Male Cope's gray treefrogs (Hyla chrysoscelis) in amplexus have elevated and correlated steroid hormones compared to solitary males.

Gonadal steroid hormones are typically elevated during the breeding season-a finding known as an associated reproductive pattern. Though less studied, there is also evidence, in both sexes, for elevated adrenal/interrenal steroids, including acute elevations on the day of mating. I investigated gonadal and interrenal steroids in wild male Cope's gray treefrogs at breeding aggregations. I collected blood from males found in amplexus with female mates (amplexed males) and males sampled at the same time and location that were actively advertising vocally and without a mate (solo males). Concentrations of plasma corticosterone, testosterone, and 17ß-estradiol (CORT, T and E2, respectively) were validated and measured. These two categories of males differed in four ways: (1) amplexed males exhibited significantly elevated concentrations of all three steroids compared to solo males (CORT: +347 %; T: +60 %; and E2: +43 %); (2) these hormone profiles alone accurately predicted male mating category with ca. 83 % accuracy using a discriminant function analysis; (3) amplexed males exhibited significant between-hormone correlations (T and E2 were positively correlated and CORT and E2 were negatively correlated) whereas no correlations were found in solo males; (4) amplexed males showed a negative correlation with CORT concentration and the time of night, whereas no such pattern was present in solo males. These findings suggest an acute and strong coactivation of the interrenal and gonadal axes that could drive phenotypic integration during this fitness-determining moment. I discuss these findings and suggest experiments to determine causation, including the role of motor behavior driving endocrine states and the role of female selection on endocrine profiles.

Within-dyad bidirectional relations among maternal depressive symptoms and child behavior problems from infancy through preschool.

Although dyadic theory focuses on the impact of a mother's mental health on her own child and the impact of a child's mental health on their own mother, commonly used statistical approaches are incapable of distinguishing the desired within-dyad processes from between-dyad effects. Using autoregressive latent trajectory modeling with structured residuals, the current study evaluated within-dyad, bidirectional associations between maternal depressive symptoms and child behavior problems from child age 1-4.5 years among a sample of low-income, Mexican American women (N = 322, Mage = 27.8) and their children. Women reported on maternal depressive symptoms and child behavior problems during laboratory visits at child age 1, 1.5, 2, 3, and 4.5 years. Results provide novel evidence of child-driven bidirectional association between maternal depressive symptoms and child behavior problems at the within-dyad level as early as child age 1 year and within-person stability in child behavior problems emerging early in life.

Hypothesis on the Synchronistic Evolution of Autotrophy and Heterotrophy.

All life on earth requires a source of energy and organic carbon. There has been a continuous debate on whether autotrophic or heterotrophic metabolism came first. A very similar discussion exists concerning the advent of oxygenic photosynthesis and aerobic respiration. I put forward the synchronistic evolution hypothesis supposing that all metabolic processes develop in a bidirectional manner from the very first. Bidirectionality is claimed to be intrinsic to the evolution of all metabolic processes as (i) all biochemical reactions and enzymes are per se bidirectional, (ii) substrates need to be regenerated, and (iii) flux regulation requires flexibility of direction. Autotrophy and heterotrophy are thus inherent to each other. A scenario for the synchronistic development of oxygenic photosynthesis and aerobic respiration is described.

The occurrence of internalizing problems and chronic pain symptoms in early childhood: what comes first?

Chronic pain and internalizing problems are characterized by concurrent associations but the directionality of this relationship in early childhood remains unclear. This prospective study aimed to investigate the bidirectional effect of chronic pain and internalizing problems and test the persistence of pain over time in a population-based sample of preschoolers. The study was embedded in Generation R, a large population-based cohort. Mothers of 3,996 children assessed their child's experienced pain and internalizing problems at 3 and 6 years. At 3 years, paternal reports were available too. Reports of family functioning, discipline practices and parental psychopathology were also collected. The prevalence of chronic pain was 2.7% (106) and 8.0% (294) at baseline and follow-up, respectively. The presence of internalizing problems at child age 3 years predicted chronic pain at 6 years, for both maternal (OR 1.05, 95% CI 1.02,1.07, p < 0.001) and paternal (OR 1.03, 95%CI 1.00, 1.06, p < 0.05) internalizing problem reports, when adjusted for potential confounding factors. In contrast, chronic pain did not increase the likelihood of internalizing problems. The temporal relationship between chronic pain and internalizing problems appears to follow a largely unidirectional trend in early childhood, with internalizing problems increasing the likelihood of concurrent physical symptoms. Current understanding of the directionality of this relationship, highlights the importance for comprehensive assessment of psychiatric problems contributing to the manifestation of chronic pain.

Parental self-efficacy: Examining its mediating and reciprocally predictive roles in supportive emotion socialization.

This longitudinal study examined the associations between child negative affect, parental self-efficacy (PSE), and parents' approaches to the provision of supportive socialization. It also investigated the bidirectionality between PSE, problem-focus socialization, and emotion-focus socialization across two time points separated by one year. Participants were 757 Hong Kong Chinese parents (47.4% fathers) of kindergarten children. At both time 1 and time 2, parents reported their PSE, problem-focus socialization, and emotion-focus socialization. Additionally, parents rated their child's negative affect at time 1. Results from the cross-lagged panel model revealed that, controlling for the effects of school's socioeconomic strata, child gender, parental age, and educational level, PSE at time 1 mediated the indirect links of child negative affect at time 1 with problem-focus (indirect effect: ß = -.02, SE = .02, p < .05) and emotion-focus (indirect effect: ß = -.02, SE = .01, p < .05) socialization at time 2 and that PSE (ß = .10, SE = .06, p < .01) and problem-focus socialization (ß = .15, SE = .03, p < .05) were reciprocally associated with each other. Findings underscored the role of PSE in understanding parental provision of supportive socialization and the co-development of belief about parenting and parenting behaviors.

The Prevalence, Directionality, and Dyadic Perpetration Types of Intimate Partner Violence in a Community Sample in Portugal: a Gender-Inclusive Inquiry.

Intimate partner violence (IPV) is a major concern across the world, and its prevalence assessment has been a priority in numerous countries. However, data about IPV prevalence in Portugal is scarce and not up-to-date. This study aims to estimate IPV prevalence in Portugal. A community sample of 1392 adults (77.4% female, mean age = 34.95 years, SD = 12.80) was collected through a web-based survey, between March and June of 2020. Participants completed a sociodemographic questionnaire and the Conflict Tactic Scales-2 (CTS-2). Accounting for all forms of IPV, a past-year prevalence of 64.4% and 64.6% were found, for victimization and perpetration, respectively. Regarding gender or sexual orientation, no significant differences were found in the past-year or the lifetime prevalence, neither concerning frequency. Directionality and dyadic concordance types were analyzed and showed that most violence was bidirectional. Having perpetrated violence in previous intimate relationships was the most influential factor when predicting past-year perpetration or victimization. Other significant predictors were age, being victimized before 15 years old, cohabitation with the intimate partner, and drug use, but the last two were only significant for victimization. Findings support the idea that IPV is a relevant phenomenon, regardless of gender and sexual orientation. It is the first nationwide, gender-inclusive study to do so in Portugal. Studies based on different samples might provide important evidence to prevent hasty conclusions about IPV prevalence and patterns and to guide empirically driven policies.

Characterization of the motility of monomeric kinesin-5/Cin8.

Cin8, the Saccharomyces cerevisiae kinesin-5, has an essential role in mitosis. In in vitro motility assays, tetrameric and dimeric Cin8 constructs showed bidirectional motility in response to ionic strength or Cin8 motor density. However, whether property-switching directionality is present in a monomeric form of Cin8 is unknown. Here we engineered monomeric Cin8 constructs with and without the Cin8-specific ∼99 residues in the loop 8 domain and examined the directionality of these constructs using an in vitro polarity-marked microtubule gliding assay within the range of the motor density or ionic strength. We found that both monomeric constructs showed only plus end-directed activity over the ranges measured, which suggested that minus end-directed motility driven by Cin8 is necessary for at least dimeric forms. Using an in vitro microtubule corkscrewing assay, we also found that monomeric Cin8 corkscrewed microtubules around their longitudinal axes with a constant left-handed pitch. Overall, our results imply that plus-end-directed and left-handed motor activity comprise the intrinsic properties of the Cin8 motor domain as with other monomeric N-kinesins.

Genetic factors underlying the bidirectional relationship between autoimmune and mental disorders - Findings from a Danish population-based study.

BACKGROUND: Previous studies have indicated the bidirectionality between autoimmune and mental disorders. However, genetic studies underpinning the co-occurrence of the two disorders have been lacking. In this study, we examined the potential genetic contribution to the association between autoimmune and mental disorders and investigated the genetic basis of overall autoimmune disease. METHODS: We used diagnostic information from patients with seven autoimmune diseases and six mental disorders from the Danish population-based case-cohort sample (iPSYCH2012). We explored the epidemiological association using survival analysis and modelled the effect of polygenic risk scores (PRSs) on autoimmune and mental diseases. Genetic factors were investigated using GWAS and imputed HLA alleles in the iPSYCH cohort. RESULTS: Of 64,039 individuals, a total of 43,902 (68.6%) were diagnosed with mental disorders and 1383 (2.2%) with autoimmune diseases. There was a significant comorbidity between the two disease classes (P = 2.67 × 10-7, OR = 1.38, 95%CI = 1.22-1.56), with an overall bidirectional association, wherein individuals with autoimmune diseases had an increased risk of subsequent mental disorders (HR = 1.13, 95%CI: 1.07-1.21, P = 7.95 × 10-5) and vice versa (HR = 1.27, 95%CI = 1.16-1.39, P = 8.77 × 10-15). Adding PRSs to these adjustment models did not have an impact on the associations. PRSs for autoimmune diseases were only slightly associated with increased risk of mental disorders (HR = 1.01, 95%CI: 1.00-1.02, p = 0.038), whereas PRSs for mental disorders were not associated with autoimmune diseases overall. Our GWAS highlighted 12 loci on chromosome 6 (minimum P = 2.74 × 10-36, OR = 1.80, 95% CI: 1.64-1.96), which were implicated in gene regulation through bioinformatic functional analyses, thereby identifying new candidate genes for overall autoimmune disease. Moreover, we observed 20 human leukocyte antigen (HLA) alleles strongly associated, either positively or negatively, with overall autoimmune disease, but we did not find significant evidence of their associations with overall mental disorders. A GWAS of a comorbid diagnosis of an autoimmune disease and a mental disorder identified a genome-wide significant locus on chromosome 7 as well (P = 1.43 × 10-8, OR = 10.65, 95%CI = 3.21-35.36). CONCLUSIONS: Our findings confirm the overall comorbidity and bidirectionality between autoimmune diseases and mental disorders and identify HLA genes which are significantly associated with overall autoimmune disease. Additionally, we identified several new candidate genes for overall autoimmune disease and ranked them based on their association with the investigated diseases.

Mathematics, executive functioning, and visual-spatial skills in Chinese kindergarten children: Examining the bidirectionality.

This study examined the bidirectional relationships among Chinese children's mathematics, executive functioning, and visual-spatial skills during their transition from kindergarten to primary school. Participants were 172 Cantonese-speaking Hong Kong children (mean age at Time 1 = 62.75 months; 88 male) and their parents. At Time 1 (kindergarten K3), children were administered the measures of mathematics (calculation and applied problems), executive functioning (working memory and inhibitory control), and visual-spatial skills. They were reassessed on these measures at Time 2 (primary 1) 1 year later. Results from the cross-lagged panel model showed that, controlling for child age, gender, and family socioeconomic status, children's visual-spatial skills at Time 1 were significantly predictive of their mathematics at Time 2 and children's executive functioning and visual-spatial skills reciprocally predicted each other across times. However, children's mathematics at Time 1 were not predictive of their executive functioning or visual-spatial skills at Time 2. The findings highlight the desirability of improving children's executive functioning and visual-spatial skills to promote their mathematical performance during the formal school transition.

Intra-individual associations between intentional self-regulation and prosocial behavior during adolescence: Evidence for bidirectionality.

INTRODUCTION: Couched in Positive Youth Development (PYD) theory and relevant empirical work, this study investigated bidirectional associations between intentional self-regulation and prosocial behavior toward strangers from age 12 to age 18. METHOD: Participants included 500 adolescents (52% female, 77% European American; age Time 1 = 12 years, Time 2 = 14 years, Time 3 = 16 years, Time 4 = 18 years) from the Northwestern United States. Adolescents self-reported on their intentional self-regulation and prosocial behavior toward strangers across four time points. A random-intercept cross-lagged panel model (RICLPM) was estimated in order to assess bidirectionality while avoiding conflating intra- and inter-individual variability. RESULTS: Results revealed intentional self-regulation and prosocial behavior toward strangers were bidirectionally related during early adolescence (i.e., from age 12 to 14). During mid-to-late adolescence (i.e. age 14 to 18), prosocial behavior toward strangers facilitated intentional selfregulation, whereas intentional self-regulation did not drive the development of prosocial behavior toward strangers. CONCLUSIONS: Findings indicate that early adolescence may be a particularly plastic developmental period in terms of PYD. Findings also suggest that investigations of relations between adolescents' personal assets and contribution factors merit further scholarly attention. Several directions for future research are presented.

Bidirectional motility of kinesin-5 motor proteins: structural determinants, cumulative functions and physiological roles.

Mitotic kinesin-5 bipolar motor proteins perform essential functions in mitotic spindle dynamics by crosslinking and sliding antiparallel microtubules (MTs) apart within the mitotic spindle. Two recent studies have indicated that single molecules of Cin8, the Saccharomyces cerevisiae kinesin-5 homolog, are minus end-directed when moving on single MTs, yet switch directionality under certain experimental conditions (Gerson-Gurwitz et al., EMBO J 30:4942-4954, 2011; Roostalu et al., Science 332:94-99, 2011). This finding was unexpected since the Cin8 catalytic motor domain is located at the N-terminus of the protein, and such kinesins have been previously thought to be exclusively plus end-directed. In addition, the essential intracellular functions of kinesin-5 motors in separating spindle poles during mitosis can only be accomplished by plus end-directed motility during antiparallel sliding of the spindle MTs. Thus, the mechanism and possible physiological role of the minus end-directed motility of kinesin-5 motors remain unclear. Experimental and theoretical studies from several laboratories in recent years have identified additional kinesin-5 motors that are bidirectional, revealed structural determinants that regulate directionality, examined the possible mechanisms involved and have proposed physiological roles for the minus end-directed motility of kinesin-5 motors. Here, we summarize our current understanding of the remarkable ability of certain kinesin-5 motors to switch directionality when moving along MTs.

Psychotic experiences and mood episodes predict each other bidirectionally: a 6-year follow-up study in a community-based population.

BACKGROUND: Psychotic experiences (PEs) are not exclusive to psychotic disorders and highly correlated with mood episodes. In this representative general population-based study, longitudinal bidirectional associations between the extended psychosis phenotype and mood episodes were investigated, accounting for other possible causes. METHODS: Households were contacted in a multistage clustered probability sampling frame covering 11 districts and 302 neighbourhoods at baseline (n = 4011) and at 6-year follow-up (n = 2185). Participants were interviewed with the relevant sections of the composite international diagnostic interview both at baseline and at follow-up. Sociodemographic, familial and environmental risk factors associated with the extended psychosis phenotype and mood episodes were assessed. Logistic regression and cross-lagged panel correlation models were used for the associations between the extended psychosis phenotype and mood episodes. RESULTS: PEs were associated with subsequent depressive and manic episodes. There was bidirectionality in that mood episodes were associated with subsequent PEs, and PEs were associated with subsequent mood episodes. The associations occurred in a sub-additive pattern. There were substantial synchronous and cross-lagged correlations between these psychopathology domains, with reciprocally similar cross-lagged correlations. Familial risk and adverse life events were associated with both psychopathology domains, whereas some sociodemographic risk factors and alcohol/cannabis use were associated with only one domain. CONCLUSION: The sub-additive bidirectional associations between PEs and mood episodes over time and the similarity of cross-lagged correlations are suggestive of mutually causal connections between affective and psychotic domains of psychopathology.

An approach to estimate bidirectional mediation effects with application to body mass index and fasting glucose.

Obesity and type 2 diabetes are major public health issues with known interdependence. Genetic variants have been associated with obesity, type 2 diabetes, or both; thus, we hypothesize that some single nucleotide polymorphisms (SNPs) associated with both conditions may be mediated through obesity to affect type 2 diabetes or vice versa. We propose a framework for bidirectional mediation analyses. Simulations show that this approach accurately estimates the parameters, whether the mediation is unidirectional or bidirectional. In many scenarios, when the mediator is regressed on the initial variable and the outcome is regressed on the mediator and the initial variable, the resulting residuals are correlated because of other unmeasured covariates not in the model. We show that the proposed model provides accurate estimates in this scenario, too. We applied the proposed approach to investigate the mediating effects of SNPs associated with type 2 diabetes and obesity using genetic data from the Multi-Ethnic Study of Atherosclerosis cohort. Specifically, we used body mass index (BMI) as a measure for obesity and fasting glucose as a measure for type 2 diabetes. We evaluated the top 6 SNPs associated with both BMI and fasting glucose. Two SNPs (rs3752355 and rs6087982) had indirect effects on BMI mediated through fasting glucose [0.2677; 95% confidence interval (CI) (0.0007, 0.6548) and 0.3301; 95% CI (0.0881, 0.8544), respectively]. The remaining four SNPs (rs7969190, rs4869710, rs10201400, and rs12421620) directly affect BMI and fasting glucose without mediating effects.

Orange Is Less Than Green: An Examination of Bidirectionality in Grapheme-Color Synesthesia.

Grapheme-color synesthetes experience a sense of color when viewing graphemes (e.g., digits and letters). Traditionally, these synesthetic perceptions are considered to be unidirectional, where viewing a grapheme elicits a nonveridical sensation of color, but viewing a color does not induce a reciprocal sense of a grapheme. A growing body of research has emerged that suggests the potential for bidirectional percepts, wherein color facilitates additional grapheme perception. We present here a novel paradigm in which we presented two sets of pure color patches, based on synesthete's reported colors, side-by-side and asked participants to indicate the color patch with the greater affiliated magnitude. Results indicated that the odds of answering correctly on trials were significantly greater for synesthetes (80.2% accuracy) than nonsynesthetes (52.1% accuracy). These results are aligned with other reports that support the notion of inducing a sense of magnitude from color in synesthetes. These findings challenge the traditional model of synesthesia as a unidirectional phenomenon and have implications of the neuronal communications that underlie perception in general.

Epilepsy is more than a simple seizure disorder: Causal relationships between epilepsy and its comorbidities.

This review draws connections between the pathogenesis of canine epilepsy and its most commonly recognised comorbidities: cognitive impairment (CI), attention deficit hyperactivity disorder (ADHD)-like behaviour, fear and anxiety. Uni/bidirectional causalities and the possibility of a common aetiology triggering both epilepsy and the associated diseases are considered. Research on this topic is sparse in dogs, so information has been gathered and assessed from human and laboratory animal studies. Anatomical structures, functional connections, disrupted neurotransmission and neuroinflammatory processes collectively serve as a common foundation for epilepsy and its comorbidities. Specific anatomical structures, especially parts of the limbic system, such as the amygdala and the hippocampus, are involved in generating seizures, as well as cognitive- and behavioural disorders. Furthermore, disturbances in inhibitory and excitatory neurotransmission influence neuronal excitability and networks, leading to underlying brain dysfunction. Functional magnetic resonance imaging (fMRI), interictal epileptiform discharges (IEDs), and electroencephalography (EEG) have demonstrated functional brain connections that are related to the emergence of both epilepsy and its various comorbidities. Neuroinflammatory processes can either cause or be a consequence of seizures, and inflammatory mediators, oxidative stress and mitochondrial dysfunction, can equally evoke mood disorders. The extensive relationships contributing to the development and progression of seizures and comorbid cognitive and behavioural conditions illustrate the complexity of the disease that is epilepsy.

Psychodynamic Psychiatry and the Care of Persons with Vision Loss and Blindness.

The authors describe the clinical relevance of the psychiatric concept of bidirectionality when caring for persons with comorbid disorders, and they propose a psychodynamic framework to guide the treatment of persons with vision loss and blindness. Since persons with vision loss have an increased risk of depressive and anxiety disorders, they recommend targeted screening, integrated services, and a biopsychosocial approach to clinical care. The psychoanalytic concept of aphanisis, first described by Ernest Jones and later developed by Lacan and Kohut, is briefly discussed. Common psychotherapy themes in the treatment of persons who experience vision loss from systemic illness include reactivation of memories of past traumas resulting in avoidance, social withdrawal, depressive states, catastrophic thinking, a sense of foreshortened future, anhedonia, and fear of disintegration and invisibility. Psychotherapy also serves to correct negative introjects from ableist societal attitudes.

Two plus blue equals green: grapheme-color synesthesia allows cognitive access to numerical information via color.

In grapheme-color synesthesia, graphemes (e.g., numbers or letters) evoke color experiences. It is generally reported that the opposite is not true: colors will not generate experiences of graphemes or their associated information. However, recent research has provided evidence that colors can implicitly elicit symbolic representations of associated graphemes. Here, we examine if these representations can be cognitively accessed. Using a mathematical verification task replacing graphemes with color patches, we find that synesthetes can verify such problems with colors as accurately as with graphemes. Doing so, however, takes time: ~250 ms per color. Moreover, we find minimal reaction time switch-costs for switching between computing with graphemes and colors. This demonstrates that given specific task demands, synesthetes can cognitively access numerical information elicited by physical colors, and they do so as accurately as with graphemes. We discuss these results in the context of possible cognitive strategies used to access the information.

Dyslipidemia Is a Risk Factor for Hypothyroidism in Women: A Longitudinal Cohort Study from South Korea.

Background: Hypothyroidism is a risk factor for dyslipidemia. We explored whether dyslipidemia is a risk factor for hypothyroidism. Methods: We performed a retrospective analysis of data from a longitudinal cohort study of South Korean adults who underwent medical examination and ≥4 biochemical assessments of thyroid function. The primary outcome was hypothyroidism (thyrotropin [TSH] >4.2 mU/L), and the secondary outcome was severe subclinical hypothyroidism (SCH; TSH ≥10.0 mU/L and normal free thyroxine [fT4] level) or overt hypothyroidism (OH; total triiodothyronine <80 ng/dL and/or fT4 < 0.93 ng/dL and high TSH values). The association of baseline dyslipidemia status with subsequent hypothyroidism was evaluated using Kaplan-Meier curves with the log-rank test and Cox proportional hazards regression models (for the entire population and respective genders). Subgroup analyses according to age (<40 and ≥40 years) and body-mass index (BMI; <23, 23-25, and ≥25 kg/m2) were performed according to gender. Results: We included 1665 participants. During a median follow-up period of 61.0 months, 24.3% (404/1665) individuals developed hypothyroidism. Among these, 36 participants (2.1%) had severe SCH or OH. Excluding patients with a first abnormal TSH level at last follow-up, 44.5% (126/283) of the patients with hypothyroidism had spontaneous TSH normalization. In respective multivariate analyses, dyslipidemia at baseline was independently associated with development of hypothyroidism in women (adjusted hazard ratio [HR] = 2.05 [1.31-3.19], p = 0.002), but not in men (adjusted HR = 1.00 [0.77-1.30], p = 0.991). In women, the presence of dyslipidemia at baseline was associated with development of severe SCH or OH (adjusted HR = 5.33 [1.41-20.12], p = 0.014). In women, respective associations according to age and BMI were as follows: age <40 years, adjusted HR = 2.90 (1.34-6.26, p = 0.007); age ≥40 years, adjusted HR = 1.85 (1.08-3.14, p = 0.023); BMI <23 kg/m2, adjusted HR = 1.68 (0.82-3.43, p = 0.151); BMI = 23-25 kg/m2, adjusted HR = 2.17 (0.93-5.07, p = 0.071); and BMI ≥25 kg/m2, adjusted HR = 2.82 (1.16-6.86, p = 0.022). Conclusions: In Korean adults, dyslipidemia was associated with development of hypothyroidism in women. Our findings require confirmation.

Children's Influence on Parents: the Bidirectional Relationship in Family Meal Selection.

Feeding a child in the 21st century can be challenging. A child's diet is thought to be a parent's responsibility, and numerous studies have explored how parents influence their child's food intake through food availability, feeding practices, and modeling. However, this relationship is likely bidirectional such that the child influences the parent as well (sometimes called "pester power"). Pester power has been studied in grocery stores and restaurants. However, no research to date investigates how children influence parent's food selection when eating at home. This study addresses this gap by asking parent and child dyads (N = 79, 95% white) to create meals together and separately. Forty 6-8 and thirty-nine 13-15 year-olds participated. Most of the parents (97.5%) and children (49.4%) who participated were female; and parents reported an average annual income of over 80,000 dollars (68.3%). Mean differences in the nutrient content of the meals were analyzed using repeated measures ANOVAs to examine the strength of influence in the bidirectional relationship. Results suggested when children were present for meal selection, they exerted influence over their parents for more palatable items. When choosing foods as a dyad versus when the parent selected meals for the family, the foods contained more calories, sugar, and less fiber. Protein was the only nutrient that parents influenced in their child's selections. These findings have important implications for understanding the often-overlooked bidirectional dynamic of the feeding relationship, and the accompanying health outcomes of child dietary intake.

The bidirectional relationship between sleep and externalizing behavior: A systematic review.

It is well-established that sleep and behavior are interrelated. Although studies have investigated this association, not many have evaluated the bidirectional relationship between the two. To our knowledge this is the first systematic review providing a comprehensive analysis of a reciprocal relationship between sleep and externalizing behavior. Five databases (PsycINFO, PubMed, Web of Science, Scopus, and Google Scholar) were utilized to yield a total of 3,762 studies of which 20 eligible studies, empirical articles examining bidirectionality of sleep and externalizing behavior, were selected for analysis. According to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis, the varying methodological approaches used in these studies were analyzed and synthesized, including examining differences and similarities in outcomes between distinct study designs (longitudinal vs cross-sectional), sleep measures (objective vs subjective vs a combination of both), informants (parents, self-report, teachers), and recruited participants (clinical, subclinical and typical populations). The assessment of risk of bias and quality of studies was guided by the instruments employed in research on sleep and behavior in the past. This review establishes that a bidirectional relationship between sleep problems and externalizing behavior clearly exists, and identifies limitations in the existing literature. Furthermore, the importance of early interventions that target both externalizing behaviors and sleep problems is highlighted as a potentially effective way of breaking the sleep-externalizing behavior relationship. Nonetheless, causality cannot be claimed until more trials that manipulate sleep and evaluate changes in externalizing behavior are conducted.