Early development of electrophysiological activity: Contribution of periodic and aperiodic components of the EEG signal

Brain function rapidly changes in the first 2 years of life. In the last decades, resting-state EEG has been widely used to explore those changes. Previous studies have focused on the relative power of the signal in established frequency bands (i.e., theta, alpha, and beta). However, EEG power is a mixture of a 1/f-like background power (aperiodic) in combination with narrow peaks that appear over that curve (periodic activity, e.g., alpha peak). Therefore, it is possible that relative power captures both, aperiodic and periodic brain activity, contributing to changes in electrophysiological activity observed in infancy. For this reason, we explored the early developmental trajectory of the relative power in theta, alpha, and beta frequency bands from infancy to toddlerhood and compared it with changes in periodic activity in a longitudinal study with three waves at age 6, 9, and 16 to 18 months. Finally, we tested the contribution of periodic activity and aperiodic components of the EEG to age changes in relative power. We found that relative power and periodic activity trajectories differed in this period in all the frequency bands but alpha. Furthermore, aperiodic EEG activity flattened between 6 and 18 months. More importantly, only alpha relative power was exclusively related to periodic activity, whereas aperiodic components of the signal significantly contributed to the relative power of activity in theta and beta bands. Thus, relative power in these frequencies is influenced by developmental changes of the aperiodic activity, which should be considered for future studies.

The Interplay between Socioeconomic Status, Parenting and Temperament Predicts Inhibitory Control at Two Years of Age

This paper investigates the interplay between environmental factors (socioeconomic status (SES) and parenting) and temperament in the development of inhibitory control (IC) at 2 years of age. We administered to toddlers (n = 59) a delay of gratification task which measures IC in the context of self-regulation. Parents reported their toddlers' temperament, parenting strategies, and SES. We hypothesized that poorer IC would be associated with more reactive temperament, less effortful control, lower SES and inconsistent/coercive parenting practices. Finally, we explored the interaction between temperament, parenting and SES. We found that both coercive parenting and low-SES were negatively correlated to IC at the age of 2 years. Temperamental reactivity was unrelated to IC, whereas temperamental effortful control (EC) was positively associated with IC. Results revealed a moderation effect of EC on the influence of coercive parenting and SES in toddlers' IC. Toddlers from lower SES backgrounds and with lower EC were more affected by inconsistent/coercive parenting practices and showed the poorest IC. In contrast, toddlers exhibiting high and average levels of EC seemed to be protected from the detrimental effect of low-SES and inconsistent/coercive parenting on IC. These results suggest that strengthening toddlers' EC and improving parents' parenting skills might be especially relevant for the development of IC in the context of self-regulation, particularly by preventing self-regulatory problems in children from socioeconomically deprived environments. Future studies with larger samples, focusing on populations from severe socioeconomically deprived environments, or intervention studies will be needed in order to confirm and expand our findings.

Predicting Effortful Control at 3 Years of Age from Measures of Attention and Home Environment in Infancy: A Machine Learning Approach

Effortful control (EC) is a dimension of temperament that encompass individual differences in self-regulation and the control of reactivity. Much research suggests that EC has a strong foundation on the development of executive attention, but increasing evidence also shows a significant contribution of the rearing environment to individual differences in EC. The aim of the current study was to predict the development of EC at 36 months of age from early attentional and environmental measures taken in infancy using a machine learning approach. A sample of 78 infants participated in a longitudinal study running three waves of data collection at 6, 9, and 36 months of age. Attentional tasks were administered at 6 months of age, with two additional measures (i.e., one attentional measure and another self-restraint measure) being collected at 9 months of age. Parents reported household environment variables during wave 1, and their child's EC at 36 months. A machine-learning algorithm was implemented to identify children with low EC scores at 36 months of age. An "attention only" model showed greater predictive sensitivity than the "environmental only" model. However, a model including both attentional and environmental variables was able to classify the groups (Low-EC vs. Average-to-High EC) with 100% accuracy. Sensitivity analyses indicate that socio-economic variables together with attention control processes at 6 months, and self-restraint capacity at 9 months, are the most important predictors of EC. Results suggest a foundational role of executive attention processes in the development of EC in complex interactions with household environments and provide a new tool to identify early markers of socio-emotional regulation development.

Influence of the environment on the early development of attentional control

The control of visual attention is key to learning and has a foundational role in the development of self-regulated behavior. Basic attention control skills emerge early in life and show a protracted development along childhood. Prior research suggests that attentional development is influenced by environmental factors in early and late childhood. Although, much less information is available about the impact of the early environment on emerging endogenous attention skills during infancy. In the current study we aimed to test the impact of parental socioeconomic status (SES) and home environment (chaos) in the emerging control of orienting in a sample of typically-developing infants. A group of 142 (73 female) 6-month-old infants were longitudinally tested at 6, 9 (n = 122; 60 female) and 16-18 (n = 91; 50 female) months of age using the gap-overlap paradigm. Median saccade latency (mdSL) and disengagement failure (DF) were computed as dependent variables for both overlap and gap conditions. Also, composite scores for a Disengagement Cost Index (DCI) and Disengagement Failure Index (DFI) were computed considering mdSL and DF of each condition, respectively. Families reported SES and chaos in the first and last follow-up sessions. Using Linear Mixed Models with Maximum Likelihood estimation (ML) we found a longitudinal decrease in mdSL in the gap but not in the overlap condition, while DF decreased with age independently of the experimental condition. Concerning early environmental factors, an SES index, parental occupation and chaos at 6 months were found to show a negative correlation with DFI at 16-18 months, although in the former case it was only marginally significant. Hierarchical regression models implementing ML showed that both SES and chaos at 6 months significantly predicted a lower DFI at 16-18 months. Results show a longitudinal progression of endogenous orienting between infancy and toddlerhood. With age, an increased endogenous control of orienting is displayed in contexts where visual disengagement is facilitated. Visual orienting involving attention disengagement in contexts of visual competition do not show changes with age. Moreover, these attentional mechanisms of endogenous control seem to be modulated by early experiences of the individual with the environment.

Attention: The grounds of self-regulated cognition

Everyone knows what paying attention is, yet not everybody knows what this means in cognitive and brain function terms. The attentive state can be defined as a state of optimal activation that allows selecting the sources of information and courses of action in order to optimize our interaction with the environment in accordance with either the saliency of the stimulation or internal goals and intentions. In this article we argue that paying attention consists in tuning the mind with the environment in a conscious and controlled mode in order to enable the strategic and flexible adaptation of responses in accordance with internal motivations and goals. We discuss the anatomy and neural mechanisms involved in attention functions and present a brief overview of the neurocognitive development of this seminal cognitive function on the grounds of self-regulated behavior. This article is categorized under: Psychology > Attention (BEAB) Brain Function and Dysfunction (BEAC) Cognitive Development (BAAD).

Predicting behavioral and brain markers of inhibitory control at preschool age from early measures of executive attention

Background

Inhibitory control (IC) is the ability to prevent prepotent responses when inappropriate. Longitudinal research on IC development has mainly focused on early childhood and adolescence, while research on IC development in the first years of life is still scarce. To address this gap in the literature, we explored the association between executive attention (EA) and elementary forms of IC in infancy and toddlerhood, with individual differences in IC later at 5 years of age.

Method

We conducted a five-wave longitudinal study in which children's EA and IC (n = 96) were tested at the age of 9 and 16 months and 2, 3, and 5 years. Children performed various age-appropriate EA and IC tasks in each wave, measuring inhibition of attention, endogenous control of attention, inhibition of the response, and conflict inhibition. At 5 years of age, IC was measured with a Go/No-go task while recording event-related potentials. After correlation analyses, structural equation model analyses were performed to predict IC at 5 years of age from EA and early IC measures.

Results

The results revealed that EA at 9 months predicted IC measures at 2 years of age. Likewise, measures of IC at 2 years predicted performance on the Go/No-go task at behavioral and neural levels. No direct association was found between EA at 9 months and IC at 5 years of age. We further observed that some EA and IC measures were not associated across time.

Conclusion

As we expected, EA skills in infancy and toddlerhood were related to better performance of children on IC tasks, toghether with a more mature inhibition-related brain functioning. Altogether, the results indicate that IC in early childhood could be predicted from EA and IC at 9 months and 2 years of age and suggest that the early emergence of IC relies on the development of particular EA and basic IC skills. However, some discontinuities in the longitudinal development of IC are observed in the first 5 years of life. These findings provide further support for the hierarchical model of IC development.

Development of visual attention control in early childhood: Associations with temperament and home environment

Endogenous visual attention orienting is early available from infancy. It shows a steady development during the preschool period towards monitoring and managing executive attention to optimize the interplay between environmental contingencies and internal goals. The current study aims at understanding this transition from basic forms of endogenous control of visual orienting towards the engagement of executive attention, as well as their association with individual differences in temperament and home environment. A total of 150 children between 2 and 4 years of age were evaluated in a Visual Sequence Learning task, measuring visual anticipations in easy (context-free) and complex (context-dependent) stimuli transitions. Results showed age to be a predictor of a reduction in exogenous attention, as well as increased abilities to attempt to anticipate and to correctly anticipate in complex transitions. Home chaos predicted more complex correct anticipations, suggesting that the exposure to more unpredictable environments could benefit learning in context-dependent settings. Finally, temperamental surgency was found to be positively related to sustained attention in the task. Results are informative of age differences in visual attention control during toddlerhood and early childhood, and their association with temperament and home environment.

Beyond group differences: Exploring the preliminary signals of target engagement of an executive function training for autistic children

Understanding both for whom and how interventions work is a crucial next step in providing personalized care to children with autism spectrum disorder (ASD). Autistic children present with heterogeneity both within core ASD criteria and with respect to co‐occurring mental health challenges, which may affect their ability to benefit from intervention. In a secondary data analysis of a randomized control trial evaluating an executive function (EF) training with 70 7‐ to 11‐year‐old autistic children, we explored: (1) whether co‐occurring attention‐deficit/hyperactivity disorder (ADHD) features or anxiety features at baseline moderated the extent to which children benefited from the EF training. In other words, we asked, “For whom is training effective?” We also explored: (2) the extent to which changes in a brain‐based measure of target engagement predicted the clinical outcomes of the EF training. This is a step towards asking, “How is training effective?” We found that EF training improved behavioral inhibition only for children with clinically significant co‐occurring ADHD features. Anxiety features, while prevalent, did not moderate EF training efficacy. Finally, for the EF training group only, there was a significant correlation between pre‐to‐post change in an EEG‐based measure of target engagement, N2 incongruent amplitude during a flanker task, and change in repetitive behaviors, a behavioral outcome that was reported in the parent RCT to have improved with training compared to waitlist control. This study provides preliminary evidence that EF training may differentially affect subgroups of autistic children and that changes at the neural level may precede changes in behavior.

A preliminary randomized, controlled trial of executive function training for children with autism spectrum disorder

LAY ABSTRACT

Executive function, which is a set of thinking skills that includes stopping unwanted responses, being flexible, and remembering information needed to solve problems, is a challenge for many children on the autism spectrum. This study tested whether executive function could be improved with a computerized executive function training program under the guidance of a coach who reinforced the use of executive function skills. Seventy children with autism spectrum disorder from age 7 to 11 years of age participated in the study. They were randomly assigned to receive training or to a waiting group. The tests most likely to determine whether the training may be effective were chosen from a larger battery before the study started and included one task measuring brain responses, two measures of executive function in the lab, and a parent questionnaire. Changes in social functioning and repetitive behaviors were also explored. All children assigned to training completed the program and families generally reported the experience was positive. Brain responses of the training group changed following training, but not within the waiting group during a similar time period. Children who received training did not exhibit behavioral changes during the two the lab-based tasks. Parent report on questionnaires indicated that neither group showed a significant change in their broad use of executive function in other settings. Yet, children who received training were reported to have fewer restricted and repetitive behaviors following training. These initial findings suggest that short executive function training activities are feasible and may improve some functioning of school-aged children on the autism spectrum.

Children's Individual Differences in Executive Function and Theory of Mind in Relation to Prejudice Toward Social Minorities

Executive function (EF) and theory of mind (ToM) are key cognitive skills for socio-emotional adjustment. Executive function develops considerably between 3 and 7 years of age, and fosters the development of social cognition skills such as ToM. Studies with adults have shown a link between EF and prejudice, as well as between empathy and prejudice. Moreover, the relationship between EF, cognitive and affective ToM and prejudice has barely been studied in children. In this study, we aimed at examining the relationship between individual differences in EF, cognitive and affective ToM and prejudice toward the Romany ethnic minority. We expected a positive association between EF and ToM skills, and a negative association between EF and prejudice. We also predicted a negative association between ToM and prejudice. A total of 86 preschool (5-6 years old, N = 43) and third-grade (8-9 years old, N = 43) children participated in the study. Results showed a negative relationship between EF and prejudice, as well as between affective ToM and prejudice, after controlling for intelligence. Moreover, we found that EF significantly predicted prejudice. Exploratory correlational analyses suggested age-related differences in the EF skills underlying prejudice regulation. These findings suggest a distinctive contribution of cognitive and affective components of ToM to prejudice, and highlight the central role of EF in social behavior regulation.

Infant temperament and family socio-economic status in relation to the emergence of attention regulation

Attention regulation refers to the ability to control attention according to goals and intentions. Disengagement of attention is one of the first mechanisms of attention regulation that emerges in infancy, involving attention control and flexibility. Disengaging attention from emotional stimuli (such as threat-related cues) is of particular interest given its implication for self-regulation. A second mechanism of attention control is the ability to flexibly switch attention according to changing conditions. In our study, we investigated 9 to 12-month-olds’ disengagement and flexibility of attention, and examined the contribution of both temperament and socioeconomic status (SES) to individual differences in the emergence of these attention regulation skills at the end of the first year of life. Our results show that both difficulty to disengage from fearful faces and poorer attention flexibility were associated with higher levels of temperamental Negative Affectivity (NA). Additionally, attention flexibility moderated the effect of NA on disengagement from fearful faces. Infants with higher NA and poorer attention flexibility showed the greatest difficulty to disengage. Low SES was also associated with poorer attention flexibility, association that was mediated by infants’ NA. These results suggest that attention flexibility together with temperament and environmental factors are key to understand individual differences in attention regulation from threat-related stimuli as early as from infancy. Our findings also stress the importance of interactions between environmental and constitutional factors for understanding individual differences in the emergence of attention regulation.

Influence of the SLC6A3-DAT1 Gene on Multifaceted Measures of Self-regulation in Preschool Children

Development of self-regulation, the capacity to voluntarily modulate thoughts, emotions and actions is strongly related to the maturation of the dopamine-mediated executive attention network (EAN). The attention control processes associated with the EAN greatly overlap with efficiency of the executive functions and are correlated with measures of effortful control. Regulation of dopamine levels within the EAN, particularly in the basal ganglia is carried out by the action of dopamine transporters. In humans, the SLC6A3/DAT1 gene carries out the synthesis of the DAT protein. The 10-repeat allele has been associated with an enhanced expression of the gene and has been related to ADHD symptoms. Little is known about the impact of DAT1 variations on children's capacity to self-regulate in contexts that impose particular demands of regulatory control such as the school or home. This study defines a multi-domain phenotype of self-regulation and examines whether variations of the DAT1 gene accounts for individual differences in performance in 4–5 year old children. Results show that presence of the 10r allele is related to a diminished ability to exert voluntary regulation of reactivity. These findings shed light on the neurobiological mechanisms underlying individual differences in self-regulation during childhood.

Development of neural mechanisms of conflict and error processing during childhood: implications for self-regulation

Regulation of thoughts and behavior requires attention, particularly when there is conflict between alternative responses or when errors are to be prevented or corrected. Conflict monitoring and error processing are functions of the executive attention network, a neurocognitive system that greatly matures during childhood. In this study, we examined the development of brain mechanisms underlying conflict and error processing with event-related potentials (ERPs), and explored the relationship between brain function and individual differences in the ability to self-regulate behavior. Three groups of children aged 4-6, 7-9, and 10-13 years, and a group of adults performed a child-friendly version of the flanker task while ERPs were registered. Marked developmental changes were observed in both conflict processing and brain reactions to errors. After controlling by age, higher self-regulation skills are associated with smaller amplitude of the conflict effect but greater amplitude of the error-related negativity. Additionally, we found that electrophysiological measures of conflict and error monitoring predict individual differences in impulsivity and the capacity to delay gratification. These findings inform of brain mechanisms underlying the development of cognitive control and self-regulation.

Behavioral and brain measures of executive attention and school competence in late childhood

This study examines the role of executive attention on school competence in early adolescence. Twelve-year-old children (N = 37) performed a combined Flanker-Go/No-Go task while their brain activation was registered using electroencephalogram (EEG). Additionally, measures of children regulation, schooling skills, and academic achievement were obtained. We observed that individual differences in executive attention and Effortful Control predict most dimensions of school competence. Also, individual differences in the amplitude of event-related potentials (ERPs) related to interference suppression predict school achievement and some skills important for school. The results are consistent with the role attributed to executive attention in self-regulation.

Enhanced efficiency of the executive attention network after training in preschool children: immediate changes and effects after two months

Executive attention is involved in the regulation of thoughts, emotions and responses. This function experiences major development during preschool years and is associated to a neural network involving the anterior cingulate cortex and prefrontal structures. Recently, there have been some attempts to improve attention and other executive functions through training. In the current study, a group of 5 years old children (n=37) were assigned to either a training-group who performed ten sessions of computerized training of attention or a non-trained control group. Assessment of performance in a range of tasks, targeting attention, intelligence and regulation of affect was carried out in three occasions: (1) before, (2) after, and (3) two months after completion of training. Also, brain function was examined with a high-density electroencephalogram system. Results demonstrate that trained children activate the executive attention network faster and more efficiently than untrained children, an effect that was still observed two months after without further training. Also, evidence of transfer of attention training to fluid intelligence and, to a lesser degree, to regulation of affect was observed. Results show that efficiency of the brain system underlying self-regulation can be enhanced by experience during development, providing opportunities for curricular improvement.

Developing Mechanisms of Self-Regulation in Early Life

Children show increasing control of emotions and behavior during their early years. Our studies suggest a shift in control from the brain's orienting network in infancy to the executive network by the age of 3-4 years. Our longitudinal study indicates that orienting influences both positive and negative affect, as measured by parent report in infancy. At 3-4 years of age, the dominant control of affect rests in a frontal brain network that involves the anterior cingulate gyrus. Connectivity of brain structures also changes from infancy to toddlerhood. Early connectivity of parietal and frontal areas is important in orienting; later connectivity involves midfrontal and anterior cingulate areas related to executive attention and self-regulation.

The Development of Executive Attention: Contributions to the Emergence of Self-Regulation

Over the past decade, developmental studies have established connections between executive attention, as studied in neurocognitive models, and effortful control, a temperament system supporting the emergence of self-regulation. Functions associated with the executive attention network overlap with the more general domain of executive function in childhood, which also includes working memory, planning, switching, and inhibitory control (Welch, 2001). Cognitive tasks used with adults to study executive attention can be adapted to children and used with questionnaires to trace the role of attention and effortful control in the development of self-regulation. In this article we focus on the monitoring and control functions of attention and discuss its contributions to self-regulation from cognitive, temperamental, and biological perspectives.

Training, maturation, and genetic influences on the development of executive attention

A neural network underlying attentional control involves the anterior cingulate in addition to lateral prefrontal areas. An important development of this network occurs between 3 and 7 years of age. We have examined the efficiency of attentional networks across age and after 5 days of attention training (experimental group) compared with different types of no training (control groups) in 4-year-old and 6-year-old children. Strong improvement in executive attention and intelligence was found from ages 4 to 6 years. Both 4- and 6-year-olds showed more mature performance after the training than did the control groups. This finding applies to behavioral scores of the executive attention network as measured by the attention network test, event-related potentials recorded from the scalp during attention network test performance, and intelligence test scores. We also documented the role of the temperamental factor of effortful control and the DAT1 gene in individual differences in attention. Overall, our data suggest that the executive attention network appears to develop under strong genetic control, but that it is subject to educational interventions during development.

Development of the time course for processing conflict: an event-related potentials study with 4 year olds and adults

Background

Tasks involving conflict are widely used to study executive attention. In the flanker task, a target stimulus is surrounded by distracting information that can be congruent or incongruent with the correct response. Developmental differences in the time course of brain activations involved in conflict processing were examined for 22 four year old children and 18 adults. Subjects performed a child-friendly flanker task while their brain activity was registered using a high-density electroencephalography system.

Results

General differences were found in the amplitude and time course of event-related potentials (ERPs) between children and adults that are consistent with their differences in reaction time. In addition, the congruency of flankers affected both the amplitude and latency of some of the ERP components. These effects were delayed and sustained for longer periods of time in the children compared to the adults.

Conclusions

These differences constitute neural correlates of children's greater difficulty in monitoring and resolving conflict in this and similar tasks.

Developing mechanisms of temperamental effortful control

Studies of temperament from early childhood to adulthood have demonstrated inverse relationships between negative affectivity and effortful control. Effortful control is also positively related to the development of conscience and appears as a protective factor in the development of behavior disorders. In this study, the development of attentional mechanisms underlying effortful control was investigated in 2- to 3-year-old children, as indexed by their performance in a) making anticipatory eye movements to ambiguous locations and b) resolving conflict between location and identity in a spatial conflict task. The ability to make anticipatory eye movements to ambiguous locations within a sequence was clearly present at 24 months. By 30 months, children could also successfully perform a spatial conflict task that introduced conflict between identity and location, and at that age, children's success on ambiguous anticipatory eye movements was related to lower interference from conflict in the spatial conflict task. Children's performance on the eye-movement task was correlated with performance and reaction time on spatial tasks, and both were related to aspects of effortful control and negative affect as measured in children's parent-reported temperament.

Development of attentional networks in childhood

Recent research in attention has involved three networks of anatomical areas that carry out the functions of orienting, alerting and executive control (including conflict monitoring). There have been extensive cognitive and neuroimaging studies of these networks in adults. We developed an integrated Attention Network Test (ANT) to measure the efficiency of the three networks with adults. We have now adapted this test to study the development of these networks during childhood. The test is a child-friendly version of the flanker task with alerting and orienting cues. We studied the development of the attentional networks in a cross-sectional experiment with four age groups ranging from 6 through 9 (Experiment 1). In a second experiment, we compared children (age 10 years) and adult performance in both child and adults versions of the ANT. Reaction time and accuracy improved at each age interval and positive values were found for the average efficiency of each of the networks. Alertness showed evidence of change up to and beyond age 10, while conflict scores appear stable after age seven and orienting scores do not change in the age range studied. A final experiment with forty 7-year-old children suggested that children like adults showed independence between the three networks under some conditions.

Developing mechanisms of temperamental effortful control

Studies of temperament from early childhood to adulthood have demonstrated inverse relationships between negative affectivity and effortful control. Effortful control is also positively related to the development of conscience and appears as a protective factor in the development of behavior disorders. In this study, the development of attentional mechanisms underlying effortful control was investigated in 2- to 3-year-old children, as indexed by their performance in a) making anticipatory eye movements to ambiguous locations and b) resolving conflict between location and identity in a spatial conflict task. The ability to make anticipatory eye movements to ambiguous locations within a sequence was clearly present at 24 months. By 30 months, children could also successfully perform a spatial conflict task that introduced conflict between identity and location, and at that age, children's success on ambiguous anticipatory eye movements was related to lower interference from conflict in the spatial conflict task. Children's performance on the eye-movement task was correlated with performance and reaction time on spatial tasks, and both were related to aspects of effortful control and negative affect as measured in children's parent-reported temperament.

Mental chronometry in the study of individual and group differences

The papers in this issue are excellent examples of the many uses of measuring reaction time in the exploration of nervous system pathologies. In our commentary we consider mental chronometry as a field that seeks to measure the time course of mental operations in the human nervous system. We draw upon diverse methods such as neuroimaging, electrical recording and reaction time to illustrate the use of chronometry in conjunction with anatomy and genetics to approach both normal individual differences and pathologies. The goal is to examine general and specific changes in neural networks that underlie both variations in normal function and changes due to pathology. Although much remains to be done along these lines, it is now possible to see how the various chronometric contributions outlined in this special issue can converge to provide a basis for improved understanding of the genetic and experiential basis of cognitive and emotional processes.