Neural correlates of cognitive control deficits in children with reading disorder

Brain connectivity and academic skills in English learners

English learners (ELs) are a rapidly growing population in schools in the United States with limited experience and proficiency in English. To better understand the path for EL's academic success in school, it is important to understand how EL's brain systems are used for academic learning in English. We studied, in a cohort of Hispanic middle-schoolers (n = 45, 22F) with limited English proficiency and a wide range of reading and math abilities, brain network properties related to academic abilities. We applied a method for localizing brain regions of interest (ROIs) that are group-constrained, yet individually specific, to test how resting state functional connectivity between regions that are important for academic learning (reading, math, and cognitive control regions) are related to academic abilities. ROIs were selected from task localizers probing reading and math skills in the same participants. We found that connectivity across all ROIs, as well as connectivity of just the cognitive control ROIs, were positively related to measures of reading skills but not math skills. This work suggests that cognitive control brain systems have a central role for reading in ELs. Our results also indicate that an individualized approach for localizing brain function may clarify brain-behavior relationships.

The Role of Environmental Chemicals in the Etiology of Learning Difficulties: A Novel Theoretical Framework

Children from economically disadvantaged communities have a disproportionate risk of exposure to chemicals, social stress, and learning difficulties. Although animal models and epidemiologic studies link exposures and neurodevelopment, little focus has been paid to academic outcomes in environmental health studies. Similarly, in the educational literature, environmental chemical exposures are overlooked as potential etiologic factors in learning difficulties. We propose a theoretical framework for the etiology of learning difficulties that focuses on these understudied exogenous factors. We discuss findings from animal models and longitudinal, prospective birth cohort studies that support this theoretical framework. Studies reviewed point to the effects of prenatal exposure to polycyclic aromatic hydrocarbons on reading comprehension and math skills via effects on inhibitory control processes. Long term, this work will help close the achievement gap in the United States by identifying behavioral and neural pathways from prenatal exposures to learning difficulties in children from economically disadvantaged families.

Effects of prenatal polycyclic aromatic hydrocarbons and childhood material hardship on reading achievement in school-age children: A preliminary study

Background

Children from socioeconomically disadvantaged backgrounds are at elevated risk for reading problems. They are also likely to live in neighborhoods with high levels of air pollution and to experience material hardship. Despite these risk factors, the links between prenatal chemical exposures, socioeconomic adversities, and reading problems in youth from disadvantaged backgrounds remain understudied. Here we examine associations between prenatal exposure to polycyclic aromatic hydrocarbons (PAH), a common air pollutant, and reading skills, and determine if this relationship is exacerbated by material hardship among Black and/or Latinx children who have been followed as part of a longitudinal urban birth cohort.

Methods

Mothers and their children, who were participants in a prospective birth cohort followed by the Columbia Center for Children's Environmental Health, were recruited for the current study. Personal prenatal PAH exposure was measured during the third-trimester of pregnancy using a personal air monitoring backpack. Mothers reported their level of material hardship when their child was age 5 and children completed measures of pseudoword and word reading [Woodcock Johnson III Tests of Achievement (WJ-III) Basic Reading Index] at age 7. We used multiple linear regression to examine the effects of the interaction between prenatal PAH and material hardship on Basic Reading Index, controlling for ethnicity/race, sex, birthweight, presence of a smoker in the home (prenatal), and maternal education (prenatal) (N = 53).

Results

A prenatal PAH × material hardship interaction significantly associated with WJ-III Basic Reading Index scores at age 7 (β = -0.347, t(44) = -2.197, p = 0.033). Exploratory analyses suggested that this effect was driven by untimed pseudoword decoding (WJ-III Word Attack: β = -0.391, t(44) = -2.550, p = 0.014).

Conclusion

Environmental chemical exposures can be particularly toxic during the prenatal period when the fetal brain undergoes rapid development, making it uniquely vulnerable to chemical perturbations. These data highlight the interactive effects of environmental neurotoxicants and unmet basic needs on children's acquisition of reading skill, specifically phonemic processing. Such findings identify potentially modifiable environmental risk factors implicated in reading problems in children from economically disadvantaged backgrounds.

Comparative research on neural dysfunction in children with dyslexia under different writing systems: A meta-analysis study

Developmental dyslexia is a special learning disorder which is prevalent in all languages. A central question in dyslexia is whether the neural mechanism of their defects is universal or distinct in different writing systems. Using meta-analytic approach, we created meta-images using activation abnormalities in Chinese and alphabetic children with dyslexia to find convergence and divergence under different writing systems. The results revealed that dyslexic children have a universal attention-related dysfunction with hypoactivation in the left inferior frontal cortex (IFC) and the anterior cingulate cortex (ACC) under different writing systems, in spite of differences of degree and spatial extent in those regions. Alphabetic dyslexic children additionally showed hypoactivation in the left occipito-temporo-parietal regions. Chinese dyslexic children showed specific hyperactivation in the right postcentral gyrus, the left rectus, and the right middle temporal gyrus. The present meta-analysis for the first time showed both shared and distinct abnormalities in children with dyslexia under Chinese and alphabetic writing systems.

Altered brain network topology during speech tracking in developmental dyslexia

Developmental dyslexia is often accompanied by altered phonological processing of speech. Underlying neural changes have typically been characterized in terms of stimulus- and/or task-related responses within individual brain regions or their functional connectivity. Less is known about potential changes in the more global functional organization of brain networks. Here we recorded electroencephalography (EEG) in typical and dyslexic readers while they listened to (a) a random sequence of syllables and (b) a series of tri-syllabic real words. The network topology of the phase synchronization of evoked cortical oscillations was investigated in four frequency bands (delta, theta, alpha and beta) using minimum spanning tree graphs. We found that, compared to syllable tracking, word tracking triggered a shift toward a more integrated network topology in the theta band in both groups. Importantly, this change was significantly stronger in the dyslexic readers, who also showed increased reliance on a right frontal cluster of electrodes for word tracking. The current findings point towards an altered effect of word-level processing on the functional brain network organization that may be associated with less efficient phonological and reading skills in dyslexia.

Altered functional connectivity density in mild cognitive impairment with moxibustion treatment: A resting-state fMRI study

PURPOSE

Mild cognitive impairment (MCI) is a general neurodegenerative disease. Moxibustion has been shown to have remarkable effect on cognitive improvement, however, less is known about the effect of moxibustion on MCI and its underlying neural mechanism. This study aimed to investigate the ameliorative brain network in MCI after treatments of acupoint-related moxibustion.

METHODS

Resting-state functional MRI were derived from 47 MCI patients and 30 healthy controls (HCs). Patients were randomized as Tiaoshen YiZhi (TSYZ, n = 27) and sham (SHAM, n = 20) acupoint moxibustion groups. Functional connectivity density (FCD) method and repeated-measures two-way analysis of variance (ANOVA) were performed to ascertain the interaction effects between groups (TSYZ and SHAM) and time (baseline and post-treatment). Abnormal FCD was examined between baseline and post-treatment in TSYZ and SHAM groups, respectively.

RESULTS

Compared with HCs, MCI showed altered FCD in the middle frontal cortex (MFC), inferior frontal cortex, temporal pole, thalamus and middle cingulate cortex. After moxibustion treatment in MCI, 1) a significant time-by-groups interaction was observed in the medial prefrontal cortex (mPFC); 2) abnormal long-range FCD (lrFCD) in the mPFC and MFC were modulated in TSYZ group; 3) significantly improved clinical symptoms; 4) changed lrFCD in the MFC was significantly negatively correlated with the increased Montreal Cognitive Assessment scores in TSYZ group.

CONCLUSIONS

These imaging findings suggest that treatments of acupoint-related moxibustion could improve lrFCD in certain regions related to self-related cognitive and decision making. Our study might promote understanding of MCI neural mechanisms and expand the clinical application of moxibustion in MCI.

Prenatal exposure to air pollution is associated with childhood inhibitory control and adolescent academic achievement

BACKGROUND

Prenatal air pollution exposure is associated with reductions in self-regulation and academic achievement. Self-regulation has been separately linked with academic achievement. Understudied, however, are the contributions of pollution exposure to inhibitory control, a facet of self-regulation, and whether pollution-related inhibitory control deficits are associated with impairment in academic achievement.

METHODS

Participants were recruited from a prospective birth cohort. Measures of prenatal airborne polycyclic aromatic hydrocarbons (PAH) during the third trimester of pregnancy, inhibitory control (NEPSY Inhibition) at mean age = 10.4 years, and Woodcock-Johnson Tests of Achievement-III at mean age = 13.7 were available for N = 200 participants. Multiple linear regression examined sex-dependent and sex independent associations among prenatal PAH, childhood inhibitory control, and academic achievement during adolescence, and whether childhood inhibitory control mediated associations between prenatal PAH and academic achievement during adolescence, controlling for ethnicity, maternal country of birth, language of prenatal interview, maternal marital status, maternal years of education, material hardship, quality of home caregiving environment, and early life stress.

RESULTS

Across all participants, higher prenatal PAH was significantly associated with worse spelling skills (WJ-III Spelling, β = -0.16, 95%Confidence Interval [CI]: 0.30, -0.02, p = .02). Trend level associations between higher prenatal PAH and worse reading comprehension (WJ-III Passage Comprehension, β = -0.13, 95%CI: 0.28, 0.01, p = .07) and math skills (WJ-III Broad Math, β = -0.11, 95%CI: 0.25, 0.03, p = .11) were detected. Across all participants, higher PAH was significantly associated with worse inhibitory control (β = -0.15, 95%CI: 0.29,-0.01 p = .03). Better inhibitory control was significantly associated with better reading comprehension (WJ-III Passage Comprehension, β = 0.22, 95%CI: 0.09, 0.36, p < .002) and math skills (WJ-III Broad Math Index, β = 0.32, 95%CI: 0.19, 0.45, p < .001), and trend level associations with better spelling skills (WJ-III Spelling, β = 0.12, 95%CI: 0.02, 0.26, p = .10). Inhibitory control significantly mediated PAH-related achievement effects for Passage Comprehension (β = -0.61, 95%CI: 1.49, -0.01) and Broad Math Index (β = -1.09, 95%CI: 2.36, -0.03).

CONCLUSIONS

Higher prenatal PAH exposure and lower childhood inhibitory control were associated with worse spelling, passage comprehension, and math in adolescence. Notably, childhood inhibitory control mediated PAH exposure-related effects on achievement in adolescents. Identifying these potential exposure-related phenotypes of learning problems may promote interventions that target inhibitory control deficits rather than content specific deficits.

Prenatal environmental tobacco smoke exposure alters children's cognitive control circuitry: A preliminary study

BACKGROUND AND OBJECTIVES

Prenatal exposure to environmental tobacco smoke (ETS) is associated with increased attention problems in children, however, the effects of such exposure on children's brain structure and function have not been studied. Herein, we probed effects of prenatal ETS on children's cognitive control circuitry and behavior.

METHODS

Forty-one children (7-9 years) recruited from a prospective longitudinal birth cohort of non-smoking mothers completed structural and task-functional magnetic resonance imaging to evaluate effects of maternal ETS exposure, measured by maternal prenatal urinary cotinine. Attention problems and externalizing behaviors were measured by parent report on the Child Behavior Checklist.

RESULTS

Compared to non-exposed children, exposed children had smaller left and right thalamic and inferior frontal gyrus (IFG) volumes, with large effect sizes (p-FDR < .05, Cohen's D range from 0.79 to 1.07), and increased activation in IFG during the resolution of cognitive conflict measured with the Simon Spatial Incompatibility Task (38 voxels; peak t(25) = 5.25, p-FWE = .005). Reduced thalamic volume was associated with increased IFG activation and attention problems, reflecting poor cognitive control. Mediation analyses showed a trend toward left thalamic volume mediating the association between exposure and attention problems (p = .05).

CONCLUSIONS

Our findings suggest that maternal ETS exposure during pregnancy has deleterious effects on the structure and function of cognitive control circuitry which in turn affects attentional capacity in school-age children. These findings are consistent with prior findings documenting the effects of active maternal smoking on chidlren's neurodevleoment, pointing to the neurotixicity of nicotine regardless of exposure pathway.

Convergent and divergent brain structural and functional abnormalities associated with developmental dyslexia

Brain abnormalities in the reading network have been repeatedly reported in individuals with developmental dyslexia (DD); however, it is still not totally understood where the structural and functional abnormalities are consistent/inconsistent across languages. In the current multimodal meta-analysis, we found convergent structural and functional alterations in the left superior temporal gyrus across languages, suggesting a neural signature of DD. We found greater reduction in grey matter volume and brain activation in the left inferior frontal gyrus in morpho-syllabic languages (e.g. Chinese) than in alphabetic languages, and greater reduction in brain activation in the left middle temporal gyrus and fusiform gyrus in alphabetic languages than in morpho-syllabic languages. These language differences are explained as consequences of being DD while learning a specific language. In addition, we also found brain regions that showed increased grey matter volume and brain activation, presumably suggesting compensations and brain regions that showed inconsistent alterations in brain structure and function. Our study provides important insights about the etiology of DD from a cross-linguistic perspective with considerations of consistency/inconsistency between structural and functional alterations.

Enhanced visceromotor emotional reactivity in dyslexia and its relation to salience network connectivity

Dyslexia is a neurodevelopmental disorder mainly defined by reading difficulties. During reading, individuals with dyslexia exhibit hypoactivity in left-lateralized language systems. Lower activity in one brain circuit can be accompanied by greater activity in another, and, here, we examined whether right-hemisphere-based emotional reactivity may be elevated in dyslexia. We measured emotional reactivity (i.e., facial behavior, physiological activity, and subjective experience) in 54 children ages 7-12 with (n = 32) and without (n = 22) dyslexia while they viewed emotion-inducing film clips. Participants also underwent task-free functional magnetic resonance imaging. Parents of children with dyslexia completed the Behavior Assessment System for Children, which assesses real-world behavior. During film viewing, children with dyslexia exhibited significantly greater reactivity in emotional facial behavior, skin conductance level, and respiration rate than those without dyslexia. Across the sample, greater emotional facial behavior correlated with stronger connectivity between right ventral anterior insula and right pregenual anterior cingulate cortex (pFWE<.05), key salience network hubs. In children with dyslexia, greater emotional facial behavior related to better real-world social skills and higher anxiety and depression. Our findings suggest there is heightened visceromotor emotional reactivity in dyslexia, which may lead to interpersonal strengths as well as affective vulnerabilities.

Functional MRI-Specific Alterations in Executive Control Network in Mild Cognitive Impairment: An ALE Meta-Analysis

Background: Mild cognitive impairment (MCI) is regarded as a transitional stage between normal aging and Alzheimer's disease (AD) dementia. MCI individuals with deficits in executive function are at higher risk for progressing to AD dementia. Currently, there is no consistent result for alterations in the executive control network (ECN) in MCI, which makes early prediction of AD conversion difficult. The aim of the study was to find functional MRI-specific alterations in ECN in MCI patients by expounding on the convergence of brain regions with functional abnormalities in ECN.

Methods: We searched PubMed, Embase, and Web of Science to identify neuroimaging studies using methods including the amplitude of low frequency fluctuation/fractional amplitude of low-frequency fluctuation, regional homogeneity, and functional connectivity in MCI patients. Based on the Activation Likelihood Estimation algorithm, the coordinate-based meta-analysis and functional meta-analytic connectivity modeling were conducted.

Results: A total of 25 functional imaging studies with MCI patients were included in a quantitative meta-analysis. By summarizing the included articles, we obtained specific brain region changes, mainly including precuneus, cuneus, lingual gyrus, middle frontal gyrus, posterior cingulate cortex, and cerebellum posterior lobe, in the ECN based on these three methods. The specific abnormal brain regions indicated that there were interactions between the ECN and other networks.

Conclusions: This study confirms functional imaging specific abnormal markers in ECN and its interaction with other networks in MCI. It provides novel targets and pathways for individualized and precise interventions to delay the progression of MCI to AD.

Different predictive roles of phonological awareness and visual attention span for early character reading fluency in Chinese

Previous studies have usually explored the possible mechanisms underlying reading fluency separately from either linguistic (e.g., phonological awareness, PA) or basic cognitive (e.g., visual attention span, VAS) levels, but relatively little is known about the systematic relationship between multiple levels of cognitive factors and reading fluency development. Thus, the present study, from a combinative point of view, investigated the relationship between VAS at a basic cognitive level and PA at a high linguistic level and explored their predictive power for reading fluency development a year later through a longitudinal method. PA and VAS were measured in sixty-five Chinese children who had just entered Grade 1 of primary school (Time 1); PA tests included syllabic and phonemic aspects, and VAS was reflected by performance in the visual 1-back task with nonverbal stimuli and no verbal response. Reading fluency was tested at the single-character level at the beginning of Grade 2 (Time 2). The results showed that phoneme awareness could not predict variation in reading fluency, while both syllable awareness and VAS showed significant predictive powers for single-character reading fluency. Additionally, further analysis revealed that the relationship between VAS and later single-character reading fluency was partially mediated by syllable awareness. These findings indicated Chinese language characteristics in the relationship among VAS, PA, and reading fluency. The possible roles of multiple levels of cognitive skills in fluent reading have been further discussed and have implications for the early diagnosis and remediation of reading dysfluency.