First Demonstration of Double Dissociation between COMT-Met158 and COMT-Val158 Cognitive Performance When Stressed and When Calmer.

We present here the first evidence of the much-predicted double dissociation between the effect of stress on cognitive skills [executive functions (EFs)] dependent on prefrontal cortex (PFC) by catechol-O-methyltransferase (COMT) genotype. The COMT gene polymorphism with methionine (Met) at codon 158 results in more dopamine (DA) in PFC and generally better EFs, while with valine (Val) at codon 158 the result is less PFC DA and generally poorer EFs. Many have predicted that mild stress, by raising PFC DA levels should aid EFs of COMT-Vals (bringing their PFC DA levels up, closer to optimal) and impair EFs of COMT-Mets (raising their PFC DA levels past optimal). We tested 140 men and women in a within-subject crossover design using extremely mild social evaluative stress. On trials requiring EFs (incongruent trials) of the Flanker/Reverse Flanker task, COMT-Val158 homozygotes performed better when mildly stressed than when calmer, while COMT-Met158 carriers performed worse when mildly stressed. Two other teams previously tried to obtain this, but only found stress impairing EFs of COMT-Mets, not improving EFs of COMT-Vals. Perhaps we found both because we used a much milder stressor. Evidently, the bandwidth for stress having a facilitative effect on EFs is exceedingly narrow.

Maturational Changes in Human Dorsal and Ventral Visual Networks.

Developmental neuroimaging studies report the emergence of increasingly diverse cognitive functions as closely entangled with a rise-fall modulation of cortical thickness (CTh), structural cortical and white-matter connectivity, and a time-course for the experience-dependent selective elimination of the overproduced synapses. We examine which of two visual processing networks, the dorsal (DVN; prefrontal, parietal nodes) or ventral (VVN; frontal-temporal, fusiform nodes) matures first, thus leading the neuro-cognitive developmental trajectory. Three age-dependent measures are reported: (i) the CTh at network nodes; (ii) the matrix of intra-network structural connectivity (edges); and (iii) the proficiency in network-related neuropsychological tests. Typically developing children (age ~6 years), adolescents (~11 years), and adults (~21 years) were tested using multiple-acquisition structural T1-weighted magnetic resonance imaging (MRI) and neuropsychology. MRI images reconstructed into a gray/white/pial matter boundary model were used for CTh evaluation. No significant group differences in CTh and in the matrix of edges were found for DVN (except for the left prefrontal), but a significantly thicker cortex in children for VVN with reduced prefrontal ventral-fusiform connectivity and with an abundance of connections in adolescents. The higher performance in children on tests related to DVN corroborates the age-dependent MRI structural connectivity findings. The current findings are consistent with an earlier maturational course of DVN.

Effects of physical activity interventions on cognitive and academic performance in children and adolescents: a novel combination of a systematic review and recommendations from an expert panel.

OBJECTIVE: To summarise the current evidence on the effects of physical activity (PA) interventions on cognitive and academic performance in children, and formulate research priorities and recommendations. DESIGN: Systematic review (following PRISMA guidelines) with a methodological quality assessment and an international expert panel. We based the evaluation of the consistency of the scientific evidence on the findings reported in studies rated as of high methodological quality. DATA SOURCES: PubMed, PsycINFO, Cochrane Central, Web of Science, ERIC, and SPORTDiscus. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: PA-intervention studies in children with at least one cognitive or academic performance assessment. RESULTS: Eleven (19%) of 58 included intervention studies received a high-quality rating for methodological quality: four assessed effects of PA interventions on cognitive performance, six assessed effects on academic performance, and one on both. All high-quality studies contrasted the effects of additional/adapted PA activities with regular curriculum activities. For cognitive performance 10 of 21 (48%) constructs analysed showed statistically significant beneficial intervention effects of PA, while for academic performance, 15 of 25 (60%) analyses found a significant beneficial effect of PA. Across all five studies assessing PA effects on mathematics, beneficial effects were reported in six out of seven (86%) outcomes. Experts put forward 46 research questions. The most pressing research priority cluster concerned the causality of the relationship between PA and cognitive/academic performance. The remaining clusters pertained to PA characteristics, moderators and mechanisms governing the 'PA-performance' relationship and miscellaneous topics. CONCLUSION: There is currently inconclusive evidence for the beneficial effects of PA interventions on cognitive and overall academic performance in children. We conclude that there is strong evidence for beneficial effects of PA on maths performance.The expert panel confirmed that more 'high-quality' research is warranted. By prioritising the most important research questions and formulating recommendations we aim to guide researchers in generating high-quality evidence. Our recommendations focus on adequate control groups and sample size, the use of valid and reliable measurement instruments for physical activity and cognitive performance, measurement of compliance and data analysis. PROSPERO REGISTRATION NUMBER: CRD42017082505.

Children's stress regulation mediates the association between prenatal maternal mood and child executive functions for boys, but not girls.

Prenatal exposure to maternal mood disturbances shapes children's cognitive development reflected in the critical construct of executive functions (EFs). Little is known, however, about underlying mechanisms. By examining cortisol responses in both everyday and lab challenge settings, we tested whether the child/offspring hypothalamic-pituitary-adrenal axis mediates effects of prenatal maternal mood on child EFs at age 6. In 107 Canadian children born to women with a wide range of anxious and depressive symptoms during pregnancy, we found that in boys but not girls, depressed and/or anxious prenatal maternal mood is associated with heightened diurnal cortisol levels in everyday settings, as well as heightened cortisol reactivity to a lab challenge and that this heightened reactivity was associated with poorer EFs. Among boys we also observed that cortisol reactivity but not diurnal cortisol mediated the association between depressed and/or anxious prenatal maternal mood and EFs. Depressed and/or anxious prenatal maternal mood was related to child EFs for both girls and boys. To our knowledge, this is the first study to demonstrate a mediating role for child stress regulation in the association between prenatal maternal stress-related mood disturbances and child EFs, providing evidence of a mechanism contributing to fetal programming of cognition.

Maternal depression trajectories from pregnancy to 3 years postpartum are associated with children's behavior and executive functions at 3 and 6 years.

The objective of this study was to investigate how patterns of maternal depressive symptoms from mid-pregnancy to 3 years postpartum are associated with children's behavior at age 3 years and executive functions. Maternal depressive symptoms were measured from mid-pregnancy to 3 years postpartum. Growth mixture modeling was used on standardized maternal depression scores (n = 147) to identify trajectories. Children's behavioral problems and mental health symptomatology (internalizing, externalizing, and attention deficit hyperactivity disorder) were obtained at 3 and 6 years. EFs were assessed by a laboratory-based computerized task and maternal-report at 6 years. Multivariable linear regressions of children's outcomes against maternal depressive symptom trajectories were conducted (n = 103). Three distinct patterns of maternal depressive symptom trajectories were identified: low (n = 105), increasing (n = 27), and decreasing (n = 15). Children of mothers whose depressive symptoms increased reported more problem behaviors at 3 years and poorer EFs at 6 years as assessed by both instruments, but no significant differences in mental health symptomatology at 6 years, relative to those whose mothers had consistently low depressive symptoms. Children whose mothers became less depressed over time had comparable levels of behavioral problems at age 3, executive functions, and internalizing and externalizing scores at age 6; and fewer reported ADHD behaviors at age 6, than those whose mothers remained less depressed over time. If mothers' depressive symptoms improve over the first 3 years postpartum, their children's outlook may be comparable to those whose mothers had consistently low depressive symptoms.

Do children need reminders on the Day-Night task, or simply some way to prevent them from responding too quickly?

We previously reported better performance on the Day-Night task when a ditty was chanted between stimulus presentation and when children could respond (Diamond, Kirkham, & Amso, 2002). Here we investigated competing hypotheses about why the ditty helps. Does it help because it imposes a brief waiting time (the child waits while the ditty is chanted before responding)? Or, does the ditty help because of its content, providing information helpful to performing the task? One-third of the 72 children (age 4) were tested with the ditty previously used which reminds them: "Think about the answer; don't tell me." Another 24 children were tested with a ditty with no task-relevant content: "I hope you have a nice time; I like you." One-third received the standard condition. Performance in both ditty conditions was comparable and better than in the standard condition. That indicates that a factor common to both ditties (that chanting them took time, allowing the prepotent response to subside and the more-considered answer to reach response threshold) likely accounts for their benefit. Whether a ditty reminded children what to do or not did not affect the results. The challenge of the Day-Night task for preschoolers is not its working memory demands but the need to inhibit a dominant response, making a different response instead.

Executive functions.

Executive functions (EFs) make possible mentally playing with ideas; taking the time to think before acting; meeting novel, unanticipated challenges; resisting temptations; and staying focused. Core EFs are inhibition [response inhibition (self-control--resisting temptations and resisting acting impulsively) and interference control (selective attention and cognitive inhibition)], working memory, and cognitive flexibility (including creatively thinking "outside the box," seeing anything from different perspectives, and quickly and flexibly adapting to changed circumstances). The developmental progression and representative measures of each are discussed. Controversies are addressed (e.g., the relation between EFs and fluid intelligence, self-regulation, executive attention, and effortful control, and the relation between working memory and inhibition and attention). The importance of social, emotional, and physical health for cognitive health is discussed because stress, lack of sleep, loneliness, or lack of exercise each impair EFs. That EFs are trainable and can be improved with practice is addressed, including diverse methods tried thus far.

Refining the understanding of inhibitory processes: how response prepotency is created and overcome.

Understanding (a) how responses become prepotent provides insights into when inhibition is needed in everyday life. Understanding (b) how response prepotency is overcome provides insights for helping children develop strategies for overcoming such tendencies. Concerning (a), on tasks such as the day-night Stroop-like task, is the difficulty with inhibiting saying the name of the stimulus due to the name being semantically related to the correct response or to its being a valid response on the task (i.e. a member of the response set) though incorrect for this stimulus? Experiment 1 (with 40 4-year-olds) suggests that prepotency is caused by membership in the response set and not semantic relation. Concerning (b), Diamond, Kirkham and Amso (2002) found that 4-year-olds could succeed on the day-night task if the experimenter sang a ditty after showing the stimulus card, before the child was to respond. They concluded that it was because delaying children's responses gave them time to compute the correct answer. However, Experiment 2 (with 90 3-year-olds) suggests that such a delay helps because it gives the incorrect, prepotent response time to passively dissipate, not because of active computation during the delay.

Assessment of Executive and Cognitive Functions in Children with Restless Sleep Disorder: A Pilot Study.

Restless sleep disorder affects children and is characterized by frequent nocturnal movements, iron deficiency, and daytime symptoms such as poor school performance or behavioral problems. Although sleep parameters have been thoroughly studied and daytime sleepiness has been previously assessed, neurocognitive and executive functions have not. In this study, we evaluated neurocognitive functions in a group of 13 children diagnosed with restless sleep disorder using the National Institute of Health Toolbox (NIH toolbox). The mean age was 10.62 (S.D. 2.785). Among them, seven were male and six were female. The fully corrected T-scores (adjusted for demographic variables: age, ethnicity, and education level) showed the lowest values for the Flanker test (selective attention) and dimensional change card sorting test (cognitive flexibility and inhibitory control), with a very large effect size vs. the corresponding expected frequencies. For all the other tests, the average scores were 50; however, individual children scored low on pattern recognition and two composite scores (fluid and total). In conclusion, these data support the fact that cognitive functions are affected in children with restless sleep disorder, especially selective attention. Clinicians must recognize sleep disorders and daytime impairment in order to promptly intervene and prevent cognitive impairments.

Correction: One Size Does Not Fit All: Assuming the Same Normal Body Temperature for Everyone is Not Justified.

[This corrects the article DOI: 10.1371/journal.pone.0245257.].

One size does not fit all: Assuming the same normal body temperature for everyone is not justified.

Despite the increasing personalization of medicine, surprisingly ~37.0°C (98.6°F) continues as the estimate of normal temperature. We investigated between-subject and within-subject thermal variability, whether a significant percentage of individuals have a low mean oral temperature, and whether these differ by sex, age, time of day, ethnicity, body mass index (BMI), or menstrual phase. Oral temperature was measured by Life Brand® Fast-Read Digital Oral Thermometers and sampled 14 times over two weeks, seven morning and seven evening readings. The volunteer sample consisted of 96 adults (42 men, 54 women; 27 couples, 42 singletons), ages 18-67 years. We found sizeable individual differences in body temperature and that the normal temperature of many individuals is considerably lower than 37.0°C (98.6°F). Mean temperatures ranged from 35.2°C (95.4°F) to 37.4°C (99.3°F). The mean temperature across all participants was 36.1°C (97.0°F)-lower than most studies have reported, consistent with recent evidence of temperature declining over decades. 77% had mean temperatures at least 0.55°C (1°F) lower than 37.0°C (98.6°F). Mean temperature did not differ by age, but women had higher temperatures than men, even within a couple with room temperature and warmth of clothing equated. Although oral temperature varied widely across individuals, it showed marked stability within individuals over days. Variability of temperature over days did not differ by sex, but was larger among younger adults. Using 37.0°C (98.6°F) as the assumed normal temperature for everyone can result in healthcare professionals failing to detect a serious fever in individuals with a low normal temperature or obtaining false negatives for those individuals when using temperature to screen for COVID-19, mistaking their elevated temperature as normal. Some have called for lowering the estimate of normal temperature slightly (e.g., 0.2°C [0.36°F]). That still seems an overly high estimate. More important, using any standardized "normal" temperature will lead to errors for many people. Individual differences are simply too great. Personalizing body temperature is needed. Temperature could be measured at yearly doctor visits, as blood pressure is now. That would be simple to implement. Since our results show marked thermal stability within an individual, sampling temperature only once yearly could provide an accurate indication of a person's normal temperature at that time of day. Such records over time would also provide a more accurate understanding of how temperature changes over the lifespan.

The Evidence Base for Improving School Outcomes by Addressing the Whole Child and by Addressing Skills and Attitudes, Not Just Content.

If we want the best academic outcomes, the most efficient and cost-effective route to achieve that is, counterintuitively, not to narrowly focus on academics, but to also address children's social, emotional, and physical development. Similarly, the best and most efficient route to physical health is through also addressing emotional, social, and cognitive wellness. Emotional wellness, similarly, depends critically on social, cognitive, and physical wellness.

Executive functions.

First, executive functions are defined. Then the development of executive functions in children, from infancy to 10-11 years of age, is briefly described. The relation between the speed of processing and the development of executive functions is addressed. Finally, tools and pointers for evaluating executive functioning in younger and older children are discussed. A cautionary note is sounded, in that almost no executive function measure requires only one executive function. A child might fail a working memory task because of problems with inhibitory control (not working memory), fail an inhibitory control task because of working memory problems, or fail a cognitive flexibility, planning, or reasoning task because of problems with inhibitory control or working memory.

Children Only 3 Years Old Can Succeed at Conditional "If, Then" Reasoning, Much Earlier Than Anyone Had Thought Possible.

That conditional, if-then reasoning does not emerge until 4-5 years has long been accepted. Here we show that children barely 3 years old can do conditional reasoning. All that was needed was a superficial change to the stimuli: When color was a property of the shapes (line drawings of a star and truck) rather than of the background (as in all past conditional discrimination [CD] testing), 3-year-olds could succeed. Three-year-olds do not seem to use color to inform them which shape is correct unless color is a property of the shapes themselves. While CD requires integrating color and shape information, the dimensional change card sort (DCCS) task requires keeping those dimension cognitively separate - inhibiting attention to one (e.g., shape) when sorting by the other (e.g., color). For DCCS, a superficial change to the stimuli that is the inverse of what helps on CD enables 3-year-olds to succeed when normally they do not until ∼ 4 ⁤ 1 2 years. As we and others have previously shown, 3-year-olds can succeed at DCCS when color is a property of the background (e.g., a white truck on a red background), instead of a property of the stimulus (e.g., a red truck on a white background, as in standard DCCS). Our findings on CD and DCCS suggest that scaffolding preschoolers' emerging conceptual skills by changing the way stimuli look (perceptual bootstrapping) enables 3-year-olds to demonstrate reasoning abilities long thought beyond their grasp. Evidently, children of 3 years have difficulty mentally separating dimensions (e.g., color and shape) of the same object and difficulty mentally integrating dimensions not part of the same object. Our present CD findings plus our earlier DCCS findings provide strong evidence against prominent cognitive complexity, conditional reasoning, and graded memory theories for why 3-year-olds fail these two tasks. The ways we have traditionally queried children may have obscured the budding reasoning competencies present at 3 years of age.

The interplay of biology and the environment broadly defined.

This special section of Developmental Psychology contains articles on the interplay of biology and the environment, broadly defined, that have the potential to change or challenge how developmental psychologists think. Topics include how experience affects gene expression; how genes affect how the environment is experienced and what effect the environment has; interactions between the environment and the presence or absence of early brain damage; motor neurons and the understanding of others' beliefs and intentions; the effect of physical fitness on cognition and the brain; evidence that our brains work and develop differently from the way traditionally thought; misconceptions that can arise from treating children as if they are simply small adults; and how research with adults can provide insights into developmental processes in children. Each of the 16 articles in the special section forges new territory and crosses disciplinary boundaries. They suggest that investigators look at variables not typically considered, or look at them from perspectives not usually taken, and especially that they pay more attention to interrelations among variables.

All or none hypothesis: a global-default mode that characterizes the brain and mind.

It is proposed that the mind and brain often work at a gross level and only with fine tuning or inhibition act in a more differentiated manner, even when one might think the domains being issued the global command should be distinct. This applies to disparate findings in cognitive science and neuroscience in both children and adults. Thus, it is easier to switch everything, or nothing, than to switch one thing (the rule one is following or which button to press) but not the other. It is easier to issue the same command to both hands than to move only one hand. If one needs to respond to the opposite (or antonym) of a stimulus, one is faster if the correct response is to the side opposite the stimulus. People tend to think of the nervous system as sending out very precise commands only to the relevant recipient, but it appears that often the command goes out more globally and then parts of the system need to be inhibited from acting on the command.

Randomized control trial of Tools of the Mind: Marked benefits to kindergarten children and their teachers.

The kindergarten program, Tools of the Mind (Tools), has been shown to improve executive functions (as assessed by laboratory measures) and academic performance. The objective here was to see if Tools can improve executive functions in the real world (in the classroom), academic outcomes not previously investigated, reduce bullying and peer ostracism, and increase teachers' and students' joy in being in the classroom. This first randomized controlled trial of Tools in Canada included 351 kindergarten children (mean age 5.2 years at entry; 51% female) in 18 public schools. Stratified randomization resulted in teachers and students in both groups being closely matched. Teachers in both groups received the same number of training hours and same funds for new materials. Outcome measures were pre and post standardized academic skill assessments and teacher online survey responses. This study replicated that Tools improves reading and shows for the first time that it improves writing (far exceeding levels the school districts had seen before), self-control and attention-regulation in the real world (e.g., time on task without supervision), reduces teacher burnout and children being ostracized or excluded, and increases the joy students and teachers experience in school. By Spring, Tools teachers were still enthusiastic about teaching; control teachers were exhausted. These results were not only better than the control group but also better than Tools teachers experienced the year before Tools. Thus, children in a kindergarten curriculum that emphasized play, improving self-regulation, working together and helping one another, and hands-on learning performed better academically, showed less bullying and peer ostracism and more kindness and helping behavior than students in more traditional classes, and teacher enthusiasm for teaching soared. Tools reduced initial disparities separating children, schools, and teachers.

Biological processes in prevention and intervention: the promotion of self-regulation as a means of preventing school failure.

This paper examines interrelations between biological and social influences on the development of self-regulation in young children and considers implications of these interrelations for the promotion of self-regulation and positive adaptation to school. Emotional development and processes of emotion regulation are seen as influencing and being influenced by the development of executive cognitive functions, including working memory, inhibitory control, and mental flexibility important for the effortful regulation of attention and behavior. Developing self-regulation is further understood to reflect an emerging balance between processes of emotional arousal and cognitive regulation. Early childhood educational programs that effectively link emotional and motivational arousal with activities designed to exercise and promote executive functions can be effective in enhancing self-regulation, school readiness, and school success.

Bootstrapping conceptual deduction using physical connection: rethinking frontal cortex.

The age at which infants can demonstrate the ability to deduce abstract rules can be reduced by more than half, from 21 months to 9 months. The key is to introduce a physical connection between the items to be conceptually related. I argue here that making the same change in how items are presented might also help some preschoolers with learning delays, especially some children with autism. I also suggest that the roles of premotor and ventrolateral prefrontal cortices in deducing abstract rules might have been misinterpreted behaviorally and anatomically. The crucial brain region may be the periarcuate, which partially overlaps both premotor and lateral prefrontal cortex. The cognitive ability made possible by this region might be something far more elementary than previously considered: the ability to perceive conceptual connections in the absence of physical connection.