EEG asymmetry, power, and temperament in children

Examining the impact of prenatal maternal internalizing symptoms and socioeconomic status on children's frontal alpha asymmetry and psychopathology

Prenatal maternal internalizing psychopathology (depression and anxiety) and socioeconomic status (SES) have been independently associated with higher risk for internalizing and externalizing problems in children. However, the pathways behind these associations are not well understood. Numerous studies have linked greater right frontal alpha asymmetry to internalizing problems; however, findings have been mixed. Several studies have also linked maternal internalizing psychopathology to children's frontal alpha asymmetry. Additionally, emerging studies have linked SES to children's frontal alpha asymmetry. To date, only a limited number of studies have examined these associations within a longitudinal design, and the majority have utilized relatively small samples. The current preregistered study utilizes data from a large prospective study of young children (N = 415; Meanage  = 7.27 years; Rangeage  = 5-11 years) to examine the association between prenatal maternal internalizing symptoms, children's frontal alpha asymmetry, and behavior problems. Prenatal maternal internalizing symptoms did not predict children's frontal alpha asymmetry, and there was no association between frontal alpha asymmetry and behavior problems. However, mothers' internalizing symptoms during pregnancy predicted children's internalizing and externalizing outcomes. Non-preregistered analyses showed that lower prenatal maternal SES predicted greater child right frontal alpha asymmetry and internalizing problems. Additional non-preregistered analyses did not find evidence for frontal alpha asymmetry as a moderator of the relation between prenatal maternal internalizing psychopathology and SES to children's behavior problems. Future research should examine the impact of SES on children's frontal alpha asymmetry in high-risk samples.

Behavioral and neural measures of infant responsivity increase with maternal multisensory input in non-irritable infants

INTRODUCTION

Parents often use sensory stimulation during early-life interactions with infants. These interactions, including gazing, rocking, or singing, scaffold child development. Previous studies have examined infant neural processing during highly controlled sensory stimulus presentation paradigms.

OBJECTIVE

In this study, we investigated infant behavioral and neural responsiveness during a mother-child social interaction during which the mother provided infant stimulation with a progressive increase in the number of sensory modalities.

METHODS

We prospectively collected and analyzed video-coded behavioral interactions and electroencephalogram (EEG) frontal asymmetry (FAS) from infants (n = 60) at 2-4 months born at ≥ 34 weeks gestation. As the number of sensory modalities progressively increased during the interaction, infant behaviors of emotional connection in facial expressiveness, sensitivity to mother, and vocal communication increased significantly. Conversely, infant FAS for the entire cohort did not change significantly. However, when we accounted for infant irritability, both video-coded behaviors and EEG FAS markers of infant responsiveness increased across the interaction in the non-irritable infants. The non-irritable infants (49%) demonstrated positive FAS, indicating readiness to engage with, rather than to withdraw from, multisensory but not unisensory interactions with their mothers.

RESULTS

These results suggest that multisensory input from mothers is associated with greater infant neural approach state and highlight the importance of infant behavioral state during neural measures of infant responsiveness.

Getting Better with Age? A Review of Psychophysiological Studies of Fear Extinction Learning Across Development

A critical developmental task is learning what constitutes reliable threat and safety signals in the environment. In humans, atypical fear learning processes are implicated in many mental health conditions, particularly fear and anxiety disorders, pointing to the potential for laboratory measures of fear learning to facilitate early identification of at-risk individuals. This chapter reviews studies of fear learning and extinction learning that incorporate peripheral measures of psychophysiological response and include a developmental sample. Broadly, these studies indicate substantial consistency in differential learning and extinction across development, as assessed with multiple paradigms, across physiological indices. Importantly, though, response coherence across measures (e.g., physiological, neural, and behavioral) was inconsistent across studies. There was also less consistency in results from studies that probed associations between anxiety and fear learning processes. These mixed findings highlight the need for additional examination of when and why there is variability, both across development and in relation to individual differences factors, including mental health, childhood adversity, and sex. In addition, there remains a need for studies that test for developmental change in extinction recall learning and whether stimulus type impacts learning across development. Longitudinal studies designed to address these questions could provide novel insight into the developmental trajectory of fear learning and extinction.

Innovative methods for remote assessment of neurobehavioral development

In response to the COVID-19 pandemic, research institutions across the globe have modified their operations in ways that have limited or eliminated the amount of permissible in-person research interaction. In order to prevent the loss of important developmentally-timed data during the pandemic, researchers have quickly pivoted and developed innovative methods for remote assessment of research participants. In this manuscript, we describe methods developed for remote assessment of a parent child cohort with a focus on examining the perinatal environment, behavioral and biological indicators of child neurobehavioral development, parent-child interaction, as well as parent and child mental and physical health. We include recommendations relevant to adapting in-laboratory assessments for remote data collection and conclude with a description of the successful dissemination of the methods to eight research sites across the United States, each of whom are involved in Phase 1 of the HEALthy Brain and Child Development (HBCD) Study. These remote methods were born out of pandemic-related necessity; however, they have much wider applicability and may offer advantages over in-laboratory neurodevelopmental assessments.

The Late Positive Potential as a Reliable Neural Marker of Cognitive Reappraisal in Children and Youth: A Brief Review of the Research Literature

The mental health of young people is a growing public health concern. With socio-emotional difficulties in youth often resulting in psychiatric disorders later in life and most with mental health conditions rather stabilizing in time, it is essential to support healthy socio-emotional development. With a comprehensive definition of mental health, since emotion regulation (ER) plays a critical role in prevention, it becomes imperative to better understand how children effectively manage their emotions from an early age. Determining effective use of ER skills relies on adequate measurements. Typical methods of data collection in children present consistent shortcomings. This review addresses research findings considering the suitability of the late positive potential measured through electroencephalogram as a neural indicator of ER in children and youth. There is growing evidence, as reported in this review, that indicates that the late positive potential may be a reliable neural indicator of children's cognitive reappraisal abilities more specifically. Results generally suggest that the late positive potential amplitudes are sensitive to directed reappraisal in children. However, given the scant research, questions remain regarding developmental trends, methodology, interindividual variability, reappraisal of various stimuli, and how the late positive potential may relate to more traditional measures of ER. Directions for future research are provided, which are expected to address unanswered research questions and fill literature gaps. Taken together, the findings reviewed indicate that the late positive potential is generally sensitive to directed cognitive reappraisal in children and that there is promise of establishing this neural marker as an indicator of ER.

Temperament and the Impact of Stuttering in Children Aged 8-14 Years

Purpose The goal of this study was to evaluate possible associations between child- and mother-reported temperament, stuttering severity, and child-reported impact of stuttering in school-age children who stutter. Method Participants were 123 children who stutter (94 boys and 29 girls) who were between 9;0 and 14;10 (years;months) and their mothers. Temperament was assessed with the revised child and parent version of the Early Adolescent Temperament Questionnaire-Revised (Ellis & Rothbart, 2001). The Overall Assessment of the Speaker's Experience of Stuttering (Yaruss & Quesal, 2006) was used to evaluate the stuttering impact. Results Child- and mother-reported Early Adolescent Temperament Questionnaire-Revised temperament factors correlated moderately. No statistically significant associations were found between temperament and stuttering severity. The temperament factors of Surgency (both child- and mother-reported) and Negative Affect (only child-reported) correlated moderately with the Overall Impact and several subsections (i.e., Speaker's Reactions, Daily Communication, and/or Quality of Life) of the Overall Assessment of the Speaker's Experience of Stuttering. Conclusions More extraverted and less fearful/shy children experience a lower overall impact of their stuttering. Children with higher levels of irritability and frustration experience a higher overall impact of their stuttering. Since children's ratings of temperament were more sensitive to these associations than mothers, this study supports the inclusion of child-reported temperament questionnaires in future research.

A longitudinal study investigating trajectories of sensitivity to threat over time and their association with alpha asymmetry among children and adolescents

Research has yet to investigate trajectories of sensitivity to threat across childhood and adolescence. Further, neural associations of these trajectories remain unknown. The current 3-year study used a latent class growth curve analysis to investigate whether there were distinct trajectories of sensitivity to threat among children and adolescents over time (N = 363; age range at Time 1 = 8-14). We also examined whether alpha asymmetry (a neural index of motivational tendencies) was associated with the different trajectories. Results revealed three distinct trajectory groups (1) high-stable sensitivity to threat, (2) moderate-increasing sensitivity to threat and (3) low-stable sensitivity to threat. The high-stable sensitivity to threat group had greater right frontal asymmetry activation (i.e., greater neural avoidance motivation) than the other two groups. Additionally, females, those with higher parental education, and individuals with more advanced pubertal development (but not age) had greater odds of being part of the high-stable sensitivity to threat group compared to the other groups. Of interest, puberty rather than age may be an important indicator of heightened sensitivity to threat.

Frontal Brain Asymmetry and the Trajectory of Shyness Across the Early School Years

Although resting right frontal electroencephalogram (EEG) asymmetry has been linked to avoidance and withdrawal-related behaviors such as shyness in previous cross-sectional studies, relatively little research has examined the influence of frontal brain electrical activity on the development of shyness in children using a prospective, longitudinal study design. Here, we tested whether resting frontal EEG asymmetry predicted the trajectory of children's shyness across five assessments. Children were enrolled in the study during the summer prior to grade 1 (N = 37; M_age = 6.39 years, S.D. = 0.15 years), at which time resting frontal EEG activity and maternal report of children's shyness were collected. Mothers then reported on their child's shyness over another four follow-up assessments, spanning 2 years (winter of grade 1, summer prior to grade 2 entry, winter of grade 2, and summer prior to grade 3). Growth curve analysis revealed that children displaying greater relative right frontal EEG activity had lower levels of shyness relative to children exhibiting greater relative left frontal EEG activity at study enrollment (i.e., age 6), but displayed statistically significant linear increases in shyness across time, with the highest levels of shyness by the summer prior to grade 3 (i.e., age 8). There was, however, no relation between left frontal EEG asymmetry and change in shyness across time. These preliminary findings suggest that right frontal EEG asymmetry may reflect a biological diathesis for the growth of shyness during the early school years.

Positive Shyness in the Brain: Frontal Electroencephalogram Alpha Asymmetry and Delta-Beta Correlation in Children

Positive shyness is thought to be an approach-dominant form of shyness, whereas non-positive shyness is thought to be an avoidance-dominant form of shyness. This study examined electrocortical and behavioral correlates of motivation and emotion in relation to these shy subtypes in 67 children (M_age  = 10.41 years, SD = 3.23). Using resting state electroencephalography, findings revealed that positive shy and low shy children had greater relative left frontal alpha asymmetry compared to non-positive shy children, and positive shy children had a higher frontal delta-beta correlation compared to other groups. Non-positive shy children scored highest on parent-reported school avoidance. These findings converge with previous work reporting distinct correlates in positive and non-positive shyness, extending this to two brain measures of motivation and emotion.

Psychophysiological influences on personality trajectories in adolescent females exposed to child maltreatment

Although child maltreatment is a major public health concern, which adversely affects psychological and physical development, we know relatively little concerning psychophysiological and personality factors that may modify risk in children exposed to maltreatment. Using a three-wave, short-term prospective design, we examined the influence of individual differences in two disparate psychophysiological measures of risk (i.e., resting frontal brain electrical activity and respiratory sinus arrhythmia) on the trajectories of extraversion and neuroticism in a sample of female adolescents (N = 55; M age = 14.02 years) exposed to child maltreatment. Adolescents exposed to child maltreatment with relatively higher left frontal absolute alpha power (i.e., lower brain activity) at rest exhibited increasing trajectories of extraversion, and adolescents exposed to child maltreatment with relatively lower respiratory sinus arrhythmia at rest displayed increasing trajectories of neuroticism over 1 year. Individual differences in psychophysiological measures indexing resting central and peripheral nervous system activity may therefore differentially influence personality characteristics in adolescent females exposed to child maltreatment.

Frontal alpha asymmetry moderates the relations between behavioral inhibition and social-effect ERN

Behavioral inhibition (BI) is an early temperamental precursor of anxiety disorders, characterized by withdrawal from novel situations. Some but not all young children with BI go on to display anxiety disorders. Neural correlates, such as frontal alpha asymmetry or event-related negativity (ERN), could moderate the relations between early BI and later anxiety. The goal of this longitudinal study was to test frontal alpha asymmetry as a potential moderator of the relation between BI and later anxiety, and of the relation between BI and the social-effect ERN. 100 children were assessed for BI at ages 2 and 3, and we collected EEG during resting state and the social Flanker task at age 12. Frontal alpha asymmetry did not correlate with BI or anxiety, nor did it moderate the relation between early BI and later anxiety. However, frontal alpha asymmetry did moderate the relation between BI and the social-effect ERN. This suggests that, in adolescents who previously manifested BI, a pattern of resting EEG associated with avoidance predicts hypersensitivity to errors in a social context.

Recruitment of orbitofrontal cortex during unpredictable threat among adults at risk for affective disorders

BACKGROUND

Mood and anxiety disorders are characterized by altered prefrontal-amygdala function and increased behavioral inhibition (BI) in response to potential threat. Whether these alterations constitute a vulnerability or a symptom of illness remains unclear. The medial orbitofrontal cortex (mOFC) is thought to play a central role in estimating probability and cost of threat, in turn informing selection of subsequent behaviors. To better understand the behavioral and neural processes that may be associated with risk for psychopathology, we used a virtual reality paradigm to examine behavioral and neural responses of psychiatrically healthy adults with familial history of affective disorders during anticipation of unpredictable threat.

METHODS

Twenty psychiatrically healthy adults with high familial risk for affective disorders and 20 low-risk matched controls underwent functional magnetic resonance imaging concurrent with a paradigm in which they explored virtual contexts associated with the threat of shock or safety from shock. Subjective anxiety ratings, skin conductance, exploratory behavior, and neural responses were examined for threat versus safe conditions.

RESULTS

High-risk adults evidenced greater right mOFC activation, as well as greater BI, compared to low-risk adults. There were no significant group differences in subjective ratings or autonomic responses. Individuals exhibiting greater activity in the right mOFC showed greater BI and decreased skin conductance response.

CONCLUSIONS

These results suggest that BI and mOFC recruitment during anticipation of aversive outcomes may reflect a vulnerability for affective disorders. However, such a response may also serve as a compensatory response, protecting these high-risk individuals from negative outcomes (i.e., increased physiological arousal). These results suggest that the OFC may play a central role in driving threat-related behaviors and thus may be a target for efforts aimed at early detection or prevention.

Frontal Electroencephalogram Asymmetry and Temperament Across Infancy and Early Childhood: An Exploration of Stability and Bidirectional Relations

The stability of frontal electroencephalogram (EEG) asymmetry, temperamental activity level and fear, as well as bidirectional relations between asymmetry and temperament across the first 4 years of life, were examined in a sample of 183 children. Children participated in annual laboratory visits through 48 months, providing EEG and maternal report of temperament. EEG asymmetry showed moderate stability between 10 and 24 months. Analyses revealed that more left asymmetry predicted later activity level across the first 3 years. Conversely, asymmetry did not predict fear. Rather, fear at 36 months predicted more right asymmetry at 48 months. Results highlight the need for additional longitudinal research of infants and children to increase understanding of bidirectional relations between EEG and temperament in typically developing populations.

Parental Perceptions of Aggressive Behavior in Preschoolers: Inhibitory Control Moderates the Association With Negative Emotionality

Inhibitory control (IC) and negative emotionality (NE) are both linked to aggressive behavior, but their interplay has not yet been clarified. This study examines different NE × IC interaction models in relation to aggressive behavior in 855 preschoolers (aged 2-5 years) using parental questionnaires. Hierarchical regression analyses revealed that NE and IC predict aggression both directly and interactively. The highest aggression levels were reported in children with high NE and low IC. Interestingly, the protective effect of IC for aggressive behavior increases with rising levels of NE. Analyses focusing on physical aggression revealed a significant NE × IC interaction in boys aged 4-5 years only. These findings shed new light on potential compensatory mechanisms for aggressive behavior in developing children.

Maternal negative affect during infancy is linked to disrupted patterns of diurnal cortisol and alpha asymmetry across contexts during childhood

Maternal negative affect in the early environment is believed to sensitize long-term coping capacities in children. Yet, little work has identified physiological systems associated with coping responses, which may serve as mechanisms for links between early maternal negativity and child outcomes. Using a longitudinal twin sample (N=89), we found that high levels of maternal negative affect during infancy were associated with dysregulation of diurnal cortisol and electroencephalograph (EEG) asymmetry, two physiological systems that may support active approach-oriented coping when children are 7years old. Flattened slopes of diurnal cortisol were also associated with greater numbers of concurrent overanxious behaviors in children. A mediation analysis supported the role of dysregulated diurnal cortisol as a mediator of the link between maternal negative affect in the early environment and childhood risk for anxiety problems.

Anxiety-like behavior in Rett syndrome: characteristics and assessment by anxiety scales

Background

Rett syndrome (RTT) is a severe neurodevelopmental disorder characterized by regression of language and motor skills, cognitive impairment, and frequent seizures. Although the diagnostic criteria focus on communication, motor impairments, and hand stereotypies, behavioral abnormalities are a prevalent and disabling component of the RTT phenotype. Among these problematic behaviors, anxiety is a prominent symptom. While the introduction of the Rett Syndrome Behavioral Questionnaire (RSBQ) represented a major advancement in the field, no systematic characterization of anxious behavior using the RSBQ or other standardized measures has been reported.

Methods

This study examined the profiles of anxious behavior in a sample of 74 girls with RTT, with a focus on identifying the instrument with the best psychometric properties in this population. The parent-rated RSBQ, Anxiety, Depression, and Mood Scale (ADAMS), and Aberrant Behavior Checklist-Community (ABC-C), two instruments previously employed in children with neurodevelopmental disorders, were analyzed in terms of score profiles, relationship with age and clinical severity, reliability, concurrent validity, and functional implications. The latter were determined by regression analyses with the Vineland Adaptive Behavior Scales-Second Edition (Vineland-II) and the Child Health Questionnaire (CHQ), a quality of life measure validated in RTT.

Results

We found that scores on anxiety subscales were intermediate in range with respect to other behavioral constructs measured by the RSBQ, ADAMS, and ABC-C. Age did not affect scores, and severity of general anxiety was inversely correlated with clinical severity. We demonstrated that the internal consistency of the anxiety-related subscales were among the highest. Test-retest and intra-rater reliability was superior for the ADAMS subscales. Convergent and discriminant validity were measured by inter-scale correlations, which showed the best profile for the social anxiety subscales. Of these, only the ADAMS Social Avoidance showed correlation with quality of life.

Conclusions

We conclude that anxiety-like behavior is a prominent component of RTT’s behavioral phenotype, which affects predominantly children with less severe neurologic impairment and has functional consequences. Based on available data on standardized instruments, the ADAMS and in particular its Social Avoidance subscale has the best psychometric properties and functional correlates that make it suitable for clinical and research applications.

Neurophysiological evidence of an association between cognitive control and defensive reactivity processes in young children

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ERN, Pe, startle reflex, and parietal asymmetry were measured in young children.

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Reduced ERN was related to a larger startle and greater right parietal activity.

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Age predicted smaller startle, larger ERN, and better behavioral performance.

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Age did not moderate the association between ERN and startle.

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Age did not moderate the association between ERN and parietal asymmetry.

Interactions between cognitive control and affective processes, such as defensive reactivity, are intimately involved in healthy and unhealthy human development. However, cognitive control and defensive reactivity processes are often studied in isolation and rarely examined in early childhood. To address these gaps, we examined the relationships between multiple neurophysiological measures of cognitive control and defensive reactivity in young children. Specifically, we assessed two event-related potentials thought to index cognitive control processes – the error-related negativity (ERN) and error positivity (Pe) – measured across two tasks, and two markers of defensive reactivity processes – startle reflex and resting parietal asymmetry – in a sample of 3- to 7-year old children. Results revealed that measures of cognitive control and defensive reactivity were related such that evidence of poor cognitive control (smaller ERN) was associated with high defensive reactivity (larger startle and greater right relative to left parietal activity). The strength of associations between the ERN and measures of defensive reactivity did not vary by age, providing evidence that poor cognitive control relates to greater defensive reactivity across early childhood years.

The nature of individual differences in inhibited temperament and risk for psychiatric disease: A review and meta-analysis

What makes us different from one another? Why does one person jump out of airplanes for fun while another prefers to stay home and read? Why are some babies born with a predisposition to become anxious? Questions about individual differences in temperament have engaged the minds of scientists, psychologists, and philosophers for centuries. Recent technological advances in neuroimaging and genetics provide an unprecedented opportunity to answer these questions. Here we review the literature on the neurobiology of one of the most basic individual differences-the tendency to approach or avoid novelty. This trait, called inhibited temperament, is innate, heritable, and observed across species. Importantly, inhibited temperament also confers risk for psychiatric disease. Here, we provide a comprehensive review of inhibited temperament, including neuroimaging and genetic studies in human and non-human primates. We conducted a meta-analysis of neuroimaging findings in inhibited humans that points to alterations in a fronto-limbic-basal ganglia circuit; these findings provide the basis of a model of inhibited temperament neurocircuitry. Lesion and neuroimaging studies in non-human primate models of inhibited temperament highlight roles for the amygdala, hippocampus, orbitofrontal cortex, and dorsal prefrontal cortex. Genetic studies highlight a role for genes that regulate neurotransmitter function, such as the serotonin transporter polymorphisms (5-HTTLPR), as well as genes that regulate stress response, such as corticotropin-releasing hormone (CRH). Together these studies provide a foundation of knowledge about the genetic and neural substrates of this most basic of temperament traits. Future studies using novel imaging methods and genetic approaches promise to expand upon these biological bases of inhibited temperament and inform our understanding of risk for psychiatric disease.

The potential of infant fMRI research and the study of early life stress as a promising exemplar

Functional magnetic resonance imaging (fMRI) research with infants and toddlers has increased rapidly over the past decade, and provided a unique window into early brain development. In the current report, we review the state of the literature, which has established the feasibility and utility of task-based fMRI and resting state functional connectivity MRI (rs-fcMRI) during early periods of brain maturation. These methodologies have been successfully applied beginning in the neonatal period to increase understanding of how the brain both responds to environmental stimuli, and becomes organized into large-scale functional systems that support complex behaviors. We discuss the methodological challenges posed by this promising area of research. We also highlight that despite these challenges, early work indicates a strong potential for these methods to influence multiple research domains. As an example, we focus on the study of early life stress and its influence on brain development and mental health outcomes. We illustrate the promise of these methodologies for building on, and making important contributions to, the existing literature in this field.

Behavioral inhibition and developmental risk: a dual-processing perspective

Behavioral inhibition (BI) is an early-appearing temperament characterized by strong reactions to novelty. BI shows a good deal of stability over childhood and significantly increases the risk for later diagnosis of social anxiety disorder (SAD). Despite these general patterns, many children with high BI do not go on to develop clinical, or even subclinical, anxiety problems. Therefore, understanding the cognitive and neural bases of individual differences in developmental risk and resilience is of great importance. The present review is focused on the relation of BI to two types of information processing: automatic (novelty detection, attention biases to threat, and incentive processing) and controlled (attention shifting and inhibitory control). We propose three hypothetical models (Top-Down Model of Control; Risk Potentiation Model of Control; and Overgeneralized Control Model) linking these processes to variability in developmental outcomes for BI children. We argue that early BI is associated with an early bias to quickly and preferentially process information associated with motivationally salient cues. When this bias is strong and stable across development, the risk for SAD is increased. Later in development, children with a history of BI tend to display normative levels of performance on controlled attention tasks, but they demonstrate exaggerated neural responses in order to do so, which may further potentiate risk for anxiety-related problems. We conclude by discussing the reviewed studies with reference to the hypothetical models and make suggestions regarding future research and implications for treatment.

Resting frontal EEG asymmetry in children: meta-analyses of the effects of psychosocial risk factors and associations with internalizing and externalizing behavior

Asymmetry of frontal cortical electroencephalogram (EEG) activity in children is influenced by the social environment and considered a marker of vulnerability to emotional and behavioral problems. To determine the reliability of these associations, we used meta-analysis to test whether variation in resting frontal EEG asymmetry is consistently associated with (a) having experienced psychosocial risk (e.g., parental depression or maltreatment) and (b) internalizing and externalizing behavior outcomes in children ranging from newborns to adolescents. Three meta-analyses including 38 studies (N = 2,523) and 50 pertinent effect sizes were carried out. The studies included in the analyses reported associations between frontal EEG asymmetry and psychosocial risk (k = 20; predominantly studies with maternal depression as the risk factor) as well as internalizing (k = 20) and externalizing (k = 10) behavior outcomes. Psychosocial risk was significantly associated with greater relative right frontal asymmetry, with an effect size of d = .36 (p < .01), the effects being stronger in girls. A non-significant relation was observed between right frontal asymmetry and internalizing symptoms (d = .19, p = .08), whereas no association between left frontal asymmetry and externalizing symptoms was observed (d = .04, p = .79). Greater relative right frontal asymmetry appears to be a fairly consistent marker of the presence of familial stressors in children but the power of frontal asymmetry to directly predict emotional and behavioral problems is modest.

Safety, pharmacokinetics, and preliminary assessment of efficacy of mecasermin (recombinant human IGF-1) for the treatment of Rett syndrome

Rett syndrome (RTT) is a severe X-linked neurodevelopmental disorder mainly affecting females and is associated with mutations in MECP2, the gene encoding methyl CpG-binding protein 2. Mouse models suggest that recombinant human insulin-like growth factor 1 (IGF-1) (rhIGF1) (mecasermin) may improve many clinical features. We evaluated the safety, tolerability, and pharmacokinetic profiles of IGF-1 in 12 girls with MECP2 mutations (9 with RTT). In addition, we performed a preliminary assessment of efficacy using automated cardiorespiratory measures, EEG, a set of RTT-oriented clinical assessments, and two standardized behavioral questionnaires. This phase 1 trial included a 4-wk multiple ascending dose (MAD) (40-120 μg/kg twice daily) period and a 20-wk open-label extension (OLE) at the maximum dose. Twelve subjects completed the MAD and 10 the entire study, without evidence of hypoglycemia or serious adverse events. Mecasermin reached the CNS compartment as evidenced by the increase in cerebrospinal fluid IGF-1 levels at the end of the MAD. The drug followed nonlinear kinetics, with greater distribution in the peripheral compartment. Cardiorespiratory measures showed that apnea improved during the OLE. Some neurobehavioral parameters, specifically measures of anxiety and mood also improved during the OLE. These improvements in mood and anxiety scores were supported by reversal of right frontal alpha band asymmetry on EEG, an index of anxiety and depression. Our data indicate that IGF-1 is safe and well tolerated in girls with RTT and, as demonstrated in preclinical studies, ameliorates certain breathing and behavioral abnormalities.

Psychometric properties of the Behavioral Inhibition Questionnaire in preschool children

We examined the psychometric properties of the Behavioral Inhibition Questionnaire (BIQ; Bishop, Spence, & McDonald, 2003), a rating scale for children's behavioral inhibition. Parent and teacher ratings, parent interviews, and laboratory observations were obtained for 495 preschoolers. Confirmatory factor analysis yielded 6 factors, each reflecting the BIQ's subscales, and all loading onto a second-order general dimension. Model fit was acceptable for parent ratings, but only marginal for teacher ratings. The convergent and discriminant validity of the BIQ was examined by using a multitrait-multimethod approach. Results indicate that the BIQ displays evidence of reliability and validity that can complement observational paradigms.

Inhibition and exuberance in preschool classrooms: associations with peer social experiences and changes in cortisol across the preschool year

Associations between behavioral inhibition and activity of the hypothalamic-pituitary-adrenocortical (HPA) system, a stress-sensitive neuroendocrine system indexed by salivary cortisol, have varied widely across studies. In the current study, we examined the role of peer social experiences in moderating patterns of association between inhibition/risk-aversion and cortisol reactivity. As expected based on previous research, preschool children (N = 165, 78 boys, 87 girls, 3.0-5.0 years) had significantly different social experiences in their preschool classrooms depending on temperament. Highly inhibited/risk-averse children were less socially integrated, less dominant, and less involved in aggressive encounters than both average and highly exuberant/risk-seeking children, but they were no more likely to be peer rejected. Highly exuberant children were more dominant, exhibited anger more often, and had friendships characterized by higher conflict. Cortisol levels fell from fall to spring for average and highly exuberant children but not for highly inhibited children. Unexpectedly, for highly inhibited children, having friends and being more dominant and popular than other highly inhibited children was associated with increasing cortisol levels over the school year. In contrast, highly exuberant children who were less socially integrated than other highly exuberant children maintained higher cortisol levels. Results indicate that the types of social experiences that affect stress-responsive biological systems may differ markedly for highly inhibited and highly exuberant children.

Do positive and negative temperament traits interact in predicting risk for depression? A resting EEG study of 329 preschoolers

Researchers have long been interested in whether particular temperamental traits in childhood connote risk for depressive disorders. For example, children characterized as having high negative emotionality (NE; sadness, fear, anger) and low positive emotionality (PE; anhedonia, listlessness, and lack of enthusiasm) are hypothesized to be at risk for depression. Few studies, however, have examined whether (and how) these two temperamental dimensions interact to confer risk. In a sample of 329 preschoolers, the present study addressed this question by examining the relation between PE and NE and asymmetry in resting EEG activity in frontal and posterior regions, which are putative biomarkers for depression. Using a laboratory battery to define temperament, we found an interaction of PE and NE on posterior asymmetry. Specifically, when PE was high, NE was associated with greater relative right activity. When PE was low, NE was not related to posterior asymmetry. These results were driven by differences in EEG activity in right posterior regions, an area associated with emotional processing and arousal, and were specific to girls. We found no relation between temperament and frontal asymmetry. These findings suggest that, at least for girls, PE and NE may have an interactive effect on risk for depression.

Emotional reactivity, regulation and childhood stuttering: a behavioral and electrophysiological study

The purpose of this preliminary study was to assess whether behavioral and psychophysiological correlates of emotional reactivity and regulation are associated with developmental stuttering, as well as determine the feasibility of these methods in preschool-age children. Nine preschool-age children who stutter (CWS) and nine preschool-age children who do not stutter (CWNS) listened to brief background conversations conveying happy, neutral, and angry emotions (a resolution conversation followed the angry conversation), then produced narratives based on a text-free storybook. Electroencephalograms (EEG) recorded during listening examined cortical correlates of emotional reactivity and regulation. Speech disfluencies and observed emotion regulation were measured during a narrative immediately after each background conversation. Results indicated that decreased use of regulatory strategies is related to more stuttering in children who stutter. However, no significant differences were found in EEG measurements of emotional reactivity and regulation between CWS and CWNS or between emotion elicitation conditions. Findings were taken to suggest that use of regulatory strategies may relate to the fluency of preschool-age children's speech-language output.

LEARNING OUTCOMES

The reader will be able to (1) describe emotional reactivity and regulation processes, (2) discuss evidence for or against the relations of emotional reactivity, regulation and stuttering, (3) understand how multiple measures can be used to measure emotional reactivity and regulation.

Temperament dimensions in stuttering and typically developing children

PURPOSE

The purpose of this study was to determine whether children who stutter (CWS) and typically developing children (TDC) differ from each other on composite temperament factors or on individual temperament scales.

METHODS

Participants consisted of 116 age and gender-matched CWS and TDC (3.04-8.11). Temperament was assessed with a Dutch version of the Children's Behavior Questionnaire (CBQ-D; Van den Bergh and Ackx, 2003), a caregiver rating scale.

RESULTS

Results indicated significant differences between participant groups on the composite temperament factors of Negative Affectivity, and Effortful Control. Analysis of the individual temperament scales showed that CWS, compared to the TDC, scored significantly lower on the scales of 'Inhibitory Control' and 'Attentional Shifting' and higher on the scales of 'Anger/Frustration', 'Approach' and 'Motor Activation'. Stuttering severity and months of therapy were not associated with either of the temperament dimensions.

CONCLUSIONS

The present study provides data that support the hypothesis that CWS and TDC differ on both composite temperament factors and temperament scales. The findings were interpreted within existing frameworks of temperament development, as well as with regard to previous studies of temperament in CWS.

EDUCATIONAL OBJECTIVES

After reading this article, the reader will be able to: (1) describe the concept of temperament, including Rothbart's temperamental model, and its functional significance; (2) explain the CBQ-based (Children's Behavior Questionnaire) temperamental differences between CWS and CWNS; and (3) explain possible pathways for interaction between temperament and the development of stuttering.

A longitudinal study of emotion regulation and anxiety in middle childhood: Associations with frontal EEG asymmetry in early childhood

We investigated whether brain electrical activity during early childhood was associated with anxiety symptoms and emotion regulation during a stressful situation during middle childhood. Frontal electroencephalogram (EEG) asymmetries were measured during baseline and during a cognitive control task at 4 1/2 years. Anxiety and emotion regulation were assessed during a stressful situation at age 9 (speech task), along with measures of heart rate (HR) and heart rate variability (HRV). Questionnaires were also used to assess anxiety and emotion regulation at age 9. Results from this longitudinal study indicated that children who exhibited right frontal asymmetry in early childhood experienced more physiological arousal (increased HR, decreased HRV) during the speech task at age 9 and less ability to regulate their emotions as reported by their parents. Findings are discussed in light of the associations between temperament and development of anxiety disorders.

Temperament at 5 years of age predicts amygdala and orbitofrontal volume in the right hemisphere in adolescence

It was of interest to determine if hemispheric differences in orbitofrontal cortex (OFC) volume would be related to behavioral inhibition observed in a peer-play setting. Magnetic resonance imaging (MRI) was carried out in 23 individuals (19 males and 4 females) at an average age of 14.87+/-1.14 years who were either at high or low risk for alcohol dependence. All subjects had previously been evaluated in a preschool peer play paradigm (5.03+/-0.78 years) assessing behavioral inhibition. Region of interest measures were traced for the OFC and the amygdala, and confirmed with voxel based morphometry. Behavioral inhibition, a behavioral tendency that often occurs in a novel setting in reaction to strangers, includes the following: greater time spent next to the mother, greater time staring at another child, and longer latency to begin play with another child. A significant relationship was seen between greater right OFC volume and indicators of behavioral inhibition including greater time spent proximal to their mother and greater time staring at the other child. Also, larger amygdala volume was associated with more time spent proximal to the mother. Behavioral control, including both over- and under-control, is likely to be subserved by neural circuitry associated with emotion regulation including the right OFC and the amygdala.

Social withdrawal in childhood

Socially withdrawn children frequently refrain from social activities in the presence of peers. The lack of social interaction in childhood may result from a variety of causes, including social fear and anxiety or a preference for solitude. From early childhood through to adolescence, socially withdrawn children are concurrently and predictively at risk for a wide range of negative adjustment outcomes, including socio-emotional difficulties (e.g., anxiety, low self-esteem, depressive symptoms, and internalizing problems), peer difficulties (e.g., rejection, victimization, poor friendship quality), and school difficulties (e.g., poor-quality teacher-child relationships, academic difficulties, school avoidance). The goals of the current review are to (a) provide some definitional, theoretical, and methodological clarity to the complex array of terms and constructs previously employed in the study of social withdrawal; (b) examine the predictors, correlates, and consequences of child and early-adolescent social withdrawal; and (c) present a developmental framework describing pathways to and from social withdrawal in childhood.

Long-term stability of electroencephalographic asymmetry and power in 3 to 9 year-old children

We investigated the test-retest stability of resting EEG asymmetry and power in the alpha frequency range across a 0.6- to 3-year interval in 125 children (57 girls and 68 boys) for two age groups, 87 preschool children (3 to 5 year-olds) and 38 school-age children (6 to 9 year-olds). Children were from families with a parent's history of unipolar or bipolar depression (36 girls and 43 boys) or control families with no parent history of depression nor any other psychiatric disorder (21 girls and 25 boys). Frontal EEG asymmetry stability was low to moderate; intraclass correlations ranged from zero to 0.48 in the eyes-open condition, and from 0.19 to 0.45 in the eyes-closed condition. Also, parietal EEG asymmetry was low to moderate; intraclass correlations ranged from 0.21 to 0.52 in the eyes-open condition and from 0.27 to 0.72 in the eyes-closed condition. Stability of EEG asymmetry was not related to age, sex of the child, or parent's history of mood disorder. Frontal and parietal EEG power appeared moderately to highly stable. Intraclass correlations were between 0.65 and 0.86 in the eyes-open condition and between 0.52 and 0.90 in the eyes-closed condition. Although stability of EEG power was not statistical significantly different between preschool and school-age children, it consistently showed higher stability values in school-age children than in preschool children. Stability in school-age children approached values as has been reported for adults. The findings provide partial support to the concept of frontal EEG asymmetry as a trait marker in childhood.

Temperamental contributions to children's performance in an emotion-word processing task: a behavioral and electrophysiological study

Seven-year-old children (N=65) participating in a study of the influence of infant temperament on socioemotional development performed an auditory selective attention task involving words that varied in both affective (positive vs. negative) and social (social vs. nonsocial) content. Parent report of contemporaneous child temperament was also collected, and individual differences in self-regulation in the affective (soothability) and cognitive (attentional control) domains were noted. Overall, children showed slower responses to stimuli that were either social or negative in content, with the largest effect elicited by words that possessed both traits. Children rated high in soothability and attentional control showed slower responses to social negative words. The other children showed little to no differential response patterns across the word categories. ERPs collected during the task indicated that processing differences were evident in the later more cognitive components of the ERP, especially in children low in attentional control. These findings indicate that performance on an auditory selective attention task can assist in identifying underlying patterns of affective processing.

Childhood and adolescent resiliency, regulation, and executive functioning in relation to adolescent problems and competence in a high-risk sample

This study first examined the respective relations of resiliency and reactive control with executive functioning. It then examined the relationship of these different domains to the development of academic and social outcomes, and to the emergence of internalizing and externalizing problem behavior in adolescence. Resiliency and reactive control were assessed from preschool to adolescence in a high-risk sample of boys and girls (n = 498) and then linked to component operations of neuropsychological executive functioning (i.e., response inhibition, interference control, fluency, working memory/set-shifting, planning, and alertness), assessed in early and late adolescence. Consistent, linear relations were found between resiliency and executive functions (average r = .17). A curvilinear relationship was observed between reactive control and resiliency, such that resiliency was weaker when reactive control was either very high or very low. In multivariate, multilevel models, executive functions contributed to academic competence, whereas resiliency and interference control jointly predicted social competence. Low resiliency, low reactive control, and poor response inhibition uniquely and additively predicted internalizing problem behavior, whereas low reactive control and poor response inhibition uniquely predicted externalizing problem behavior. Results are discussed in relation to recent trait models of regulation and the scaffolded development of competence and problems in childhood and adolescence.

Ordinary variations in maternal caregiving influence human infants' stress reactivity

We sought to extend earlier work by examining whether there are ordinary variations in human maternal caregiving behavior (MCB) that are related to stress reactivity in infants. We observed 185 mother-infant dyads and used standard coding systems to identify variations in caregiving behavior. We then created two extreme groups and found that infants receiving low-quality MCB showed more fearfulness, less positive joint attention, and greater right frontal electroencephalographic asymmetry than infants receiving high-quality MCB. Group differences in stress reactivity were not a result of measured infant temperament. However, infants receiving low-quality MCB manifested significantly more negative affect during caregiving activities than did infants receiving high-quality MCB. The results suggest that ordinary variations in MCB may influence the expression of neural systems involved in stress reactivity in human infants.

Temperament and anxiety disorders

Recently, multidisciplinary research teams have come together to assess the emergence, course, and treatment of anxiety disorders in young children and adolescents. A number of researchers have suggested that early temperament traits may play a significant role in the causes and maintenance of early anxiety. This article reviews the current understanding of temperament and anxiety as separate constructs and then attempts to examine the developmental links between the two constructs. The authors examine the outstanding issues that must be addressed before the benefits of bridging these traditionally independent fields of study can be fully exploited.

Genetic and environmental influences on frontal EEG asymmetry: a twin study

Research suggests that frontal EEG asymmetry (FA) is a relatively stable trait associated with individual differences in dispositional affect (affective style) and liability to mood disorders. If FA is genetically determined, it can potentially serve as an endophenotype in genetic studies of temperament and mood disorders. The purpose of this study was to assess heritability of FA as well as alpha band EEG power measured at different frontal recording sites. Resting EEG data from a population-based sample of 246 young adult female twins including 73 monozygotic (MZ) and 50 dizygotic (DZ) pairs were analyzed using linear structural equation modeling. FA measured at mid-frontal locations (F3 and F4) showed low but significant heritability, suggesting that 27% of the observed variance can be accounted for by genetic factors. There was no evidence for genetic influences on FA measured at lateral-frontal (F7 and F8) locations. In contrast, alpha band power was highly heritable at all four frontal sites (85-87%). These findings suggest that: (1) genetic influences on FA are very modest and therefore FA has a limited utility as an endophenotype for genetic studies of mood disorders and (2) prefrontal neural circuitry underlying individual differences in affective style is characterized by high developmental plasticity.

Behavioral Inhibition: Linking Biology and Behavior within a Developmental Framework

Behavioral inhibition refers to a temperament or style of reacting that some infants and young children exhibit when confronted with novel situations or unfamiliar adults or peers. Research on behavioral inhibition has examined the link between this set of behaviors to the neural systems involved in the experience and expression of fear. There are strong parallels between the physiology of behaviorally inhibited children and the activation of physiological systems associated with conditioned and unconditioned fear. Research has examined which caregiving behaviors support the frequency of behavioral inhibition across development, and work on the interface of cognitive processes and behavioral inhibition reveal both how certain cognitive processes moderate behavioral inhibition and how this temperament affects the development of cognition. This research has taken place within a context of the possibility that stable behavioral inhibition may be a risk factor for psychopathology, particularly anxiety disorders in older children. The current chapter reviews these areas of research and provides an integrative account of the broad impact of behavioral inhibition research.

Frontal EEG asymmetry as a moderator and mediator of emotion

Frontal EEG asymmetry appears to serve as (1) an individual difference variable related to emotional responding and emotional disorders, and (2) a state-dependent concomitant of emotional responding. Such findings, highlighted in this review, suggest that frontal EEG asymmetry may serve as both a moderator and a mediator of emotion- and motivation-related constructs. Unequivocal evidence supporting frontal EEG asymmetry as a moderator and/or mediator of emotion is lacking, as insufficient attention has been given to analyzing the frontal EEG asymmetries in terms of moderators and mediators. The present report reviews the frontal EEG asymmetry literature from the framework of moderators and mediators, and overviews data analytic strategies that would support claims of moderation and mediation.

Biology, context, and developmental inquiry

This chapter summarizes some of the conceptual changes in developmental research over the last half-century. These advances include an acknowledgment of the role of maturation; also recognized have been the need for positing distinct psychological structures, the influence of temperament, the malleability of the infant, the role of the local context, and the dynamic nature of the categories describing human psychological types.

Neonatal novelty exposure, dynamics of brain asymmetry, and social recognition memory

Brief and transient early-life stimulation via neonatal handling and neonatal novelty exposure can lead to differential changes within the right and left brains. In rats, these lateralized changes have been demonstrated behaviorally, neuroanatomically, and neurophysiologically. Recently, we found that neonatal novelty exposure can prolong the duration of social recognition memory from less than 2 hr to at least 24 hr among male rats reared in social isolation and that this enhancement is associated with an initial right-turn preference in a novel testing cage. In contrast to stable forms of asymmetry, such as handedness, we show that this turning asymmetry is dynamic-decreasing as the animal adjusts to the novel testing environment over a 2-day period. This change in turning asymmetry was found only among animals that experienced neonatal novelty exposure during the first 3 weeks of their lives. Furthermore, individual differences in short-term social recognition memory for a conspecific can be predicted by this change in functional asymmetry.