Increased Resting-State Functional Connectivity in the Cingulo-Opercular Cognitive-Control Network after Intervention in Children with Reading Difficulties

Localized alterations in cortical thickness and sulcal depth of the cingulo-opercular network in relation to lower reading fluency skills in children with dyslexia

The traditional models of reading development describe how language processing and word decoding contribute to reading comprehension and how impairments in word decoding, a defining feature of dyslexia, affect reading comprehension outcomes. However, these models do not include word and sentence reading (contextual reading) fluency, both of which engage executive functions, with notably decreased performance in children with dyslexia. In the current study, we compared cortical thickness and sulcal depth (CT/SD) in the cingulo-opercular (CO) executive functions brain network in children with dyslexia and typical readers and examined associations with word vs. contextual reading fluency. Overall, CT was lower in insular regions and higher in parietal and caudal anterior cingulate cortex regions in children with dyslexia. Children with dyslexia showed positive correlations between word reading fluency and CT/SD in insular regions, whereas no significant correlations were observed in typical readers. For sentence reading fluency, negative correlations with CT/SD were found in insular regions in children with dyslexia, while positive correlations with SD were found in insular regions in typical readers. These results demonstrate the differential relations between word and sentence reading fluency and anatomical circuitry supporting executive functions in children with dyslexia vs. typical readers. It also suggests that word and sentence reading fluency, relate to morphology of executive function-related regions in children with dyslexia, whereas in typical readers, only sentence reading fluency relates to morphology of executive function regions. The results also highlight the role of the insula within the CO network in reading fluency. Here we suggest that word and sentence reading fluency are distinct components of reading that should each be included in the Simple View of Reading traditional model.

Functional connectivity is linked to working memory differences in children with reading learning disability

Reading learning disability (RLD) is characterized by a specific difficulty in learning to read that is not better explained by an intellectual disability, lack of instruction, psychosocial adversity, or a neurological disorder. According to the domain-general hypothesis, a working memory deficit is the primary problem. Working memory in this population has recently been linked to altered resting-state functional connectivity within the default mode network (DMN), salience network (SN), and frontoparietal network (FPN) compared to that in typically developing individuals. The main purpose of the present study was to compare the within-network functional connectivity of the DMN, SN, FPN, and reading network in two groups of children with RLD: a group with lower-than-average working memory (LWM) and a group with average working memory (AWM). All subjects underwent resting-state functional magnetic resonance imaging (fMRI), and data were analyzed from a network perspective using the network brain statistics framework. The results showed that the LWM group had significantly weaker connectivity in a network that involved brain regions in the DMN, SN, and FPN than the AWM group. Although there was no significant difference between groups in reading network in the present study, other studies have shown relationship of the connectivity of the angular gyrus, supramarginal gyrus, and inferior parietal lobe with the phonological process of reading. The results suggest that although there are significant differences in functional connectivity in the associated networks between children with LWM and AWM, the distinctive cognitive profile has no specific effect on the reading network.

Greater utilization of executive functions networks when listening to stories with visual stimulation is related to lower reading abilities in children

Narrative comprehension relies on basic sensory processing abilities, such as visual and auditory processing, with recent evidence for utilizing executive functions (EF), which are also engaged during reading. EF was previously related to the "supporter" of engaging the auditory and visual modalities in different cognitive tasks, with evidence of lower efficiency in this process among those with reading difficulties in the absence of a visual stimulus (i.e. while listening to stories). The current study aims to fill out the gap related to the level of reliance on these neural circuits while visual aids (pictures) are involved during story listening in relation to reading skills. Functional MRI data were collected from 44 Hebrew-speaking children aged 8-12 years while listening to stories with vs without visual stimuli (i.e., pictures). Functional connectivity of networks supporting reading was defined in each condition and compared between the conditions against behavioral reading measures. Lower reading skills were related to greater functional connectivity values between EF networks (default mode and memory networks), and between the auditory and memory networks for the stories with vs without the visual stimulation. A greater difference in functional connectivity between the conditions was related to lower reading scores. We conclude that lower reading skills in children may be related to a need for greater scaffolding, i.e., visual stimulation such as pictures describing the narratives when listening to stories, which may guide future intervention approaches.

An executive-functions-based reading training enhances sensory-motor systems integration during reading fluency in children with dyslexia

The Simple View of Reading model suggests that intact language processing and word decoding lead to proficient reading comprehension, with recent studies pointing at executive functions as an important component contributing to reading proficiency. Here, we aimed to determine the underlying mechanism(s) for these changes. Participants include 120 8- to 12-year-old children (n = 55 with dyslexia, n = 65 typical readers) trained on an executive functions-based reading program, including pre/postfunctional MRI and behavioral data collection. Across groups, improved word reading was related to stronger functional connections within executive functions and sensory networks. In children with dyslexia, faster and more accurate word reading was related to stronger functional connections within and between sensory networks. These results suggest greater synchronization of brain systems after the intervention, consistent with the "neural noise" hypothesis in children with dyslexia and support the consideration of including executive functions as part of the Simple View of Reading model.

Combined and sequential exposure to prenatal second hand smoke and postnatal maternal distress is associated with cingulo-opercular global efficiency and attention problems in school-age children

BACKGROUND

Prenatal exposure to secondhand (environmental) tobacco smoke (SHS) is associated with adverse neurodevelopmental outcomes, including altered functional activation of cognitive control brain circuitry and increased attention problems in children. Exposure to SHS is more common among Black youth who are also disproportionately exposed to socioeconomic disadvantage and concomitant maternal distress. We examine the combined effects of exposure to prenatal SHS and postnatal maternal distress on the global efficiency (GE) of the brain's cingulo-opercular (CO) and fronto-parietal control (FP) networks in childhood, as well as associated attention problems.

METHODS

Thirty-two children of non-smoking mothers followed in a prospective longitudinal birth cohort at the Columbia Center for Children's Environmental Health (CCCEH) completed magnetic resonance imaging (MRI) at ages 7-9 years old. GE scores were extracted from general connectivity data collected while children completed the Simon Spatial Incompatibility functional magnetic resonance imaging (fMRI) task. Prenatal SHS was measured using maternal urinary cotinine from the third trimester; postnatal maternal distress was assessed at child age 5 using the Psychiatric Epidemiology Research Interview (PERI-D). The Child Behavior Checklist (CBCL) measured Attention and Attention Deficit Hyperactivity Disorder (ADHD) problems at ages 7-9. Linear regressions examined the interaction between prenatal SHS and postnatal maternal distress on the GE of the CO or FP networks, as well as associations between exposure-related network alterations and attention problems. All models controlled for age, sex, maternal education at prenatal visit, race/ethnicity, global brain correlation, and mean head motion.

RESULTS

The prenatal SHS by postnatal maternal distress interaction term associated with the GE of the CO network (β = 0.673, Bu = 0.042, t(22) = 2.427, p = .024, D = 1.42, 95% CI [0.006, 0.079], but not the FP network (β = 0.138, Bu = 0.006, t(22) = 0.434, p = .668, 95% CI [-0.022, 0.033]). Higher GE of the CO network was associated with more attention problems (β = 0.472, Bu = 43.076, t(23) = 2.780, p = .011, D = 1.74, n = 31, 95% CI [11.024, 75.128], n = 31) and ADHD risk (β = 0.436, Bu = 21.961, t(29) = 2.567, p = .018, D = 1.81, 95% CI [4.219, 39.703], n = 30).

CONCLUSIONS

These preliminary findings suggest that sequential prenatal SHS exposure and postnatal maternal distress could alter the efficiency of the CO network and increase risk for downstream attention problems and ADHD. These findings are consistent with prior studies showing that prenatal SHS exposure is associated with altered function of brain regions that support cognitive control and with ADHD problems. Our model also identifies postnatal maternal distress as a significant moderator of this association. These data highlight the combined neurotoxic effects of exposure to prenatal SHS and postnatal maternal distress. Critically, such exposures are disproportionately distributed among youth from minoritized groups, pointing to potential pathways to known mental health disparities.

Structural neural connectivity correlates with pre-reading abilities in preschool children

Pre-reading abilities are predictive of later reading ability and can be assessed before reading begins. However, the neural correlates of pre-reading abilities in young children are not fully understood. To address this, we examined 246 datasets collected in an accelerated longitudinal design from 81 children aged 2-6 years (age = 4.6 ± 0.98 years, 47 males). Children completed pre-reading assessments (NEPSY-II Phonological Processing and Speeded Naming) and underwent a diffusion magnetic resonance imaging (MRI) scan to assess white matter connectivity. We defined a core neural network of reading and language regions based on prior literature, and structural connections within this network were assessed using graph theory analysis. Linear mixed models accounting for repeated measures were used to test associations between children's pre-reading performance and graph theory measures for the whole bilateral reading network and each hemisphere separately. Phonological Processing scores were positively associated with global efficiency, local efficiency, and clustering coefficient in the bilateral and right hemisphere networks, as well as local efficiency and clustering coefficient in the left hemisphere network. Our findings provide further evidence that structural neural correlates of Phonological Processing emerge in early childhood, before and during early reading instruction.

Language First, Cognition Later: Different Trajectories of Subcomponents of the Future-Reading Network in Processing Narratives from Kindergarten to Adolescence

Narrative comprehension is a linguistic ability that emerges early in life and has a critical role in language development, reading acquisition, and comprehension. According to the Simple View of Reading model, reading is acquired through word decoding and linguistic comprehension. Here, within and between networks, functional connectivity in several brain networks supporting both language and reading abilities was examined from prereading to proficient reading age in 32 healthy children, ages 5-18 years, scanned annually while listening to stories over 12 years. Functional connectivity changes within and between the networks were assessed and compared between the years using hierarchical linear regression and were related to reading abilities. At prereading age, the networks related to basic language processing accounted for 32.5% of the variation of reading ability at reading age (at 12-14 years) (R2 = 0.325, p = 0.05). At age 17, more complex cognitive networks were involved and accounted for 97.4% of the variation in reading ability (R2 = 0.974, p = 0.022). Overall, networks composing the future-reading network are highly involved in processing narratives along development; however, networks related to semantic, phonological, and syntactic processing predict reading ability earlier in life, and more complex networks predict reading proficiency later in life.

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.

Changes in Brain Network Connections After Exposure and Response Prevention Therapy for Obsessive-Compulsive Disorder in Adolescents and Adults

BACKGROUND

Functional alterations of tripartite neural networks during cognitive control (i.e., frontoparietal network [FPN], cingulo-opercular network, and default mode network) occur in patients with obsessive-compulsive disorder (OCD) and may contribute to illness expression. However, the degree to which changes in these networks are elicited by gold standard treatment (e.g., exposure and response prevention [EX/RP]) remains unknown. Understanding how EX/RP modulates network connectivity in adolescent versus adult patients with OCD may aid the identification of developmentally sensitive treatment targets that enhance cognitive control.

METHODS

Data from a total of 169 adolescents (13-17 years) and adults (25-40 years; 57% female) were analyzed, including healthy control participants (n = 58) and patients with OCD (n = 111) who were randomized to either EX/RP or an active control therapy (stress management training). Participants performed a flanker task during functional magnetic resonance imaging pre- and posttreatment. To retain sensitivity to individual differences in connectivity, group iterative multiple model estimation was used to assess functional connectivity (i.e., density) within and between brain networks.

RESULTS

Significant increases in FPN density and decreases in FPN-default mode network density were observed from pre- to posttreatment in patients who received EX/RP. The opposite patterns of change occurred in patients who received stress management training. These treatment-related changes in network density did not differ across age group.

CONCLUSIONS

Results suggest EX/RP-specific changes in task-based connectivity in patients with OCD. Given baseline differences between healthy control participants and patients by age group, these treatment-related changes may indicate restoration of healthy FPN and default mode network development across patients, providing targets for improving response to EX/RP.

Executive functions-based reading training engages the cingulo-opercular and dorsal attention networks

The aim of this study was to determine the effect of a computerized executive functions (EFs)-based reading intervention on neural circuits supporting EFs and visual attention. Seed-to-voxel functional connectivity analysis was conducted focusing on large-scale attention system brain networks, during an fMRI reading fluency task. Participants were 8- to 12-year-old English-speaking children with dyslexia (n = 43) and typical readers (n = 36) trained on an EFs-based reading training (n = 40) versus math training (n = 39). Training duration was 8 weeks. After the EFs-based reading intervention, children with dyslexia improved their scores in reading rate and visual attention (compared to math intervention). Neurobiologically, children with dyslexia displayed an increase in functional connectivity strength after the intervention between the cingulo-opercular network and occipital and precentral regions. Noteworthy, the functional connectivity indices between these brain regions showed a positive correlation with speed of processing and visual attention scores in both pretest and posttest. The results suggest that reading improvement following an EFs-based reading intervention involves neuroplastic connectivity changes in brain areas related to EFs and primary visual processing in children with dyslexia. Our results highlight the need for training underlying cognitive abilities supporting reading, such as EFs and visual attention, in order to enhance reading abilities in dyslexia.

Fluent contextual reading is associated with greater synchronization of the visual and auditory networks, fluent reading and better speed of processing in children with dyslexia

The asynchrony theory of dyslexia postulates weaker visual (orthographical processing) and auditory (phonological processing) network synchrony in dyslexic readers. The weaker visual-auditory network synchronization is suggested to contribute to slow processing speed, which supports cognitive control, contributing to single-word reading difficulty and lower reading fluency. The current study aims to determine the neurobiological signature for this theory and to examine if prompting enhanced reading speed through deleted text is associated with a greater synchronization of functional connectivity of the visual and auditory networks in children with dyslexia and typical readers (TRs). We further aimed to determine if the change in visual-auditory connectivity prompted by deleted text is associated with reading fluency and processing speed abilities. Nineteen children with dyslexia and 21 typical readers ages 8-12 years old participated in a fMRI under two types of reading conditions: a still text condition and deleted text condition, in which letters was sequentially deleted from the screen. Effects of diagnostic group and condition on functional connectivity (FC) of visual and auditory networks were examined. Results revealed a significant overall effect of condition with a marginally significant Group × Condition interaction, such that as compared with TRs, children with dyslexia showed a significantly greater increase in visual-auditory FC between the still and deleted text conditions. Additionally, for children with dyslexia, this FC increase was significantly correlated with better reading fluency and verbal/nonverbal processing speed. These results support a relationship between the synchronization of the visual and auditory networks, fluent reading and increased speed of processing abilities in children with dyslexia, which can help guide fluency-based intervention strategies.

Neural Changes in Children With Residual Speech Sound Disorder After Ultrasound Biofeedback Speech Therapy

PURPOSE

Children with residual speech sound disorders (RSSD) have shown differences in neural function for speech production, as compared to their typical peers; however, information about how these differences may change over time and relative to speech therapy is needed. To address this gap, we used functional magnetic resonance imaging (fMRI) to examine functional activation and connectivity on adaptations of the syllable repetition task (SRT-Early Sounds and SRT-Late Sounds) in children with RSSD before and after a speech therapy program.

METHOD

Sixteen children with RSSD completed an fMRI experiment before (Time 1) and after (Time 2) a speech therapy program with ultrasound visual feedback for /ɹ/ misarticulation. Progress in therapy was measured via perceptual ratings of productions of untreated /ɹ/ word probes. To control for practice effects and developmental change in patterns of activation and connectivity, 17 children with typical speech development (TD) completed the fMRI at Time 1 and Time 2. Functional activation was analyzed using a region-of-interest approach and functional connectivity was analyzed using a seed-to-voxel approach.

RESULTS

Children with RSSD showed a range of responses to therapy. After correcting for multiple comparisons, we did not observe any statistically significant cross-sectional differences or longitudinal changes in functional activation. A negative relationship between therapy effect size and functional activation in the left visual association cortex was on the SRT-Late Sounds after therapy, but it did not survive correction for multiple comparisons. Significant longitudinal changes in functional connectivity were observed for the RSSD group on SRT-Early Sounds and SRT-Late Sounds, as well as for the TD group on the SRT-Early Sounds. RSSD and TD groups showed connectivity differences near the left insula on the SRT-Late Sounds at Time 2.

CONCLUSION

RSSD and treatment with ultrasound visual feedback may thus be associated with neural differences in speech motor and visual association processes recruited for speech production.

Neurobiological perspective on the development of executive functions

Executive functions are a set of top-down cognitive processes necessary for emotional self-regulation and goal-directed behaviour supporting, among others, academic abilities. Premature infants are at high risk for subsequent cognitive, psychosocial, or behavioural problems even in the absence of medical complications and in spite of normal brain imaging. Given that this is a sensitive period of brain growth and maturation, these factors may place preterm infants at high risk for executive function dysfunction, disrupted long-term development, and lower academic achievements. Therefore, careful attention to interventions at this age is essential for intact executive functions and academic development.

Verbal Working Memory-Balance program training alters the left fusiform gyrus resting-state functional connectivity: A randomized clinical trial study on children with dyslexia

Sufficient activation of the left fusiform gyrus is important in reading ability acquisition due to its role in reading and naming, working memory (WM), and balance tasks. Recently, a newly-designed training program, Verbal Working Memory-Balance (VWM-B), has been evaluated on children with dyslexia, and its positive effects were shown on reading ability, WM capacity, and postural control. In the present study, we aimed to estimate the functional connectivity alterations of the left fusiform gyrus following training by the VWM-B. Before and after 15 sessions of training, the fMRI and other tools data were collected on a sample of children with dyslexia, who were allocated into two control and experiment groups. Data analyses showed the increased functional connectivity of the left fusiform gyrus between the left anterior temporal fusiform cortex, left and right Crus II regions of the cerebellum, and the left middle frontal gyrus. Moreover, VWM-B training significantly improved the reading and naming ability, WM capacity, and postural control of participants in the experiment group in comparison to the control. The current study findings emphasize the critical role of the left fusiform gyrus in reading ability. Moreover, it provides evidence to support the existence of cerebellar deficits in dyslexia.

The Role of Neural and Genetic Processes in Learning to Read and Specific Reading Disabilities: Implications for Instruction

To learn to read, the brain must repurpose neural systems for oral language and visual processing to mediate written language. We begin with a description of computational models for how alphabetic written language is processed. Next, we explain the roles of a dorsal sublexical system in the brain that relates print and speech, a ventral lexical system that develops the visual expertise for rapid orthographic processing at the word level, and the role of cognitive control networks that regulate attentional processes as children read. We then use studies of children, adult illiterates learning to read, and studies of poor readers involved in intervention, to demonstrate the plasticity of these neural networks in development and in relation to instruction. We provide a brief overview of the rapid increase in the field's understanding and technology for assessing genetic influence on reading. Family studies of twins have shown that reading skills are heritable, and molecular genetic studies have identified numerous regions of the genome that may harbor candidate genes for the heritability of reading. In selected families, reading impairment has been associated with major genetic effects, despite individual gene contributions across the broader population that appear to be small. Neural and genetic studies do not prescribe how children should be taught to read, but these studies have underscored the critical role of early intervention and ongoing support. These studies also have highlighted how structured instruction that facilitates access to the sublexical components of words is a critical part of training the brain to read.

Characterizing different cognitive and neurobiological profiles in a community sample of children using a non-parametric approach: An fMRI study

Executive Functions (EF) is an umbrella term for a set of mental processes geared towards goal-directed behavior supporting academic skills such as reading abilities. One of the brain's functional networks implicated in EF is the Default Mode Network (DMN). The current study uses measures of inhibitory control, a main sub-function of EF, to create cognitive and neurobiological "inhibitory control profiles" and relate them to reading abilities in a large sample (N = 5055) of adolescents aged 9-10 from the Adolescent Brain Cognitive Development (ABCD) study. Using a Latent Profile Analysis (LPA) approach, data related to inhibitory control was divided into four inhibition classes. For each class, functional connectivity within the DMN was calculated from resting-state data, using a non-parametric algorithm for detecting group similarities. These inhibitory control profiles were then related to reading abilities. The four inhibitory control groups showed significantly different reading abilities, with neurobiologically different DMN segregation profiles for each class versus controls. The current study demonstrates that a community sample of children is not entirely homogeneous and is composed of different subgroups that can be differentiated both behaviorally/cognitively and neurobiologically, by focusing on inhibitory control and the DMN. Educational implications relating these results to reading abilities are noted.

Disruption of Functional Brain Networks Underlies the Handwriting Deficit in Children With Developmental Dyslexia

Developmental dyslexia (DD) is a neurological-based learning disorder that affects 5-17.5% of children. Handwriting difficulty is a prevailing symptom of dyslexia, but its neural mechanisms remain elusive. Using functional magnetic resonance imaging (fMRI), this study examined functional brain networks associated with handwriting in a copying task in Chinese children with DD (n = 17) and age-matched children (n = 36). We found that dyslexics showed reduced network connectivity between the sensory-motor network (SMN) and the visual network (VN), and between the default mode network (DMN) and the ventral attention network (VAN) during handwriting, but not during drawing geometric figures. Moreover, the connectivity strength of the networks showing group differences was correlated with handwriting speed, reading and working memory, suggesting that the handwriting deficit in DD is linked with disruption of a large-scale brain network supporting motoric, linguistic and executive control processes. Taken together, this study demonstrates the alternations of functional brain networks that underly the handwriting deficit in Chinese dyslexia, providing a new clue for the neural basis of DD.

Structural white matter characteristics for working memory and switching/inhibition in children with reading difficulties: The role of the left superior longitudinal fasciculus

Reading difficulties (RDs) are characterized by slow and inaccurate reading as well as additional challenges in cognitive control (i.e., executive functions, especially in working memory, inhibition, and visual attention). Despite evidence demonstrating differences in these readers' language and visual processing abilities, white matter differences associated with executive functions (EFs) difficulties in children with RDs are scarce. Structural correlates for reading and EFs in 8- to 12-year-old children with RDs versus typical readers (TRs) were examined using diffusion tensor imaging (DTI) data. Results suggest that children with RDs showed significantly lower reading and EF abilities versus TRs. Lower fractional anisotropy (FA) in left temporo-parietal tracts was found in children with RDs, who also showed positive correlations between reading and working memory and switching/inhibition scores and FA in the left superior longitudinal fasciculus (SLF). FA in the left SLF predicted working memory performance mediated by reading ability in children with RDs but not TRs. Our findings support alterations in white matter tracts related to working memory, switching/inhibition, and overall EF challenges in children with RDs and the linkage between working memory difficulties and FA alterations in the left SLF in children with RDs via reading.

The Functional Neuroanatomy of Reading Intervention

The present article reviews the literature on the brain mechanisms underlying reading improvements following behavioral intervention for reading disability. This includes evidence of neuroplasticity concerning functional brain activation, brain structure, and brain connectivity related to reading intervention. Consequently, the functional neuroanatomy of reading intervention is compared to the existing literature on neurocognitive models and brain abnormalities associated with reading disability. A particular focus is on the left hemisphere reading network including left occipito-temporal, temporo-parietal, and inferior frontal language regions. In addition, potential normalization/compensation mechanisms involving right hemisphere cortical regions, as well as bilateral sub-cortical and cerebellar regions are taken into account. The comparison of the brain systems associated with reading intervention and the brain systems associated with reading disability enhances our understanding of the neurobiological basis of typical and atypical reading development. All in all, however, there is a lack of sufficient evidence regarding rehabilitative brain mechanisms in reading disability, which we discuss in this review.

Neural connectome features of procrastination: Current progress and future direction

Procrastination refers to an irrationally delay for intended courses of action despite of anticipating a negative consequence due to this delay. Previous studies tried to reveal the neural substrates of procrastination in terms of connectome-based biomarkers. Based on this, we proposed a unified triple brain network model for procrastination and pinpointed out what challenges we are facing in understanding neural mechanism of procrastination. Specifically, based on neuroanatomical features, the unified triple brain network model proposed that connectome-based underpinning of procrastination could be ascribed to the abnormalities of self-control network (i.e., dorsolateral prefrontal cortex, DLPFC), emotion-regulation network (i.e., orbital frontal cortex, OFC), and episodic prospection network (i.e., para-hippocampus cortex, PHC). Moreover, based on the brain functional features, procrastination had been attributed to disruptive neural circuits on FPN (frontoparietal network)-SCN (subcortical network) and FPN-SAN (salience network), which led us to hypothesize the crucial roles of interplay between these networks on procrastination in unified triple brain network model. Despite of these findings, poor interpretability and computational model limited further understanding for procrastination from theoretical and neural perspectives. On balance, the current study provided an overview to show current progress on the connectome-based biomarkers for procrastination, and proposed the integrative neurocognitive model of procrastination.

Reading intervention and neuroplasticity: A systematic review and meta-analysis of brain changes associated with reading intervention

Behavioral research supports the efficacy of intervention for reading disability, but the brain mechanisms underlying improvement in reading are not well understood. Here, we review 39 neuroimaging studies of reading intervention to characterize links between reading improvement and changes in the brain. We report evidence of changes in activation, connectivity, and structure within the reading network, and right hemisphere, frontal and sub-cortical regions. Our meta-analysis of changes in brain activation from pre- to post- reading intervention in eight studies did not yield any significant effects. Methodological heterogeneity among studies may contribute to the lack of significant meta-analytic findings. Based on our qualitative synthesis, we propose that brain changes in response to intervention should be considered in terms of interactions among distributed cognitive, linguistic and sensory systems, rather than via a "normalized" vs. "compensatory" dichotomy. Further empirical research is needed to identify effects of moderating factors such as features of intervention programs, neuroimaging tasks, and individual differences among participants.

Higher maternal education is related to negative functional connectivity between attention system networks and reading-related regions in children with reading difficulties compared to typical readers

Ten to 15% of school-age children have reading difficulties (RD, or dyslexia), defined by deficits in phonological processing, fluency, and executive functions (EFs). Although RD is referred to as a genetic disorder, reading ability may also be affected by environmental factors such as inadequate exposure to literacy and a lack of parental involvement. These environmental components are a part of the socioeconomic status (SES) measure, which is defined by parental occupation, educational attainment, and household income and are positively correlated to reading ability. The goal of the current study was to relate maternal education, a construct of SES to executive functions (EFs) that relate to reading in children with RD compared to typical readers (TRs) using behavioral and neurobiological resting-state fMRI data. The results show that higher maternal education is negatively correlated to inhibitory control for TRs and not for children with RD. Higher maternal education was also associated with negative functional connectivity of the frontal-parietal network to the left central opercular cortex and left occipital gyrus for children with RD compared to TRs. These results suggest that higher maternal education has contrasting roles on the behavioral and neurobiological correlates of EFs for children with RD compared to TRs. We conclude that higher education levels for mothers may provide their children with a structured environment and educational resources that may assist their children with RD and TRs with cognitive development based on their reading profile.

Neuro-Behavioral Correlates of Executive Dysfunctions in Dyslexia Over Development From Childhood to Adulthood

Dyslexia is a neurobiological learning disability in the reading domain that has symptoms in early childhood and persists throughout life. Individuals with dyslexia experience difficulties in academia and cognitive and emotional challenges that can affect wellbeing. Early intervention is critical to minimize the long-term difficulties of these individuals. However, the behavioral and neural correlates which predict dyslexia are challenging to depict before reading is acquired. One of the precursors for language and reading acquisition is executive functions (EF). The present review aims to highlight the current atypicality found in individuals with dyslexia in the domain of EF using behavioral measures, brain mapping, functional connectivity, and diffusion tensor imaging along development. Individuals with dyslexia show EF abnormalities in both behavioral and neurobiological domains, starting in early childhood that persist into adulthood. EF impairment precedes reading disability, therefore adding an EF assessment to the neuropsychological testing is recommended for early intervention. EF training should also be considered for the most comprehensive outcomes.

Similar but distinct - Effects of different socioeconomic indicators on resting state functional connectivity: Findings from the Adolescent Brain Cognitive Development (ABCD) Study®

Early socioeconomic status (SES) has consistently been associated with child health and cognitive outcomes, in addition to alterations in brain function and connectivity. The goal of the present study was to probe the effects of different facets of SES (parent education, income, and neighborhood disadvantage), that likely represent varying aspects of the environment, on resting state functional connectivity (rsFC). We investigated this question in a large sample of 9475 children (aged 9–10 years) from the Adolescent Brain Cognitive Development (ABCD) Study. Specifically, we analyzed the association between household SES (parent education, income-to-needs ratio) and neighborhood disadvantage, and system-level rsFC using within-sample split-half replication. We then tested whether the associations were unique to each SES measure, and whether household SES and neighborhood disadvantage had interactive effects on rsFC. SES measures had both common and distinct effects on rsFC, with sensory-motor systems (e.g., sensorimotor network) and cognitive networks (e.g., front-parietal network) particularly implicated. Further, the association between neighborhood disadvantage and sensorimotor network connectivity was less pronounced in the presence of high income-to-needs. Findings demonstrate that different facets of SES have distinct and interacting effects on rsFC, highlighting the importance of considering different indicators when studying the effects of SES on the brain.

Longer Screen Vs. Reading Time is Related to Greater Functional Connections Between the Salience Network and Executive Functions Regions in Children with Reading Difficulties Vs. Typical Readers

An adverse relationship between screen exposure time and brain functional/structural connectivity was reported in typically developing children, specifically related to neurobiological correlates of reading ability. As children with reading difficulties (RD) suffer from impairments in reading and executive functions (EF), we sought to determine the association between the ratio of screen time duration to reading time duration and functional connectivity of EF networks to the entire brain in children with RD compared to typical readers (TRs) using resting state data. Screen/reading time ratio was related to reduced reading and EF abilities. A larger screen/reading time ratio was correlated with increased functional connectivity between the salience network and frontal-EF regions in children with RD compared to TRs. We suggest that whereas greater screen/reading time ratio is related to excessive stimulation of the visual processing system in TRs, it may be related to decreased efficiency of the cognitive control system in RDs.

Childhood trauma is linked to decreased temporal stability of functional brain networks in young adults

BACKGROUND

Both childhood trauma and disruptions in brain functional networks are implicated in the development of psychiatric disorders in early adulthood. However, the relationships between these two factors remain unclear. This study aimed to investigate whether and how childhood trauma would relate to changes of functional network dynamics in young adults.

METHODS

Resting-state functional magnetic resonance imaging data were collected from 53 young healthy adults, whose childhood trauma histories were assessed by the Childhood Trauma Questionnaire (CTQ). Network switching rate, a measure of stability of dynamic brain networks over time, was calculated at both global and local levels for each participant. Switching rates at both levels were compared between participants with and without childhood trauma, and further correlated with CTQ total score.

RESULTS

In the current sample, 19 (35.8%) participants reported a history of childhood trauma. At the global level, participants with childhood trauma showed significantly higher network switching rates than those without trauma (F = 10.021, p = 0.003). A significant positive correlation was found between network switching rates and CTQ scores in the entire sample (r = 0.378, p = 0.007). At the local level, these effects were mainly observed in the default-mode, fronto-parietal, cingulo-opercular, and occipital subnetworks.

CONCLUSIONS

Our study provides preliminary evidence for a possible long-term effect of childhood trauma on brain functional dynamism. These findings may have potential contributions to psychiatric disorders during adulthood.

Identifying Dyslexia: Link between Maze Learning and Dyslexia Susceptibility Gene, DCDC2, in Young Children

Dyslexia is a common learning disability that affects processing of written language despite adequate intelligence and educational background. If learning disabilities remain untreated, a child may experience long-term social and emotional problems, which influence future success in all aspects of their life. Dyslexia has a 60% heritability rate, and genetic studies have identified multiple dyslexia susceptibility genes (DSGs). DSGs, such as DCDC2, are consistently associated with the risk and severity of reading disability (RD). Altered neural connectivity within temporoparietal regions of the brain is associated with specific variants of DSGs in individuals with RD. Genetically altering DSG expression in mice results in visual and auditory processing deficits as well as neurophysiological and neuroanatomical disruptions. Previously, we demonstrated that learning deficits associated with RD can be translated across species using virtual environments. In this 2-year longitudinal study, we demonstrate that performance on a virtual Hebb-Williams maze in pre-readers is able to predict future reading impairment, and the genetic risk strengthens, but is not dependent on, this relationship. Due to the lack of oral reporting and use of letters, this easy-to-use tool may be particularly valuable in a remote working environment as well as working with vulnerable populations such as English language learners.

Greater reading gain following intervention is associated with low magnetic resonance spectroscopy derived concentrations in the anterior cingulate cortex in children with dyslexia

BACKGROUND/OBJECTIVE

The "neural noise" hypothesis suggests that individuals with dyslexia have high glutamate concentrations associated with their reading challenges. Different reading intervention programs have showed low GLX (a combined measure for glutamine and glutamate obtained with in vivo magnetic resonance spectroscopy) in association with reading improvement. Several studies demonstrated improved reading and increased activation in the anterior cingulate cortex following an-executive-function (EF)-based reading intervention. The goals of the current study are two-fold: 1) to determine if the effect of the EF-based reading program extends also to the metabolite concentrations and in particular, on the GLX concentrations in the anterior cingulate cortex; 2) to expand the neural noise hypothesis in dyslexia also to neural networks supporting additional parts of the reading networks, i.e. in specific regions related to executive function skills.

METHODS

Children with dyslexia and typical readers were trained on the EF-based reading program. Reading ability was assessed before and after training while spectroscopy data was obtained at the end of the program. The association between change in reading scores following intervention and GLX concentrations was examined.

RESULTS

Greater "gains" in word reading were associated with low GLX, Glu, Cr, and NAA concentrations for children with dyslexia compared to typical readers.

CONCLUSIONS

These results suggest that the improvement reported following the EF-based reading intervention program also involved a low GLX concentration, as well as additional metabolites previously associated with better reading ability (Glx, Cr, NAA) which may point at the decreased neural noise, especially in the anterior cingulate cortex, as a possible mechanism for the effect of this program.

Neural correlates of cognitive control deficits in children with reading disorder

Reading disorder (RD) is characterized by deficient phonological processing, but children with RD also have cognitive control deficits, the neural correlates of which are not fully understood. We used fMRI to assess neural activity during the resolution of cognitive conflict on the Simon Spatial Incompatibility task and patterns of resting-state functional connectivity (RSFC) from task control (TC) regions in 7-12-year-old children with RD compared to their typically developing (TD) peers. Relative to TD children (n = 17), those with RD (n = 16) over-engaged a right superior/medial frontal cluster during the resolution of conflict (p = .05). Relative to TD children (n = 18), those with RD (n = 17) also showed reduced RSFC (voxel-wise p < .001; cluster-size p < .05, FDR corrected) from cingulo-opercular seeds to left hemisphere fronto-parietal and temporo-parietal reading-related regions, perhaps reflecting reduced organization of TC circuits and reduced integration with reading-related regions. Children with RD additionally showed reduced RSFC between fronto-parietal and default mode network regions. Follow-up analyses in a subset of children with both useable task and resting state data (RD = 13; TD = 17) revealed that greater conflict-related activation of the right frontal Simon task ROI associated with better word-reading, perhaps suggesting a compensatory role for this over-engagement. Connectivity from fronto-parietal seeds significantly associated with Simon task performance and word-reading accuracy in RD children. These findings suggest that altered functioning and connectivity of control circuits may contribute to cognitive control deficits in children with RD. Future studies should assess the utility of adding cognitive control training to reading remediation programs.

Associations Between Neighborhood Disadvantage, Resting-State Functional Connectivity, and Behavior in the Adolescent Brain Cognitive Development Study: The Moderating Role of Positive Family and School Environments

BACKGROUND

Neighborhood disadvantage has consistently been associated with mental health and cognitive function, in addition to alterations in brain function and connectivity. However, positive environmental influences may buffer these effects. The aim of this study was to examine the association between neighborhood disadvantage and resting-state functional connectivity (rsFC), the moderating role of positive parenting and school environment, and relationships between disadvantage-associated rsFC patterns and mental health and cognition.

METHODS

In this preregistered study, we tested this hypothesis in a large sample of 7618 children (aged 9-10 years) from the Adolescent Brain Cognitive Development (ABCD) study. Specifically, we analyzed the relationship between neighborhood disadvantage and system-level FC. We also tested whether positive family and school environmental factors and sex moderated effects. Finally, we investigated multivariate relationships between disadvantage-associated rsFC patterns and cognition and mental health.

RESULTS

Disadvantage was associated with widespread alterations in FC across both higher-order (e.g., default mode network and dorsal attention network) and sensorimotor functional systems, some of which were moderated by positive environments. Implicated connections showed multivariate associations with behavior, whereby disadvantage-associated rsFC was generally associated with worse cognition and mental health. Disadvantage-associated connections also predicted variation in cognitive scores using machine learning models.

CONCLUSIONS

Our findings shed light on potential mechanisms (i.e., alteration of neural circuitry) through which neighborhood disadvantage may affect youth cognition and mental well-being. This work highlights the importance of positive family and school environments in mitigating some of these effects.

An Evolutionary Perspective of Dyslexia, Stress, and Brain Network Homeostasis

Evolution fuels interindividual variability in neuroplasticity, reflected in brain anatomy and functional connectivity of the expanding neocortical regions subserving reading ability. Such variability is orchestrated by an evolutionarily conserved, competitive balance between epigenetic, stress-induced, and cognitive-growth gene expression programs. An evolutionary developmental model of dyslexia, suggests that prenatal and childhood subclinical stress becomes a risk factor for dyslexia when physiological adaptations to stress promoting adaptive fitness, may attenuate neuroplasticity in the brain regions recruited for reading. Stress has the potential to blunt the cognitive-growth functions of the predominantly right hemisphere Ventral and Dorsal attention networks, which are primed with high entropic levels of synaptic plasticity, and are critical for acquiring beginning reading skills. The attentional networks, in collaboration with the stress-responsive Default Mode network, modulate the entrainment and processing of the low frequency auditory oscillations (1-8 Hz) and visuospatial orienting linked etiologically to dyslexia. Thus, dyslexia may result from positive, but costly adaptations to stress system dysregulation: protective measures that reset the stress/growth balance of processing to favor the Default Mode network, compromising development of the attentional networks. Such a normal-variability conceptualization of dyslexia is at odds with the frequent assumption that dyslexia results from a neurological abnormality. To put the normal-variability model in the broader perspective of the state of the field, a traditional evolutionary account of dyslexia is presented to stimulate discussion of the scientific merits of the two approaches.

Reading in developmental dyslexia: the role of phonemic awareness and executive functions

Abstract This study investigated the correlations and the possible deficits in reading, phonemic awareness, and executive functions among students with developmental dyslexia. A total of 28 students participated in the study, between 9 and 11 years old, 14 with developmental dyslexia and 14 without reading difficulties. Specific instruments were used to assess reading, phonemic awareness, and executive functions. The Spearman test indicated moderate and very significant correlations between performance in tasks of phonemic awareness and reading (recognition and comprehension) and tasks that assessed cognitive functioning involving the following executive functions: cognitive flexibility, working memory, inhibitory control, and orthographic verbal fluency. No correlation was found between the reading and phonemic awareness assessments and the results of the planning done with the Tower of London instrument. The results allowed the researchers to hypothesize that an intervention planned for the development of phonemic awareness and executive functions may have an effect in improving the reading performance of dyslexics.

Changed functional connectivity at rest in functional illiterates after extensive literacy training

Background

About 6.2 million adults in Germany cannot read and write properly despite attending school for several years. They are considered to be functional illiterates (FI). Since the ability to read and write is crucial for being employed and socially accepted, we developed a special literacy training to overcome these deficits.

Methods

In this study, we investigate training-related changes in intrinsic functional connectivity (iFC) at rest in a group of 20 FI and 20 adult normal readers using resting state functional magnetic resonance imaging (rsfMRI). We used independent component analysis (ICA) to define different networks.

Results

Before training, the between group analysis showed increased iFC in FI in a left-fronto-parietal network (LFPN; anterior insula, medial frontal cortex, lateral and frontal parietal regions) and in the Basal Ganglia network (BGN: thalamus, caudate, putamen, pallidum, amygdala, supplementary motor cortex and cingulate gyrus). Furthermore, the Visual Network-1 (VN1; temporal occipital fusiform gyrus, lateral occipital cortex, occipital pole, lingual gyrus, thalamus) showed decreased iFC in FI. After training the FI group showed reversal of the “hyperconnectivity” in middle frontal gyrus and in the frontal orbital cortex and between supramarginal gyrus and the BGN. Furthermore, functional connectivity increased in FI VN1 (lateral occipital cortex, insular cortex). These changes in connectivity correlated with gains in reading speed and spelling accuracy.

Conclusions

These findings show that poor reading and writing abilities are associated with abnormalities in iFC in several brain areas subserving cognitive processes important for reading. Intensive literacy training induces changes in the functional connectivity between and within neural networks important for literacy skills.

Children Use Regions in the Visual Processing and Executive Function Networks during a Subsequent Memory Reading Task

Memory encoding is a critical process for memory function, which is foundational for cognitive functioning including reading, and has been extensively studied using subsequent memory tasks. Research in adults using such tasks indicates the participation of visual and cognitive-control systems in remembered versus forgotten words. However, given the known developmental trajectories of these systems, the functional neuroanatomy of memory encoding in children may be different than in adults. We examined brain activation for silent word reading and checkerboard viewing during an event-related reading task in 8-12 year-old children. Results indicate greater activation for checkerboard viewing than lexical processing in early visual regions, as well as for lexical processing versus checkerboard viewing in regions in left sensorimotor mouth, cingulo-opercular and dorsal-attention networks. Greater activation for remembered than forgotten words was observed in bilateral visual system and left lateralized regions within the ventral- and dorsal-attention, cingulo-opercular and fronto-parietal networks. These findings suggest a relatively mature reliance on the cognitive-control system, but greater reliance on the visual system in children when viewing words subsequently remembered. The location of regions with greater activity for remembered words reinforces the involvement of the attention and cognitive-control systems in subsequent memory in reading.

Reading in children with drug-resistant epilepsy was related to functional connectivity in cognitive control regions

AIM

This study aimed to define whether individuals with drug-resistant focal epilepsy also used regions related to cognitive control to facilitate reading.

METHODS

We focused on patients with drug-resistant focal epilepsy in 2011-2014, who were aged 8-20 years and were being treated at the Cincinnati Children's Hospital, USA. They performed a verb generation functional magnetic resonance imaging task known to involve language and cognitive control, as well as a formal reading assessment. The reading scores were correlated with functional connectivity of the anterior cingulate cortex (ACC) using seed-to-voxel analysis.

RESULTS

There were 81 potential patients and 13 (seven females) met the inclusion criteria. Their age at seizure onset was 0-13 years, and they had a mean age of 12.66 ± 3.17 years at the time of the study. Individuals with epilepsy demonstrated average intelligence and word reading ability. Their reading scores were positively correlated with functional connectivity between the ACC and regions related to emotional processing (right amygdala), learning and language processing (left cerebellum) and visual processing.

CONCLUSION

Our results support the role that the ACC plays in proficient reading among children with drug-resistant epilepsy, even in those with epileptogenic foci in areas related to language.

Children with dyslexia utilize both top-down and bottom-up networks equally in contextual and isolated word reading

INTRODUCTION

Executive functions (EF) include cognitive processes that support learning and reading. Children with dyslexia experience challenges with both reading and reading comprehension. The neurobiological support for EF deficits during reading comprehension, however, has yet to be defined. Here we aimed to identify the neural networks related to EF during a reading comprehension task focusing on top-down and bottom-up networks in children with dyslexia and typical readers (TR).

METHOD

Twenty children with dyslexia and 19 TR aged 8-12 were scanned during a sentence comprehension (SC) task that included isolated words and sentences that make sense, in addition to undergoing reading and EF behavioral assessment. Functional connectivity within and between four EF networks related to top-down and bottom-up processing were calculated.

RESULTS

Children with dyslexia scored significantly lower in reading and EF testing in several subdomains compared to TR. Children with dyslexia displayed decreased accuracy in both task conditions compared to TR during the SC task. Neuroimaging data analysis revealed that TR had greater functional connectivity within and between top-down and bottom-up processes, in the sentence vs. isolated word condition, compared to children with dyslexia.

DISCUSSION

TR demonstrate a reliance on top-down and bottom-up networks only during sentence comprehension. In children with dyslexia, however, this reliance was not found in either of the task conditions, suggesting that both conditions were equally challenging for them. These findings emphasize the involvement of EF networks in the reading comprehension process and highlight their impaired functionality among children with reading difficulties.

Dyslexia as an adaptation to cortico-limbic stress system reactivity

A new school of thought in evolutionary developmental biology, combined with research in the neurobiology of stress, suggest that early exposure to stressful circumstances may be a cause of dyslexia. A balance between epigenetic, stress-induced and cognitive-growth genetic programs modulates the brain's cellular, regional, and network homeostasis. This balance is essential for adaptability to the normative range of everyday stress. However, even mild chronic stress exposition may overactivate the hypothalmic-pituitary-adrenal stress axis, upsetting the homeostatic balance between these programs, and exposing the brain to harmful levels of stress hormones. A protective strategy to sustained disequilibrium precociously advances maturation at the cost of neuroplasticity, which blunts stress axis reactivity but also compromises learning potential in the prefrontal cortex and networks associated with dyslexia. Stress exceeding an individual's range of resilience: (1) reduces levels of TFEB and BDNF, gene regulatory factors prolonging maturation and neuroplasticity; (2) interferes with the insular cortex, amygdala and hippocampus in coordinating afferent visceral signals with cognitive performance; (3) over-recruits the brain's Default Mode network; and (4) amplifies release from the Locus coeruleus/norepinephrine system which impairs the entrainment of oscillations in the lower phonological frequencies of speech. Evidence supporting a stress-growth imbalance is preliminary, but holds promise for reconceptualizing the neurobiology of dyslexia and reducing its prevalence.

Greater functional connectivity within the cingulo-opercular and ventral attention networks is related to better fluent reading: A resting-state functional connectivity study

Executive functions are higher-order cognitive abilities that affect many of our daily actions, including reading. A two-system model for cognitive control comprises a bottom-up system composed of the dorsal and ventral attention networks and a more evolved top-down system involving the frontoparietal and cingulo-opercular networks. We examined both within- and between-network functional connectivity of these four networks in 26 8-12-year-old children with readong difficulties and 30 age-matched typical readers using resting-state functional MRI. Fluency and nonfluency behavioral reading measures were collected, and the scores were analyzed together with the functional data. Children with reading difficulties did not differ in functional connectivity for the four networks compared to typical readers. Grouping the entire cohort into low vs. high fluency-level reading groups, however, revealed significantly higher functional connectivity values within the cingulo-opercular and ventral attention cognitive-control networks for the high fluency group. Higher functional connectivity Trends between the cognitive-control networks were also observed in the high fluency group compared to the low fluency group. A similar analysis using a nonfluency word-reading task grouping did not uncover differences between the two groups. The results emphasize the complexity of the fluency task, as a test that relies on cognitive-control abilities, at both the bottom-up and top-down levels. Therefore, it may be posited that the fluency task may also be a challenge for typical readers despite their intact performance. The results reinforce the relationship between fluent reading and functional connectivity of the cognitive-control networks, emphasizing the various cognitive-control abilities that underlie this complex reading ability.

Study protocol of a randomized controlled trial of home-based computerized executive function training for children with cerebral palsy

BACKGROUND

Cerebral palsy (CP) is frequently associated with specific cognitive impairments, such as executive dysfunction which are related to participation and quality of life (QOL). The proposed study will examine whether a computerized executive function (EF) training programme could provide superior benefits for executive functioning, participation, QOL and brain plasticity, as compared to usual care.

METHODS

A single-blind randomized controlled trial (RCT) design will be performed. Thirty children with CP aged 8 to 12 years will participate in a home-based computerized multi-modal executive training programme (12 weeks, 5 days a week, 30 min a day training, total dose = 30 h). Thirty children with CP matched by age, sex, motor and intelligence quotient (IQ) will compose the waitlist group. Cognitive, behavioural, emotional, participation and QOL measures will be obtained at three time points: before, immediately after and 9 months after completing the training. Additionally, structural and functional (resting state) magnetic resonance images (MRI) will be obtained in a subsample of 15 children from each group. Outcomes between groups will be compared following standard principles for RCTs.

DISCUSSION

The study will test whether the cognitive training programme exerts a positive effect not only on neuropsychological and daily functioning of children with CP but also on other measures such as participation and QOL. We will also use brain MRI to test brain functional and structural changes after the intervention. If this on-line and home-based training programme proves effective, it could be a cost-effective intervention with short- and long-term effects on EF, participation or QOL in CP.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04025749. Registered 19 July 2019. Retrospectively registered.

Educational fMRI: From the Lab to the Classroom

Functional MRI (fMRI) findings hold many potential applications for education, and yet, the translation of fMRI findings to education has not flowed. Here, we address the types of fMRI that could better support applications of neuroscience to the classroom. This 'educational fMRI' comprises eight main challenges: (1) collecting artifact-free fMRI data in school-aged participants and in vulnerable young populations, (2) investigating heterogenous cohorts with wide variability in learning abilities and disabilities, (3) studying the brain under natural and ecological conditions, given that many practical topics of interest for education can be addressed only in ecological contexts, (4) depicting complex age-dependent associations of brain and behaviour with multi-modal imaging, (5) assessing changes in brain function related to developmental trajectories and instructional intervention with longitudinal designs, (6) providing system-level mechanistic explanations of brain function, so that useful individualized predictions about learning can be generated, (7) reporting negative findings, so that resources are not wasted on developing ineffective interventions, and (8) sharing data and creating large-scale longitudinal data repositories to ensure transparency and reproducibility of fMRI findings for education. These issues are of paramount importance to the development of optimal fMRI practices for educational applications.

Altered association between executive functions and reading and math fluency tasks in children with reading difficulties compared with typical readers

Fluent reading in children relies on executive functions (EF). Recent research suggests that EF skills also affect arithmetic abilities. Children with reading difficulties (RD) experience deficits in EF. It is still unknown to what extent these EF deficits are the basis for both reading and arithmetic skills in children with RD compared with typical readers. To define the role of EF in reading and arithmetic in children with RD and typical readers, EF measures and reading and arithmetic fluency and non-fluency measures were assessed in 8 to 12-year-old children with RD and age-matched typical readers. Comparison and correlation analyses were performed within and between the two groups. Children with RD scored lower on reading and arithmetic fluency and non-fluency tasks compared with typical readers. For both groups, fluency measures were lower than non-fluency measures. Strong correlations were found within the entire study population between fluency measures and EF, as well as between non-fluency measures and EF compared with mixed correlations observed for the groups separately. Fluency was related to subcomponents of EF expressed in both reading and arithmetic domains for the two groups. The role of each domain and comparison with non-fluency results for each group are discussed.

Altered Functional Connectivity of the Executive Functions Network During a Stroop Task in Children with Reading Difficulties

Children with reading difficulties (RDs) often receive related accommodations in schools, such as additional time for examinations and reading aloud written material. Existing data suggest that these readers share challenges in executive functions (EFs). Our study was designed to determine whether children with RDs have specific challenges in EFs and define neurobiological signatures for such difficulties using magnetic resonance imaging (MRI) data. Reading and EFs abilities were assessed in 8-12-year-old children with RDs and age-matched typical readers. Functional MRI data were acquired during a Stroop task, and functional connectivity of the EFs defined network was calculated in both groups and related to reading ability. Children with RDs showed lower reading and EFs abilities and demonstrated greater functional connectivity between the EFs network and visual, language, and cognitive control regions during the Stroop task, compared to typical readers. Our results suggest that children with RDs utilize neural circuits supporting EFs more so than do typical readers to perform a cognitive task. These results also provide a neurobiological explanation for the challenges in EFs shared by children with RDs and explain challenges this group shares outside of the reading domain.

Functional Connectivity of Cognitive Control and Visual Regions During Verb Generation Is Related to Improved Reading in Children

Reading is a complex cognitive ability, which relies on visual and language processing as well as on executive functions (EFs). Recent studies have demonstrated that increased reading ability in children aged 7-17 years is related to greater activation of cognitive control regions during verb generation, a task which merges linguistic and cognitive control ability. The aim of the current study is to determine the relationships between neural circuits specifically related to EF and reading ability. We focused on functional connectivity between the dorsolateral prefrontal cortex (DLPFC), a region involved in EF and is part of the frontoparietal network during a verb generation task, and reading ability in seventeen 8-12-year-old typical readers. Results show positive functional connectivity between the left and right DLPFCs and regions related to cognitive control and visual processing while generating verbs. Increased reading ability was positively correlated with greater functional connectivity between the left and right DLPFCs and right-lateralized visual processing regions. The current study highlights the importance of neural circuits related to EF during both verb generation and reading and points to the role of the right occipital cortex in generating verbs as well as automatic word recognition in typical readers.

Increased Functional Connectivity Within and Between Cognitive-Control Networks from Early Infancy to Nine Years During Story Listening

The cingulo-opercular (CO) and frontoparietal (FP) networks are part of the cognitive-control system of the brain. Evidence suggests that over the course of development, brain regions supporting cognitive-control functions become more integrated within their networks (i.e., have increased within-network connectivity), more separated from other networks, and, due to increased maturation along development, are more functionally connected between the networks. The focus of this study was to characterize the developmental trajectory of the CO and FP networks from early infancy (17 months) to 9 years of age in typically developing children while listening to stories, using functional connectivity analyses. Seventy-four children underwent a functional magnetic resonance imaging session while listening to stories inside the scanner. Within- and between-network functional connectivity and graph theory measures were compared during development. Developmental increase in functional connectivity within the CO network and between the CO and FP networks, as well as global efficiency of the CO network from 17 months to 9 years of age, was observed. These findings highlight the involvement of the CO and FP networks in story listening from early infancy, which increases along development. Future studies examining failures in language acquisition to further explore the role of these networks in story listening are warranted.

Brain activity in struggling readers before intervention relates to future reading gains

Neural markers for reading-related changes in response to intervention could inform intervention plans by serving as a potential index of the malleability of the reading network in struggling readers. Of particular interest is the role of brain activation outside the reading network, especially in executive control networks important for reading comprehension. However, it is unclear whether any intervention-related executive control changes in the brain are specific to reading tasks or reflect more domain general changes. Brain changes associated with reading gains over time were compared for a sentence comprehension task as well as for a non-lexical executive control task (a behavioral inhibition task) in upper-elementary struggling readers, and in grade-matched non-struggling readers. Functional MRI scans were conducted before and after 16 weeks of reading intervention. Participants were grouped as improvers and non-improvers based on the consistency and size of post-intervention gains across multiple post-test measures. Engagement of the right fusiform during the reading task, both before and after intervention, was related to gains from remediation. Additionally, pre-intervention activation in regions that are part of the default-mode network (precuneus) and the fronto-parietal network (right posterior middle temporal gyrus) separated improvers and non-improvers from non-struggling readers. None of these differences were observed during the non-lexical inhibitory control task, indicating that the brain changes seen related to intervention outcome in struggling readers were specific to the reading process.

Differential effect of reading training on functional connectivity in children with reading difficulties with and without ADHD comorbidity

A comorbidity of attention deficit hyperactivity disorder (ADHD) with reading difficulties (RD) is common in children. However, children with ADHD+RD have a different reading and executive functions (EF) profile than children with RD alone. We compared the effect of an EF-based intervention on neural circuits related to EF in children with RD and those with ADHD+RD. Functional connectivity MRI data from a lexical decision task suggest that the RD-alone group showed greater improvement in EF and reading tests and greater functional connectivity between networks related to both higher-and lower-level visual processing and those related to ventral attention and dorsal attention, as well as semantic processing. Children with ADHD+RD showed greater connectivity between networks related to attention and dorsal attention and those related to visual processing and EF. Results are consistent with the Cognitive Subtype hypothesis and suggest that RD and ADHD+RD, although related behaviourally, are distinct disorders with regard to network response and connectivity during reading and after an EF-based intervention.

Dyslexia on a continuum: A complex network approach

We investigated the efficacy of graph-theoretic metrics of task-related functional brain connectivity in predicting reading difficulty and explored the hypothesis that task conditions emphasizing audiovisual integration would be especially diagnostic of reading difficulty. An fMRI study was conducted in which 24 children (8 to 14 years old) who were previously diagnosed with dyslexia completed a rhyming judgment task under three presentation modality conditions. Regression analyses found that characteristic connectivity metrics of the reading network showed a presentation modality dependent relationship with reading difficulty: Children with more segregated reading networks and those that used fewer of the available connections were those with the least severe reading difficulty. These results are consistent with the hypothesis that a lack of coordinated processing between the neural regions involved in phonological and orthographic processing contributes towards reading difficulty.

Applying a network framework to the neurobiology of reading and dyslexia

Background

There is a substantial literature on the neurobiology of reading and dyslexia. Differences are often described in terms of individual regions or individual cognitive processes. However, there is a growing appreciation that the brain areas subserving reading are nested within larger functional systems, and new network analysis methods may provide greater insight into how reading difficulty arises. Yet, relatively few studies have adopted a principled network-based approach (e.g., connectomics) to studying reading. In this study, we combine data from previous reading literature, connectomics studies, and original data to investigate the relationship between network architecture and reading.

Methods

First, we detailed the distribution of reading-related areas across many resting-state networks using meta-analytic data from NeuroSynth. Then, we tested whether individual differences in modularity, the brain’s tendency to segregate into resting-state networks, are related to reading skill. Finally, we determined whether brain areas that function atypically in dyslexia, as identified by previous meta-analyses, tend to be concentrated in hub regions.

Results

We found that most resting-state networks contributed to the reading network, including those subserving domain-general cognitive skills such as attention and executive function. There was also a positive relationship between the global modularity of an individual’s brain network and reading skill, with the visual, default mode and cingulo-opercular networks showing the highest correlations. Brain areas implicated in dyslexia were also significantly more likely to have a higher participation coefficient (connect to multiple resting-state networks) than other areas.

Conclusions

These results contribute to the growing literature on the relationship between reading and brain network architecture. They suggest that an efficient network organization, i.e., one in which brain areas form cohesive resting-state networks, is important for skilled reading, and that dyslexia can be characterized by abnormal functioning of hub regions that map information between multiple systems. Overall, use of a connectomics framework opens up new possibilities for investigating reading difficulty, especially its commonalities across other neurodevelopmental disorders.

Electronic supplementary material

The online version of this article (10.1186/s11689-018-9251-z) contains supplementary material, which is available to authorized users.