Pre-adolescence repeat exposure to sub-anesthetic doses of ketamine induces long-lasting behaviors and cognition impairment in male and female rat adults

In pre-adolescence, repeated anesthesia may be required for therapeutic interventions. Adult cognitive and neurobehavioral problems may result from preadolescent exposure to anesthetics. This study examined the long-term morphological and functional effects of repeated sub-anesthetic doses of ketamine exposure on male and female rat adults during pre-adolescence. Weaned 48 pre-adolescent rats from eight mothers and were randomly divided into four equal groups: control group and the ketamine group of males and females (20 mg/kg daily for 14 days); then animals received care for 20-30 days. Repeated exposure to sub-anesthetic doses of ketamine on cognitive functions was assayed using Social discrimination and novel object tests. Besides, an elevated plus maze and fear conditioning apparatus were utilized to determine exploratory and anxiety-like behavior in adults. Toluidine blue stain was used to evaluate the number of dead neurons in the hippocampus, and the effects of ketamine on synaptic plasticity were compared in the perforant pathway of the CA1 of the hippocampus. Our study indicates that repeated exposure to sub-anesthetic doses of ketamine during pre-adolescence can result in neurobehavioral impairment in male and female rat adulthood but does not affect anxiety-like behavior. We found a significant quantifiable increase in dark neurons. Recorded electrophysiologically, repeat sub-anesthetic doses of ketamine resulted in hampering long-term potentiation and pair pulse in male adult animals. Our results showed that repeated exposure to sub-anesthetic doses of ketamine during pre-adolescence can induce hippocampus and neuroplasticity changes later in adulthood. This study opens up a new line of inquiry into potential adverse outcomes of repeated anesthesia exposure in pre-adolescent rats.

Non-specific and ski-specific performance development in peri-pubertal cross-country skiers

PURPOSE

To evaluate non-specific and ski-specific performance development in male (M) and female (F) peri-pubertal cross-country skiers and to evaluate their relationship with cross-country skiing (XCS) performance and biological maturation within each age category and sex.

METHODS

Twenty-one and 19 athletes under 14 and 16 years old, respectively (U14 and U16), were tested for biological maturation; non-specific speed, agility, strength, endurance, and balance; ski-specific speed, agility, and endurance. XCS index was considered as average percentage time-gap from the winner in four official races. Sex and age-category effects were verified and a model predicting XCS index was extrapolated for each group.

RESULTS

Performance capacities raised across age categories (p < 0.05) except for non-specific speed, agility, balance, and relative arm strength (p > 0.05). F showed advanced biological maturation and greater balance than M (p < 0.05), while M showed higher performance capacities (p < 0.05). XCS index was not related to biological maturation within each group (p > 0.05); its variance was explained by non-specific speed and ski-specific upper-body endurance in M-U14 (p = 0.014), lower-limb strength and ski-specific agility in M-U16 and F-U14 (both p = 0.001), ski-specific upper-body endurance in F-U16 (p = 0.002).

CONCLUSION

Ski-specific performance capacities still develop during peri-puberty, with peri-pubertal M overperforming with respect to F of comparable performance level. XCS index was not influenced by biological maturation withing each age category, but it was rather explained by specific parameters that commonly undergo the "adolescent spurts", accordingly to the average biological maturation level of M and F athletes of each age category.

Beyond the RewP: The reward feedback-elicited LPP and its potential associations with perceived stress and internalizing symptoms in late childhood

Internalizing problems increase substantially during late childhood and early adolescence, which are known to be associated with elevated perceived stress as children transition into adolescence. One risk factor that may moderate the stress-symptom association is reward processing. While neurophysiological research in this field has focused on the reward positivity component (RewP) elicited during reward processing, little work has examined the reward feedback-elicited late positive potential (LPP) and its association with internalizing psychopathology. The present study examined the moderating roles of the RewP and feedback-elicited LPP in the relationship between perceived stress and internalizing symptoms in late childhood. A community sample of 115 nine-to-12-year-old children (66 girls, Mean age = 11.00 years, SD = 1.16) completed an EEG version of the reward feedback paradigm, the Doors task, and completed questionnaires on perceived stress and internalizing symptoms. A principal component analysis revealed three temporo-spatial factors that were temporally and spatially analogous to the RewP, anterior LPP, and posterior LPP, respectively. As expected, an enlarged RewP was found towards the win condition compared to the loss condition. We also observed a potentiated LPP towards loss relative to win feedback, which may reflect the evaluation and reappraisal processes following unsuccessful performance (i.e., loss). We did not, however, find significant moderating effects of any ERP components on the stress-symptom association. Our study was first to isolate the feedback-elicited LPP in a reward processing paradigm in children and provide initial evidence on the modulation of the ERP component by task conditions. Future research is warranted to further explore the functional significance of the reward feedback-elicited LPP in association with perceived stress and internalizing psychopathology in youths.

Associations between parental and pre-adolescents' physical activity and diet quality: The role of parental child care involvement and child's sex

BACKGROUND

Research has demonstrated the importance of the family environment in the eating and activity levels of offspring. We examined the cross-sectional associations between moderate-to-vigorous physical activity (MVPA) and diet quality of parents and the MVPA and diet quality of pre-adolescents. Interactions were tested to assess whether the child's sex and the parental level of involvement in daily child care moderated these associations.

METHODS

Data from 2467 pre-adolescents (age 11.5 ± 0.2 years; collected in 2015-2016) and their parents or caregivers from a large-scale prospective birth cohort study in Amsterdam (ABCD-study) was used. Parents and pre-adolescents individually reported their diet quality and physical activity. Child care involvement was assessed using the Caregiver Child Interaction Scale. With hierarchical linear regression analyses, we assessed the independent contribution of fathers and mothers.

RESULTS

An association between mother-child MVPA was found (β = 0.013; 95 % CI: 0.006;0.021). The association between father-child MVPA was only significant for highly involved fathers (β = 0.014; 95 % CI: 0.004;0.023). The child's sex did not change these MVPA associations. Regarding diet quality, associations were found between mother-child diet quality score (DQS) (β = 0.254; 95 % CI: 0.192;0.316) and father-child DQS, with stronger associations between fathers and sons (β = 0.234; 95 % CI: 0.169;0.298) than between fathers and daughters (β = 0.114; 95 % CI: 0.047;0.181). Parental levels of involvement did not change these associations.

CONCLUSION

These findings demonstrate that both parental behaviours represent an important factor in physical activity and diet quality in pre-adolescents in a sex-specific manner. As such, it is essential to include both parents in research to obtain the necessary insights for developing effective interventions to promote children's healthy eating and physical activity behaviours.

Sex differences in emotional and meta-emotional intelligence in pre-adolescents and adolescents

The study focuses on sex differences in emotional and meta-emotional intelligence in a sample of 355 pre-adolescents and 164 adolescents. Emotional and meta-emotional intelligence were measured using the multi-trait multi-method IE-ACCME test, allowing to define individuals' profiles of ability EI, emotional self-concept, meta-emotional knowledge, meta-emotional ability in self-evaluation and meta-emotional beliefs. Meta-emotional dimensions refer to the awareness of individuals about their emotional abilities and to their beliefs about the functioning of emotions in everyday life. Results demonstrated that girls scored better than boys in ability-EI, in particular in adolescents' group, whereas boys reported higher score than girls in emotional self-concept in both groups of age. Result about meta-emotional knowledge and meta-emotional ability in self-evaluation revealed that boys systematically overestimate their emotional abilities whereas girls, particularly in the adolescent group, tend to underestimate them. Finally, in both age groups, girls scored higher than males in metaemotional beliefs. The adoption of the meta-emotional intelligence framework may help to explain the discordances about sex differences found in previous studies using self-report vs. performance measures of EI. Moreover, it may contribute to shed light on the nature-nurture debate and on the role of meta-emotional variables for explaining sex differences in EI.

Tweens are not teens: the problem of amalgamating broad age groups when making pandemic recommendations

Demarcating childhood into two distinct and broad 10-year age bands of over and under age 10 is a disservice to our tween population (9–12 years), and may be overlooking our role in understanding the negative impacts of SARS-CoV-2 (COVID-19) during a formative period of development. In this commentary, we discuss the importance of considering tweens as a unique population of youth who are differentially impacted by the COVID-19 pandemic. We first describe the distinctive progress of tweens across various facets of developmental health, followed by recommendations to improve understanding and address impact of the pandemic and its restrictions on tweens. The COVID-19 pandemic has had a large impact on the day-to-day lives of tweens and what we do now will have long-lasting effects on their lifelong trajectories.

Low-income mothers' perspectives on the involvement of family members in child feeding

Nearly all research on child feeding has focused on mothers. Very little is known about other family members' roles in feeding children nor how mothers engage with these family members regarding child feeding. The objective of this study was to examine mothers' perceptions of other family members' child feeding roles and practices within low-income families, including the challenges experienced and strategies employed by mothers when sharing responsibility for child feeding. Low-income mothers (n = 100) of pre-adolescent children participated in semi-structured interviews regarding child feeding including shared responsibility for child feeding. A content analysis was then conducted to identify main themes in mothers' responses, with three main themes arising from the interviews. First, many family members were actively involved in child feeding and food-related decision-making. The majority of mothers (85%) reported that another family member was involved in feeding their child including fathers and father figures, who were involved in feeding in 63% of families. Other family members, mainly grandparents, were involved in feeding in 35% of families. Mothers identified several concerns regarding their child's eating when with other family members, particularly when grandparents fed children. Finally, mothers employed several strategies to control their children's eating when children were cared for by other family members. Future interventions to promote healthy child feeding among low-income families may benefit from helping mothers negotiate child feeding with other family members, particularly grandparents, and supporting family members' engagement in child feeding.

Unraveling Prospective Reciprocal Effects between Parental Invalidation and Pre-Adolescents' Borderline Traits: Between- and Within-Family Associations and Differences with Common Psychopathology-Parenting Transactions

The etiology of borderline personality pathology has consistently been framed as an interactional process between child vulnerability (i.e. emotional sensitivity and reactivity; Linehan, 1993) and invalidating parenting strategies, which evolves into increased emotion dysregulation and disinhibited behavior of the child and in turn activates more parental invalidation. Despite the strong theoretical base in support of these high-risk parent-child transactions, invalidating parenting behaviors have mostly been explored as a cause of child dysregulation and disinhibition, rather than as a result of child-driven effects. Also, most transactional research in this regard focused at differences between families, thereby not addressing potential changes within families across time. The current study therefore examines bidirectional between- and within-family effects of childhood borderline-related traits and maternal invalidation in the sensitive developmental phase of pre-adolescence (n = 574; 54.4% girls) along three assessment points. Cross-Lagged Panel Models and Random-Intercept Cross-Lagged Panel Models indicated detrimental parenting effects of invalidation on subsequent development in borderline-related traits of the child both between and within families, and additional child-driven effects for subsequent invalidating parenting strategies within families. Beyond these transactions between borderline-related traits and parenting, the current study also indicates significant differences in the direction of effects when exploring transactions between more common dimensions of child internalizing/externalizing symptomatology and parental invalidation, suggesting a more substantial parenting etiology in the developmental process of borderline traits throughout pre-adolescence. Future longitudinal research may explore to what extent the transactional nature of borderline personality traits during important developmental stages indeed holds unique aspects compared to more common manifestations of symptomatology at young age.

The role of family conflict in mediating impulsivity to early substance exposure among preteens

OBJECTIVES

Preadolescence substance exposure, which increases the risk of regular substance use, has been a public health concern. Although studies found that impulsivity is a predisposing factor of early substance exposure, the pathways through which impulsivity is associated with early substance exposure remain unclear. This study examined how family conflict mediates this association among U.S. preteens as family environment plays an essential role in pre-adolescent development.

METHODS

Respondents (N = 11,800, 9-10 years old) from the Adolescent Brain Cognitive Development (ABCD) Study Release 2.01 (July 2019) were included in this study. Generalized structural equation modeling was performed to investigate the mediation effects of family conflict on the associations between childhood impulsivity and early exposure to alcohol and tobacco use, controlling for covariates based on the Problem Behavior Theory.

RESULTS

Pre-adolescents with high impulsivity levels (≥90^th percentile) were more likely to report early alcohol and tobacco exposure (total effect: ORs = 1.49 and 1.70, respectively), where 4.13% and 12.41% of the associations, respectively, were meditated by family conflict (indirect effect: ORs = 1.02 and 1.07; Sobel test ps = 0.022 and 0.005, respectively).

CONCLUSIONS

Family conflict mediates the associations between childhood impulsivity and early substance exposure among preteens, with higher impulsivity leading to more severe family conflicts that are, in turn, associated with a higher likelihood of early substance exposure. To prevent preteens with high impulsivity level from early use of substances, interventions may focus on reducing family conflicts such as parenting counseling that guides parents to strengthen conflict-resolution skills and create a stable home environment for preteens.

What Predicts Pre-adolescent Compliance with Family Rules? A Longitudinal Analysis of Parental Discipline, Procedural Justice, and Legitimacy Evaluations

During adolescence, individuals make judgements on the legitimacy of authorities to make and enforce rules and they differentiate between various types of rules. This study tracked a socially and racially diverse sample (47% White) of 800 Brazilians for three years, ages 11-13 (50% female), allowing for variation between issues and individuals. The strongest predictors of compliance were adolescents' beliefs that parents were legitimate authorities. Other significant predictors were authorities' procedural justice and disciplinary practices. Legitimacy attributions partially mediated the relationship between procedural justice and compliance. Compliance and legitimacy varied across issues. Across time, parenting variables diminished in predictive strength while legitimacy attributions increased. Procedural justice practices may partially establish parental legitimacy, while disciplinary practices are less effective and perhaps counter-productive.

Preaching and practicing multicultural education: Predicting students' outgroup attitudes from perceived teacher norms and perceived teacher-classmate relations

Research on the role of teachers in bringing about positive interethnic attitudes among their students has largely focused on the norms teachers express about cultural diversity in the classroom without considering teacher's enactment of these norms in their relationships with students. The current study assessed to what extent students' ethnic outgroup attitudes are affected by perceived positive teacher norms about cultural diversity, together with perceived positive teacher-classmate interactions that may serve as an example to students. We investigated whether and how teacher norms and practices interact to affect students' attitudes, and whether these effects may differ for minority and majority students. Data was gathered in two waves among 186 native (majority) Dutch students, and 129 students with a Turkish-Dutch, or Moroccan-Dutch (minority) background in 29 4th-6th grade classrooms. Results showed that both majority and minority students expressed more positive attitudes towards ethnic outgroups when they perceived their teacher to have a positive relationship with their majority classmates, but only when supported by positive teacher norms. Ethnic majority students had more favorable outgroup attitudes when perceiving positive teacher relationships with minority classmates, but only in the absence of positive teacher norms. These results indicate that students in culturally diverse classrooms consider their teachers' interpersonal relationships with classmates to inform their own attitudes about ethnic outgroups.

Challenging anxious cognitions or accepting them? Exploring the efficacy of the cognitive elements of cognitive behaviour therapy and acceptance and commitment therapy in the reduction of children's fear of the dark

Anxiety is highly prevalent in pre‐adolescent children. Distorted cognitions are characteristic for dysfunctional levels of anxiety. However, applying cognitive elements in pre‐adolescent children cannot be fully ascertained, as it is not until adolescence before children can apply logical and abstract reasoning in a sophisticated manner. Cognitive behaviour therapy (CBT) and acceptance and commitment therapy (ACT) both target distorted cognitions. Whereas CBT encourages children to change the content of negative cognitions by applying cognitive restructuring, ACT stimulates youth to have a more accepting attitude towards these thoughts by applying cognitive defusion. The current study examined the efficacy of applying cognitive elements and compared the cognitive elements of CBT and ACT in pre‐adolescent children. We included no behavioural elements to specifically study the developmental appropriateness of the cognitive elements in this age group. Highly anxious children, aged 8–12 years were randomised to a 30‐minute cognitive restructuring (n = 21) or cognitive defusion intervention (n = 22). Subjective fear of the dark levels, behavioural darkness toleration, and comprehension and fun associated with the interventions were assessed. Both interventions had a significantly positive impact on children's fear of the dark. Cognitive restructuring led to more favourable results on subjective fear than cognitive defusion, no differences were found for darkness toleration.

Physical activity is associated with bone geometry of premenarcheal girls in a dose-dependent manner

OBJECTIVE

To determine the relationship between habitual physical activity (PA) level and peripheral qualitative computed tomography-determined quantitative tibia characteristics of premenarcheal girls.

METHODS

Premenarcheal girls matched for age (10-13 years), bone age and maturity level were assigned into: a) low PA group (LPA, n=25), b) moderate PA group (MPA, n=17), and c) high PA group (HPA, n=18). Participants' daily dietary intake, tibia's geometry and serum levels of calcium and vitamin D were assessed.

RESULTS

Premenarcheal girls demonstrating HPA exhibited greater pericortical thickness, cross-sectional area (CSA) and bone mineral content (BMC) (p<.001) in cortical bone, greater BMC, volumetric bone density (vBMD) and polar stress strength index (SSIp) in trabecular bone (p<0.001-0.05) and greater total BMC (p<.05) and vBMD (p<.01) when compared to their physically inactive or moderately active counterparts. MPA exhibited greater values of cortical BMC (p<.01) and SSIp (p<.05) than LPA. Partial correlation analysis (adjusted for BMI) revealed modest associations between PA score and bone geometry parameters (r=0.36-0.49, p<.05) at 38% of tibia length.

CONCLUSIONS

Habitual PA affects geometry of both cortical and trabecular areas of a long bone of premenarcheal girls in a dose-dependent manner. Specifically, PA increases both the density and size of cortical bone but only the density of trabecular bone during preadolescence. Given the importance of peak bone mass for future fracture risk, high levels of PA during childhood could be a major target for public health interventions aimed at optimising bone health in prepubertal children when the greatest bone gains occur.