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Obstructive sleep apnea-hypopnea syndrome (OSAHS) significantly impairs children's growth and cognition. This study aims to elucidate the pathophysiological mechanisms underlying OSAHS in children, with a particular focus on the alterations in cortical information interaction during respiratory events. We analyzed sleep electroencephalography before, during, and after events, utilizing Symbolic Transfer Entropy (STE) for brain network construction and information flow assessment. The results showed a significant increase in STE after events in specific frequency bands during N2 and rapid eye movement (REM) stages, along with increased STE during N3 stage events. Moreover, a noteworthy rise in the information flow imbalance within and between hemispheres was found after events, displaying unique patterns in central sleep apnea and hypopnea. Importantly, some of these alterations were correlated with symptom severity. These findings highlight significant changes in brain region coordination and communication during respiratory events, offering novel insights into OSAHS pathophysiology in children. [ABSTRACT FROM AUTHOR]

Major depressive disorder (MDD) is a prevalent psychiatric condition often accompanied by severe impairments in cognitive and functional capacities. This research was conducted to identify RNA modification-related gene signatures and associated functional pathways in MDD. Differentially expressed RNA modification-related genes in MDD were first identified. And a random forest model was developed and distinct RNA modification patterns were discerned based on signature genes. Then, comprehensive analyses of RNA modification-associated genes in MDD were performed, including functional analyses and immune cell infiltration. The study identified 29 differentially expressed RNA modification-related genes in MDD and two distinct RNA modification patterns. TRMT112, MBD3, NUDT21, and IGF2BP1 of the risk signature were detected. Functional analyses confirmed the involvement of RNA modification in pathways like phosphatidylinositol 3-kinase signaling and nucleotide oligomerization domain (NOD)-like receptor signaling in MDD. NUDT21 displayed a strong positive correlation with type 2 T helper cells, while IGF2BP1 negatively correlated with activated CD8 T cells, central memory CD4 T cells, and natural killer T cells. In summary, further research into the roles of NUDT21 and IGF2BP1 would be valuable for understanding MDD prognosis. The identified RNA modification-related gene signatures and pathways provide insights into MDD molecular etiology and potential diagnostic biomarkers. [ABSTRACT FROM AUTHOR]

Although the United States (US) have been monitoring the autism spectrum disorder (ASD) prevalence, whether the prevalence has continued to increase, decrease, fluctuate or reached a stable level remained unclear during the COVID-19 pandemic. We have requested the 2016–2021 National Survey of Children's Health (NSCH) data in the United States to estimate weighted ASD prevalence and assess linearity/nonlinearity in the time trend. We did not observe linear or nonlinear trends of the ASD prevalence during the 2016–2021 periods. The current ASD prevalence experienced a 0.3% drop from 2019 to 2020 but a 0.3% uptick in 2021, suggesting a stable trend during the COVID-19 pandemic. Our findings shed lights on the need for the modified strategy of monitor ASD prevalence during the COVID-19 era. [ABSTRACT FROM AUTHOR]

Neural tuning for print refers to differential neural responses (e.g., the N1 component of event-related potentials) to different orthographic forms and other visual stimuli. While impaired neural tuning for print has been well established in dyslexic children who read alphabetic scripts, it remains unclear whether such effects exist in dyslexic children who read Chinese, which dramatically differs in visual and linguistic characteristics from alphabetic words. To fill this gap, we examined two levels of the neural tuning for print: coarse tuning (i.e., false character vs. stroke combination), and fine tuning (i.e., sub-lexical tuning: pseudo character vs. false character; and lexical tuning: real character vs. pseudo character). Using the event-related potential technique, we examined 14 typically developing children and 16 dyslexic children who were screened from 216 nine-year-old children in the third grade. For typically developing children, we observed both coarse and sub-lexical tuning. Critically, for dyslexic children, we found stronger N1 for false character than for stroke combination, suggesting intact coarse tuning, but a reduced N1 difference between false character and pseudo character, suggesting impaired sub-lexical tuning. These results clearly show selective impairments in fine neural tuning at the sub-lexical level in Chinese dyslexic children. Our findings may be associated with unique features of Chinese characters. [ABSTRACT FROM AUTHOR]

Attention to words is closely related to the process of learning to read. However, it remains unclear how attention to words in environmental print (such as words on product labels) is changed with the growth of preschool children's reading ability. We thus used eye tracking technique to compare attention to words in environmental print in children at low (32, 15 males, 5.12 years) and high (32, 17 males, 5.16 years) reading levels during a free viewing task. To characterize which aspects of visual word form children attend to, we constructed three types of stimuli embedded in the same context: words in environment print, symbol strings (similar shape to words but without strokes), and character strings (comparable with words in the number of strokes and the structures). We observed that children at both reading levels showed lower percentages of fixations and fixation time in words relative to symbol strings, suggesting they start to attend to the coarse aspect of visual word form. Interestingly, only children at higher reading level showed lower percentages of fixations and fixation time for words relative to character strings, suggesting that attention to the fine-grained aspect of visual word form emerged, and was closely to reading ability. [ABSTRACT FROM AUTHOR]

It has been well established that very-high-altitude (>4000 m) environments can affect human cognitive function and brain activity. However, the effects of long-term exposure to moderate altitudes (2000–3000 m) on cognitive function and brain activity are not well understood. In the present cross-sectional study, we utilized an N-back working memory task and resting-state functional near-infrared spectroscopy to examine the effects of two years of exposure to 2260 m altitude on working memory and resting-state brain activity in 208 college students, compared with a control group at the sea level. The results showed that there was no significant change in spatial working memory performance after two years of exposure to 2260 m altitude. In contrast, the analysis of resting-state brain activity revealed changes in functional connectivity patterns in the prefrontal cortex (PFC), with the global efficiency increased and the local efficiency decreased after two years of exposure to 2260 m altitude. These results suggest that long-term exposure to moderate altitudes has no observable effect on spatial working memory performance, while significant changes in functional connectivity and brain network properties could possibly occur to compensate for the effects of mild hypoxic environments. To our knowledge, this study is the first to examine the resting state activity in the PFC associated with working memory in people exposed to moderate altitudes. [ABSTRACT FROM AUTHOR]

The judgments of moral goodness and moral beauty objectively refer to the perception and evaluation of moral traits, which are generally influenced by facial attractiveness. For centuries, people have equated beauty with the possession of positive qualities, but it is not clear whether the association between beauty and positive qualities exerts a similarly implicit influence on people's responses to moral goodness and moral beauty, how it affects those responses, and what is the neural basis for such an effect. The present study is the first to examine the neural responses to facial attractiveness in the judgments of moral goodness and moral beauty. We found that beautiful faces in both moral judgments activated the left ventral occipitotemporal cortices sensitive to the geometric configuration of the faces, demonstrating that both moral goodness and moral beauty required the automatic visual analysis of geometrical configuration of attractive faces. In addition, compared to beautiful faces during moral goodness judgment, beautiful faces during moral beauty judgment induced unique activity in the ventral medial prefrontal cortex and midline cortical structures involved in the emotional-valenced information about attractive faces. The opposite comparison elicited specific activity in the left superior temporal cortex and premotor area, which play a critical role in the recognition of facial identity. Our results demonstrated that the neural responses to facial attractiveness in the process of higher order moral decision-makings exhibit both task-general and task-specific characteristics. Our findings contribute to the understanding of the essence of the relationship between morality and aesthetics. [ABSTRACT FROM AUTHOR]

Human papillomavirus (HPV) integrating into human genome is the main cause of cervical carcinogenesis. HPV integration selection preference shows strong dependence on local genomic environment. Due to this theory, it is possible to predict HPV integration sites. However, a published bioinformatic tool is not available to date. Thus, we developed an attention-based deep learning model DeepHPV to predict HPV integration sites by learning environment features automatically. In total, 3608 known HPV integration sites were applied to train the model, and 584 reviewed HPV integration sites were used as the testing dataset. DeepHPV showed an area under the receiver-operating characteristic (AUROC) of 0.6336 and an area under the precision recall (AUPR) of 0.5670. Adding RepeatMasker and TCGA Pan Cancer peaks improved the model performance to 0.8464 and 0.8501 in AUROC and 0.7985 and 0.8106 in AUPR, respectively. Next, we tested these trained models on independent database VISDB and found the model adding TCGA Pan Cancer performed better (AUROC: 0.7175, AUPR: 0.6284) than the model adding RepeatMasker peaks (AUROC: 0.6102, AUPR: 0.5577). Moreover, we introduced attention mechanism in DeepHPV and enriched the transcription factor binding sites including BHLHA15, CHR, COUP-TFII, DMRTA2, E2A, HIC1, INR, NPAS, Nr5a2, RARa, SCL, Snail1, Sox10, Sox3, Sox4, Sox6, STAT6, Tbet, Tbx5, TEAD, Tgif2, ZNF189, ZNF416 near attention intensive sites. Together, DeepHPV is a robust and explainable deep learning model, providing new insights into HPV integration preference and mechanism. Availability: DeepHPV is available as an open-source software and can be downloaded from https://github.com/JiuxingLiang/DeepHPV.git , Contact: huzheng1998@163.com, liangjiuxing@m.scnu.edu.cn, lizheyzy@163.com [ABSTRACT FROM AUTHOR]

Although substantial progress has been made in the identification of genetic substrates underlying physiology, neuropsychology, and brain organization, the genotype–phenotype associations remain largely unknown in the context of high‐altitude (HA) adaptation. Here, we related HA adaptive genetic variants in three gene loci (EGLN1, EPAS1, and PPARA) to interindividual variance in a set of physiological characteristics, neuropsychological tests, and topological attributes of large‐scale structural and functional brain networks in 135 indigenous Tibetan highlanders. Analyses of individual HA adaptive single‐nucleotide polymorphisms (SNPs) revealed that specific SNPs selectively modulated physiological characteristics (erythrocyte level, ratio between forced expiratory volume in the first second to forced vital capacity, arterial oxygen saturation, and heart rate) and structural network centrality (the left anterior orbital gyrus) with no effects on neuropsychology or functional brain networks. Further analyses of genetic adaptive scores, which summarized the overall degree of genetic adaptation to HA, revealed significant correlations only with structural brain networks with respect to local interconnectivity of the whole networks, intermodule communication between the right frontal and parietal module and the left occipital module, nodal centrality in several frontal regions, and connectivity strength of a subnetwork predominantly involving in intramodule edges in the right temporal and occipital module. Moreover, the associations were dependent on gene loci, weight types, or topological scales. Together, these findings shed new light on genotype–phenotype interactions under HA hypoxia and have important implications for developing new strategies to optimize organism and tissue responses to chronic hypoxia induced by extreme environments or diseases. [ABSTRACT FROM AUTHOR]

Background: Depressive patients show less altruistic behavior. While, older adults present higher tendencies for altruism than younger adults. Depression and age are two of the influencing factors of altruism, kynurenine (KYN), and its metabolites. However, the characteristics of altruism in late-life depression (LLD) and its possible underlying mechanism have not been studied. Objective: We aimed to explore the characteristics of altruism in LLD patients and its neurobiological mechanism and structural brain network. We investigated whether the levels of metabolites in kynurenine pathway (KP) and white matter (WM) network topological features would influence the altruistic behavior in LLD patients. Methods: Thirty-four LLD patients and 36 heathy controls (HCs) were included. Altruism was evaluated by the Dictator Game (DG) paradigm. Serum concentrations of KP metabolites were detected by the liquid chromatography-tandem mass spectrometry method. The topological features of the WM network were calculated from diffusion tensor imaging data in conjunction with graph-theoretical analysis. Results: The LLD participants exhibited a higher level of altruism and WM global network properties than the HCs. Kynurenic acid to kynurenine (KYNA/KYN) ratio was associated with the DG performance in LLD group. KYNA/KYN ratio was associated with the WM network properties in HC group. Conclusions: KYN metabolism played an important role in altruistic behavior in LLD. [ABSTRACT FROM AUTHOR]

How a child's brain develops specialization for print is poorly understood. One longstanding account is selective neuronal tuning to regularity of visual-orthographic features, which predicts a monotonically increased neural activation for inputs with higher regularity during development. However, we observed a robust interaction between a stimulus' orthographic regularity (bottom-up input) and children's lexical classification ability (top-down prediction): N1 response, which is the first negative component of the event-related potential (ERP) occurring at posterior electrodes, was stronger to lower-regularity stimuli, but only in children who were less efficient in lexically classifying these stimuli (high prediction error). In contrast, N1 responses were reduced to lower-regularity stimuli in children who showed high efficiency of lexical classification (low prediction error). The modulation of children's lexical classification efficiency on their neural responses to orthographic stimuli supports the predictive coding account of neural processes of reading. [ABSTRACT FROM AUTHOR]

Background: A combination of magnetic resonance spectroscopy (MRS) and functional (f)MRI is a promising method for studying brain activity. Negative results have, however, produced uncertainty as to the validity of the approach. Using a MEGA-PRESS sequence adapted to suppress the macromolecule signal (GABA-) has been suggested as a key methodological improvement, but there is some doubt as to the relationship between such estimates and those from the standard sequence (GABA+), making interpretation difficult.Purpose: To investigate the relationship between GABA+ and GABA- estimates from the posterior cingulate and occipital cortices. The second aim was to test for a correlation between occipital GABA and blood oxygenation level-dependent (BOLD) responses in the visual cortex to establish which of the two MEGA-PRESS sequences was more related to the functional responses.Study Type: Prospective.Subjects: Thirty-one healthy participants.Field Strength/sequence: 3T/single-voxel 1 H-MRS and gradient-echo echo planar imaging (EPI).Assessment: GABA estimates were made using the Gannet toolbox. fMRI data were analyzed with FSL and Python scripts.Statistical Test: Relationships between different variables were tested with Pearson's correlation.Results: GABA+ and GABA- concentrations were found to be correlated in both regions (r = 0.52, 95% confidence interval [CI] = 0.35 0.66, pFDR  = 0.002). No relationship was found between either the GABA+ or the GABA- concentrations and the amplitude of the BOLD response in the occipital cortex (GABA+, r = -0.14, pFDR  > 0.1; GABA-, r = -0.29, pFDR  >0.1). However, adding these results to those of prior studies in a meta-analysis of correlation coefficients did provide overall support for a negative correlation between GABA and BOLD response amplitudes (r = -0.39, 95% CI = -0.15-0.64).Data Conclusion: The current findings highlight potential methodological issues that continue to interfere with relating MRS GABA estimates with fMRI responses but, taken in sum, provide support for this general approach.Level Of Evidence: 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:1285-1294. [ABSTRACT FROM AUTHOR]

The process of reading words depends heavily on efficient visual skills, including analyzing and decomposing basic visual features. Surprisingly, previous reading-related studies have almost exclusively focused on gross aspects of visual skills, while only very few have investigated the role of finer skills. The present study filled this gap and examined the relations of two finer visual skills measured by grating acuity (the ability to resolve periodic luminance variations across space) and Vernier acuity (the ability to detect/discriminate relative locations of features) to Chinese character-processing as measured by character form-matching and lexical decision tasks in skilled adult readers. The results showed that Vernier acuity was significantly correlated with performance in character form-matching but not visual symbol form-matching, while no correlation was found between grating acuity and character processing. Interestingly, we found no correlation of the two visual skills with lexical decision performance. These findings provide for the first time empirical evidence that the finer visual skills, particularly as reflected in Vernier acuity, may directly contribute to an early stage of hierarchical word processing. [ABSTRACT FROM AUTHOR]

Abstract: Which temporal features that can characterize different brain states (i.e., consciousness or unconsciousness) is a fundamental question in the neuroscience of consciousness. Using resting‐state functional magnetic resonance imaging (rs‐fMRI), we investigated the spatial patterns of two temporal features: the long‐range temporal correlations (LRTCs), measured by power‐law exponent (PLE), and temporal variability, measured by standard deviation (SD) during wakefulness and anesthetic‐induced unconsciousness. We found that both PLE and SD showed global reductions across the whole brain during anesthetic state comparing to wakefulness. Importantly, the relationship between PLE and SD was altered in anesthetic state, in terms of a spatial “decoupling.” This decoupling was mainly driven by a spatial pattern alteration of the PLE, rather than the SD, in the anesthetic state. Our results suggest differential physiological grounds of PLE and SD and highlight the functional importance of the topographical organization of LRTCs in maintaining an optimal spatiotemporal configuration of the neural dynamics during normal level of consciousness. The central role of the spatial distribution of LRTCs, reflecting temporo‐spatial nestedness, may support the recently introduced temporo‐spatial theory of consciousness (TTC). [ABSTRACT FROM AUTHOR]

Visual word N170 is an index of perceptual expertise for visual words across different writing systems. Recent developmental studies have shown the early emergence of visual word N170 and its close association with individual's reading ability. In the current study, we investigated whether fine-tuning N170 for Chinese characters could emerge after short-term literacy learning in young pre-literate children. Two groups of Chinese preschool children were trained for visual identification and free writing respectively. Results showed that visual identification learning led to enhanced N170 sensitivity to characters over radical-combinations in the left hemisphere and line-combinations in the right hemisphere, and writing learning led to enhanced N170 sensitivity to characters over radical-combinations and line-combinations in the right hemisphere. These results suggested that the N170 component became more sensitive for the local graphic feature (strokes) of characters rapidly after brief literacy learning even in young children; and writing learning experiences specifically led to enhanced orthographic sensitivity in the right hemisphere. [ABSTRACT FROM AUTHOR]

Practice improves our perceptual ability. However, the neural mechanisms underlying this experience-dependent plasticity in adult brain remain unclear. Here, we studied the long-term neural correlates of motion perceptual learning. Subjects' behavioral performance and BOLD signals were tracked before, immediately after, and 2 weeks after practicing a motion direction discrimination task in noise over six daily sessions. Parallel to the specificity and persistency of the behavioral learning effect, we found that training sharpened the cortical tuning in MT, and enhanced the connectivity strength from MT to the intraparietal sulcus (IPS, a motion decision-making area). In addition, the decoding accuracy for the trained motion direction was improved in IPS 2 weeks after training. The dual changes in the sensory and the high-level cortical areas suggest that learning refines the neural representation of the trained stimulus and facilitates the information transmission in the decision process. Our findings are consistent with the functional specialization in the visual cortex, and provide empirical evidence to the reweighting theory of perceptual learning at a large spatial scale. Hum Brain Mapp 38:6029-6042, 2017. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Structural MRI (sMRI)-identified tissue “growth” after neuropsychological training has been reported in many studies but the origins of those apparent tissue changes (ATC) still remain elusive. One possible contributor to ATC is brain perfusion since T1-weighted MRI, the tool used to identify ATC, is sensitive to perfusion-change induced tissue T1 alterations. To test the hypothetical perfusion contribution to ATC, sMRI data were acquired before and after short-term global and regional perfusion manipulations via intaking a 200 mg caffeine pill and performing a sensorimotor task. Caffeine intake caused a global CBF reduction and apparent tissue density reduction in temporal cortex, anterior cingulate cortex, and the limbic area; sensorimotor task induced CBF increase and apparent tissue increase in spatially overlapped brain regions. After compensating CBF alterations through a voxel-wise regression, the ATC patterns demonstrated in both experiments were substantially suppressed. These data clearly proved existence of the perfusion contribution to short-term ATC, and suggested a need for correcting perfusion changes in longitudinal T1-weighted structural MRI analysis if a short-term design is used. [ABSTRACT FROM AUTHOR]

Neuroimaging and neuropsychological studies have identified the involvement of the right posterior region in the processing of visual words. Interestingly, in contrast, ERP studies of the N170 typically demonstrate selectivity for words more strikingly over the left hemisphere. Why is right hemisphere selectivity for words during the N170 epoch typically not observed, despite the clear involvement of this region in word processing? One possibility is that amplitude differences measured on averaged ERPs in previous studies may have been obscured by variation in peak latency across trials. This study examined this possibility by using single-trial analysis. Results show that words evoked greater single-trial N170s than control stimuli in the right hemisphere. Additionally, we observed larger trial-to-trial variability on N170 peak latency for words as compared to control stimuli over the right hemisphere. Results demonstrate that, in contrast to much of the prior literature, the N170 can be selective to words over the right hemisphere. This discrepancy is explained in terms of variability in trial-to-trial peak latency for responses to words over the right hemisphere. [ABSTRACT FROM AUTHOR]

Introduction Interpersonal hypersensitivity is often observed in schizophrenia and has been associated with psychopathological deficits in schizophrenia. Here, we investigated dysfunctions of interpersonal information processing in schizophrenia at both conscious and subconscious levels. Methods The experiment included 143 schizophrenia patients and 59 healthy controls. A continuous flashing suppression approach based on binocular rivalry was employed, which included two modes: invisible (subconscious) and visible (conscious). The accuracy and reaction time of a Gabor patch direction-detection task were assessed under three types of stimuli in both modes: images with no person (type 1), images with two to three noncommunicating persons (type 2), and images with more than three communicating individuals (type 3). Results In the visible mode, the accuracy of the Gabor patch direction-detection task in the case group was significantly lower than in the control group for the third type of stimuli ( P = 0.015). In the invisible mode, however, the accuracy was higher in the case group than in the control group ( P = 0.037). The response time difference of the Gabor patch direction-detection task for the third type of images in the invisible mode was negatively correlated with the duration of the illness ( P = 0.008). Discussion These findings suggest that schizophrenia patients exhibit attentional bias to interpersonal interaction behaviors at both conscious and subliminal levels but toward opposite directions. Our findings shed light on the subconscious deficits under the paranoid symptom in schizophrenia. [ABSTRACT FROM AUTHOR]

Two types of encoding tasks have been employed in previous research to investigate the beneficial effect of unitisation on familiarity-based associative recognition (unitised familiarity effect), namely the compound task and the interactive imagery task. Here we show how these two tasks could differentially engage subsequent recollection-based associative recognition and consequently lead to the turn-on or turn-off of the unitised familiarity effect. In thecompound task, participants studied unrelated word pairs as newly learned compounds. In the interactive imagery task, participants studied the same word pairs as interactive images. An associative recognition task was used in combination with the Remember/Know procedure to measure recollection-based and familiarity-based associative recognition. The results showed that the unitised familiarity effect was present in the compound task but was absent in the interactive imagery task. A comparison of the compound and the interactive imagery task revealed a dramatic increase in recollection-based associative recognition for the interactive imagery task. These results suggest that unitisation could benefit familiarity-based associative recognition; however, this effect will be eliminated when the memory trace formed is easily accessed by strong recollection without the need for a familiarity assessment. [ABSTRACT FROM AUTHOR]

Objective: We aimed to investigate the roles of different resting-state networks in predicting both the actual level of consciousness and its recovery in brain injury patients.Methods: We investigated resting-state functional connectivity within different networks in patients with varying levels of consciousness: unresponsive wakefulness syndrome (UWS; n = 56), minimally conscious state (MCS; n = 29), and patients with brain lesions but full consciousness (BL; n = 48). Considering the actual level of consciousness, we compared the strength of network connectivity among the patient groups. We then checked the presence of connections between specific regions in individual patients and calculated the frequency of this in the different patient groups. Considering the recovery of consciousness, we split the UWS group into 2 subgroups according to recovery: those who emerged from UWS (UWS-E) and those who remained in UWS (UWS-R). The above analyses were repeated on these 2 subgroups.Results: Functional connectivity strength in salience network (SN), especially connectivity between the supragenual anterior cingulate cortex (SACC) and left anterior insula (LAI), was reduced in the unconscious state (UWS) compared to the conscious state (MCS and BL). Moreover, at the individual level, SACC-LAI connectivity was more present in MCS than in UWS. Default-mode network (DMN) connectivity strength, especially between the posterior cingulate cortex (PCC) and left lateral parietal cortex (LLPC), was reduced in UWS-R compared with UWS-E. Furthermore, PCC-LLPC connectivity was more present in UWS-E than in UWS-R.Interpretation: Our findings show that SN (SACC-LAI) connectivity correlates with behavioral signs of consciousness, whereas DMN (PCC-LLPC) connectivity instead predicts recovery of consciousness. [ABSTRACT FROM AUTHOR]

Three experiments examined whether a Stroop effect emerges in the processing of complex Chinese characters that contain a color-related radical. In Experiment 1, a Stroop effect occurred when participants responded to the black or white color of the simple characters [InlineMediaObject not available: see fulltext.] (black) and [InlineMediaObject not available: see fulltext.] (white) by making a left or right keypress. For Experiment 2, in which the stimuli were complex characters whose meanings were unrelated to color but that contained [InlineMediaObject not available: see fulltext.] or [InlineMediaObject not available: see fulltext.] as a radical, a Stroop effect also occurred, although it was smaller than in Experiment 1. Furthermore, this Stroop effect as a function of radical meaning was shown again in Experiment 3 for low-frequency complex characters but not high-frequency ones. These results suggest that the semantic representations of the complex characters' color-related radicals are accessed in the context of a Stroop color word task, especially for low-frequency characters. Reduction of the Stroop effect in complex characters composed of one radical with color meaning and one without is similar to dilution of the Stroop effect that occurs when a color word is accompanied by a neutral word. Possible implications of the results for accounts of Stroop dilution are discussed. [ABSTRACT FROM AUTHOR]

In this study, we investigated whether the meanings of radicals are involved in reading ideogrammic compounds in a spatial Stroop task. We found spatial Stroop effects of similar size for the simple characters [InlineMediaObject not available: see fulltext.] ('up') and [InlineMediaObject not available: see fulltext.] ('down') and for the complex characters [InlineMediaObject not available: see fulltext.] ('nervous') and [InlineMediaObject not available: see fulltext.] ('nervous'), which are ideogrammic compounds containing a radical [InlineMediaObject not available: see fulltext.] or [InlineMediaObject not available: see fulltext.], in Experiments 1 and 2. In Experiment 3, the spatial Stroop effects were also similar for the simple characters [InlineMediaObject not available: see fulltext.] ('east') and [InlineMediaObject not available: see fulltext.] ('west') and for the complex characters [InlineMediaObject not available: see fulltext.] ('state') and [InlineMediaObject not available: see fulltext.] ('spray'), which contain [InlineMediaObject not available: see fulltext.] and [InlineMediaObject not available: see fulltext.] as radicals. This outcome occurred regardless of whether the task was to identify the character (Exps. 1 and 3) or its location (Exp. 2). Thus, the spatial Stroop effect emerges in the processing of radicals just as it does for processing simple characters. This finding suggests that when reading ideogrammic compounds, (a) their radicals' meanings can be processed and (b) ideogrammic compounds have little or no influence on their radicals' semantic processing. [ABSTRACT FROM AUTHOR]

Recent studies have demonstrated resting-state abnormalities in midline regions in vegetative state/unresponsive wakefulness syndrome and minimally conscious state patients. However, the functional implications of these resting-state abnormalities remain unclear. Recent findings in healthy subjects have revealed a close overlap between the neural substrate of self-referential processing and the resting-state activity in cortical midline regions. As such, we investigated task-related neural activity during active self-referential processing and various measures of resting-state activity in 11 patients with disorders of consciousness (DOC) and 12 healthy control subjects. Overall, the results revealed that DOC patients exhibited task-specific signal changes in anterior and posterior midline regions, including the perigenual anterior cingulate cortex (PACC) and posterior cingulate cortex (PCC). However, the degree of signal change was significantly lower in DOC patients compared with that in healthy subjects. Moreover, reduced signal differentiation in the PACC predicted the degree of consciousness in DOC patients. Importantly, the same midline regions (PACC and PCC) in DOC patients also exhibited severe abnormalities in the measures of resting-state activity, that is functional connectivity and the amplitude of low-frequency fluctuations. Taken together, our results provide the first evidence of neural abnormalities in both the self-referential processing and the resting state in midline regions in DOC patients. This novel finding has important implications for clinical utility and general understanding of the relationship between the self, the resting state, and consciousness. Hum Brain Mapp 35:1997-2008, 2014. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Numerous studies have shown cerebellar involvement in item-specific association, a form of explicit learning. However, very few have demonstrated cerebellar participation in automation of non-motor cognitive tasks. Applying fMRI to a repeated verb-generation task, we sought to distinguish cerebellar involvement in learning of item-specific noun-verb association and automation of verb generation skill. The same set of nouns was repeated in six verb-generation blocks so that subjects practiced generating verbs for the nouns. The practice was followed by a novel block with a different set of nouns. The cerebellar vermis (IV/V) and the right cerebellar lobule VI showed decreased activation following practice; activation in the right cerebellar Crus I was significantly lower in the novel challenge than in the initial verb-generation task. Furthermore, activation in this region during well-practiced blocks strongly correlated with improvement of behavioral performance in both the well-practiced and the novel blocks, suggesting its role in the learning of general mental skills not specific to the practiced noun-verb pairs. Therefore, the cerebellum processes both explicit verbal associative learning and automation of cognitive tasks. Different cerebellar regions predominate in this processing: lobule VI during the acquisition of item-specific association, and Crus I during automation of verb-generation skills through practice. [ABSTRACT FROM AUTHOR]

The objective of the study was to further elucidate the potential mechanisms underlying left hemiparalexia induced by a splenium lesion in corpus callosum. A patient KY, who had infarctions in the splenium and the left ventral medial occipitotemporal area, was examined with neuropsychological tests and fMRI. KY presented left hemiparalexia when he read aloud characters presented in central foveal field tachistoscopically as well as in free-view field. KY also showed left hemialexia for characters in left visual field, while no left hemiparalexia occurred when characters were presented in the right visual field. KY performed poorly in lexical decision tasks. He could judge the directions of Landolt's rings gaps in the left or right visual field equally. The result of fMRI indicated that characters in the left visual field could not activate the visual word form area (VWFA), such as left mid-fusiform cortex. All the above neuropsychological and fMRI findings have provided evidences against the assumption of left hemineglect dyslexia. Instead, they support the mechanism of disconnection of visual word form processing pathway. In conclusion, the evidences suggested that the visual information transmission of characters in the left visual field from right occipital area to the VWFA in the left hemisphere was interrupted by the splenium lesion. [ABSTRACT FROM AUTHOR]

Parents and teachers worldwide believe that a visual environment rich with print can contribute to young children's literacy. Children seem to recognize words in familiar logos at an early age. However, most of previous studies were carried out with alphabetic scripts. Alphabetic letters regularly correspond to phonological segments in a word and provide strong cues about the identity of the whole word. Thus it was not clear whether children can learn to read words by extracting visual word form information from environmental prints. To exclude the phonological-cue confound, this study tested children's knowledge of Chinese words embedded in familiar logos. The four environmental logos were employed and transformed into four versions with the contextual cues (i.e., something apart from the presentation of the words themselves in logo format like the color, logo and font type cues) gradually minimized. Children aged from 3 to 5 were tested. We observed that children of different ages all performed better when words were presented in highly familiar logos compared to when they were presented in a plain fashion, devoid of context. This advantage for familiar logos was also present when the contextual information was only partial. However, the role of various cues in learning words changed with age. The color and logo cues had a larger effect in 3- and 4- year-olds than in 5-year-olds, while the font type cue played a greater role in 5-year-olds than in the other two groups. Our findings demonstrated that young children did not easily learn words by extracting their visual form information even from familiar environmental prints. However, children aged 5 begin to pay more attention to the visual form information of words in highly familiar logos than those aged 3 and 4. [ABSTRACT FROM AUTHOR]

Previous studies have identified an area in the left lateral fusiform cortex that is highly responsive to written words and has been named the visual word form area (VWFA). However, there is disagreement on the specific functional role of this area in word recognition. Chinese characters, which are dramatically different from Roman alphabets in the visual form and in the form to phonological mapping, provide a unique opportunity to investigate the properties of the VWFA. Specifically, to clarify the orthographic sensitivity in the mid-fusiform cortex, we compared fMRI response amplitudes (Exp. 1) as well as the spatial patterns of response across multiple voxels (Exp. 2) between Chinese characters and stimuli derived from Chinese characters with different orthographic properties. The fMRI response amplitude results suggest the existence of orthographic sensitivity in the VWFA. The results from multi-voxel pattern analysis indicate that spatial distribution of the responses across voxels in the occipitotemporal cortex contained discriminative information between the different types of character-related stimuli. These results together suggest that the orthographic rules are likely represented in a distributed neural network with the VWFA containing the most specific information regarding a stimulus' orthographic regularity. [ABSTRACT FROM AUTHOR]

Representational similarity analysis (RSA) is a rapidly developing multivariate platform to investigate the structure of neural activities. Similarity/dissimilarity is the core concept of RSA, realized by the construction of a representational dissimilarity matrix, that addresses the closeness/distance for each pair of research elements (e.g., one minus the correlation between the brain responses to 2 different stimuli) and in turn, constitutes a multivariate pattern as its analytic foundation. This approach is also welcome for its sensitivity in detecting subtle differences of distributed experimental effects in the brain. Importantly, RSA is not only an experimental tool but a promising data-analytical framework that can integrate cross-modal imaging signals, explore brain-behavior link, and verify computational models according to measured neural activities. RSA substantiates its integrative power by relating similarity structure in one domain (e.g., stimulus features) to that in another domain (e.g., neural activities). This review summarizes dissimilarity/similarity definition of RSA, introduces how to derive the dissimilarity structure in neural response pattern, and carry out connectivity analysis based on RSA platform. Several recent advances are highlighted, such as the extraction of across-subjects regularity, cross-validation of brain reactivity in human beings and monkeys, the incorporation of computational models and behavioral profiles into RSA. Voxel receptor field modeling, another promising multivariate tool of pattern elucidation, is presented and compared. The application of RSA is expected to surge and extend in many fields of neuroscience, computation, psychology and medicine. We also discuss the limitations of RSA and some critical questions that need to be addressed in future research. [ABSTRACT FROM AUTHOR]

Multivariate pattern analysis (MVPA) is a recently-developed approach for functional magnetic resonance imaging (fMRI) data analyses. Compared with the traditional univariate methods, MVPA is more sensitive to subtle changes in multivariate patterns in fMRI data. In this review, we introduce several significant advances in MVPA applications and summarize various combinations of algorithms and parameters in different problem settings. The limitations of MVPA and some critical questions that need to be addressed in future research are also discussed. [ABSTRACT FROM AUTHOR]

The familiarity to the subject of any potential stimuli presents one of the major difficulties for the investigation of the self; the separation of effects resulting from familiarity from self-effects being extremely problematic. The aim of this study was thus to investigate the neural distinction between self and familiarity by combining two sets of fMRI data with a meta-analysis. In the first fMRI experiment, regions responding to self/familiarity were investigated using the subject's own name and names of familiar others. These effects were confirmed and extended in a second fMRI experiment using the subject's own name and a stranger's name, as spoken by familiar and unfamiliar voices. Finally, a meta-analysis of self- and familiarity-related studies was conducted. Neural activity in the anterior brain regions, such as the anterior cingulate (ACC) and anterior insula (AI), was found to be specific for self-specific stimuli. In contrast, posterior brain regions, such as the posterior cingulate, were activated by familiar stimuli. Finally, the distinction between anterior and posterior regions for self and familiarity was confirmed by meta-analytic data. This study demonstrates a clear anterior-posterior cortical partition between self-specificity and familiarity. Hum Brain Mapp, 2012. © 2010 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

It remains controversial and hotly debated whether foveal information is double-projected to both hemispheres or split at the midline between the two hemispheres. We investigated this issue in a unique patient with lesions in the splenium of the corpus callosum and the left medial occipitotemporal region, through a series of neuropsychological tests and multimodal MRI scans. Behavioral experiments showed that (1) the patient had difficulties in reading simple and compound Chinese characters when they were presented in the foveal but left to the fixation, (2) he failed to recognize the left component of compound characters when the compound characters were presented in the central foveal field, (3) his judgments of the gender of centrally presented chimeric faces were exclusively based on the left half-face and he was unaware that the faces were chimeric. Functional MRI data showed that Chinese characters, only when presented in the right foveal field but not in the left foveal field, activated a region in the left occipitotemporal sulcus in the mid-fusiform, which is recognized as visual word form area. Together with existing evidence in the literature, results of the current study suggest that the representation of foveal stimuli is functionally split at object processing levels. [ABSTRACT FROM AUTHOR]

Regulation of food intake is very important for health. It has been reported that people have decreased appetite at high altitude (HA). The current study recruited long-term HA residents to participate in an fMRI experiment which involved food craving. Result shows that the HA group showed decreased activation in the neural circuit for food craving, accompanied by decreased activation in regions for cognitive control and increased activation in regions for emotional processing. Such results also reflect the decreased gray matter volume and the hypometabolism mechanism under prolonged hypoxia stress at HA. [ABSTRACT FROM AUTHOR]

Early-stage romantic love has been studied previously in the United States and United Kingdom (Aron et al. []: J Neurophysiol 94:327-337; Bartels and Zeki []: Neuroreport 11:3829-3834; Ortigue et al. []: J Cogn Neurosci 19:1218-1230), revealing activation in the reward and motivation systems of the brain. In this study, we asked what systems are activated for early-stage romantic love in Easterners, specifically Chinese participants? Are these activations affected by individual differences within a cultural context of Traditionality and Modernity? Also, are these brain activations correlated with later satisfaction in the relationship? In Beijing, we used the same procedure used by Aron et al. (Aron et al. []: J Neurophysiol 94:327-337). The stimuli for 18 Chinese participants were a picture of the face of their beloved, the face of a familiar acquaintance, and a countback task. We found significant activations specific to the beloved in the reward and motivation systems, particularly, the ventral tegmental area and the caudate. The mid-orbitofrontal cortex and cerebellum were also activated, whereas amygdala, medial orbitofrontal, and medial accumbens activity were decreased relative to the familiar acquaintance. Self-reported Traditionality and Modernity scores were each positively correlated with activity in the nucleus accumbens, although in different regions and sides of the brain. Activity in the subgenual area and the superior frontal gyrus was associated with higher relationship happiness at 18-month follow-up. Our results show that midbrain dopamine-rich reward/motivation systems were activated by early-stage romantic love in Chinese participants, as found by other studies. Neural activity was associated with Traditionality and Modernity attitudes as well as with later relationship happiness for Chinese participants. Hum Brain Mapp, 2011. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Oxygen is critical to normal brain functioning and development. In high altitude where the oxygen concentration and pressure are very low, human cognitive capability such as working memory has been found to be jeopardized. Such effect might persist with long-term high-altitude residence. The current study investigated the verbal working memory of 28 high-altitude residents with blood level oxygen dependent (BOLD) functional magnetic resonance imaging (fMRI), in contrast with that of the 30 sea level residents. All of the subjects were healthy college students, matched on their age, gender ratio and social-economic status; they also did not show any difference on their hemoglobin level. The high-altitude subjects showed longer reaction time and decreased response accuracy in behavioral performance. Both groups showed activation in the typical regions associated with the 2-back verbal working memory task, and the behavioral performance of both groups showed significant correlations with the BOLD signal change amplitude and Granger causality values (as a measure of the interregional effective connectivity) between these regions. With group comparison statistics, the high-altitude subjects showed decreased activation at the inferior and middle frontal gyrus, the middle occipital and the lingual gyrus, the pyramis of vermis, as well as the thalamus. In conclusion, the current study revealed impairment in verbal working memory among high-altitude residents, which might be associated with the impact of prolonged chronic hypoxia exposure on the brain functionality. [ABSTRACT FROM AUTHOR]

Drug-related memories persist long into abstinence and are potent elicitors of drug craving and relapse. We report two experiments examining whether heroin-dependent individuals are impaired in intentionally suppressing drug-related memories. Experiment 1 adopted the Item paradigm where addicts and healthy controls were presented with a list of words each followed by a remember or forget cue. Experiment 2 adopted the List paradigm where they studied one list of items and were then split into a remember group and a forget group. Both groups studied a second list, except that the forget group was told to forget the first list. Compared with controls, addicts showed a reduced directed forgetting effect in the Item method and a total absence of one measure of directed forgetting in the List method (List 2 benefits). Results indicate that heroin addicts are impaired in directed forgetting and that the deficits are likely associated with memory encoding as opposed to retrieval. Possible problems include reduced ability in actively suppressing/stopping encoding of irrelevant information into memory or inability in changing/resetting encoding strategies. In neither experiment did the addicts show any differential directed forgetting effects between drug-related words and neutral words, indicating the generic nature of their intentional forgetting deficits. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to investigate the relationship between medial cortical activation and the presence of self and consciousness in healthy subjects and patients with vegetative state and minimally conscious state using functional magnetic resonance imaging (fMRI). Experiment design: We first conducted two fMRI experiments in healthy subjects to identify brain regions specifically associated with self-perception through the use of different auditory stimuli that had different grades of self-relatedness. We then applied these regions as functional localizers to examine the relationship between neural activity changes during self-relatedness and consciousness level in the patients with disorders of consciousness (DOC). Principal observations: We demonstrated recruitment of various anterior medial cortical regions including the anterior cingulate cortex (ACC) in healthy subjects during auditory perception of self-related stimuli. We further showed that patients with DOC showed signal changes in the ACC during auditory perception of self-related stimuli. Finally, it was shown that these signal changes correlate with the level of consciousness in the patients with DOC. Conclusion: The degree of consciousness in patients with DOC was correlated with neural activity in the ACC induced by self-related stimuli. Our results not only shed light on the pathophysiology of DOC, but may also suggest a useful neural, and thus diagnostic, marker of the dysfunction of consciousness in vegetative patients. Hum Brain Mapp, 2010. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Independent component analysis (ICA) is a data-driven approach that has exhibited great utility for functional magnetic resonance imaging (fMRI). Standard ICA implementations, however, do not provide the number and relative importance of the resulting components. In addition, ICA algorithms utilizing gradient-based optimization give decompositions that are dependent on initialization values, which can lead to dramatically different results. In this work, a new method, RAICAR (Ranking and Averaging Independent Component Analysis by Reproducibility), is introduced to address these issues for spatial ICA applied to fMRI. RAICAR utilizes repeated ICA realizations and relies on the reproducibility between them to rank and select components. Different realizations are aligned based on correlations, leading to aligned components. Each component is ranked and thresholded based on between-realization correlations. Furthermore, different realizations of each aligned component are selectively averaged to generate the final estimate of the given component. Reliability and accuracy of this method are demonstrated with both simulated and experimental fMRI data. Hum Brain Mapp, 2008. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Whether the cerebellum is involved in voluntary motor learning or motor performance is the subject of a new debate. Using functional magnetic resonance imaging (fMRI), we examined cerebellar activation in eight volunteers before and after an extended period of training. Activation volume on both sides of cerebellum after learning was significantly reduced compared to that before learning even under the same motor frequency. Remarkably, while motor frequency for the training sequence was significantly higher than the control sequence after 41 d of learning, activation in the cerebellum for both sequences, with respect to activation loci and volumes, was very similar. These results suggest that the cerebellum was involved in motor learning but not motor performance. Changes of cerebellar activation from training thus appear to be associated with learning but not with improvement on task performance. [ABSTRACT FROM AUTHOR]

After Newman and Twieg ([]: Hum Brain Mapp 14:39-47) and others, we used a fast event-related functional magnetic resonance imaging (fMRI) design and contrasted the lexical processing of pseudowords and real words. Participants carried out an auditory lexical decision task on a list of randomly intermixed real and pseudo Chinese two-character (or two-syllable) words. The pseudowords were constructed by recombining constituent characters of the real words to control for sublexical code properties. Processing of pseudowords and real words activated a highly comparable network of brain regions, including bilateral inferior frontal gyrus, superior, middle temporal gyrus, calcarine and lingual gyrus, and left supramarginal gyrus. Mirroring a behavioral lexical effect, left inferior frontal gyrus (IFG) was significantly more activated for pseudowords than for real words. This result disconfirms a popular view that this area plays a role in grapheme-to-phoneme conversion, as such a conversion process was unnecessary in our task with auditory stimulus presentation. An alternative view was supported that attributes increased activity in left IFG for pseudowords to general processes in decision making, specifically in making positive versus negative responses. Activation in left supramarginal gyrus was of a much larger volume for real words than for pseudowords, suggesting a role of this region in the representation of phonological or semantic information for two-character Chinese words at the lexical level. Hum Brain Mapp 25:212-221, 2005. © 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The impact of learning on brain functional laterality has not been systematically investigated. We employed an event-related functional magnetic resonance imaging combined with a delayed sequential movement task to investigate brain activation pattern and laterality during a transient practice in 12 subjects. Both hemispheres, involving motor areas and posterior parietal cortex, were engaged during motor preparation and execution, with larger activation volume in the left hemisphere than in the right. Activation volume in these regions significantly decreased after a transient practice, with more reduction in the right hemisphere resulting increase in left lateralization. The theoretical implications of these findings are discussed in relation to the physiological significance of brain functional laterality. [ABSTRACT FROM AUTHOR]

The impact of learning on brain functional laterality has not been systematically investigated. We employed an event-related functional magnetic resonance imaging combined with a delayed sequential movement task to investigate brain activation pattern and laterality during a transient practice in 12 subjects. Both hemispheres, involving motor areas and posterior parietal cortex, were engaged during motor preparation and execution, with larger activation volume in the left hemisphere than in the right. Activation volume in these regions significantly decreased after a transient practice, with more reduction in the right hemisphere resulting increase in left lateralization. The theoretical implications of these findings are discussed in relation to the physiological significance of brain functional laterality. [ABSTRACT FROM AUTHOR]

Quite a few studies in functional magnetic resonance imaging (fMRI) have tested that, even in a resting state, motor cortices constitute a network. It has never been investigated how the network modulates from the resting state to the motor task state. In this report, by a newly developed approach taking into account n-to-1 connectivity using 1-to-1 connectivity measures instead of conventional pairwise connectivity, we show the existence of a large organized functional connectivity network related to motor function in the resting brain with fMRI. More importantly, we found that such a network can be modulated from a conscious resting state to planning, initiation, coordination, guidance, and termination of voluntary movement state, exhibited by significant changes of functional connectivity of some brain regions in different brain activity. Moreover, a quantitative description of such a functional modulation has also been presented. Hum. Brain Mapp. 22:65-73, 2004. © 2004 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Investigates the hemodynamic responses in the primary motor cortex (M1), supplementary motor area (SMA) and premotor cortex (PMC) in six healthy right-handed subjects. Details of the experiment in which the subjects performed a visually-guided finger-tapping task with their dominant or non-dominant hands; Finding of significant activation in M1, SMA and PMC during this simple task; The dominant hand movements engaging contralateral motor areas; Non-dominant hand movements activating ipsilateral SMA and PMC; Suggestion that the secondary motor areas are involved in simple voluntary movements; Suggestion that dominant-hand movements engage the contralateral secondary motor areas; Suggestion that non-dominant hand movements activate bilateral secondary motor areas.

Objectives: To characterize the brain activation patterns evoked by manual and electroacupuncture on normal human subjects. Design: We used functional magnetic resonance imaging (fMRI) to investigate the brain regions involved in electroacupuncture and manual acupuncture needle stimulation. A block design was adopted for the study. Each functional run consists of 5 minutes, starting with 1-minute baseline and two 1-minute stimulation, the interval between the two stimuli was 1 minute. Four functional runs were performed on each subject, two runs for electroacupuncture and two runs for manual acupuncture. The order of the two modalities was randomized among subjects. During the experiment, acupuncture needle manipulation was performed at Large Intestine 4 (LI4, Hegu) on the left hand. For each subject, before scanning started, the needle was inserted perpendicular to the skin surface to a depth of approximately 1.0 cm. Electroacupuncture stimulation was delivered using a continuous rectangular wave form (pulse width 30 ms) at a frequency of 3 Hz. For manual acupuncture, the needle was rotated manually clockwise and counterclockwise at a rate of about 180 times per minute (3 Hz). Subjects: Eleven right-handed, normal, healthy volunteer adults, 6 male and 5 female, ages 21-64 participated in the experiment. Results: Results showed that electroacupuncture mainly produced fMRI signal increases in precentral gyrus, postcentral gyrus/inferior parietal lobule, and putamen/insula; in contrast, manual needle manipulation produced prominent decreases of fMRI signals in posterior cingulate, superior temporal gyrus, putamen/insula. Conclusion: These results indicate that different brain networks are involved during manual and electroacupuncture stimulation. It suggests that different brain mechanisms may be recruited during manual and electroacupuncture. [ABSTRACT FROM AUTHOR]

Background: Developmental dyslexia (DD) is a specific learning disorder concerning reading acquisition that may has a lifelong negative impact on individuals. A reliable estimate of the prevalence of DD serves as the basis for diagnosis, intervention, and evidence-based health resource allocation and policy-making. Hence, the present meta-analysis aims to generate a reliable prevalence estimate of DD worldwide in primary school children and explore the potential variables related to that prevalence. Methods: Studies from the 1950s to June 2021 were collated using a combination of search terms related to DD and prevalence. Study quality was assessed using the STROBE guidelines according to the study design, with study heterogeneity assessed using the I2 statistic, and random-effects meta-analyses were conducted. Variations in the prevalence of DD in different subgroups were assessed via subgroup meta-analysis and meta-regression. Results: The pooled prevalence of DD was 7.10% (95% CI: 6.27–7.97%). The prevalence in boys was significantly higher than that in girls (boys: 9.22%, 95%CI, 8.07–10.44%; girls: 4.66%, 95% CI, 3.84–5.54%; p < 0.001), but no significant difference was found in the prevalence across different writing systems (alphabetic scripts: 7.26%, 95%CI, 5.94–8.71%; logographic scripts: 6.97%, 95%CI, 5.86–8.16%; p > 0.05) or across different orthographic depths (shallow: 7.13%, 95% CI, 5.23–9.30%; deep: 7.55%, 95% CI, 4.66–11.04%; p > 0.05). It is worth noting that most articles had small sample sizes with diverse operational definitions, making comparisons challenging. Conclusions: This study provides an estimation of worldwide DD prevalence in primary school children. The prevalence was higher in boys than in girls but was not significantly different across different writing systems. [ABSTRACT FROM AUTHOR]