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Animal models are crucial to understanding the mechanisms underlying the deleterious consequences of early-life stress. Here, we aimed to examine the effect of the limited bedding nesting (LBN) paradigm on early life development milestones and anxiety- and/or depression-like behavior in adolescent and adult mice from two inbred mice of both sexes. C57BL/6NCrl and BALB/c litters were exposed to the LBN paradigm postnatal day (PND) 2-9. Maternal behavior recording occurred on PND 3-9, and pups were weighed daily and examined to verify the eye-opening on PND 10-22. The male and female offspring underwent evaluation in the open field test, elevated plus-maze, and the forced swimming test during adolescence (PND 45-49) and adulthood (PND 75-79). We found that LBN impaired the maternal behavior patterns of both strain dams, mainly on C57BL/6NCrl strain. Also, LBN delayed the pup's eye-opening time and reduced body weight gain, impacting C57BL/6NCrl pups more. We also found that LBN decreased anxiety-related indices in adolescent and adult male but not female mice of both strains. Furthermore, LBN decreased depression-related indices only adolescent female and male BALB/c and female but not male C57BL/6NCrl mice. These findings reinforce the evidence that the LBN paradigm impairs the maternal behavior pattern and pup's early developmental milestones but does not induce anxiety- or depressive-like behavior outcomes during later life.

The role of visual experience in the development of face processing has long been debated. We present a new angle on this question through a serendipitous study that cannot easily be repeated. Infants viewed short blocks of faces during fMRI in a repetition suppression task. The same identity was presented multiple times in half of the blocks (Repeat condition) and different identities were presented once each in the other half (Novel condition). In adults, the fusiform face area (FFA) tends to show greater neural activity for Novel vs. Repeat blocks in such designs, suggesting that it can distinguish same vs. different face identities. As part of an ongoing study, we collected data before the COVID-19 pandemic and after an initial State lockdown was lifted. The resulting sample of 12 infants (9–24 months) divided equally into pre- and post-lockdown groups with matching ages and data quantity/quality. The groups had strikingly different FFA responses: pre-lockdown infants showed repetition suppression (Novel>Repeat), whereas post-lockdown infants showed the opposite (Repeat>Novel), often referred to as repetition enhancement. These findings provide speculative evidence that altered visual experience during the lockdown, or other correlated environmental changes, may have affected face processing in the infant brain.

Methamphetamine use by women, even throughout pregnancy, is common. But there is limited knowledge about the effects in prenatally methamphetamine-exposed children. This study investigated how prenatal methamphetamine exposure in rats, via maternal i.v. self-administration, affected the sensitivity of adult offspring to methamphetamine in comparison with controls. The offspring were generated from dams either self-administering methamphetamine daily under limited-access conditions prior to and throughout pregnancy, or their respective saline-yoked control dams. Spontaneous and methamphetamine-induced locomotor activity was assessed in male and female offspring of both exposure groups after a range of methamphetamine doses. In a separate group of offspring, acquisition of i.v. methamphetamine self-administration, responding under fixed and progressive ratio schedules of methamphetamine reinforcement, and reinstatement of extinguished drug-seeking behavior were assessed. Methamphetamine dose-dependently increased locomotor activity in both exposure groups. However, methamphetamine-exposed males showed significantly enhanced locomotor activity compared with controls at 1 mg/kg, and methamphetamine-exposed females showed significantly enhanced locomotor activity compared with controls at 3.2 mg/kg. Methamphetamine-exposed offspring of both sexes acquired methamphetamine self-administration faster and showed overall higher levels of methamphetamine-induced reinstatement compared with controls. Taken together, these results indicate that prenatal methamphetamine exposure to relatively low levels alters methamphetamine sensitivity in male and female adult offspring.

While extensive research has supported the developmental programming hypothesis regarding contributions of prenatal psychosocial or nutritional adversity to offspring stress physiology, fewer studies consider both exposures together with maternal stress physiology. This study examined newborn cortisol output during a stressor as a function of maternal pre-pregnancy health status and nutritional history (pre-pregnancy body mass index [PPBMI]), economic resources (household income), and maternal cortisol awakening response (mCAR) in late pregnancy. Participants were 102 mother-infant pairs from an economically and racial/ethnically diverse sample. Offspring salivary cortisol response to a neurobehavioral exam was assessed at 1 month. Income and maternal PPBMI were positively associated with mCAR in late pregnancy. mCAR was positively related to 1-month newborn cortisol response. The interaction of income and PPBMI was positively associated with newborn cortisol output during an exam at 1-month. Mothers with the highest PPBMI and lowest income had offspring with higher cortisol responses than offspring of mothers with higher income and lower PPBMI. There was no evidence of indirect mediation effects of predictors (PPBMI, income, and interaction) on infant cortisol via mCAR. The differential effects of the interaction of PPBMI and income suggest that these exposures influence infant cortisol output in the context of one another, independent of maternal pregnancy cortisol.

Exercise has been shown to be beneficial in reducing symptoms of affective disorders and to increase the expression of brain-derived neurotrophic factor (BDNF). The BDNF Val66Met polymorphism is associated with reduced activity-dependent BDNF release and increased risk for anxiety and depression. Male and female Val66Met rats were given access to running wheels from 3 weeks of age and compared to sedentary controls. Anxiety- and depression-like behaviors were measured in adulthood using the elevated plus maze (EPM), open field (OF), and forced swim test (FST). Expression of BDNF and a number of stress-related genes, the glucocorticoid receptor (Nr3c1), serum/glucocorticoid-regulated kinase 1 (Sgk1), and FK506 binding protein 51 (Fkbp5) in the hippocampus were also measured. Rats given access to running wheels developed high levels of voluntary exercise, decreased open-arm time on the EPM and center-field time in the OF, reduced overall exploratory activity in the open field, and increased immobility time in the FST with no differences between genotypes. Chronic exercise induced a significant increase in Bdnf mRNA and BDNF protein levels in the hippocampus with some of these effects being genotype specific. Exercise decreased the expression of Nr3c1 and Sgk1, but increased the expression of Fkbp5. These results suggest that chronic running-wheel exercise from adolescence increased anxiety and depression-like phenotypes in adulthood, independent of BDNF Val66Met genotype. Further studies are required to confirm that increased indices of anxiety-like behavior are independent from reduced overall locomotor activity.

In cross-sectional analyses, early institutional care is associated with shorter stature but not obesity during puberty in children adopted into US families. We examined whether shorter stature and leaner body composition in youth adopted internationally from institutions would continue as puberty progressed. We also examined whether current psychosocial stress would moderate the association between early institutional deprivation and growth during adolescence. Using an accelerated longitudinal design and linear mixed-effects models, we examined the height and body mass index (BMI) of 132 previously institutionalized (PI) and 176 nonadopted (NA) youth. We examined youth aged 7-15 at the beginning of the study three times across 2 years. Nurses assessed anthropometrics and pubertal status. Current psychosocial stress was measured using the Youth Life Stress Interview. Our results indicated that PI youth remained shorter and leaner across three assessments than NA youth. However, age-and-sex-adjusted BMI increased faster in PI youth. Psychosocial stress during puberty predicted greater age-and-sex-adjusted BMI, but this effect did not differ by group. The gap in BMI but not height appears to close between PI and NA youth. Higher psychosocial stress was associated with higher BMI during puberty.

A growing body of research has focused on the physiological impact of media on older children and adolescents. Less research has been focused on the potential physiological impact of media on infants and younger children, especially media designed to be age appropriate and educational in content. In this study, we examined respiratory sinus arrhythmia (RSA) in infants (N = 269, M

The purpose of this study was to investigate the role of skin conductance level reactivity (SCLR) and respiratory sinus arrhythmia reactivity (RSAR) in preschoolers' social dominance, as well as potential gender differences in these associations. Reactivity was assessed in response to viewing videos of social exclusion and a post-aggression discussion. In a community sample of 94 preschool children followed over one calendar year, reactivity to the post-aggression discussion, but not exclusion, video was related to social dominance. Specifically, increased RSAR to the post-aggression discussion video was positively associated with concurrent social dominance for both boys and girls. Longitudinally, for boys only, coactivation (i.e., increases in SCLR accompanied by increases in RSAR) to the post-aggression discussion video, which may reflect dysregulated, emotionally labile reactions to stress, was associated with relatively low levels of social dominance across the course of the year. Overall, findings contribute to a growing literature documenting the role of autonomic reactivity in preschoolers' social adjustment and extend this work to their capacity to achieve and maintain socially dominant positions with peers.

The home auditory environment influences the development of early language abilities, and excessive noise exposure is increasingly linked with deficits in language and reading scores in children. However, fewer studies have considered the role of noise exposure in shaping the development of attentional processing in early infancy, a foundational neurocognitive skill relevant for learning. Here, we used passive at-home auditory recording to investigate how multiple dimensions of infants’ home auditory environments, including both the quantity and the predictability of auditory input, impacts neural and behavioral measures of sustained attention in a sociode-mographically diverse sample of 3-month-old infants (N = 98 infants, 62 males; age M = 3.48 months, SD = 0.39; 52% Hispanic/Latino). Results indicated that infants who were exposed to more predictable patterns of auditory input in the home demonstrated longer overall time in sustained attention during laboratory assessments. In addition, infants’ who experienced more predictable auditory input also demonstrated greater relative increases in electroencephalography frontal theta power during periods of sustained attention, a neural marker relevant to information processing and attentional control. These findings provide novel evidence into the importance of the predictability of early environmental inputs in shaping developing cortical circuitry and attentional systems from the first months of postnatal life.

Temperamental risk, such as surgency, negative affect, and poor effortful control, has been posited as a predictor of externalizing symptom development. However, autonomic nervous system (ANS) activity underlying processes of reactivity and regulation may moderate associations between early temperament and later externalizing behaviors during early childhood. The aim of the present study was to examine how interactions between resting sympathetic (SNS) and parasympathetic (PNS) activity at age 5 may moderate associations between temperamental risk at age 3 and externalizing behavior at age 6 (n = 87). Results demonstrate different interactions between resting ANS activity and temperamental risk to predict externalizing behaviors. For children with lower SNS activation at rest, surgency was positively associated with externalizing behaviors. Negative affect was positively associated with externalizing behaviors except when there were either high levels of SNS and PNS activity or low levels of SNS and PNS activity. Effortful control was not associated with externalizing behaviors, though SNS and PNS activity interacted to predict externalizing behaviors after accounting for effortful control. Taken together, the results highlight the importance to examine multisystem resting physiological activity as a moderator of associations between temperamental risk and the development of externalizing behaviors.

Although there is evidence of sex differences in responding to social stress, and that age when stressed matters, females are understudied and adult-stress comparisons are few. Here, we investigated stress effects on reward sensitivity by examining rats' choice of social versus sucrose reward in a continuous spatial allocation design. We predicted social instability stress (SS) in adolescence would result in greater social discounting (spend less time near a novel peer when provided access to sucrose) relative to nonstressed controls (CTLs) and relative to SS in adulthood. All increased sucrose intake as the concentration increased, with no evidence of social discounting. SS males tested soon after the stress had a decrease in intake, whereas those tested long after had an increase in both time near the peer and in intake. CTL and SS females did not differ in intake, although their dose-response curves differed when tested soon after the SS. We also tested whether SS changed the stimulus value of the rat as a social peer; when tested in triads, CTL rats spent similar time in interaction with SS versus CTL rats. In sum, effects of SS on reward sensitivity were greater for males irrespective of administered in adolescence versus adulthood.

Recent scholarship has highlighted the importance of understanding relations between hormones, rather than studying hormones in isolation. Considering neuroendocrine coupling, or the coordination of hypothalamic-pituitary-adrenal axis and hypothalamic-pituitary-gonadal axis hormones over time, is one way to investigate how systems governing stress responsiveness and pubertal development covary during critical periods. To date, however, most work has considered hormone coupling cross-sectionally. The current study investigated neuroendocrine coupling in a longitudinal sample from the Northeastern United States. Youth (N = 437, 53% male, 90% White) provided saliva samples for analysis of diurnal hormone activity at ages 9 (three samples per day across 3 days) and 12 (one sample per day on the same weekday for 4 weeks). At both timepoints, samples collected 30-min after waking were assayed for cortisol, dehydroepiandrosterone (DHEA), and testosterone. Multilevel growth modeling was used to determine how levels of morning cortisol changed in tandem with DHEA and testosterone. Morning cortisol-DHEA coupling varied by child sex, as males' cortisol-DHEA diminished over time, especially among pubertally advanced males. Females, in contrast, demonstrated strengthening cortisol-DHEA coupling over time, especially more pubertally advanced females. Morning cortisol-testosterone coupling did not vary by sex or pubertal status, demonstrating strengthening associations between ages 9 and 12. The current findings contribute to the literature on hormone coupling across development and expand this work into an earlier developmental phase than previously investigated.