Assessing dehydroepiandrosterone in saliva: a simple radioimmunoassay for use in studies of children, adolescents and adults

Forgiveness in the HPA axis: The roles of cumulative genetic effects and cortisol reactivity in trait and situational forgiveness

Trait and situational forgiveness are vital coping mechanisms and stress responses in the face of interpersonal transgressions. The hypothalamic-pituitary-adrenal (HPA) axis plays a key role in regulating these strategies in response to such transgressions. Building on this foundation, Study 1 examined the impact of cumulative genetic effects of the HPA axis (i.e., a weighted measure of genetic predisposition, calculated by combining the relative contributions of multiple genetic polymorphisms and the number of protective alleles associated with positive psychological traits) on trait forgiveness (N = 852). Study 2 investigated the relationship between these genetic effects, cortisol reactivity, and forgiveness responses following romantic partner conflict (N = 200). Results from Study 1 revealed that higher cumulative genetic scores were associated with stronger trait forgiveness. Study 2 showed that individuals with the higher cumulative genetic scores exhibited more forgiveness responses toward their partners after conflict. Moreover, participants who experienced stronger negative emotions and greater cortisol reactivity were more likely to exhibit forgiveness responses toward their partners. These findings highlight the biological mechanisms underlying forgiveness, emphasizing how genetic and physiological factors of the HPA axis shape adaptive interpersonal coping strategies.

Maternal History of Child Maltreatment Predicts Dysregulated Offspring Stress Response System Functioning

Identifying proximal and multigenerational distal risk mechanisms through which adversity exposure may shape neuroendocrine dysregulation among children is critical to advancing effective preventive interventions for adversity-exposed individuals. Utilizing longitudinal data (N = 247), the current study examined maternal and offspring history of childhood maltreatment (CM) as predictors of offspring cortisol/DHEA ratios, and, in exploratory analyses, extended this longitudinally to offspring depressive symptoms in young adulthood. Youth (ages 8-13 years) initially attended a research camp, then were followed up approximately eight years later (ages 18-22 years). Maternal history of CM significantly predicted their offspring's childhood cortisol/DHEA ratio over and above the effects of the offspring's history of CM. Offspring CM was not a significant predictor of the ratio. The cortisol/DHEA ratio did not mediate the relationship between maternal history of CM and offspring emerging adulthood depression. Results highlight an intergenerational cascade of CM and negative outcomes and support inclusion of maternal experiences in screening for at-risk youth.

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.

Person-centered methods to advance developmental psychopathology

Dante Cicchetti's remarkable contributions to the field of developmental psychopathology include the advancement of key principles such as the interplay of typical and atypical development, multifinality and equifinality, the dynamic processes of resilience, and the integration of multiple levels of analysis into developmental theories. In this paper we assert that person-centered data analytic methods are particularly well-suited to advancing these tenets of developmental psychopathology. We illustrate their utility with a brief novel empirical study focused on underlying patterns of childhood neuroendocrine regulation and prospective links with emerging adult functioning. Results indicate that a childhood neuroendocrine profile marked by high diurnal cortisol paired with low diurnal DHEA was uniquely associated with more adaptive functioning in emerging adulthood. We discuss these findings, and person-centered methods more broadly, within the future of developmental psychopathology.

Salivary uric acid dynamics are associated with stress response hormones among African Americans in an urban sample

Acute physiological responses to psychosocial stressors are a potential pathway underlying racial disparities in stress-related illnesses. Uric acid (UA) is a potent antioxidant that has been linked to disparities in stress-related illnesses, and recent research has shown that UA is responsive to acute social stress. However, an examination of the relationships between the purinergic system and other commonly measured stress systems is lacking. Here, we measure and characterize associations of salivary uric acid (sUA) with markers of hypothalamic-pituitary-adrenal (HPA) axis activation, sympathetic-adreno-medullar (SAM) axis activation, and acute inflammation. A community sample of 103 African Americans (33 male, 70 female) completed the Trier Social Stress Test to induce social-evaluative threat. Passive drool collected before, during, and after the stressor task provided salivary reactivity measures of UA (sUA), cortisol, dehydroepiandrosterone sulfate (DHEAS), salivary alpha amylase (sAA - a surrogate marker of SAM activity) and C-reactive protein (sCRP). Multiple regressions revealed that total activation of cortisol, DHEAS, and sCRP were each positively associated with higher total activation of sUA. Additionally, DHEAS reactivity was positively associated with sUA reactivity. Relationships between HPA-axis markers and sUA were especially observed among younger and male participants. Overall, findings suggest potential coordination of stress systems with sUA in response to acute stress, which may further the contributions of biological stress processes to racial health disparities.

Pubertal development and pain incidence and characteristics in children: a 1-year prospective cohort study of a national sample

ABSTRACT

Sex differences in pain become apparent during puberty. However, the influence of key pubertal characteristics and pubertal hormones on pain is largely unknown. We examined the prospective associations between self-reported and hormone-indicated pubertal characteristics and pain incidence and severity in 10- to 11-year-old pain-free youth in the Adolescent Brain Cognitive Development (ABCD) Study over 1 year. Puberty was measured at baseline and follow-up with self-report (Pubertal Development Scale [PDS]) and hormonal assessment (salivary dehydroepiandrosterone [DHEA], testosterone, and estradiol). Pain status (yes/no), intensity, and interference (0-10 numerical rating scale) in the past month were self-reported at follow-up. Pubertal maturity, progression, and asynchrony were examined in relation to pain onset and severity through confounder-adjusted generalized estimating equations modified Poisson and linear mixed regression models. Among 6631 pain-free youth at baseline, 1-year incident pain was 30.7%. In both sexes, higher PDS scores were associated with greater risk of pain onset (relative risk [RR] = 1.10 to 1.27, P s < 0.01). In boys, higher PDS item variance was associated with greater pain incidence (RR = 1.11, 95% CI, 1.03-1.20) and interference (beta = 0.40, 95% CI, 0.03-0.76); higher PDS overall and gonadal scores were associated with higher pain intensity ( P s < 0.05). Associations with hormones were seen in boys only, with each 10-fold higher testosterone levels associated with a 40% lower risk of pain incidence (95% CI, -55% to -22%) and 1.30-point lower (95% CI, -2.12 to -0.48) pain intensity, and higher DHEA levels were associated with lower pain intensity ( P = 0.020). Relationships between pubertal development and pain in peripubertal adolescents are sex specific and puberty measurement specific and warrant further investigation.

Profiles of diurnal cortisol and DHEA regulation among children: Associations with maltreatment experiences, symptomatology, and positive adaptation

Person-centered methods represent an important advance in the simultaneous examination of multiple indicators of neuroendocrine functioning and may facilitate a more nuanced understanding of the impact of child maltreatment on hypothalamic-pituitary-adrenal axis dysregulation. The aims of the present study were threefold: (a) identify naturally occurring patterns of diurnal cortisol and dehydroepiandrosterone (DHEA) regulation among a sample of N = 1,258 children with and without histories of maltreatment, (b) investigate which neuroendocrine profiles characterize children with exposure to maltreatment, and (c) examine which profiles are related to adaptive outcomes and symptomatology among children. Cortisol and DHEA were sampled three times per day (9 a.m., 12 p.m., and 4 p.m.) across 5 and 2 days, respectively. Four profiles of cortisol and DHEA regulation were identified. Among females, a pattern marked by high cortisol and low DHEA was associated with more pervasive maltreatment experiences. Furthermore, we found evidence of adaptive interpersonal resilience such that children with maltreatment exposure who evidenced this pattern of high cortisol and low DHEA were viewed as more likeable than maltreated children with other neuroendocrine patterns. Finally, results pointed to higher levels of internalizing symptoms among children who displayed a profile marked by average cortisol and high DHEA.

The implications of socioeconomic factors on salivary bioscience methodological variables in a large pediatric multi-site study

Introduction

Salivary bioscience has found increased utilization within pediatric research, given the non-invasive nature of self-collecting saliva for measuring biological markers. With this growth in pediatric utility, more understanding is needed of how social-contextual factors, such as socioeconomic factors or status (SES), influence salivary bioscience in large multi-site studies. Socioeconomic factors have been shown to influence non-salivary analyte levels across childhood and adolescent development. However, less is understood about relationships between these socioeconomic factors and salivary collection methodological variables (e.g., time of saliva collection from waking, time of day of saliva collection, physical activity prior to saliva collection, and caffeine intake prior to saliva collection). Variability in salivary methodological variables between participants may impact the levels of analytes measured in a salivary sample, thus serving as a potential mechanism for non-random systematic biases in analytes.

Methods

Our objective is to examine relationships between socioeconomic factors and salivary bioscience methodological variables within the Adolescent Brain Cognitive Development Study© cohort of children aged 9-10 years old (n = 10,567 participants with saliva samples).

Results

We observed significant associations between household socioeconomic factors (poverty status, education) and salivary collection methodological variables (time since waking, time of day of sampling, physical activity, and caffeine intake). Moreover, lower levels of household poverty and education were significantly associated with more sources of potential bias in salivary collection methodological variables (e.g., longer times since waking, collections later in the day, higher odds of caffeine consumption, and lower odds of physical activity). Consistent associations were not observed with neighborhood socioeconomic factors and salivary methodological variables.

Discussion

Previous literature demonstrates associations between collection methodological variables and measurements of salivary analyte levels, particularly with analytes that are more sensitive to circadian rhythms, pH levels, or rigorous physical activity. Our novel findings suggest that unintended distortions in measured salivary analyte values, potentially resulting from the non-random systematic biases in salivary methodology, need to be intentionally incorporated into analyses and interpretation of results. This is particularly salient for future studies interested in examining underlying mechanisms of childhood socioeconomic health inequities in future analyses.

Testosterone and Cortisol Salivary Samples Are Stable Across Multiple Freeze-Thaw Cycles

ABSTRACT

Sontag, SA, Cabarkapa, D, and Fry, AC. Testosterone and cortisol salivary samples are stable across multiple freeze-thaw cycles. J Strength Cond Res 37(4): 915-918, 2023-When processing salivary samples for biomarker analysis, avoiding multiple freeze-thaw cycles is generally recommended. However, confusing tissue handling instructions or challenges with collections in the field sometimes makes this problematic. Thus, the purpose of this study was to examine if the stability of salivary testosterone (T) and cortisol (C) hormones remains unchanged when exposed to multiple freeze-thaw cycles. Seven healthy recreationally active adults provided salivary samples at rest (i.e., 1600 hours) for analysis of T and C. Samples were separated into 4 aliquots for each hormone and underwent 4 freeze-thaw cycles (T1-T4 and C1-C4) before being analyzed by enzyme-linked immunosorbent assay. The overall analysis of variance model was significant for T ( p = 0.008) and nonsignificant for C ( p = 0.820). A follow-up post hoc comparison indicated significant differences in salivary hormonal concentrations between T1 and T4 ( p = 0.029), T2 and T4 ( p = 0.007), and T3 and T4 ( p = 0.032). The findings of this study indicate that salivary steroid hormones seem to be relatively stable following multiple freeze-thaw cycles. However, C seems to be more stable when exposed to multiple freeze-thaw cycles, as T concentrations did reveal a significant decrease by the fourth thaw cycle.

The Effects of Physical Exercise on Saliva Composition: A Comprehensive Review

Saliva consists of organic and inorganic constituents. During exercise, analysis of the saliva can provide valuable information regarding training stress, adaptation and exercise performance. The objective of the present article was to review the effect of physical exercise on saliva composition. The shift in the composition of the saliva, during and after a workout, reflects the benefits of exercise, its potential risks and the capability of the saliva to serve as a health indicator. The type and the frequency of training, the physical condition and the athletes’ general health influence the hormones, immunoglobulins and saliva enzymes. The correlation between saliva and physical exercise has to be further investigated and the available knowledge to be applied for the benefit of the athletes during sports activities.

The effect of pilates training on hormonal and psychophysical function in older women

BACKGROUND

DHEA-S and cortisol and their ratio are important determinants of some physiological and psychological function during aging. The present study aimed to determine the effect of eight weeks of pilates training on diurnal salivary cortisol, dehydroepiandrosterone sulfate (DHEA-S), and cortisol to DHEA-S ratio, cardiorespiratory fitness (CF), and psychological function in older women.

METHODS

Twenty-seven healthy older women (aged 60-65 years) participated in the study voluntarily and were divided into two groups of pilates training (N.=15) and control (N.=12), randomly. Before and after the experiment, salivary samples (at wake up and 30-min postawakening, midday, 5 p.m., and 9 p.m.) were taken and the participants completed the questionnaires. Cognitive function was assessed by the MMSE questionnaire. Pilates training was performed three times weekly, in non-consecutive days.

RESULTS

Pilates training increased V̇O2<inf>max</inf> (48%, P<0.001) and cognitive function (73%, P<0.001) and decreased BMI (16%, P=0.042), anxiety (53%, P<0.001) and depression (67%, P<0.001) compared to the control group. Also, in pilates training group, mean cortisol (16%, P=0.039), CAR (24%, P=0.010), fall after peak of cortisol (15%, P=0.50), morning DHEA-S (43%, P<0.001) and mean DHEA-S (34%, P=0.002) increased compared to the control group.

CONCLUSIONS

This study suggests that pilates training could improve mental and physical function which was accompanied by changes of diurnal cortisol and DHEA as one of the possible effective factors.

Impact of short-term hydrocortisone intake on pituitary and adrenal function in healthy young male subjects

PURPOSE

The aim of this study was to evaluate the impact of short-term therapeutic hydrocortisone intake on pituitary and adrenal function in healthy young male subjects.

METHODS

Ten physically active men received 50 mg/per day of hydrocortisone at 8:00 a.m. for 5 days. Cortisol, DHEA, and ACTH concentrations in plasma, and cortisol and DHEA concentrations in saliva were determined the week before, just before (8:00 a.m.) and 2 h after (10:00 a.m.) drug ingestion on days 1, 3, and 5 of treatment and day 1 post treatment.

RESULTS

Hydrocortisone intake induced a significant increase in both plasma cortisol (×3) and saliva cortisol (×10) concentrations 2 h after administration. Plasma and saliva DHEA concentrations were significantly decreased, as were plasma ACTH concentrations, 2 h after administration, with an increase in the cortisol/DHEA and cortisol/ACTH ratios. However, no change in cortisol, DHEA, ACTH, cortisol/DHEA, or cortisol/ACTH was observed 24 h after the last intake during treatment or post treatment, except for a downward trend in saliva DHEA at days 3 and 5. The correlations between plasma and saliva cortisol, DHEA, and cortisol/DHEA were significant: respectively, r = 0.80, r = 0.80, and r = 0.88.

CONCLUSIONS

Once-daily oral therapeutic administration of hydrocortisone for 5 days altered adrenal DHEA secretion by inhibiting pituitary ACTH, but this effect seemed transient without significant impairment of basal adrenal or pituitary function 24 h after administration. Given the high correlations between plasma and saliva, saliva samples may be offered as a sensitive surrogate for blood sampling to estimate adrenal and pituitary function.

Effects of Ginseng Ingestion on Salivary Testosterone and DHEA Levels in Healthy Females: An Exploratory Study

Ginseng is a traditional herbal adaptogen that has been historically used in China and the Far East. Ginsenosides are the active component of ginseng known to exert several actions by targeting "multi-receptor systems", both extracellular and intracellular. In humans, ginseng effects remain unclear. This study aimed to investigate whether ginseng can influence salivary androgen levels (testosterone and dehydroepiandrosterone (DHEA)) in females. The study followed a parallel partially controlled design. Healthy women (n = 24) were recruited and divided into two groups (A = 20-32 and B = 38-50 years). Volunteers were asked to maintain a food diary pre and post ginseng consumption and collected four salivary samples (7 a.m., 9 a.m., 12 p.m., and 5 p.m.) before and after ingesting 75 mg red Korean ginseng extract per day for seven days. Testosterone and DHEA were then assayed by ELISA methods. Group A's mean daily salivary testosterone pre ginseng ingestion increased from 76.3 ± 16.6 to 98.4 ± 21.1 pg/mL post ginseng (p < 0.01) with significant difference at all time points, and mean daily salivary DHEA increased from 1.53 ± 0.63 to 1.98 ± 0.89 ng/mL post ginseng (p = 0.02). Group B's mean daily salivary testosterone pre ginseng ingestion was 61.2 ± 16.9 and post ginseng 68.1 ± 11.5 pg/mL (p = 0.132), and daily salivary DHEA increased from 0.91 ± 0.32 to 1.62 ± 0.49 ng/mL post ginseng (p = 0.014) with significant difference at all time points. In conclusion, it appears that ginseng intake significantly increased salivary testosterone levels in the younger women group, but only slightly in the older group. However, DHEA levels in the older women showed a marked and significant increase. These results suggest a potential role for ginseng in modulating salivary androgen levels and that such effect may be more evident in older women where the levels of androgens (DHEA) start to decline. However, it has to be stressed that our results are preliminary and further properly controlled trials are justified.

Adrenal function links to early postnatal growth and blood pressure at age 6 in children born extremely preterm

BACKGROUND

Low birth weight in term-born individuals correlates with adverse cardiometabolic outcomes; excess glucocorticoid exposure has been linked to these relationships. We hypothesized that cortisol and adrenal androgens would correlate inversely with birthweight and directly with markers of cardiometabolic risk in school-aged children born extremely preterm; further, preterm-born would have increased cortisol and adrenal androgens compared to term-born children.

METHODS

Saliva samples were obtained at age 6 from 219 preterm-born children followed since birth and 40 term-born children and analyzed for dehydroepiandrosterone (DHEA) and cortisol. Cortisol was also measured at home (awakening, 30' later, evening).

RESULTS

For preterm-born children, cortisol and DHEA correlated inversely with weight and length Z-scores at 36 weeks PMA and positively with systolic BP. DHEA was higher in preterm-born than term-born children (boys p < 0.01; girls p = 0.04). Cortisol was similar between preterm-born and term-born at study visit; however, preterm-born children showed a blunted morning cortisol. In term-born children, DHEA correlated with BMI (p = 0.04), subscapular, and abdominal skinfold thicknesses (both p < 0.01).

CONCLUSION

Cortisol and DHEA correlated inversely with early postnatal growth and directly with systolic BP in extremely preterm-born children, suggesting perinatal programming. Blunted morning cortisol may reflect NICU stress, as seen after other adverse childhood experiences (ACEs).

Relationships between adrenarcheal hormones, hippocampal volumes and depressive symptoms in children

Early timing of puberty (i.e., advanced pubertal maturation relative to same-age peers) has been associated with depressive symptoms during adolescence. To date, research on this relationship has focused on gonadarche, the second phase of puberty, while less is known about the first phase of puberty, adrenarche. Increasing evidence suggests that androgens that rise during adrenarche, most notably dehyrdoepiandrosterone (DHEA) and testosterone, may be involved both in the development of the hippocampus, and risk for depression. The current study investigated whether hippocampal volumes mediated the relationship between adrenarcheal timing (based on relative levels of adrenarcheal hormones) and depressive symptoms in children. Data were collected from a cross-sectional sample of 88 children (46 female) selected to have relatively increased variance in these androgens. Participants completed brain MRI structural scans, provided saliva samples for hormones, and completed the Children's Depression Inventory (CDI). Contrary to predictions, larger right hippocampi significantly partially mediated the positive relationship between early timing of testosterone exposure (i.e., relatively high levels of testosterone for one's age) and depressive symptoms in girls. No other evidence of significant mediation effects was obtained, however DHEA and testosterone exposure showed unique effects on hippocampal volumes in males and females, and larger hippocampal volumes predicted higher depressive symptoms in the entire sample. These results suggest that adrenarcheal timing may be related to hippocampal development and depressive symptoms, extending current knowledge of pubertal risk processes.

Development of a Derivatization Method for Investigating Testosterone and Dehydroepiandrosterone Using Tandem Mass Spectrometry in Saliva Samples from Young Professional Soccer Players Pre- and Post-Training

In the last decade, high-performance liquid chromatography/tandem mass spectrometry (LC/MS/MS) combined with electrospray ionization (ESI) has been widely used for determining low concentrations of steroids, and derivatization has often been employed to enhance detection. In the present study, endogenous steroids were extracted using a Strata-XL polymeric reverse phase cartridge. The isolated steroids were reacted with 2-hydrazino-1- methylpyridine (HMP) at 50 °C for 30 min. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used in a positive mode with multiple reaction monitoring (MRM) for the quantification of testosterone (T) and its precursor, dehydroepiandrosterone (DHEA), in saliva samples collected from twenty young Saudi professional soccer players. The analytes were separated on an ACE Ultracore 2.5 Superphenylhexyl column (150 × 3.0 mm id). The extraction recovery during the pre-treatment was >89% and gave <±20% for inter- and intra-assay precision and accuracy. The limits of quantification (LOQ) were found to be 20 pg/mL for (T and DHEA) and 50 pg/mL for Epitestosterone (EPI). The results showed no significant variation in the concentration of T between pre and post training, whereas DHEA was significantly increased after short-term exercise. These results could indicate that there is no correlation between T and its precursor DHEA level following short term physical activity. EPI concentrations could not be detected with a LOQ of 50 pg/mL in the saliva samples.

Investigating multilevel pathways of developmental consequences of maltreatment

The impact of maltreatment spreads across many developmental domains and extends across the entire life span. Identifying unidirectional or bidirectional drivers of developmental cascades of the effects of maltreatment experiences is critical to efficiently employing interventions to promote resilient development in maltreated children. This 1-year longitudinal study utilized a multiple-levels approach, investigating "bottom-up" and "top-down" cascades using structural equation modeling between cortisol regulation, externalizing behavior, and peer aggression. Neither a bottom-up model driven by cortisol regulation nor a top-down model driven by peer aggression fit the data well. Instead, lower rates of externalizing behavior at Year 1 most strongly predicted improvements at all levels of analysis (reduced cortisol, externalizing behavior, and peer aggression) at Year 2. These results provide initial indication of a mechanism through which interventions for maltreated children may be most effective and result in the most substantial positive changes across developmental domains.

Stress physiology and memory for emotional information: Moderation by individual differences in pubertal hormones

In contrast to a large body of work concerning the effects of physiological stress reactivity on children's socioemotional functioning, far less attention has been devoted to understanding the effects of such reactivity on cognitive, including mnemonic, functioning. How well children learn and remember information under stress has implications for a range of educational, clinical, and legal outcomes. We evaluated 8-14 year olds' (N = 94, 50 female) memory for negative, neutral, and positive images. Youth had seen the images a week previously as a part of a laboratory stress task. At encoding and retrieval, and in between, youth provided saliva samples that were later assayed for cortisol, salivary α amylase (sAA), testosterone, and dehydroepiandrosterone (DHEA). Overall, higher cortisol reactivity to the lab task predicted enhanced memory for emotional but not neutral images. However, cortisol further interacted with pubertal hormones (testosterone and DHEA) to predict memory. Among girls with lower pubertal hormone levels, greater cortisol reactivity was associated with enhanced memory for negative information, whereas among boys with higher pubertal hormone levels, cortisol reactivity was associated with enhanced memory for positive information. sAA, was unrelated to memory. Overall, our findings reveal that individual differences in hormone levels associated with pubertal development have implications for our understanding of how stress-responsive biological systems directly and interactively influence cognitive outcomes. (PsycINFO Database Record

Genetic and environmental influences on pubertal hormones in human hair across development

Puberty is a complex biopsychosocial process that can affect an array of psychiatric and medical disorders emerging in adolescence. Although the pubertal process is driven by neuroendocrine changes, few quantitative genetic studies have directly measured puberty-relevant hormones. Hair samples can now be assayed for accumulation of hormones over several months. In contrast to more conventional salivary measures, hair measures are not confounded by diurnal variation or hormonal reactivity. In an ethnically and socioeconomically diverse sample of 1286 child and adolescent twins and multiples from 672 unique families, we estimated genetic and environmental influences on hair concentrations of testosterone, DHEA, and progesterone across the period of 8-18 years of age. On average, male DHEA and testosterone were highly heritable, whereas female DHEA, progesterone, and puberty were largely influenced by environmental components. We identified sex-specific developmental windows of maximal heritability in each hormone. Peak heritability for DHEA occurred at approximately 10 years of age for males and females. Peak heritability for testosterone occurred at age 12.5 and 15.2 years for males and females, respectively. Peak heritability for male progesterone occurred at 11.2 years, while the heritability of female progesterone remained uniformly low. The identification of specific developmental windows when genetic signals for hormones are maximized has critical implications for well-informed models of hormone-behavior associations in childhood and adolescence.

3β-HSD expression in the CNS of a manakin and finch

The prohormone, dehydroepiandrosterone (DHEA) circulates in vertebrate blood with the potential for actions on target tissues including the central nervous system (CNS). Many actions of DHEA require its conversion into more active products, some of which are catalyzed by the enzyme 3β-hydroxysteroid-dehydrogenase/isomerase (3β-HSD). Studies of birds show both expression and activity of 3β-HSD in brain and its importance in regulating social behavior. In oscine songbirds, 3β-HSD is expressed at reasonably high levels in brain, possibly linked to their complex neural circuitry controlling song. Studies also indicate that circulating DHEA may serve as the substrate for neural 3β-HSD to produce active steroids that activate behavior during non-breeding seasons. In the golden-collared manakin (Manacus vitellinus), a sub-oscine bird, low levels of courtship behavior are displayed by males when circulating testosterone levels are basal. Therefore, we asked whether DHEA circulates in blood of manakins and whether the brain expresses 3β-HSD mRNA. Given that the spinal cord is a target of androgens and likely important in regulating acrobatic movements, we also examined expression of this enzyme in the manakin spinal cord. For comparison, we examined expression levels with those of an oscine songbird, the zebra finch (Taeniopygia guttata), a species in which brain, but not spinal cord, 3β-HSD has been well studied. DHEA was detected in manakin blood at levels similar to that seen in other species. As described previously, 3β-HSD was expressed in all zebra finch brain regions examined. By contrast, expression of 3β-HSD was only detected in the manakin hypothalamus where levels were greater than zebra finches. In spinal cord, 3β-HSD was detected in some but not all regions in both species. These data point to species differences and indicate that manakins have the substrate and neural machinery to convert circulating DHEA into potentially active androgens and/or estrogens.

Chemical analysis in saliva and the search for salivary biomarkers – a tutorial review

A review of the uses of saliva biomarkers, detection methods and requirements for new biomarkers.

Social media as a shield: Facebook buffers acute stress

Facebook remains the most widely used social media platform. Research suggests that Facebook may both enhance and undermine psychosocial constructs related to well-being, and that it may impair physiological stress recovery. However, little is known about its influence on stress reactivity. Using novel experimental methods, this study examined how Facebook influences reactivity to an acute social stressor. Facebook users (n=104, 53 males, mean age 19.50, SD=1.73) were randomly assigned to use their own Facebook account or sit quietly with the option of reading electronic magazines before experiencing an acute social stressor. All participants showed significant changes in subjective and physiological stress markers in response to the stressor. However, participants who used Facebook experienced lower levels of psychosocial stress, physiological stress, and rated the stressor as less threatening (p's<0.05) when controlling for gender and emotional investment in the website compared to controls. Results suggest that Facebook use may buffer stress-in particular psychosocial stress-if used before experiencing an acute social stressor. This study is among the first to incorporate both objective and subjective measures in investigating the complex relationship between Facebook use and well-being.

Social Media under the Skin: Facebook Use after Acute Stress Impairs Cortisol Recovery

Social media's influence on stress remains largely unknown. Conflicting research suggests that Facebook use may both enhance and undermine psychosocial constructs related to well-being. Using novel experimental methods, this study examined the impact of social media use on stress recovery. Facebook users (n = 92, 49 males, mean age 19.55 SD = 1.63) were randomly assigned to use their own Facebook profile or quietly read after experiencing an acute social stressor. All participants showed significant changes in subjective and physiological stress markers during recovery. Participants who used Facebook experienced greater sustained cortisol concentration (p < 0.05) when controlling for gender and emotional investment in the website compared to controls. Results suggest that social media use may delay or impair recovery after experiencing an acute social stressor. This novel study incorporated objective physiological markers with subjective psychosocial measures to show that Facebook use may negatively impact well-being.

Perceived Discrimination, Racial Identity, and Multisystem Stress Response to Social Evaluative Threat Among African American Men and Women

OBJECTIVE

Understanding individual differences in the psychobiology of the stress response is critical to grasping how psychosocial factors contribute to racial and ethnic health disparities. However, the ways in which environmentally sensitive biological systems coordinate in response to acute stress is not well understood. We used a social-evaluative stress task to investigate coordination among the autonomic nervous system, hypothalamic-pituitary-adrenal axis, and immune/inflammatory system in a community sample of 85 healthy African American men and women.

METHODS

Six saliva samples, 2 at each of baseline, event, and recovery phases of the stressor task, were assayed for cortisol, dehydroepiandrosterone-sulfate, salivary alpha-amylase, and salivary C-reactive protein. Individual differences in perceived discrimination and racial identity were also measured.

RESULTS

Factor analysis demonstrated that stress systems were largely dissociated before stressor exposure but became aligned during event and recovery phases into functional biological stress responses (factor loadings ≥ .58). Coordinated responses were related to interactions of perceived discrimination and racial identity: when racial identity was strong, highly perceived discrimination was associated with low hypothalamic-pituitary-adrenal axis activity at baseline (B's = .68-.72, p < .001), low stress mobilization during the task (B's = .46-.62, p < .049), and a robust inflammatory response (salivary C-reactive protein) during recovery (B's = .72-.94, p < .002).

CONCLUSION

Culturally relevant social perceptions may be linked to a specific pattern of changing alignment in biological components of the stress response. Better understanding these links may significantly advance understanding of stress-related illnesses and disparities.

Concurrent and prospective associations between HPA axis activity and depression symptoms in newlywed women

We investigated the extent to which individual differences in activity of the hypothalamic pituitary adrenal axis (HPA) are associated with depressive symptoms among newlywed couples. Participants were 218 couples (M age 28.4 years; 94% White) who provided 5 saliva samples (later assayed for cortisol and DHEA-S) before and after participation in a discussion of a major area of disagreement in their relationship. Depressive symptoms were assessed initially, and approximately 19- and 37-months later. Results revealed an interactive effect suggesting that concordant levels of cortisol and DHEA-S (either both high or both low) were concurrently and prospectively associated with higher depression scores. Interestingly, this interactive effect was observed for wives only - not for husbands. These observations underscore contemporary theoretical assumptions that the expression of the association between HPA activity and depression is dependent on factors related to the interaction between characteristics of the person and features of the social environment, and moderated by co-occurring variation in endocrine milieu.

Anabolic hormone profiles in elite military men

We recently characterized the awakening responses and daily profiles of the catabolic stress hormone cortisol in elite military men. Anabolic hormones follow a similar daily pattern and may counteract the catabolic effects of cortisol. This companion report is the first to characterize daily profiles of anabolic hormones dehydroepiandrosterone (DHEA) and testosterone in this population. Overall, the men in this study displayed anabolic hormone profiles comparable to that of healthy, athletic populations. Consistent with the cortisol findings in our prior report, summary parameters of magnitude (hormone output) within the first hour after awakening displayed superior stability versus summary parameters of pattern for both DHEA (r range: 0.77-0.82) and testosterone (r range: 0.62-0.69). Summary parameters of evening function were stable for the two hormones (both p<0.001), while the absolute decrease in testosterone across the day was a stable proxy of diurnal function (p<0.001). Removal of noncompliant subjects did not appreciably affect concentration estimates for either hormone at any time point, nor did it alter the repeatability of any summary parameter. The first of its kind, this report enables accurate estimations of anabolic balance and resultant effects upon health and human performance in this highly resilient yet chronically stressed population.

Rapid Effects of an Aggressive Interaction on Dehydroepiandrosterone, Testosterone and Oestradiol Levels in the Male Song Sparrow Brain: a Seasonal Comparison

Across vertebrates, aggression is robustly expressed during the breeding season when circulating testosterone is elevated, and testosterone activates aggression either directly or after aromatisation into 17β-oestradiol (E2 ) in the brain. In some species, such as the song sparrow, aggressive behaviour is also expressed at high levels during the nonbreeding season, when circulating testosterone is non-detectable. At this time, the androgen precursor dehydroepiandrosterone (DHEA) is metabolised within the brain into testosterone and/or E2 to promote aggression. In the present study, we used captive male song sparrows to test the hypothesis that an acute agonistic interaction during the nonbreeding season, but not during the breeding season, would alter steroid levels in the brain. Nonbreeding and breeding subjects were exposed to either a laboratory simulated territorial intrusion (L-STI) or an empty cage for only 5 min. Immediately afterwards, the brain was rapidly collected and flash frozen. The Palkovits punch technique was used to microdissect specific brain regions implicated in aggressive behaviour. Solid phase extraction followed by radioimmunoassay was used to quantify DHEA, testosterone and E2 in punches. Overall, levels of DHEA, testosterone and E2 were higher in brain tissue than in plasma. Local testosterone and E2 levels in the preoptic area, anterior hypothalamus and nucleus taeniae of the amygdala were significantly higher in the breeding season than the nonbreeding season and were not affected by the L-STI. Unexpectedly, subjects that were dominant in the L-STI had lower levels of DHEA in the anterior hypothalamus and medial striatum in both seasons and lower levels of DHEA in the nucleus taeniae of the amygdala in the breeding season only. Taken together, these data suggest that local levels of DHEA in the brain are very rapidly modulated by social interactions in a context and region-specific pattern.

Adrenarche and the Emotional and Behavioral Problems of Late Childhood

PURPOSE

Mental and behavioral disorders increase in prevalence with the passage through puberty. Yet the first symptoms for many children emerge between seven and 11 years, before the pubertal rise in gonadal hormones. A possibility that symptom onset may be linked to the adrenarchal rise in androgens has been little explored.

METHODS

The Childhood to Adolescence Transition Study recruited a stratified random sample of 1,239 eight-nine year olds from primary schools in Melbourne, Australia. Saliva samples were assayed for dehydroepiandrosterone, dehydroepiandrosterone-sulphate (DHEA-S), and testosterone. Emotional and behavioral problems were assessed through parental report on the Strengths and Difficulties Questionnaire.

RESULTS

In males, high levels of all androgens were associated with greater total difficulties and peer problems. Higher dehydroepiandrosterone and testosterone were associated with emotional symptoms and DHEA-S with conduct problems. In females, DHEA-S was associated with peer problems.

CONCLUSIONS

In late childhood, androgens are associated with emotional and behavioral problems in males, raising a possibility that the adrenarchal transition plays a contributing role. If so, the late primary school years may prove to be an important phase for preventing the onset of mental health and behavioral problems in boys.

Genetic and Environmental Contributions to Covariation Between DHEA and Testosterone in Adolescent Twins

Although several studies have shown that pubertal tempo and timing are shaped by genetic and environmental factors, few studies consider to what extent endocrine triggers of puberty are shaped by genetic and environmental factors. Doing so moves the field from examining correlated developmentally-sensitive biomarkers toward understanding what drives those associations. Two puberty related hormones, dehydroepiandrosterone and testosterone, were assayed from salivary samples in 118 MZ (62 % female), 111 same sex DZ (46 % female) and 103 opposite-sex DZ twin pairs, aged 12-16 years (M = 13.1, SD = 1.3). Pubertal status was assessed with a composite of mother- and self-reports. We used biometric models to estimate the genetic and environmental influences on the variance and covariance in testosterone and DHEA, with and without controlling for their association with puberty, and to test for sex differences. In males, the variance in testosterone and pubertal status was due to shared and non-shared environmental factors; variation in DHEA was due to genetic and non-shared environmental factors. In females, variance in testosterone was due to genetic and non-shared environmental factors; genetic, shared, and non-shared environmental factors contributed equally to variation in DHEA. In males, the testosterone-DHEA covariance was primarily due to shared environmental factors that overlapped with puberty as well as shared and non-shared environmental covariation specific to testosterone and DHEA. In females, the testosterone-DHEA covariance was due to genetic factors overlapping with pubertal status, and shared and non-shared environmental covariation specific to testosterone and DHEA.

Tactics for modeling multiple salivary analyte data in relation to behavior problems: Additive, ratio, and interaction effects

Individual differences in the psychobiology of the stress response have been linked to behavior problems in youth yet most research has focused on single signaling molecules released by either the hypothalamic-pituitary-adrenal axis or the autonomic nervous system. As our understanding about biobehavioral relationships develops it is clear that multiple signals from the biological stress systems work in coordination to affect behavior problems. Questions are raised as to whether coordinated effects should be statistically represented as ratio or interactive terms. We address this knowledge gap by providing a theoretical overview of the concepts and rationales, and illustrating the analytical tactics. Salivary samples collected from 446 youth aged 11-12 were assayed for salivary alpha-amylase (sAA), dehydroepiandrosterone-sulfate (DHEA-s) and cortisol. Coordinated effect of DHEA-s and cortisol, and coordinated effect of sAA and cortisol on externalizing and internalizing problems (Child Behavior Checklist) were tested with the ratio and the interaction approaches using multi-group path analysis. Findings consistent with previous studies include a positive association between cortisol/DHEA-s ratio and internalizing problems; and a negative association between cortisol and externalizing problems conditional on low levels of sAA. This study highlights the importance of matching analytical strategy with research hypothesis when integrating salivary bioscience into research in behavior problems. Recommendations are made for investigating multiple salivary analytes in relation to behavior problems.

Therapeutic glucocorticoid administration alters the diurnal pattern of dehydroepiandrosterone

Significant alteration in hypothalamic-pituitary-adrenal function has been demonstrated in patients after short-term glucocorticoid therapy, but its impact on the circadian rhythm of steroid hormones has never been investigated. This study examined the effects of short-term prednisone administration on the diurnal patterns of dehydroepiandrosterone (DHEA) and testosterone. Saliva samples were collected from 11 healthy, physically active, male volunteers for DHEA and testosterone analysis, as follows: every 4 h from 0800 to 2000 h on 2 control days without medication, and after 1 week of oral therapeutic prednisone treatment (60 mg daily) (days 0-3). Overall, a diurnal decline in the two steroid hormones was observed on the control days. After short-term glucocorticoid administration, DHEA concentrations were significantly decreased with a complete disappearance of the DHEA diurnal pattern, which lasted 2 days post-treatment. No glucocorticoid effect was observed for testosterone. The results indicate that short-term prednisone treatment affects the circadian pattern of saliva DHEA but not testosterone in healthy active volunteers. Further studies are necessary to determine whether this alteration in DHEA circadian pattern has clinical consequences in patients with chronic glucocorticoid therapy.

Developmental and contextual considerations for adrenal and gonadal hormone functioning during adolescence: Implications for adolescent mental health

Substantial research has implicated the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes independently in adolescent mental health problems, though this literature remains largely inconclusive. Given the cross-talk between the HPA and HPG axes and their increased activation in adolescence, a dual-axis approach that examines both axes simultaneously is proposed to predict the emergence and persistence of adolescent mental health problems. After briefly orienting readers to HPA and HPG axis functioning, we review the literature examining associations between hormone levels and changes with behavior during adolescence. Then, we provide a review of the literature supporting examination of both axes simultaneously and present the limited research that has taken a dual-axis approach. We propose future directions including consideration of between-person and within-person approaches to address questions of correlated changes in HPA and HPG hormones. Potential moderators are considered to increase understanding of the nuanced hormone-behavior associations during key developmental transitions.

Effect of collection material and sample processing on pig oral fluid testing results

The effect of sampling material, sample processing, and collection order on the detection of analytes in pig oral fluid specimens was evaluated. Oral fluid samples were collected from 104 pens of commercial wean-to-finish pigs using ropes made of three different materials. Processed (centrifuged and filtered) and unprocessed oral fluid samples were tested using commercial ELISAs for porcine reproductive and respiratory syndrome virus (PRRSV) antibodies and total IgM, IgA, and IgG. Unprocessed samples were tested for PRRSV nucleic acid and processed samples were assayed for PRRSV neutralizing antibodies. Analysis of the data using repeated measures ANOVA and Tukey-Kramer adjusted t tests found statistically significant, non-uniform, and assay-dependent effects of all three factors. Therefore, when testing oral fluid specimens, swine health specialists, veterinarians, and diagnosticians should be aware of the potential impact of these factors on specific analytes. For monitoring health and welfare parameters, oral fluid samples should be collected using cotton-based materials and undergo minimal post-collection processing.

Diurnal patterns of salivary cortisol and DHEA using a novel collection device: electronic monitoring confirms accurate recording of collection time using this device

The accurate indication of saliva collection time is important for defining the diurnal decline in salivary cortisol as well as characterizing the cortisol awakening response. We tested a convenient and novel collection device for collecting saliva on strips of filter paper in a specially constructed booklet for determination of both cortisol and DHEA. In the present study, 31 healthy adults (mean age 43.5 years) collected saliva samples four times a day on three consecutive days using filter paper collection devices (Saliva Procurement and Integrated Testing (SPIT) booklet) which were maintained during the collection period in a large plastic bottle with an electronic monitoring cap. Subjects were asked to collect saliva samples at awakening, 30 min after awakening, before lunch and 600 min after awakening. The time of awakening and the time of collection before lunch were allowed to vary by each subjects' schedule. A reliable relationship was observed between the time recorded by the subject directly on the booklet and the time recorded by electronic collection device (n=286 observations; r(2)=0.98). However, subjects did not consistently collect the saliva samples at the two specific times requested, 30 and 600 min after awakening. Both cortisol and DHEA revealed diurnal declines. In spite of variance in collection times at 30 min and 600 min after awakening, the slope of the diurnal decline in both salivary cortisol and DHEA was similar when we compared collection tolerances of ±7.5 and ±15 min for each steroid. These unique collection booklets proved to be a reliable method for recording collection times by subjects as well as for estimating diurnal salivary cortisol and DHEA patterns.

Child maltreatment and gender interactions as predictors of differential neuroendocrine profiles

Child maltreatment is a potent stressor associated with neuroendocrine dysregulation and increased risk for mental and physical disorders throughout the lifespan. Gender differences in stress reactivity and adult psychopathology prevalence may be related to sex-specific responsivity to stress. The purpose of this study is to examine whether gender interacts with the stress of maltreatment to produce differential neuroendocrine profiles in children. Participants included 137 maltreated and 110 nonmaltreated low-income, racially and ethnically diverse children (range: 7.9-10.9 years; M=9.42 years; 52% male) who attended a summer research day camp. Saliva was collected 3 times across the day for 5 days for cortisol and dehydroepiandosterone (DHEA) analysis. Department of Human Services records were examined to determine the type, severity, chronicity, onset, and recency of maltreatment for children in the maltreated group. Significant interactions between gender and maltreatment pervasiveness predicted diurnal cortisol, DHEA, and cortisol/DHEA ratio levels. Elevated daily cortisol levels were reported for boys compared to girls in the group with more pervasive maltreatment. Boys with less pervasive maltreatment had lower DHEA and higher cortisol/DHEA ratio levels than girls with similar experiences, nonmaltreated boys, and boys with more pervasive maltreatment. Further results are consistent with down-regulation of cortisol production in girls with more pervasive maltreatment and girls who experienced maltreatment that was early onset and not recent. The effectiveness of interventions for maltreated children may be improved with greater knowledge of how maltreatment differentially affects neuroendocrine regulation by gender.

Mediators of yoga and stretching for chronic low back pain

Although yoga is an effective treatment for chronic low back pain, little is known about the mechanisms responsible for its benefits. In a trial comparing yoga to intensive stretching and self-care, we explored whether physical (hours of back exercise/week), cognitive (fear avoidance, body awareness, and self-efficacy), affective (psychological distress, perceived stress, positive states of mind, and sleep), and physiological factors (cortisol, DHEA) mediated the effects of yoga or stretching on back-related dysfunction (Roland-Morris Disability Scale (RDQ)). For yoga, 36% of the effect on 12-week RDQ was mediated by increased self-efficacy, 18% by sleep disturbance, 9% by hours of back exercise, and 61% by the best combination of all possible mediators (6 mediators). For stretching, 23% of the effect was mediated by increased self-efficacy, 14% by days of back exercise, and 50% by the best combination of all possible mediators (7 mediators). In open-ended questions, ≥20% of participants noted the following treatment benefits: learning new exercises (both groups), relaxation, increased awareness, and the benefits of breathing (yoga), benefits of regular practice (stretching). Although both self-efficacy and hours of back exercise were the strongest mediators for each intervention, compared to self-care, qualitative data suggest that they may exert their benefits through partially distinct mechanisms.

Effects of water restriction on reproductive physiology and affiliative behavior in an opportunistically-breeding and monogamous songbird, the zebra finch

Wild zebra finches form long-term monogamous pair-bonds that are actively maintained year-round, even when not in breeding condition. These desert finches are opportunistic breeders, and breeding is highly influenced by unpredictable rainfall. Their high levels of affiliation and complex breeding patterns make zebra finches an excellent model in which to study the endocrine regulation of affiliation. Here, we compared zebra finch pairs that were provided with water ad libitum (control) or water restricted. We examined (1) reproductive physiology, (2) pair-maintenance behaviors in several contexts, and (3) circulating and brain steroid levels. In females, water restriction profoundly reduced largest ovarian follicle size, ovary size, oviduct size, and egg laying. In males, water restriction had no effect on testes size but decreased systemic testosterone levels. However, in the hypothalamus, local testosterone and estradiol levels were unaffected by water restriction in both sexes. Systemic and local levels of the androgen precursor dehydroepiandrosterone (DHEA) were also unaffected by water restriction. Lastly, in three different behavioral paradigms, we examined a variety of pair-maintenance behaviors, and none were reduced by water restriction. Taken together, these correlational data are consistent with the hypothesis that local production of sex steroids in the brain promotes the expression of pair-maintenance behaviors in non-breeding zebra finches.

Mining the salivary proteome with grating-coupled surface plasmon resonance imaging and surface plasmon coupled emission microarrays

Biological indicators have numerous and widespread utility in personalized medicine, but the measurement of these indicators also poses many technological and practical challenges. Blood/plasma has typically been used as the sample source with which to measure these indicators, but the invasiveness associated with sample procurement has led to increased interest in saliva as an attractive alternative. However, there are unique issues associated with the measurement of saliva biomarkers. These issues are compounded by the imperfect correlation between saliva and plasma with respect to biomarker profiles. In this manuscript, we address the technical challenges associated with saliva biomarker quantification. We describe a high-content microarray assay that employs both grating-coupled surface plasmon resonance imaging and surface plasmon-coupled emission modalities in a highly sensitive assay with a large dynamic range. This powerful approach provides the tools to map the proteome of saliva, which in turn should greatly enhance the utility of salivary biomarker profiles in personalized medicine.

Year-round territorial aggression is independent of plasma DHEA in the European nuthatch Sitta europaea

Plasma testosterone can play an important role in promoting aggressive behaviors relating to territory defense in breeding male birds. Some birds defend territories also during the non-breeding phase, when testosterone circulates at basal levels. In such species, plasma levels of the pro-hormone dehydroepiandrosterone (DHEA) may support non-breeding territoriality by acting as a local substrate for sex steroids. To test this possible role of plasma DHEA, we examined the seasonal DHEA profile of male (and female) European nuthatches Sitta europaea: a male and female nuthatch pair will defend an all-purpose territory throughout the year. We hypothesized that plasma DHEA would be detectable in wintering nuthatches with a territory. However, only ca. half of the territorial wintering males (and females) displayed detectable DHEA levels, suggesting that plasma DHEA is not a major sex steroid precursor during non-breeding. Further, among hatching-year birds, plasma DHEA was significantly lower in territorial birds than in "floaters", i.e., subordinate birds without a territory. To experimentally examine the role of DHEA in non-breeding territoriality, we treated adult wintering males with DHEA and measured effects on aggressive responses to conspecific challenge. DHEA treatment elevated plasma levels of DHEA (and testosterone), but did not enhance territorial behaviors or their persistence. Taken together, our data suggest that DHEA (and, indeed, sex steroids per se) do not regulate non-breeding territoriality in the nuthatch. Given that territorial aggression in nuthatches is expressed year-round, a hormone for its activation may be redundant.

Incorporating salivary biomarkers into nursing research: an overview and review of best practices

Analytes and biomarkers present in saliva may provide insight into individual differences in environmental chemical exposures, variation in reproductive hormones, therapeutic and illegal substance use, changes in stress-related physiology, and the immunologic footprints of infectious disease. The wealth of information provided by salivary analytes has the potential to enrich biobehavioral nursing research by enabling researchers to measure these individual differences in the clinic as well as in patients' and participants' everyday social worlds. In this article, the authors provide a roadmap for researchers new to this area who would like to learn more about integrating salivary biospecimens into the next generation of health research. In addition, the authors highlight best practices and strategies to avoid common pitfalls for researchers already engaged in this field.

The relationship between puberty and social emotion processing

The social brain undergoes developmental change during adolescence, and pubertal hormones are hypothesized to contribute to this development. We used fMRI to explore how pubertal indicators (salivary concentrations of testosterone, oestradiol and DHEA; pubertal stage; menarcheal status) relate to brain activity during a social emotion task. Forty-two females aged 11.1 to 13.7 years underwent fMRI scanning while reading scenarios pertaining either to social emotions, which require the representation of another person’s mental states, or to basic emotions, which do not. Pubertal stage and menarcheal status were used to assign girls to early or late puberty groups. Across the entire sample, the contrast between social versus basic emotion resulted in activity within the social brain network, including dorsomedial prefrontal cortex (DMPFC), the posterior superior temporal sulcus, and the anterior temporal cortex (ATC) in both hemispheres. Increased hormone levels (independent of age) were associated with higher left ATC activity during social emotion processing. More advanced age (independent of hormone levels) was associated with lower DMPFC activity during social emotion processing. Our results suggest functionally dissociable effects of pubertal hormones and age on the adolescent social brain.

Soft song during aggressive interactions: seasonal changes and endocrine correlates in song sparrows

It is well known that songbirds produce high amplitude songs ("broadcast songs"). Songbirds also produce low amplitude songs ("soft songs") during courtship or territorial aggression in the breeding season. Soft songs are important social signals but have been studied far less than broadcast songs. To date, no studies have examined seasonal changes in soft song or its endocrine regulation. Here, in male song sparrows, we examined soft songs during a simulated territorial intrusion in the breeding season and non-breeding season. We also measured plasma testosterone and dehydroepiandrosterone (DHEA) levels in subjects immediately after the aggressive encounter. The total number of songs produced (broadcast+soft songs) did not vary between seasons. However, there was a dramatic increase in the percentage of soft song in the non-breeding season. Further, the percentage of soft song was negatively correlated with plasma testosterone levels in the non-breeding season. There were seasonal differences in the acoustic structure of two major elements of soft song, trills and buzzes. The minimum frequency of trills was lower in the non-breeding season, and the element repetition rate of buzzes was lower in the non-breeding season. To our knowledge, this is the first study to (1) examine soft songs outside of the breeding season and (2) to identify endocrine correlates of soft songs, which are important social signals in songbirds.