White matter tracts and executive functions: a review of causal and correlation evidence

Effects of postural loading during static posture holding on concurrent executive function task performance

This study investigated the effects of postural loading during static posture holding on the performance of concurrent executive function tasks. Three executive function tasks, the letter memory, number-letter, and Stroop tasks, were employed for updating, shifting, and inhibition, respectively. Static posture holding involved three levels of postural loading (PL1, PL2, and PL3), corresponding to OWAS classes 1, 2, and 4, respectively. Increased postural loading resulted in decreased performance across tasks. At PL2 and PL3, compared to PL1, total score in the letter memory task decreased by 4.56% and 13.68%, switch trial reaction time in the number-letter task increased by 1.47% and 15.63%, and incongruent trial reaction time in the Stroop task increased by 4.15% and 13.44%. These findings contribute to a more comprehensive understanding of the relationship between postural loading and executive functions, and offer valuable insights into how managing postural demands may enhance cognitive task performance.

White matter microstructural and cognitive function changes in bipolar depression patients with suicidal ideation

The pathophysiological mechanisms underlying suicidal ideation and decreased cognitive function in bipolar depression remain elusive. This study sought to elucidate the potential neuroanatomical basis of these phenomena using diffusion tensor imaging (DTI). 40 patients experiencing bipolar depressive episodes were enrolled, comprising 20 individuals with suicidal ideation (BDSI +), 20 without suicidal ideation (BDSI-), and 20 healthy controls (HCs), all of whom underwent DTI scanning. Clinical assessments primarily utilized the Beck Scale for Suicide Ideation (BSSI) and the Trail Making Test (TMT). Differences in fractional anisotropy (FA) values among the groups were compared using Tract-Based Spatial Statistics (TBSS). The identified differential brain regions were designated as regions of interest (ROIs), and covariance analysis was employed to compare the FA values among the three groups. Partial correlation analyses were conducted between the FA values in the ROIs and clinical symptoms. Differences in brain regions identified through TBSS were observed in the genu of the corpus callosum and the left anterior corona radiata (p < 0.05). Covariance analysis revealed that the BDSI + group exhibited significantly lower FA values in these regions compared to the HCs (p < 0.05). Partial correlation analyses showed that the FA values in the genu of corpus callosum were negatively correlated with BSSI scores (r = -0.592, p = 0.026) and TMT-A scores (r = -0.642, p = 0.013). The findings from this study suggest that alterations in the connectivity of the genu of the corpus callosum may relate to suicidal ideation and visuospatial function in patients with bipolar depression.

Brain basis for physical activity levels mediate beta Inhibition to improve cognitive function in elderly based on multimodality monitoring

The ameliorative effect of regular physical activity (PA) on cognitive function (CF) in older adults has been demonstrated. However, there are differences in the effects of different levels of PA on CF over time. To provide a more efficient exercise prescription for older adults, we compared differences in CF with neural mechanisms in individuals with different weekly activity levels. In this study, 68 older adults (n = 68, M = 47, F = 21, Age = 62.43 ± 4.36) were categorized according to the International Physical Activity Questionnaire (IPAQ) into high volume PA group (HG) (MET-min/week = 1516.64 ± 138.68), moderate volume PA group (MG) (MET-min/week = 1248.02 ± 119.86), and control group (MET-min/week = 1248.02 ± 119.86). 1516.64 ± 138.68), moderate volume PA group (MG) (MET-min/week = 1248.02 ± 119.86), and control group (MET-min/week = 846.78 ± 97.53). Differences in Stop Signal, Stroop, and 2-Back were compared among the three groups. Electroencephalogram (EEG), event-related potential (ERP), and magnetic resonance imaging (MRI) features were also observed. The results showed that for CF, 2-Back with Stroop was significantly higher in MG versus HG than in CG (F = 121.45, P < 0.01; F = 88.74, P < 0.01), and the opposite was true for response (F = 236.83, P < 0.01; F = 187.64, P < 0.01). Stroop was higher in HG than in MG (F = 38.78, P = 0.037) and Stop Signal was higher than in CG (F = 52.03, P < 0.01). In terms of EEG, the alpha band share of HG was higher than CG at rest (F = 41.34, P = 0.040) and the opposite in work (F = 25.67, P = 0.046). Although the remaining results were not statistically significant, PA levels were inversely proportional to resting midrange-band β (CG = 8.98 ± 1.02, MG = 8.07 ± 0.76, HG = 8.13 ± 0.88), and positively proportional to midrange and high-band β in WORK (midrange β: CG = 12.41 ± 2.29, MG = 12.98 ± 3.04, HG = 13.21 ± 2.85; high β: CG = 6.76 ± 2.23, MG = 7.35 ± 1.96, HG = 7.91 ± 2.3). In ERP, the latencies of N200, P300, and N450 were significantly shorter than those of CG in HG (F = 44.63, P = 0.041; F = 29.69, P = 0.045; F = 76.48, P < 0.01), and only N450 was shorter than that of CG in MG (F = 59.62, P < 0.01). On MRI, HG had Middle Frontal Gyrus (MFG) (HG > CG, voxel = 188, t = 3.72), Right Superior Frontal Gyrus (RSFG) (HG > CG, voxel = 238, t = 4.07), Left Cingulate (HG > CG, voxel = 343, t = 4.36), and Left Supplementary Motor Area (LSMA) (HG > CG, voxel = 343, t = 4.36) were activated more than CG. MFG (MG > CG, voxel = 172, t = 3.56), LSMA (MG > CG, voxel = 331, t = 4.28), and PHG (MG > CG, voxel = 204, t = 3.35) were activated more than CG. It was concluded that PA significantly enhanced CF in older adults, and that high volume PA was more effective than moderate volume. Specifically, VPA was found to be significantly more effective than MPA and LPA in enhancing individuals' inhibition function, cognitive flexibility, working memory, and reaction speed. This may be attributed to the increase in ERP amplitude with shorter latency and greater gray matter density in frontal and temporal lobe regions.

Specific radiosensitivity of brain structures (areas or regions) and cognitive impairment after focal or whole brain radiotherapy: A review

Delayed neurocognitive impairment is observed following encephalic radiotherapy, including brain parts (areas), leading to a substantial deterioration of the quality of life. These delayed radiotherapy side effects are variable in terms of intensity of symptoms and time of occurrence, characterized by minor-to-severe cognitive deficits, such as attention or memory disorders and/or dysexecutive syndrome. However, the precise mechanisms leading to these cognitive disorders remain mostly unknown. Various tissue alterations have been reported after brain radiotherapy, in specific brain structures as the hippocampus, the cerebral white matter or the cerebral cortex. Sparing these structures during brain radiotherapy may be a potential approach to limit the development of late cognitive impairment; however, few dose constraints have been published regarding brain areas (regions) involved in cognitive functions. The main purposes of this literature review are to report the pathophysiological process leading to the radiation-induced cognitive impairment, to describe the tolerance and radiological modifications induced by radiation of specific healthy cerebral tissues, to better understand their radiosensitivity and to describe potential improvements.

Perinatal Mother-to-Child Chikungunya Virus Infection: Screening of Cognitive and Learning Difficulties in a Follow-Up Study of the Chimere Cohort on Reunion Island

In this cohort study, we evaluated the cognitive and learning difficulties of school-age children perinatally infected with Chikungunya virus (CHIKV) on Reunion Island using the Evaluation of Cognitive Functions and Learning in Children (EDA) battery screening test compared to the healthy children cohort used for EDA development. Of the 19 infected children, 11 (57.9%) exhibited subnormal or abnormal scores, of whom 3 were classified as high risk, and 8 were classified as at risk for cognitive and learning difficulties. Children who had encephalopathy were at higher risk for displaying at least one difficulty than non-encephalopathic children (relative risk 2.13; 95% CI 1.05-4.33). The difficulties observed affected verbal functions, non-verbal functions, and learning abilities, such as phonology, lexical evocation and comprehension, graphism, selective visual attention, planning, visual-spatial reasoning, dictation and mathematics, as well as core executive functions, such as inhibitory control, shifting, and working memory. Neurocognitive dysfunctions could be linked to severe brain damage, as evidenced by severe white matter reduction mainly in the frontal lobes and corpus callosum and potentially in all functional networks involved in difficulties. These results should motivate further investigation of intellectual and adaptive functioning to diagnose intellectual deficiency and severe maladaptive behaviour in children perinatally infected with Chikungunya virus.

Executive Function Response to Moderate-to-High-Intensity Rope Skipping in Overweight Adolescents Aged 12-14: A Preliminary Study

Background: Previous studies have shown that a high body mass index (BMI) is detrimental to executive function (EF) in children and elderly populations but may be improved by physical activity (PA). However, research on adolescents aged 12-14 is lacking. This study explores two parts: Part 1: cross-sectional correlation between BMI and EF; Part 2: the effect of an 8-week rope skipping intervention. Methods: Recruit 166 adolescents to participate in EF tasks. Screen and select 96 adolescents to be assigned to the normal weight control group (N-C, n = 23) and the normal weight exercise group (N-E, n = 23), the overweight control group (OV-C, n = 13), and the overweight exercise group (OV-E, n = 14), the obese control group (OB-C, n = 12), and the obese exercise group (OB-E, n = 11). Exercise program: moderate-to-high-intensity rope skipping training. Control program: Self-directed reading. Data were recorded for BMI and EF tasks. Results: Part 1, EF and BMI exhibit a negative linear correlation. Part 2, the reaction time of EF tasks in N-E, OV-E and OB-E decreased about 9, 14, 13% (p < 0.05), respectively, while the average BMI in OV-E and OB-E decreased about 10% and 11% (p < 0.05), suggesting a potential correlation between the reduction in BMI and the improvement in EF, which means that the exercise intervention significantly improved EF performance. Conclusions: Among adolescents aged 12-14, overweight and obese individuals exhibit weaker EF compared with normal weight individuals. An 8-week moderate-to-high-intensity rope skipping exercise program can improve EF in adolescents aged 12-14 with different BMIs, and the improvement is greater in overweight and obese individuals.

Fiber Microstructure Quantile (FMQ) Regression: A Novel Statistical Approach for Analyzing White Matter Bundles from Periphery to Core

The structural connections of the brain's white matter are critical for brain function. Diffusion MRI tractography enables the in-vivo reconstruction of white matter fiber bundles and the study of their relationship to covariates of interest, such as neurobehavioral or clinical factors. In this work, we introduce Fiber Microstructure Quantile (FMQ) Regression, a new statistical approach for studying the association between white matter fiber bundles and scalar factors (e.g., cognitive scores). Our approach analyzes tissue microstructure measures based on quantile-specific bundle regions . These regions are defined in a data-driven fashion according to the quantiles of fractional anisotropy (FA) of a population fiber bundle, which pools all individuals' bundles. The FA quantiles induce a natural subdivision of a fiber bundle, defining regions from the periphery (low FA) to the core (high FA) of the population fiber bundle. To investigate how fiber bundle tissue microstructure relates to covariates of interest, we employ the statistical technique of quantile regression. Unlike ordinary regression, which only models a conditional mean, quantile regression models the conditional quantiles of a response variable. This enables the proposed analysis, where a quantile regression is fitted for each quantile-specific bundle region. To demonstrate FMQ Regression, we perform an illustrative study in a large healthy young adult tractography dataset derived from the Human Connectome Project-Young Adult (HCP-YA), focusing on particular bundles expected to relate to particular aspects of cognition and motor function. In comparison with traditional regression analyses based on FA Mean and Automated Fiber Quantification (AFQ), we find that FMQ Regression provides a superior model fit with the lowest mean squared error. This demonstrates that FMQ Regression captures the relationship between scalar factors and white matter microstructure more effectively than the compared approaches. Our results suggest that FMQ Regression, which enables FA analysis in data-driven regions defined by FA quantiles, is more powerful for detecting brain-behavior associations than AFQ, which enables FA analysis in regions defined along the trajectory of a bundle. FMQ Regression finds significant brain-behavior associations in multiple bundles, including findings unique to males or to females. In both males and females, language performance is significantly associated with FA in the left arcuate fasciculus, with stronger associations in the bundle's periphery. In males only, memory performance is significantly associated with FA in the left uncinate fasciculus, particularly in intermediate regions of the bundle. In females only, motor performance is significantly associated with FA in the left and right corticospinal tracts, with a slightly lower relationship at the bundle periphery and a slightly higher relationship toward the bundle core. No significant relationships are found between executive function and cingulum bundle FA. Our study demonstrates that FMQ Regression is a powerful statistical approach that can provide insight into associations from bundle periphery to bundle core. Our results also identify several brain-behavior relationships unique to males or to females, highlighting the importance of considering sex differences in future research.

Visual-Motor Functions and Associated Cognitive Outcomes in Pediatric Cancer Survivors

INTRODUCTION

Pediatric cancer survivors are at high risk for visual-motor and cognitive deficits that persist throughout life. These domains are related to academic performance. The current study examined (i) whether both visuomotor and cognitive functions and (ii) whether visuomotor functions alone mediate the relationship between age and cognitive functions.

METHODS

In total, there were 210 participants (7-17 years): 70 posterior fossa tumors (Mage = 12.1  ±  3.2 years, 44% female) and 70 acute lymphoblastic leukemia (Mage = 12.3  ±  3.4 years, 45% female) survivors and 70 (Mage = 12.2 ± 3.3 years, 41% female) healthy controls. Visual motor integration, motor coordination and visual perception were assessed using the Beery VMI test. Working memory, attention and planning were assessed using CANTAB.

RESULTS

Impaired motor function is significantly more pronounced than cognitive impairment in both groups of cancer survivors (effect size from 25 to 30% for visual-motor and from 5 to 7% for cognitive functions). A multiple regression model revealed that age and visual motor functions are significant predictors of attention (in the ALL group β = -0.490, t = -4.88, p = 0.000) and working memory (in the PFT group β = 0.264, t = 2.72, p = 0.008; in the ALL group β = 0.215, t = 2.24, p = 0.028).

CONCLUSIONS

In children who have experienced acute lymphoblastic leukemia and tumors of the posterior cranial fossa, visual-motor dysfunction is more pronounced than cognitive impairment. In addition, there is an association between visual-motor function disorders and working memory. These findings can be used to develop more specific rehabilitation protocols.

Large-Scale High-Resolution Probabilistic Maps of the Human Superior Longitudinal Fasciculus Subdivisions and their Cortical Terminations

The superior longitudinal fasciculus (SLF) is the large white matter association tract connecting the prefrontal and posterior parietal cortices. Past studies in non-human primates have parcellated the SLF into three subdivisions and have outlined the specific cortico-cortical organization and terminations for each subdivision. However, it is difficult to characterize these structural connections in humans to the specificity of tract-tracing studies in animals. This has led to disagreement on how the SLF subdivisions are organized in the human brain, including if the dorsomedial SLF (SLF-I) is part of the cingulum subsystem. Here, we present a novel large-scale, probabilistic map of the SLF subdivisions, using high-resolution diffusion imaging data from the Human Connectome Project (HCP). We used image data from 302 adult males and 405 adult females to model the three SLF subdivisions in each hemisphere, and attempted to characterize the frontal and parietal termination points for each subdivision. SLF subdivisions were successfully modeled in each subject, showing the dorsomedial-to-ventrolateral organization similar to that in nonhuman primate histological studies. We also found minimal differences between SLF-I models with and without the cingulate gyrus excluded, suggesting that the SLF-I may be a separable tract from the cingulum. Lastly, the SLF subdivisions showed differentiable associations with major cognitive domains such as memory and executive functions. While histological confirmation is needed beyond tractography, these probabilistic masks offer a first step in guiding future exploration of frontoparietal organization by providing detailed characterization of the SLF subdivisions and their potential cortical terminations.Significance statement The prefrontal and posterior parietal areas are interconnected via the SLF, which has been characterized in great detail in monkeys. However, it is difficult to map the SLF organization in the human brain, and previous diffusion MRI findings have been inconsistent. Using diffusion MRI data from 707 individuals, our probabilistic tractography revealed dorsomedial-to-ventrolateral organization of the three SLF subdivisions and their cortical terminations. Our tractography also suggests limited shared volume between the SLF-I and the cingulum, a controversy in recent literature. The SLF subdivisions also differ in their cognitive associations. As a result, we created a large-scale, high-resolution probabilistic parcellation of the SLF, representing an advancement toward standardizing the mapping of human frontoparietal structural connections for clinical and scientific research.

Poststroke Ipsilesional Motor Performance: Microstructural Biomarkers and Their Associations With Executive Function

BackgroundUnilateral hemispheric stroke can impair the ipsilesional motor performance, which is crucial for attaining optimal functional outcomes poststroke. However, the specific brain structures contributing to ipsilesional motor performance impairment remain unclear.ObjectiveTo explore the link between ipsilesional motor performance and the microstructural integrity of relevant neural pathways.MethodsThis study enrolled 60 consecutive patients in the early subacute phase of stroke recovery. Ipsilesional motor performance was assessed using the Box and Block Test. Multiple linear regression was used to evaluate the associations between ipsilesional motor performance and the microstructural integrity of relevant white matter tracts (Biomarker models) and cognitive function test scores (Cognition models).ResultsBiomarker models, including the genu of the corpus callosum, ipsilesional cingulum, fornix, uncinate fasciculus, superior longitudinal fasciculus, and contralesional inferior longitudinal fasciculus, showed a significant association with ipsilesional motor performance. Cognition models, including Mini-Mental State Examination and Trail Making Test-B, were significantly associated with ipsilesional motor performance. Final regression models (combined Cognition and Biomarker models) revealed that the performance time of Trail Making Test-B, in combination with biomarkers, including the genu of the corpus callosum, ipsilesional superior longitudinal fasciculus, and ipsilesional cingulum, predicted ipsilesional motor performance with high explanatory power (adjusted R2 = .721, .709, and .696, respectively).ConclusionsThis study demonstrated that executive function is associated with poststroke ipsilesional motor performance, as evidenced by the microstructural biomarkers involved in executive function. Our findings highlight that the comprehensive role of cognitive functioning rather than the motor system is closely linked to poststroke ipsilesional motor performance.

Executive functions in adolescence: A longitudinal study comparing evaluations before and after the COVID-19 pandemic

The change in the educational model derived from the COVID-19 pandemic might have an impact on cognitive development, particularly on Executive Functions (EFs). The aim of this study was to explore cognitive performance in adolescents at two time points (12 and 14 years of age), before and after the pandemic restrictions. We also analyzed possible sex differences in the results. We evaluated EFs using the Neuropsychological Battery of Executive Functions and Frontal Lobes (BANFE-2), which includes four cognitive indices corresponding to specific cognitive functions and associated prefrontal areas: Orbitofrontal Cortex (OC index -OCI-), Anterior Prefrontal Cortex (APCI), Dorsolateral Prefrontal Cortex (DCI), and Prefrontal cortex as an index of global EFs (EFI). The ANOVA conducted to compare the evaluations before and after the pandemic revealed no significant pre-post-pandemic differences in any sex and in any BANFE-2 index, except for the OCI, in which post-pandemic performance was impaired in boys (pre and post mean score = 96.61 vs. 66.53), but not in girls (pre and post mean score = 93.55 vs. 95.0). Our findings are thus compatible with the idea of a different vulnerability to change in the educational model between sexes, and they also reveal which specific EFs may have been affected during the pandemic.

Reduced white matter integrity and disrupted brain network in children with type 2 and 3 spinal muscular atrophy

BACKGROUND

Spinal muscular atrophy (SMA) is caused by reduced expression of survival motor neuron (SMN) protein. Previous studies indicated SMA causes not only lower motor neuron degeneration but also extensive brain involvement. This study aimed to investigate the changes of brain white matter and structural network using diffusion tensor imaging (DTI) in children with type 2 and 3 SMA.

METHODS

Forty-two type 2 and 3 pediatric SMA patients and 42 age- and gender-matched healthy controls (HC) were prospectively enrolled in this study. The tract-based spatial statistics (TBSS) was used to assess white matter integrity and the structural network properties were calculated based on DTI white matter fiber tracking and the graph theory approach. A partial correlation was performed to explore the relationship between white matter parameters and clinical characteristics.

RESULTS

In total, 42 patients (mean age, 10.86 ± 4.07 years; 23 men) were included. TBSS analysis revealed widespread white matter changes in SMA patients. The SMA patients showed changes in multiple small-world and network efficiency parameters. Compared to the HC group, SMA showed increased characteristic path length (Lp), normalized clustering coefficient (γ), small-world characteristic (σ), and decreased global efficiency (Eglob) (all p < 0.05). In the node properties, right supramarginal gyrus, right orbital part of superior frontal gyrus, right supplementary motor area, and left median cingulate and paracingulate gyri changed in SMA patients. A decreased axial diffusivity (AD) value was associated with lower Hammersmith Functional Motor Scale-Expanded scores (r = 0.45, p = 0.02), which means that the symptoms of SMA patients are more severe.

CONCLUSIONS

This study found white matter and DTI-based brain network abnormalities in SMA patients, suggesting SMN protein deficiency may affect white matter development.

Unraveling the pathophysiology of restless legs syndrome from multimodal MRI techniques: A systematic review

BACKGROUND

Restless Legs Syndrome (RLS) is a common neurological disorder currently diagnosed based on clinical features only, and characterized by a compulsive urge to move the legs triggered by rest or diminished arousal. This systematic review aimed at integrating all current brain magnetic resonance imaging (MRI) modalities for a convergent pathophysiological understanding of RLS phenomenology.

METHODS

We performed a MEDLINE (PubMed)-based systematic review for research articles in patients with primary RLS published in English from 2010 till November 2023. Studies meeting the inclusion criteria according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria were systematically assessed for quality using modality-specific checklists, bias using AXIS tool and a narrative synthesis of the results was conducted.

RESULTS

A total of 49 studies (22 structural, 12 DTI, 7 iron-imaging, 4 spectroscopy with 10 datasets combining multiple approaches) involving 1273 patients (414 males) and 1333 healthy controls (478 males) met the eligibility criteria. Despite participant, technical/device-related and statistical heterogeneity, most agree that patients with primary RLS have structural and metabolite alterations, changes in multiple white matter tract architectures, and disrupted functional connectivity within multiple brain areas. Most of the studies (n = 43, 88 %) have a low-risk of bias on the AXIS scale. Scores on the modality-specific checklist ranged from 46 to 92 %, 70-93 % and 54-92 % for structural MRI, DTI and MRS Datasets, respectively.

CONCLUSIONS

Notwithstanding the large heterogeneity in the methods employed, global connectivity alterations suggest the utility of casting RLS within a system-level perspective rather than viewing it as related to the dysfunction of a single or particular brain region. A holistic approach and its integration within the framework of molecular vulnerability and neurotransmitter alterations are warranted to disentangle the complex pathophysiology of RLS and to identify new therapeutic targets.

Normative data for executive function tests in an Ecuadorian Waranka minority population

Objective: To generate normative data (ND) for executive functions tests in the Waranka minority population of Ecuador. Method: Four-hundred participants aged 6-17 completed the Symbol-Digit Modalities Test (SDMT), Trail-Making Test (TMT), Modified-Wisconsin Card Sorting Test (M-WCST), and Test of Colors-Words (STROOP). Scores were normed using multiple linear regressions, including age, age2, natural logarithm of mean parent education (MPE), sex, bilingualism, and two-way interactions as predictors. Results: Age by MPE and Age2 by MPE interactions arose for SDMT, so that children with illiterate parents scored lower than those with literate parents. Girls scored higher in SDMT. All TMT and M-WCST scores were influenced by age2. Age by MPE interaction was found for TMT-A, so that children with higher MPE went faster; and age by bilingualism interaction for TMT-B, so that more bilingual children needed less time. Stroop-Word and Color were influenced by age2 by MPE interaction, so that children, while older, scored higher, especially those with higher MPE. Also, age2 by sex interaction arose, so that girls increased scores curvilinearly while boys linearly. Word-Color was influenced by age, while Stroop-interference by age2. Age by MPE interaction was found for MCST-Categories and Perseveration, so that perseverations decreased to then increased, especially in those with illiterate parents. M-WCST-Category scores increased to then decrease later on age in children with illiterate parents. Z-scores calculated through indigenous ND were significantly lower than generated through non-indigenous norms. Conclusions: ND for minority populations are critical since Waranka sample performed worse when using non-indigenous norms for z-score calculation.

The role of sleep disturbances in associations between early life adversity and subsequent brain and language development during childhood

Sleep disturbances are posited to play a key role in the development of poor mental and physical health outcomes related to early life adversity (ELA), in part through effects on brain development. Language development is critically important for health and developmental outcomes across the lifespan, including academic achievement and emotion regulation. Yet, very little research has focused on the dynamic contributions of ELA, sleep, and brain development on language outcomes. In this mini review, we summarize the current pediatric literature independently connecting ELA and sleep to language development, as well as the effects of ELA and sleep on language-relevant aspects of brain structure and function. We then propose a framework suggesting that sleep disturbances and subsequent effects on brain structure and function may act as key mechanisms linking ELA and language development. Future research investigating the associations among ELA, sleep, brain, and language development will refine our proposed framework and identify whether sleep should be included as an intervention target to mitigate the effects of early life adversity on language development.

Connectome-based prediction modeling of cognitive control using functional and structural connectivity

BACKGROUND

Cognitive control involves flexibly configuring mental resources and adjusting behavior to achieve goal-directed actions. It is associated with the coordinated activity of brain networks, although it remains unclear how both structural and functional brain networks can predict cognitive control. Connectome-based predictive modeling (CPM) is a powerful tool for predicting cognitive control based on brain networks.

METHODS

The study used CPM to predict cognitive control in 102 healthy adults from the UCLA Consortium for Neuropsychiatric Phenomics dataset and further compared structural and functional connectome characteristics that support cognitive control.

RESULTS

Our results showed that both structural (r values 0.263-0.375) and functional (r values 0.336-0.503) connectomes can significantly predict individuals' cognitive control subcomponents. There is overlap between the functional and structural networks of all three cognitive control subcomponents, particularly in the frontoparietal (FP) and motor (Mot) networks, while each subcomponent also has its own unique weight prediction network. Overall, the functional and structural connectivity that supports different cognitive control subcomponents manifests overlapping and distinct spatial patterns.

CONCLUSIONS

The structural and functional connectomes provide complementary information for predicting cognitive control ability. Integrating information from both connectomes offers a more comprehensive understanding of the neural underpinnings of cognitive control.

SIRT6 modulates lesion microenvironment in LPC induced demyelination by targeting astrocytic CHI3L1

Demyelination occurs widely in the central nervous system (CNS) neurodegenerative diseases, especially the multiple sclerosis (MS), which with a complex and inflammatory lesion microenvironment inhibiting remyelination. Sirtuin6 (SIRT6), a histone/protein deacetylase is of interest for its promising effect in transcriptional regulation, cell cycling, inflammation, metabolism and longevity. Here we show that SIRT6 participates in the remyelination process in mice subjected to LPC-induced demyelination. Using pharmacological SIRT6 inhibitor or activator, we found that SIRT6 modulated LPC-induced damage in motor or cognitive function. Inhibition of SIRT6 impaired myelin regeneration, exacerbated neurological deficits, and decreased oligodendrocyte precursor cells (OPCs) proliferation and differentiation, whereas activation of SIRT6 reversed behavioral performance in mice, demonstrating a beneficial effect of SIRT6. Importantly, based on RNA sequencing analysis of the corpus callosum tissues, it was further revealed that SIRT6 took charge in regulation of glial activation during remyelination, and significant alterations in CHI3L1 were obtained, a glycoprotein specifically secreted by astrocytes. Impaired proliferation and differentiation of OPCs could be induced in vitro using supernatants from reactive astrocyte, especially when SIRT6 was inhibited. Mechanistically, SIRT6 regulates the secretion of CHI3L1 from reactive astrocytes by histone-H3-lysine-9 acetylation (H3K9Ac). Adeno-associated virus-overexpression of SIRT6 (AAV-SIRT6-OE) in astrocytes improved remyelination and functional recovery after LPC-induced demyelination, whereas together with AAV-CHI3L1-OE inhibits this therapeutic effect. Collectively, our data elucidate the role of SIRT6 in remyelination and further reveal astrocytic SIRT6/CHI3L1 as the key regulator for improving the remyelination environment, which may be a potential target for MS therapy.

Trail making test - black & white (TMT B&W): Normative study for the Chilean population

The trailmaking test (TMT) has an educational bias that makes it inapplicable to people with low levels of education due to its dependence on the alphabet. The TMT standardization is the only one available in Chile, and there is a need for alternative ways of using the TMT that do not depend on the level of education for its applicability. To determine the normative scores of the TMT - black & white (TMT B&W), considering sociodemographic factors in adult and elderly Chilean population. A total sample of 227 participants (133 healthy, 94 cognitively impaired) from the Ageing Mets cohort were recruited from three areas in Chile (Antofagasta, Santiago, and Puerto Montt). The TMT B&W was administered to all participants. A multiple regression model was used to generate normative data only in the cognitively healthy group, considering the effect of age, education and sex. A significant effect of age was found in the score of the TMT B&W Parts A and B. The level of education influenced the part B of the test; however, the completion rate of the TMT B&W parts A and B was over 90% in cognitively healthy people. Norms for the number of errors were obtained, and differences between groups were found after controlling for the effect of age and education. This study is the first to provide normative data for the Chilean version of the TMT B&W and will benefit clinical neuropsychologists by improving the procedures for more accurately assessing executive functions and its impairments.

A diffusion MRI tractography atlas for concurrent white matter mapping across Eastern and Western populations

The study of brain differences across Eastern and Western populations provides vital insights for understanding potential cultural and genetic influences on cognition and mental health. Diffusion MRI (dMRI) tractography is an important tool in assessing white matter (WM) connectivity and brain tissue microstructure across different populations. However, a comprehensive investigation into WM fiber tracts between Eastern and Western populations is challenged due to the lack of a cross-population WM atlas and the large site-specific variability of dMRI data. This study presents a dMRI tractography atlas, namely the East-West WM Atlas, for concurrent WM mapping between Eastern and Western populations and creates a large, harmonized dMRI dataset (n=306) based on the Human Connectome Project and the Chinese Human Connectome Project. The curated WM atlas, as well as subject-specific data including the harmonized dMRI data, the whole brain tractography data, and parcellated WM fiber tracts and their diffusion measures, are publicly released. This resource is a valuable addition to facilitating the exploration of brain commonalities and differences across diverse cultural backgrounds.

Structural brain networks correlating with poststroke cognition

Cognitive deficits are a common and debilitating consequence of stroke, yet our understanding of the structural neurobiological biomarkers predicting recovery of cognition after stroke remains limited. In this longitudinal observational study, we set out to investigate the effect of both focal lesions and structural connectivity on poststroke cognition. Sixty-two patients with stroke underwent advanced brain imaging and cognitive assessment, utilizing the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE), at 3-month and 12-month poststroke. We first evaluated the relationship between lesions and cognition at 3 months using voxel-based lesion-symptom mapping. Next, a novel correlational tractography approach, using multi-shell diffusion-weighted magnetic resonance imaging (MRI) data collected at both time points, was used to evaluate the relationship between the white matter connectome and cognition cross-sectionally at 3 months, and longitudinally (12 minus 3 months). Lesion-symptom mapping did not yield significant findings. In turn, correlational tractography analyses revealed positive associations between both MoCA and MMSE scores and bilateral cingulum and the corpus callosum, both cross-sectionally at the 3-month stage, and longitudinally. These results demonstrate that rather than focal neural structures, a consistent structural connectome underpins the performance of two frequently used cognitive screening tools, the MoCA and the MMSE, in people after stroke. This finding should encourage clinicians and researchers to not only suspect cognitive decline when lesions affect these tracts, but also to refine their investigation of novel approaches to differentially diagnosing pathology associated with cognitive decline, regardless of the aetiology.