNS, was related to low SE in girls. Nevertheless, when therapeutically accompanied, the "glow up moment" during the shoot (high on PE and SE; low on negative state emotions) could be used as an index moment for therapeutic reflection.