Evidence of substantial development of inhibitory control and sustained attention between 6 and 8years of age on an unpredictable Go/No-Go task

The developmental trajectory of task-related frontal EEG theta/beta ratio in childhood

Attention control, the ability to focus on task-relevant information while blocking out irrelevant information, is crucial for successful task completion throughout development. However, the neurodevelopment of attention control during tasks remains underexplored, particularly from an electrophysiogical perpective. Therefore, the present study investigated the developmental trajectory of frontal TBR, a well-established EEG correlate of attention control, in a large sample of 5, 207 children aged 5-14 during a visuospatial working memory task. Results revealed that frontal TBR in tasks exhibited a different developmental trajectory (quadratic) compared to the baseline condition (linear). More importantly, we found that the association between task-related frontal TBR and age was modulated by task difficulty, with the age-related decrease in frontal TBR being more pronounced in more challenging conditions. Overall, by demonstrating a fine-grained age-related change in the frontal TBR based on a large dataset covering continuous age groups, our study provided electrophysiogical evidence about the maturation of attention control, suggesting potentially distinct developmental paths for attention control across the baseline and task conditions.

Prospective Memory, Sustained Attention and Response Inhibition in Poly-Substance Users Stable on Methadone Maintenance Treatment

Background: Prospective memory and response inhibition are interrelated constructs, though studied separately in the drug addiction literature. Also, although sustained attention underlies response inhibition, its role in the relation between these functions has been largely neglected. The limited research on the cognitive effects of methadone-maintenance treatment (MMT) further stresses the importance of investigating these effects. Objective: Therefore, the current study focused on possible effects of MMT combined with long-term drug abuse on all these functions. Thirty five long term opiate/poly-substance users in MMT and thirty four drug-free controls were screened for socioeconomic status, anxiety, depression and general, non-verbal intelligence and then tested on a self-report measure of prospective memory and on the Go/No-Go task. Results: Compared to controls, the MMT group scored worse in all functions assessed. Prospective memory scores were also negatively related to Go/NoGo accuracy scores. Conclusion: As predicted, (a) the MMT participants show impairments in prospective memory, sustained attention and response inhibition and (b) prospective memory, response inhibition and sustained attention are related constructs. The results of this study could inform current rehabilitation and relapse prevention cognitive training practices.

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.

Inhibitory Control Development: A Network Neuroscience Perspective

As one of the core executive functions, inhibition plays an important role in human life through development. Inhibitory control is defined as the ability to suppress actions when they are unlikely to accomplish valuable results. Contemporary neuroscience has investigated the underlying neural mechanisms of inhibitory control. The controversy started to arise, which resulted in two schools of thought: a modulatory and a network account of inhibitory control. In this systematic review, we survey developmental mechanisms in inhibitory control as well as neurodevelopmental diseases related to inhibitory dysfunctions. This evidence stands against the modulatory perspective of inhibitory control: the development of inhibitory control does not depend on a dedicated region such as the right inferior frontal gyrus (rIFG) but relies on a more broadly distributed network.

Can Stimulus Valence Modulate Task-Switching Ability? A Pilot Study on Primary School Children

Executive functions and emotional processes follow a time-dependent development that reflects the brain’s anatomo-functional maturation. Though the assessment of these cognitive functions is largely examined, in children the role of emotions in the mental set-shifting is still rarely investigated. The aim of this study was to assess how attention shifting can be modulated by the valence of emotional stimuli. To this end, sixty-two primary school children were tested with a new emotional task-switching paradigm obtained by manipulating the emotional valence and physical features of the stimulus pool. Thus, two tasks were alternatively presented: the Valence task and the Color task. Based on executive performance results, we found a lengthening of response times and a lower accuracy in the emotionally connoted task (Valence task), compared to the neutral task (Color task). The data demonstrate that the processing of emotional stimuli modulates the task-switching performance during development. These findings could help in the implementation of teaching strategies that can promote the development of executive functions and, therefore, functionally improve the overall academic performance of children. Finally, a better understanding of the developmental trajectories of executive functions can help neuropsychologists both in the early diagnosis and treatment of potential executive alterations.

Higher Tablet Use Is Associated With Better Sustained Attention Performance but Poorer Sleep Quality in School-Aged Children

There are growing concerns that increased screen device usage may have a detrimental impact on classroom behaviour and attentional focus. The consequences of screen use on child cognitive functioning have been relatively under-studied, and results remain largely inconsistent. Screen usage may displace the time usually spent asleep. The aim of this study was to examine associations between screen use, behavioural inattention and sustained attention control, and the potential modifying role of sleep. The relations between screen use, behavioural inattention, sustained attention and sleep were investigated in 162 6- to 8-year-old children, using parent-reported daily screen use, the SWAN ADHD behaviour rating scale, The sustained attention to response task and the children’s sleep habits questionnaire. Tablet use was associated with better sustained attention performance but was not associated with classroom behavioural inattention. Shorter sleep duration was associated with poorer behavioural inattention and sustained attention. Sleep quality and duration did not act as mediators between screen usage and behavioural inattention nor sustained attention control. These findings suggest that careful management of the amount of time spent on electronic screen devices could have a beneficial cognitive impact on young children. The results also highlight the critical role of sleep in enhancing both behavioural attention and sustained attention, which are essential for supporting cognitive development and learning.

Cognitive flexibility in children with Developmental Language Disorder: Drawing of nonexistent objects

Cognitive flexibility is the ability to adapt thoughts and behaviors to new environments. Previous studies investigating cognitive flexibility in children with Developmental Language Disorder (DLD) present contradictory findings. In the current study, cognitive flexibility was assessed in 5- and 6-year-old preschoolers with DLD (n = 23) and peers with typical development (TD; n = 50) using a nonexistent object drawing (NEOD) task. The children were asked to draw a nonexistent man and a nonexistent house. The children with DLD did not differ from their peers with TD on simple category changes, which were comprised of changes in the size or shape of parts of the object, change of the whole shape of the object, and deletion of parts of the object. Nevertheless, children with DLD made fewer more complex, high-level category changes, which included same-category insertions, position exchange of object's parts, and cross-category insertions. The difference between DLD and TD on high-level category changes was related to differences between the two groups in verbal short-term memory and inhibition. Furthermore, children with DLD made no changes to their original drawings of an existing man and house more often than their peers with TD. It is concluded that children with DLD aged 5-6 years show less flexibility on the NEOD task than age-matched children with TD. This difference in cognitive flexibility may be related to lower levels of verbal short-term memory and inhibition ability of children with DLD, or to different use of these cognitive skills on the NEOD task.

Selective Inhibitory Control in Middle Childhood

The main aim of this study was to investigate the development of selective inhibitory control in middle childhood, a critical period for the maturation of inhibition-related processes. To this end, 64 children aged 6–7 and 56 children aged 10–11 performed a stimulus-selective stop-signal task, which allowed us to estimate not only the efficiency of response inhibition (the stop-signal reaction time or SSRT), but also the strategy adopted by participants to achieve task demands. We found that the adoption of a non-selective (global) strategy characterized by stopping indiscriminately to all stimuli decreased in older children, so that most of them were able to interrupt their ongoing responses selectively at the end of middle childhood. Moreover, compared to younger children, older children were more efficient in their ability to cancel an initiated response (indexed by a shorter SSRT), regardless of which strategy they used. Additionally, we found improvements in other forms of impulsivity, such as the control of premature responding (waiting impulsivity), and attentional-related processes, such as intra-individual variability and distractibility. The present results suggest that middle childhood represents a milestone in the development of crucial aspects of inhibitory control, including selective stopping.

Effect of obesity on inhibitory control in preadolescents during stop-signal task. An event-related potentials study

Preadolescence is a period in which structural and functional changes occur in brain network reorganization that relate to the development of executive control functions, particularly in the areas of attention and cognitive inhibition. Obesity has been associated with a deficit in executive functions and behavioral and electrophysiological differences using the go/no-go task (proactive inhibition), but no study has assessed brain-electrical activity using the stop-signal task (reactive inhibition) in this population. Therefore, we hypothesized that obese preadolescents would show less efficiency in reactive inhibition than their same-age non-obese peers. To test this hypothesis, event-related potentials (ERPs) were collected during a stop-signal task and compared between 27 obese preadolescents (mean BMI = 25.9; 9.65 years old) and 29 normal-weight preadolescents (mean BMI = 17.5; 9.60 years old). No significant differences between groups were observed in behavioral responses. As for ERPs, the obese group had an electrophysiological pattern associated with less efficient conflict monitoring during the "no-go" condition (i.e., less modulation of N200 latency based on the experimental condition), differences in attentional allocation in the "go" condition (less modulation of P300a latency based on experimental condition), and difficulties in rule retrieval from working memory associated with the trial-type in both experimental conditions (smaller P300b amplitude). We conclude that obese preadolescents displayed less ability to modulate conflict-monitoring in the "no-go" condition and attention allocation in the "go" condition, evidencing differences between groups in the development of attention and inhibitory control.

Assessing the Three Attentional Networks and Vigilance in the Adolescence Stages

Attention involves three functionally and neuroanatomically distinct neural networks: alerting, orienting, and executive control. This study aimed to assess the attentional networks and vigilance in adolescents aged between 10 and 19 years using the attentional network test for interaction and vigilance (ANTI-V). One hundred and eighty-two adolescents divided into three groups (early adolescents, middle adolescents, late adolescents) participated in the study. The results indicate that after age 15, adolescents adopt a more conservative response strategy and increase the monitoring of self-errors. All the attentional networks seem to continue to develop during the age range considered in this study (10–19 y). Performance improved from early adolescence to middle adolescence and began to stabilize in late adolescence. Moreover, a low level of vigilance seems to harm alerting and orienting abilities.

Longitudinal Trajectories of Sustained Attention Development in Children and Adolescents with ADHD

The present study characterizes changes in sustained attention ability over ages 9-14, and whether longitudinal trajectories of attention development differ between persistent ADHD, remitted ADHD and control groups. The Sustained Attention to Response Task (SART) was administered to 120 children with ADHD and 123 controls on three occasions between ages 9 and 14. Trajectories of sustained attention development, indicated by changes in SART performance (standard deviation of response time [SDRT], omission errors, and ex-Gaussian parameters sigma and tau), were examined using generalized additive mixed models. For all measures there was a significant main effect of age; response time variability and number of omission errors improved linearly as children aged. However, children with ADHD had significantly greater SDRT, tau and omission errors than controls across waves. There were no significant group differences in sigma, indicating that the greater overall response time variability (SDRT) observed in ADHD was likely driven by more intermittent long responses (larger tau). Trajectories of sustained attention performance did not differ between children with persistent ADHD or ADHD in remission. Longitudinal trajectories of sustained attention development are comparable between ADHD and controls, however children with ADHD (regardless of remission status) display a performance deficit equivalent to typical controls 1-3 years younger. Findings highlight the need for continued clinical support for children in remission from ADHD and provide support for tau as an endophenotype of ADHD.

Longitudinal associations between inhibitory control and externalizing and internalizing symptoms in school-aged children

Inhibitory control (IC) deficits have been associated with psychiatric symptoms in all ages. However, longitudinal studies testing the direction of the associations in childhood are scarce. We used a sample of 2,874 children (7 to 9 years old) to test the following three hypotheses: (a) IC deficits are an underlying risk factor with a potentially causal role for psychopathology, (b) IC deficits are a complication of psychopathology, and (c) IC deficits and psychopathology are associated at the trait level but not necessarily causally related. We used the go/no-go task to assess IC, the parent-rated Strengths and Difficulties Questionnaire to evaluate externalizing/internalizing symptoms, and the random intercepts cross-lagged panel model to test the hypotheses. The results showed no support for the underlying risk factor hypothesis, suggesting that IC unlikely has a causal role in this age group's psychopathology. The complication hypothesis received support for externalizing symptoms, suggesting that externalizing symptoms may hamper the normal development of IC. IC deficits and both externalizing and internalizing symptoms were correlated at the trait level, indicating a possible common origin. We suggest that it may be useful to support children with externalizing symptoms to promote and protect their IC development.

The developing predictive brain: How implicit temporal expectancy induced by local and global prediction shapes action preparation across development

Human behavior is continuously shaped not just as a function of explicitly responding to external world events but also by internal biases implicitly driven by the capacity to extract statistics from complex sensory patterns. Two possible sources of predictability engaged to generate and update temporal expectancy are the implicit extraction of either local or global statistical contingencies in the events' temporal structure. In the context of action preparation the local prediction has been reported to be stable from the age of 6. However, there is no evidence about how the ability to extract and use global statistical patterns to establish temporal expectancy changes across development. Here we used a new, child-friendly reaction time task purposely designed to investigate how local (within-trial expectancy bias) and global (between-block expectancy bias) prediction interplay to generate temporal expectancy and consequently shape action preparation in young (5- to 6-year-old), middle-aged (7- to 8-year-old) and old (9- to 10-year-old) typically developing children. We found that while local temporal prediction showed stable developmental trajectories, the ability to use a global rule to action preparation in terms of both accuracy and speed becomes stable after the age of seven. These findings are discussed by adopting a neuroconstructivist-inspired theoretical account, according to which the developmental constraints on learning from hierarchically nested levels of sensory complexity may constitute a necessary prerequisite for mastering complex domains.

Schoolchildren's Compensatory Strategies and Skills in Relation to Attention and Executive Function App Training

BACKGROUND

Given the importance of attention and executive functions (EF) in children's behavior, programs aimed at improving these processes are of special interest. Nexxo-training combines the use of the Nexxo touchscreen application (inhibition and vigilance tasks) with procedural metacognitive strategies (imparted by an instructor) for all the individuals using the app, regardless of their level of ability, plus compensatory strategies based on individual child performance. This study presents an analysis of the compensatory strategies that schoolchildren (aged 6-8 years old) receive when experiencing difficulties with EF tasks, in addition to an analysis of the developmental factors and cognitive skills that may modulate EF task performance.

METHODS

For this study, we use data from a previous randomized active-controlled study (under review), in which forty-six typically developing children aged between 6 and 8 years old (24 girls/22 boys) were enrolled in the training group. The selected children were in the 1st grade (n = 28, x ¯ = 78.32 ± 4.037 months) and 3rd grade of primary education (n = 18, x ¯ = 102.11 ± 3.445). We collected data on EF training performance, compensatory strategies needed and neuropsychological assessments.

RESULTS

A total of 80.43% participants required some form of compensatory strategy during training. Regarding required compensatory strategies, those who had lower scores in EF training needed more compensatory strategies, in particular, instructional comprehension (r = -0.561, p < 0.001 for inhibition-tasks; r = -0.342, p < 0.001 for vigilance-tasks). Concerning developmental factors, age significantly predicted better performance in both EF tasks (β = 0.613, p < 0.001 for inhibition; β = 0.706, p < 0.001 for attention). As regards task performance, those with better performance in inhibition tasks also had better performance in vigilance tasks (r = 0.72, p < 0.001). Finally, regarding cognitive skills, participants with higher performance in fluid intelligence (Q1, n = 12) had higher scores (U = 14.5, p < 0.05) than the group with the lowest performance (Q4, n = 11) in vigilance.

CONCLUSION

As previous literature suggests, inhibition is one of the core processes of EF. Therefore, we should focus training on the core EF processes. Inhibition and vigilance are closely related processes. In terms of the use of compensatory strategies, these are more needed for participants with lower levels of performance in inhibition or vigilance. Regarding strategy analysis, instructional comprehension and self-instruction (goal setting and planning) seem to be the most useful strategies for those with difficulties in inhibitory and vigilance task performance. Regarding development, as expected, age moderates task performance in inhibition and attention. Finally, cognitive skills, such as fluid intelligence and cognitive flexibility, predicted better results in attention. EF training using not only an app, but also compensatory strategies based on user performance, is a new research direction offering more opportunities to generalize EF training in everyday life.

Neural Substrates of Inhibitory Control Maturation in Adolescence

Inhibitory control matures through adolescence and into early adulthood, impacting decision-making. Impairments in inhibitory control are associated with various psychopathologies, many of which emerge during adolescence. In this review, we examine the neural basis of developmental improvements in inhibitory control by integrating findings from humans and non-human primates, identifying the structural and functional specialization of executive brain systems that mediates cognitive maturation. Behavioral manifestations of response inhibition suggest that adolescents are capable of producing adult level responses on occasion, but lack the ability to engage systems mediating response inhibition in a consistent fashion. Maturation is associated with changes in structural anatomy as well as local and systems-level connectivity. Functional changes revealed by neuroimaging and neurophysiology indicate that maturation of inhibitory control is achieved through improvements in response preparation, error processing, and planned responses.

Aspects of attention and inhibitory control are associated with on-task classroom behaviour and behavioural assessments, by both teachers and parents, in children with high and low symptoms of ADHD

There is often weak association between performance on cognitive tasks and the behavioural symptoms of ADHD. One possible reason is the use of rating scales rather than direct observations of behaviours. This exploratory study used well established measures of attention and response inhibition with both direct observation and behavioural rating scales to examine these associations. Twenty-two children (mean age 9.6 years) identified by their teachers as displaying high levels of ADHD symptoms, and 22 matched controls (mean age 9.8 years), completed the Fixed and Random Sustained Attention to Response Tasks (SART). Their on-task classroom behaviour was assessed using the ASEBA Direct Observation Form (DOF). ADHD symptoms were also assessed using the Conners 3 Short Form and the SWAN. Children with high symptoms of ADHD performed the SARTs with more errors of commission and were more variable with their responding, and spent less time on-task in the classroom than controls. Performance on the Fixed SART was not associated with on-task classroom behaviour; in contrast three Random SART measures, commission and omission errors, moment-to-moment variability, were negatively associated with on-task classroom behaviour. There were strong associations between the commission error counts on both SARTs and the Teacher SWAN scores, and one of the Parent SWAN scores. The Teacher SWAN scores were associated with on-task classroom behaviour; the Parent SWAN scores were not. These findings provide preliminary evidence of an association between cognitive measures of inhibitory control and some measures of inattention, and both observed behaviour and the ADHD behavioural symptoms.

Socioeconomic status and neural processing of a go/no-go task in preschoolers: An assessment of the P3b

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Children aged 4.5–5.5 years completed a go/no-go task while recording EEG.

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P3b amplitudes were assessed, indexing inhibition and attention processes.

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Higher household income related to larger P3b amplitudes on go and no-go trials.

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Results show that SES has implications for children’s neural processing.

While it is well established that lower socioeconomic status (SES) is associated with poorer executive functioning (EF), how SES relates to the neural processing of EF in childhood remains largely unexplored. We examined how household income and parent education related to amplitudes of the P3b, an event-related potential component, during one EF task. We assessed the P3b, indexing inhibition and attention allocation processes, given the importance of these skills for academic success. Children aged 4.5–5.5 years completed a go/no-task, which assesses inhibitory control and attention, while recording EEG. The P3b was assessed for both go trials (indexing sustained attention) and no-go trials (indexing inhibition processes). Higher household income was related to larger P3b amplitudes on both go and no-go trials. This was a highly educated sample, thus results indicate that P3b amplitudes are sensitive to household income even within the context of high parental education. Findings build on the behavioral literature and demonstrate that SES also has implications for the neural mechanisms underlying inhibition and attention processing in early childhood.

Developmental Shifts in Detection and Attention for Auditory, Visual, and Audiovisual Speech

PURPOSE

Successful speech processing depends on our ability to detect and integrate multisensory cues, yet there is minimal research on multisensory speech detection and integration by children. To address this need, we studied the development of speech detection for auditory (A), visual (V), and audiovisual (AV) input.

METHOD

Participants were 115 typically developing children clustered into age groups between 4 and 14 years. Speech detection (quantified by response times [RTs]) was determined for 1 stimulus, /buh/, presented in A, V, and AV modes (articulating vs. static facial conditions). Performance was analyzed not only in terms of traditional mean RTs but also in terms of the faster versus slower RTs (defined by the 1st vs. 3rd quartiles of RT distributions). These time regions were conceptualized respectively as reflecting optimal detection with efficient focused attention versus less optimal detection with inefficient focused attention due to attentional lapses.

RESULTS

Mean RTs indicated better detection (a) of multisensory AV speech than A speech only in 4- to 5-year-olds and (b) of A and AV inputs than V input in all age groups. The faster RTs revealed that AV input did not improve detection in any group. The slower RTs indicated that (a) the processing of silent V input was significantly faster for the articulating than static face and (b) AV speech or facial input significantly minimized attentional lapses in all groups except 6- to 7-year-olds (a peaked U-shaped curve). Apparently, the AV benefit observed for mean performance in 4- to 5-year-olds arose from effects of attention.

CONCLUSIONS

The faster RTs indicated that AV input did not enhance detection in any group, but the slower RTs indicated that AV speech and dynamic V speech (mouthing) significantly minimized attentional lapses and thus did influence performance. Overall, A and AV inputs were detected consistently faster than V input; this result endorsed stimulus-bound auditory processing by these children.

A systematic assessment of socioeconomic status and executive functioning in early childhood

Lower socioeconomic status (SES) consistently relates to poorer executive function (EF). This study used a systematic and nuanced approach to understand how SES relates to children's EF at a process level. We assessed children aged 4.5-5.5 years. This is a key developmental period because EF is no longer a unitary construct but rather EF components statistically load on separate factors and index distinct aspects of EF. Children completed a working memory task that involved a cognitive load component and a go/no-go task to assess inhibitory control and vigilance. Accuracy and reaction time were assessed, and each task involved four blocks to assess performance over time. Lower SES related to lower accuracy for working memory, inhibitory control, and vigilance as well as slower reaction time for working memory. SES did not relate to go/no-go reaction time. For working memory, lower SES related to poorer accuracy on lower cognitive load trials, but there were no SES differences on higher cognitive load trials. SES did not relate to maintenance of performance over time. Results suggest that for this age group the majority of domains showed SES differences. However, there were no SES differences in performance for remembering two items and maintaining performance. Thus, although overall lower SES related to poorer EF performance, there were no SES effects for skills that are still emerging for all children, namely, maintaining task performance across time and remembering two items at once. Results highlight the importance of assessing EF as a multidimensional construct and may help to identify targets for intervention.

Conflict processing in kindergarten children: New evidence from distribution analyses reveals the dynamics of incorrect response activation and suppression

The development of cognitive control is known to follow a long and protracted development. However, whether the interference effect in conflict tasks in children would entail the same core processes as in adults, namely an automatic activation of incorrect response and its subsequent suppression, remains an open question. We applied distributional analyses to reaction times and accuracy of 5- and 6-year-old children performing three conflict tasks (flanker, Simon, and Stroop) in a within-participants design. This revealed both strong commonalities and differences between children and adults. As in adults, fast responses were more error prone than slow ones on incompatible trials, indicating a fast "automatic" activation of the incorrect response. In addition, the strength of this activation differed across tasks, following a pattern similar to that of adults. Moreover, modeling the data with a drift diffusion model adapted for conflict tasks allowed one to better assess the origin of the typical slowing down observed in children. Besides showing that advanced distribution analyses can be successfully applied to children, the current results support the notion that interference effects in 5- and 6-year-olds are driven by mechanisms very similar to the ones at play in adults but with different time courses.

Intra-Individual Variability of Error Awareness and Post-error Slowing in Three Different Age-Groups

Background: Error awareness (EA) and post-error slowing (PES) are two crucial components of an adequate performance monitoring because, respectively, they allow being aware of an error and triggering performance adjustments following unexpected events. Objective: The purpose of the present study was to investigate the ontogenetic trajectories of EA and PES, as well as to examine how EA and PES interact with each other. Methods: The performance of three groups of participants (children, younger, and older adults) in a modified version of the Error Awareness task (EAT; Hester et al., 2005) was compared. In particular, in this study not only variations of the average performance were examined, but also intra-individual variability (IIV), considered in terms of variations of SD and ex-Gaussian parameters (mu, sigma, and tau). Results: Two distinct ontogenetic trajectories of EA and PES were observed. Regarding EA, we observe a U-shaped curve that describes an increase of the process from childhood to early adulthood and a progressive reduction advancing age in late adulthood. Furthermore, a greater IIV in older adults indicated a susceptibility of EA to the aging process. The ontogenetic trajectory of PES seems substantially different from the trajectory that describes EA since in PES we do not observe age-related differences. Conclusion: These results suggest that EA and PES are two independent processes. Furthermore, it appears that EA and PES are differently prone to short-term fluctuations in performance across the lifespan. While EA presents an increase in IIV in aging, PES seems to be immune to these changes.

Prenatal and postnatal polybrominated diphenyl ether (PBDE) exposure and measures of inattention and impulsivity in children

Exposure to polybrominated diphenyl ethers (PBDEs) during fetal development may be associated with deficits in attention and impulse control. However, studies examining postnatal PBDE exposures and inattention and impulsivity have been inconsistent. Using data from 214 children in the Health Outcomes and Measures of the Environment (HOME) Study, a prospective pregnancy and birth cohort with enrollment from 2003 to 2006 in the Greater Cincinnati Area, we investigated the relationship of both prenatal and postnatal PBDE exposures with attention and impulse control. Serum PBDEs were measured at 16±3weeks of gestation and during childhood at 1, 2, 3, 5, and 8years. We assessed children's attention and impulse control using the Conners' Continuous Performance Test-Second Edition (CPT-II) at 8years. We used multiple informant models to estimate associations of repeated PBDE measures with inattention and impulsivity. There was a pattern of associations between PBDEs and poorer performance on CPT-II measures of attention. For BDE-153, adverse associations extended to exposures at preschool and kindergarten ages; ten-fold increases in exposure were associated with higher omission errors (BDE-153 at 3years: β=4.0 [95% CI: -2.4, 10.5]; at 5years: β=4.6 [95% CI: -2.8, 12.0]; at 8years: β=4.1 [95% CI: -3.4, 11.5]). Longer hit reaction times, indicated by the exponential part of the hit reaction curve, were also observed with 10-fold increases in BDE-153 during the prenatal period and throughout childhood (Prenatal: β=15.0 milliseconds (ms) [95% CI: -15.8, 45.8]; 5years: β=20.6ms [95% CI: -20.8, 61.9]; 8years: β=28.6ms [95% CI: -12.1, 69.4]). Significant impairment in discriminability, as indicated by detectability (d'), between targets and non-targets was also noted with 5 and 8-year PBDE concentrations. Associations between PBDEs and inattention significantly differed by child sex, with males performing more poorly than females with regard to omission errors and measures of reaction times. Collectively, these results do not strongly support that PBDEs are associated with poorer impulse and attention control among 8year old children. However, there may be a possible relationship between prenatal and concurrent PBDEs and inattention, which requires additional research.