Publications by authors named "Ruiwang Huang"

106 Publications

Time-delay structure predicts clinical scores for patients with disorders of consciousness using resting-state fMRI.

Neuroimage Clin 2021 Aug 28;32:102797. Epub 2021 Aug 28.

Key Laboratory of Brain, Cognition and Education Sciences (South China Normal University), Ministry of Education; School of Psychology; Center for Studies of Psychological Application; Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou 510631, China. Electronic address:

Background: The detection of intrinsic brain activity (iBA) could assist clinical assessment for disorder of consciousness (DOC) patients. Previous studies have revealed the altered iBA in thalamocortical, frontoparietal, and default mode network in DOC patients using functional connectivity (FC) analysis. However, due to the assumption of synchronized iBA in FC, these studied may be inadequate for understanding the effect of severe brain injury on the temporal organization of iBA and the relationship between temporal organization and clinical feature in DOC patients. Recently, the time delay estimation (TDE) and probabilistic flow estimation (PFE) were proposed to analyze temporal organization, which could provide propagation structure and propagation probability at whole-brain level.

Methods: We applied voxel-wise TDE and PFE to assess propagation structure and propagation probability for the DOC patients and then applied the connectome-based predictive modeling (CPM) to predict clinical scores for patients based on the ROI-wise TDE and PFE.

Results: We found that: 1) the DOC patients showed abnormal voxel-wise time delay (TD) and probabilistic flow (PF) in the precentral gyrus, precuneus, middle cingulate cortex, and postcentral gyrus, 2) the range of TD value in the patients was shorter than that in the controls, and 3) the ROI-wise TD had a better predictive performance for clinical scores of the patients compared with that based on ROI-wise PF.

Conclusion: Our findings may suggest that the propagation structure of iBA could be used to predict clinical scores in DOC patients.
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http://dx.doi.org/10.1016/j.nicl.2021.102797DOI Listing
August 2021

Altered microstructural properties of superficial white matter in patients with Parkinson's disease.

Brain Imaging Behav 2021 Aug 19. Epub 2021 Aug 19.

Key Laboratory of Brain, Cognition and Education Sciences (South China Normal University), Ministry of Education, School of Psychology, Center for Studies of Psychological Application, Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou, 510631, China.

Parkinson's disease (PD), a chronic neurodegenerative disease, is characterized by sensorimotor and cognitive deficits. Previous diffusion tensor imaging (DTI) studies found abnormal DTI metrics in white matter bundles, such as the corpus callosum, cingulate, and frontal-parietal bundles, in PD patients. These studies mainly focused on alterations in microstructural features of long-range bundles within the deep white matter (DWM) that connects pairs of distant cortical regions. However, less is known about the DTI metrics of the superficial white matter (SWM) that connects local cortical regions in PD patients. To determine whether the DTI metrics of the SWM were different between the PD patients and the healthy controls, we recruited DTI data from 34 PD patients and 29 gender- and age-matched healthy controls. Using a probabilistic tractographic approach, we first defined a population-based SWM mask across all the subjects. Using a tract-based spatial statistical (TBSS) analytic approach, we then identified the SWM bundles showing abnormal DTI metrics in the PD patients. We found that the PD patients showed significantly lower DTI metrics in the SWM bundles connecting the sensorimotor cortex, cingulate cortex, posterior parietal cortex (PPC), and parieto-occipital cortex than the healthy controls. We also found that the clinical measures in the PD patients was significantly negatively correlated with the fractional anisotropy in the SWM (FA) that connects core regions in the default mode network (DMN). The FA in the bundles that connected the PPC was significantly positively correlated with cognitive performance in the PD patients. Our findings suggest that SWM may serve as the brain structural basis underlying the sensorimotor deficits and cognitive degeneration in PD patients.
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http://dx.doi.org/10.1007/s11682-021-00522-8DOI Listing
August 2021

A Comparative Multimodal Meta-analysis of Anisotropy and Volume Abnormalities in White Matter in People Suffering From Bipolar Disorder or Schizophrenia.

Schizophr Bull 2021 Aug 10. Epub 2021 Aug 10.

Laboratory of Cognitive Control and Brain Healthy, Department of Psychology, School of Public Health, Southern Medical University, Guangzhou, China.

Schizophrenia (SZ) and bipolar disorder (BD) share some similarities in terms of genetic-risk genes and abnormalities of gray-matter structure in the brain, but white matter (WM) abnormalities have not been studied in depth. We undertook a comparative multimodal meta-analysis to identify common and disorder-specific abnormalities in WM structure between SZ and BD. Anisotropic effect size-signed differential mapping software was used to conduct a comparative meta-analysis of 68 diffusion tensor imaging (DTI) and 34 voxel-based morphometry (VBM) studies comparing fractional anisotropy (FA) and white matter volume (WMV), respectively, between patients with SZ (DTI: N = 1543; VBM: N = 1068) and BD (DTI: N = 983; VBM: N = 518) and healthy controls (HCs). The bilateral corpus callosum (extending to the anterior and superior corona radiata) showed shared decreased WMV and FA in SZ and BD. Compared with BD patients, SZ patients showed remarkable disorder-specific WM abnormalities: decreased FA and increased WMV in the left cingulum, and increased FA plus decreased WMV in the right anterior limb of the internal capsule. SZ patients showed more extensive alterations in WM than BD cases, which may be the pathophysiological basis for the clinical continuity of both disorders. The disorder-specific regions in the left cingulum and right anterior limb of the internal capsule provided novel insights into both disorders. Our study adds value to further understanding of the pathophysiology, classification, and differential diagnosis of SZ and BD.
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http://dx.doi.org/10.1093/schbul/sbab093DOI Listing
August 2021

Anomalous static and dynamic functional connectivity of amygdala subregions in individuals with high trait anxiety.

Depress Anxiety 2021 08 12;38(8):860-873. Epub 2021 Jul 12.

Department of Psychology, School of Public Health, Southern Medical University, Guangzhou, China.

Background: Trait anxiety is considered a susceptible factor for stress-related disorders, and is characterized by abnormal brain activity and connectivity in the regions related to emotional processing (e.g., the amygdala). However, only a few studies have examined the static and dynamic changes of functional connectivity in trait anxiety.

Method: We compared the resting-state static and dynamic functional connectivity (sFC/dFC) in individuals with high trait anxiety (HTA, n = 257) and low trait anxiety (LTA, n = 264) using bilateral amygdala subregions as the seeds, that is, the centromedial amygdala (CMA), basolateral amygdala (BLA), and superficial amygdala (SFA).

Results: The CMA, BLA, and SFA all showed reduced sFC with the executive control network (ECN) and anomalous dFC with the default mode network (DMN) in individuals with HTA. The CMA only showed reduced sFC with the ECN and reduced dFC with the DMN in individuals with HTA. The BLA showed reduced sFC with the salience network (mainly in the anterior and median cingulate), and increased dFC between the BLA and the DMN in individuals with HTA compared to those with LTA. Notably, HTA showed widespread anomalous functional connectivity in the SFA, including the visual network, mainly in the calcarine fissure, limbic system (olfactory cortex), and basal ganglia (putamen).

Conclusion: The anomalous sFC and dFC in individuals with HTA may reflect altered mechanisms in prefrontal control, salient stimuli processing, and amygdaloidal responsivity to potential threats, leading to alterations in associative, attentional, interpretative, and regulating processes that sustain a threat-related processing bias in HTA individuals.
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http://dx.doi.org/10.1002/da.23195DOI Listing
August 2021

Human spatial navigation: Neural representations of spatial scales and reference frames obtained from an ALE meta-analysis.

Neuroimage 2021 09 12;238:118264. Epub 2021 Jun 12.

Key Laboratory of Brain, Cognition and Education Sciences (South China Normal University), Ministry of Education; School of Psychology, Center for Studies of Psychological Application, and Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou, Guangdong, 510631, China. Electronic address:

Humans use different spatial reference frames (allocentric or egocentric) to navigate successfully toward their destination in different spatial scale spaces (environmental or vista). However, it remains unclear how the brain represents different spatial scales and different spatial reference frames. Thus, we conducted an activation likelihood estimation (ALE) meta-analysis of 47 fMRI articles involving human spatial navigation. We found that both the environmental and vista spaces activated the parahippocampal place area (PPA), retrosplenial complex (RSC), and occipital place area in the right hemisphere. The environmental space showed stronger activation than the vista space in the occipital and frontal regions. No brain region exhibited stronger activation for the vista than the environmental space. The allocentric and egocentric reference frames activated the bilateral PPA and right RSC. The allocentric frame showed more stronger activations than the egocentric frame in the right culmen, left middle frontal gyrus, and precuneus. No brain region displayed stronger activation for the egocentric than the allocentric navigation. Our findings suggest that navigation in different spatial scale spaces can evoke specific and common brain regions, and that the brain regions representing spatial reference frames are not absolutely separated.
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http://dx.doi.org/10.1016/j.neuroimage.2021.118264DOI Listing
September 2021

Efficacy and acceptability of transcranial direct current stimulation for treating depression: A meta-analysis of randomized controlled trials.

Neurosci Biobehav Rev 2021 07 28;126:481-490. Epub 2021 Mar 28.

The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou Medical University, Guangzhou, China; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China; Laboratory of Neuropsychology and Human Neuroscience, The University of Hong Kong, Hong Kong, China; Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong-Macao, Greater Bay Area, China. Electronic address:

Background: Transcranial direct current stimulation (tDCS) is a promising nonpharmacological intervention for treating depression. We aimed to provide an updated meta-analysis assessing the anti-depressant efficacy of tDCS.

Methods: We searched the literature from the first available date to 30 December 2020 to identify relevant randomized controlled trials (RCTs).

Results: 27 RCTs (N = 1204 patients, 653 in active tDCS and 551 in sham tDCS) were included. Active tDCS was superior to sham tDCS (g = 0.46, 95 % CI 0.15-0.76) in modulating depressive symptoms measured by depression rating scales. Active tDCS was also superior to sham tDCS in reducing response and remission rates, but these differences did not reach statistically significant levels (OR = 1.75, 95 % CI 0.85-3.58; OR = 1.29, 95 % CI 0.59-2.83). The two groups had comparable dropout rates (OR = 1.28, 95 % CI 0.62-1.64).

Conclusion: For treatments of depressive episodes, tDCS may be efficacious. Specific tDCS parameters (e.g., a 2-mA stimulation current and 30-min sessions) and clinical characteristics (e.g., antidepressant-free) may augment the treatment efficacy of tDCS.
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http://dx.doi.org/10.1016/j.neubiorev.2021.03.026DOI Listing
July 2021

Cortical myelin content mediates differences in affective temperaments.

J Affect Disord 2021 03 14;282:1263-1271. Epub 2021 Jan 14.

Key Laboratory of Brain, Cognition and Education Sciences (South China Normal University), Ministry of Education; School of Psychology, Center for Studies of Psychological Application; Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou, 510631, China. Electronic address:

Background: Affective temperaments are regarded as subclinical forms and precursors of mental disorders. It may serve as candidates to facilitate the diagnosis and prediction of mental disorders. Cortical myelination likely characterizes the neurodevelopment and the evolution of cognitive functions and reflects brain functional demand. However, little is known about the relationship between affective temperaments and myelin plasticity. This study aims to analyze the association between the affective temperaments and cortical myelin content (CMC) in human brain.

Methods: We measured affective temperaments using the Temperament Evaluation of Memphis, Pisa, Paris and San Diego Autoquestionnaire (TEMPS-A) on 106 healthy adults and used the ratio of T1- and T2-weighted images as the proxy for CMC. Using the unsupervised k-means clustering algorithm, we classified the cortical gray matter into heavily, intermediately, and lightly myelinated regions. The correlation between affective temperaments and CMC was calculated separately for different myelinated regions.

Results: Hyperthymic temperament correlated negatively with CMC in the heavily myelinated (right postcentral gyrus and bilateral precentral gyrus) and lightly myelinated (bilateral frontal and lateral temporal) regions. Cyclothymic temperament showed a downward parabola-like correlation with CMC across the heavily, intermediately, and lightly myel0inated areas of the bilateral parietal-temporal regions.

Limitations: The analysis was constrained to cortical regions. The results were obtained from healthy subjects and we did not acquired data from patients of affective disorder, which may compromise the generalizability of the present findings.

Conclusion: The findings suggest that hyperthymic and cyclothymic temperaments have a CMC basis in extensive brain regions.
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http://dx.doi.org/10.1016/j.jad.2021.01.038DOI Listing
March 2021

White Matter Microstructure Underlies the Effects of Sleep Quality and Life Stress on Depression Symptomatology in Older Adults.

Front Aging Neurosci 2020 13;12:578037. Epub 2020 Nov 13.

Institute of Neuroscience and Medicine (INM-2), Forschungszentrum Jülich, Jülich, Germany.

Sleep complaints are the most prevalent syndromes in older adults, particularly in women. Moreover, they are frequently accompanied with a high level of depression and stress. Although several diffusion tensor imaging (DTI) studies reported associations between sleep quality and brain white matter (WM) microstructure, it is still unclear whether gender impacts the effect of sleep quality on structural alterations, and whether these alterations mediate the effects of sleep quality on emotional regulation. We included 389 older participants (176 females, age = 65.5 ± 5.5 years) from the 1000BRAINS project. Neuropsychological examinations covered the assessments of sleep quality, depressive symptomatology, current stress level, visual working memory, and selective attention ability. Based on the DTI dataset, the diffusion parameter maps, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD), were calculated and normalized to a population-specific FA template. According to the global Pittsburgh Sleep Quality Index (PSQI), 119 poor sleepers (PSQI: 10∼17) and 120 good sleepers (PSQI: 3∼6) were identified. We conducted a two by two (good sleepers/poor sleepers) × (males/females) analysis of variance by using tract-based spatial statistics (TBSS) and JHU-ICBM WM atlas-based comparisons. Moreover, we performed a voxel-wise correlation analysis of brain WM microstructure with the neuropsychological tests. Finally, we applied a mediation analysis to explore if the brain WM microstructure mediates the relationship between sleep quality and emotional regulation. No significant differences in brain WM microstructure were detected on the main effect of sleep quality. However, the MD, AD, and RD of pontine crossing tract and bilateral inferior cerebellar peduncle were significant lower in the males than females. Voxel-wise correlation analysis revealed that FA and RD values in the corpus callosum were positively related with depressive symptomatology and negatively related with current stress levels. Additionally, we found a significantly positive association between higher FA values in visual-related WM tracts and better outcomes in a visual pattern recognition test. Furthermore, a mediation analysis suggested that diffusion metrics within the corpus callosum partially mediated the associations between poor sleep quality/high stress and depressive symptomatology.
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http://dx.doi.org/10.3389/fnagi.2020.578037DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7691589PMC
November 2020

Specific white matter connectomic changes in schizophrenia compared with psychotic bipolar disorder.

Asian J Psychiatr 2021 Jan 2;55:102468. Epub 2020 Nov 2.

Department of Psychiatry, the Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Guangzhou, Guangdong Province, 510630, China. Electronic address:

Background: Schizophrenia (SZ) and bipolar disorder with psychosis (BDP) can be clinically confusing. The specific connectomic changes in SZ compared with BDP may lead to a deeper comprehension of the pathophysiological core of SZ. Therefore, this study explored the common and distinct white matter (WM) structural connectomic alterations between these two diseases.

Method: Diffusion tensor imaging data were collected from 19 drug-naïve patients with first episode SZ, 19 drug-naïve patients with BDP, and 19 healthy controls (HC). A graph theoretical approach was used to assess the brain WM network properties.

Results: Except for the clustering coefficients, no significant differences in the global parameters was found between SZ and BDP. Five brain regions, the right precentral, right post-cingulum, right insula, left superior occipital, and left inferior temporal gyri, showed specific differences in the nodal parameters in SZ compared with BDP and HC. Nine brain regions, the left rectus, left lingual, right inferior parietal, left superior temporal, right precentral, right postcentral, bilateral middle frontal, and right post-cingulum gyri, showed specific differences in the nodal parameters in BDP. Significant correlations between clinical symptoms and connectomic changes were detected in the right insula and left superior occipital gyrus in patients with SZ but in the left lingual gyrus in patients with BDP.

Conclusions: Identifying shared and distinct WM structural networks between SZ and BDP may improve the understanding of the neuroanatomy of mental diseases. Specifically, the insula, the inferior temporal, superior temporal, and the lingual gyri may help to distinguish between SZ and BDP.
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http://dx.doi.org/10.1016/j.ajp.2020.102468DOI Listing
January 2021

Structural and functional brain signatures of endurance runners.

Brain Struct Funct 2021 Jan 7;226(1):93-103. Epub 2020 Nov 7.

Department of Physical Education, Shenzhen University, Shenzhen, 518060, China.

Although endurance running (ER) seems to be a simple repetitive exercise, good ER performance also requires and relies on multiple cognitive and motor control processes. Most of previous neuroimaging studies on ER were conducted using a single MRI modality, yet no multimodal study to our knowledge has been performed in this regard. In this study, we used multimodal MRI data to investigate the brain structural and functional differences between endurance runners (n = 22; age = 26.27 ± 6.07 years; endurance training = 6.23 ± 2.41 years) and healthy controls (HCs; n = 20; age = 24.60 ± 4.14 years). Compared with the HCs, the endurance runners showed greater gray matter volume (GMV) and cortical surface area in the left precentral gyrus, which at the same time had higher functional connectivity (FC) with the right postcentral and precentral gyrus. Subcortically, the endurance runners showed greater GMV in the left hippocampus and regional inflation in the right hippocampus. Using the bilateral hippocampi as seeds, further seed-based FC analyses showed higher hippocampal FC with the supplementary motor area, middle cingulate cortex, and left posterior lobe of the cerebellum. Moreover, compared with the HCs, the endurance runners also showed higher fractional anisotropy in several white matter regions, involving the corpus callosum, left internal capsule, left corona radiata, left external capsule, left posterior lobe of cerebellum and bilateral precuneus. Taken together, our findings provide several lines of evidence for the brain structural and functional differences between endurance runners and HCs. The current data suggest that these brain characteristics may have arisen as a result of regular ER training; however, whether they represent the neural correlates underlying the good ER performances of the endurance runners requires further investigations.
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http://dx.doi.org/10.1007/s00429-020-02170-yDOI Listing
January 2021

The neural correlates of moral comparison.

Neuropsychologia 2020 12 28;149:107662. Epub 2020 Oct 28.

Key Laboratory of Brain, Cognition and Education Sciences (South China Normal University), Ministry of Education, Guangzhou, 510631, China; School of Psychology, South China Normal University, Guangzhou, 510631, China; Center for Studies of Psychological Application, South China Normal University, Guangzhou, 510631, China; Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou, 510631, China. Electronic address:

Moral comparison supports the moral judgment that then evaluates social behaviors and restrains social interactions. However, previous studies have not investigated what neural networks support the process of moral comparison. The present study examined neural networks of moral and physical size comparisons using a distance paradigm and functional magnetic resonance imaging. In the experiment, participants judged which picture/sentence presented a more moral scenario in the moral comparison run or which picture/sentence had a larger physical size in the physical comparison run. Results demonstrated that both moral and physical comparisons induced a distance effect-participants' responses were faster for high than low distance comparisons. Moreover, moral and physical comparisons recruited similar neural networks, including the bilateral dorsomedial prefrontal cortex, bilateral intraparietal sulcus, and bilateral insula. Interestingly, compared with physical size comparisons, moral comparisons elicited stronger activity in the bilateral precuneus, bilateral angular gyrus, and bilateral superior frontal gyrus. Meanwhile, compared with moral comparisons, physical size comparisons elicited stronger activity in the right inferior parietal lobule. Together, these results suggest that the neural substrates of moral and physical comparisons not only share the frontoparietal network but also rely on specific neural underpinnings, depending on the specific comparison recruited.
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http://dx.doi.org/10.1016/j.neuropsychologia.2020.107662DOI Listing
December 2020

Altered gray matter structural covariance networks at both acute and chronic stages of mild traumatic brain injury.

Brain Imaging Behav 2021 Aug;15(4):1840-1854

Center for Studies of Psychological Application, South China Normal University, Guangzhou, 510631, China.

Cognitive and emotional impairments observed in mild traumatic brain injury (mTBI) patients may reflect variances of brain connectivity within specific networks. Although previous studies found altered functional connectivity (FC) in mTBI patients, the alterations of brain structural properties remain unclear. In the present study, we analyzed structural covariance (SC) for the acute stages of mTBI (amTBI) patients, the chronic stages of mTBI (cmTBI) patients, and healthy controls. We first extracted the mean gray matter volume (GMV) of seed regions that are located in the default-mode network (DMN), executive control network (ECN), salience network (SN), sensorimotor network (SMN), and the visual network (VN). Then we determined and compared the SC for each seed region among the amTBI, the cmTBI and the healthy controls. Compared with healthy controls, the amTBI patients showed lower SC for the ECN, and the cmTBI patients showed higher SC for the both DMN and SN but lower SC for the SMN. The results revealed disrupted ECN in the amTBI patients and disrupted DMN, SN and SMN in the cmTBI patients. These alterations suggest that early disruptions in SC between bilateral insula and the bilateral prefrontal cortices may appear in amTBI and persist into cmTBI, which might be potentially related to the cognitive and emotional impairments.
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http://dx.doi.org/10.1007/s11682-020-00378-4DOI Listing
August 2021

Connectome-based models can predict processing speed in older adults.

Neuroimage 2020 12 29;223:117290. Epub 2020 Aug 29.

The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China; Laboratory of Neuropsychology, The University of Hong Kong, Hong Kong, China; Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, China; Laboratory of Emotion and Cognition, The Affiliated Hospital of Guangzhou Medical University, China. Electronic address:

Decrement in processing speed (PS) is a primary cognitive morbidity in clinical populations and could significantly influence other cognitive functions, such as attention and memory. Verifying the usefulness of connectome-based models for predicting neurocognitive abilities has significant translational implications on clinical and aging research. In this study, we verified that resting-state functional connectivity could be used to predict PS in 99 older adults by using connectome-based predictive modeling (CPM). We identified two distinct connectome patterns across the whole brain: the fast-PS and slow-PS networks. Relative to the slow-PS network, the fast-PS network showed more within-network connectivity in the motor and visual networks and less between-network connectivity in the motor-visual, motor-subcortical/cerebellum and motor-frontoparietal networks. We further verified that the connectivity patterns for prediction of PS were also useful for predicting attention and memory in the same sample. To test the generalizability and specificity of the connectome-based predictive models, we applied these two connectome models to an independent sample of three age groups (101 younger adults, 103 middle-aged adults and 91 older adults) and confirmed these models could specifically be generalized to predict PS of the older adults, but not the younger and middle-aged adults. Taking all the findings together, the identified connectome-based predictive models are strong for predicting PS in older adults. The application of CPM to predict neurocognitive abilities can complement conventional neurocognitive assessments, bring significant clinical benefits to patient management and aid the clinical diagnoses, prognoses and management of people undergoing the aging process.
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http://dx.doi.org/10.1016/j.neuroimage.2020.117290DOI Listing
December 2020

Dynamic Properties of Human Default Mode Network in Eyes-Closed and Eyes-Open.

Brain Topogr 2020 11 17;33(6):720-732. Epub 2020 Aug 17.

Key Laboratory of Brain, Cognition and Education Sciences (South China Normal University), Ministry of Education, Guangzhou, 510631, China.

The default mode network (DMN) reflects spontaneous activity in the resting human brain. Previous studies examined the difference in static functional connectivity (sFC) of the DMN between eyes-closed (EC) and eyes-open (EO) using the resting-state functional magnetic resonance imaging (rs-fMRI) data. However, it remains unclear about the difference in dynamic FC (dFC) of the DMN between EC and EO. To this end, we acquired rs-fMRI data from 19 subjects in two different statues (EC and EO) and selected a seed region-of-interest (ROI) at the posterior cingulate cortex (PCC) to generate the sFC map. We identified the DMN consisting of ten clusters that were significantly correlated with the PCC. By using a sliding-window approach, we analyzed the dFC of the DMN. Then, the Newman's modularity algorithm was applied to identify dFC states based on nodal total connectivity strength in each sliding-window. In addition, graph-theory based network analysis was applied to detect dynamic topological properties of the DMN. We identified three group-level dFC states (State1, 2 and 3) that reflects the strength of dFC within the DMN between EC and EO in different time. The following results were reached: (1) no significant difference in sFC between EC and EO, (2) dFC was lower in State2 but higher in State3 in EC than in EO, (3) lower clustering coefficient, local efficiency, and global efficiency, but higher characteristic path length in State2 in EC than in EO, and (4) lower nodal strength in the precuneus (PCUN), PCC, angular gyrus (ANG), middle temporal gyrus (MTG) and medial prefrontal cortex (MPFC) in State3 in EC. These results suggested different resting statuses, EC and EO, may induce different time-varying neural activity in the DMN.
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http://dx.doi.org/10.1007/s10548-020-00792-3DOI Listing
November 2020

Open eyes and closed eyes elicit different temporal properties of brain functional networks.

Neuroimage 2020 11 7;222:117230. Epub 2020 Aug 7.

Key Laboratory of Brain, Cognition and Education Sciences (South China Normal University), Ministry of Education, China; School of Psychology, South China Normal University, 510631 Guangzhou, China; Center for Studies of Psychological Application, South China Normal University, 510631 Guangzhou, China; Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, 510631 Guangzhou, China. Electronic address:

The eyes are our windows to the brain. There are differences in brain activity between people who have their eyes closed (EC) and eyes open (EO). Previous studies focused on differences in brain functional properties between these eyes conditions based on an assumption that brain activity is a static phenomenon. However, the dynamic nature of the brain activity in different eyes conditions is still unclear. In this study, we collected resting-state fMRI data from 21 healthy subjects in the EC and EO conditions. Using a sliding time window approach and a k-means clustering algorithm, we calculated the temporal properties of dynamic functional connectivity (dFC) states in the eyes conditions. We also used graph theory to estimate the dynamic topological properties of functional networks in the two conditions. We detected two dFC states, a hyper-connected State 1 and a hypo-connected State 2. We showed the following results: (i) subjects in the EC condition stayed longer in the hyper-connected State 1 than those in the EO; (ii) subjects in the EO condition stayed longer in the hypo-connected State 2 than those in the EC; and (iii) the dFC state transformed into the other state more frequently during EC than during EO. We also found the variance of the characteristic path length was higher during EC than during EO in the hyper-connected State 1. These results indicate that brain activity may be more active and unstable during EC than during EO. Our findings may provide insights into the dynamic nature of the resting-state brain and could be a useful reference for future rs-fMRI studies.
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http://dx.doi.org/10.1016/j.neuroimage.2020.117230DOI Listing
November 2020

Common and specific neural correlates underlying insight and ordinary problem solving.

Brain Imaging Behav 2021 Jun;15(3):1374-1387

Center for Studies of Psychological Application, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, South China Normal University, Guangzhou, 510631, China.

Previous studies have investigated the cognitive and neural mechanisms underlying insight problem solving (INPS). However, it is still unclear which mechanisms are common to both INPS and ordinary problem solving (ORPS), and which are distinctly involved in only one of these processes. In this study, we selected two types of Chinese character chunk decompositions, ordinary Chinese character chunk decomposition (OCD) and creative Chinese character chunk decomposition (CCD), as representatives of ORPS and INPS, respectively. By using functional magnetic resonance imaging (fMRI) to record brain activations when subjects executed OCD or CCD operations, we found that both ORPS and INPS resulted in significant activations in the widespread frontoparietal cognitive control network, including the middle frontal gyrus, inferior frontal gyrus, and inferior parietal lobe. Furthermore, compared with ORPS, INPS led to greater activations in higher-level brain regions related to symbolic processing in the default mode network, including the anterior cingulate cortex, superior temporal gyrus, angular gyrus, and precuneus. Conversely, ORPS induced greater activations than INPS in more posterior brain regions related to visuospatial attention and visual perception, such as the inferior temporal gyrus, hippocampus, and middle occipital gyrus/superior parietal gyrus/fusiform gyrus. In addition, an ROI analysis corroborated the neural commonalities and differences between ORPS and INPS. These findings provide new evidence that ORPS and INPS rely on common as well as distinct cognitive processes and cortical mechanisms.
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http://dx.doi.org/10.1007/s11682-020-00337-zDOI Listing
June 2021

Age of Acquisition of Mandarin Modulates Cortical Thickness in High-Proficient Cantonese-Mandarin Bidialectals.

J Psycholinguist Res 2021 Aug;50(4):723-736

Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, South China Normal University, Guangzhou, 510631, People's Republic of China.

Previous studies showed that the onset age of second language acquisition (AoA-L2) can modulate brain structure of bilinguals. However, the underlying mechanism of anatomical plasticity induced by AoA-L2 is still a question in debate. In order to explore the issue, we recruited two groups of native Cantonese-Mandarin speakers, the early group began to speak in Mandarin at about 3.5 and the late group at about 6.5 years old. In addition, the early group had earlier experience in reading Chinese characters than the late group did. Through estimating the cortical thickness (CT), we found that (1) compared with the late group, the early group had thicker CT in the lateral occipital region, left middle temporal gyrus, and left parahippocampal region, which are all involved in visuospatial processing, probably reflecting the effect induced by the earlier or later experiences in processing the characters of Chinese for the two groups; and (2) compared with the late group, the early group had thicker CT in left superior parietal region, which is believed to be involved in language switching, maybe for the early group had the earlier experience in switching back and forth between Cantonese and Mandarin and therefore recruited the executive control network earlier. Our findings revealed the effects of the AoA-L2 in oral language acquisition as well as in written language acquisition as the main determinants of bilingual language structural representation in human brain.
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http://dx.doi.org/10.1007/s10936-020-09716-5DOI Listing
August 2021

Dynamic Language Network in Early and Late Cantonese-Mandarin Bilinguals.

Front Psychol 2020 18;11:1189. Epub 2020 Jun 18.

Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, South China Normal University, Guangzhou, China.

The brain representation of language in bilinguals is sculptured by several factors, such as age of acquisition (AoA) and proficiency level (PL) in second language. Although the effect of AoA-L2 on brain function and structure has been studied, little attention is devoted to dynamic properties of the language network and their differences between early and late bilinguals. In this study, we acquired resting-state fMRI data from early and late Cantonese (L1)-Mandarin (L2) bilinguals with high PLs of verbal fluency in both languages. We then analyzed dynamic functional connectivity (dFC) by using the sliding-windows approach, estimated the dFC states by using the -means clustering algorithm, and calculated the dynamic topological properties of the language network for the early and late bilinguals. We detected four dFC states, State 1, State 2, State 3, and State 4, which may be related to phonetic processing, semantic processing, language control, and syntactic processing, respectively. Compared to the late bilinguals, the early bilinguals showed higher dFC between the inferior frontal area and the temporal area in State 1 and State 2, while higher dFC between the cerebellum and other regions in State 3. The early bilinguals showed a higher clustering coefficient and local and global efficiency in State 1 and State 3, but lower characteristic path length in State 1, than the late bilinguals. Together, these results suggested that AoA-L2 affects temporal neural activation and dynamic topological properties of the language network. These findings provide new information to understand the effect of experience of L2 acquisition on language network in bilinguals.
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http://dx.doi.org/10.3389/fpsyg.2020.01189DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7314931PMC
June 2020

The role of altered brain structural connectivity in resilience, vulnerability, and disease expression to schizophrenia.

Prog Neuropsychopharmacol Biol Psychiatry 2020 07 10;101:109917. Epub 2020 Mar 10.

Department of Psychiatry, the Third Affiliated Hospital of Sun Yat-sen University, 600 Tianhe Road, Guangzhou, Guangdong Province, China. Electronic address:

Background: Schizophrenia (SCZ) is a highly heritable disorder associated with brain connectivity changes. Although the mechanism of disease expression and vulnerability of SCZ have been reported by previous studies, the mechanism of resilience to SCZ based on the brain structural connectivity is poorly understood. The goal of the present study was to identify the structural brain connectivity related with the resilience to SCZ, which is defined here as the capacity to avoid or delay the onset of SCZ in unaffected siblings of SCZ probands.

Method: We collected diffusion tensor imaging (DTI) data of 49 medication-naive, first-episode SCZ (FE-SCZ) patients, 56 unaffected siblings of SCZ probands (SIB-SCZ), and 90 healthy controls. Then we used graph theoretical approach to calculate the topological properties of the brain structural network, including global, subnetwork, and regional parameters. Finally, we compared the parameters between the three groups, and identified the brain structural network related to the resilience, vulnerability and disease expression to SCZ.

Results: With respect to resilience, only the SIB-SCZ showed significantly increased connectivity in the subnetworks of the left cuneus-precuneus and left posterior cingulate gyrus-precuneus, and in brain areas of right supramarginal gyrus and right inferior temporal gyrus. With respect to vulnerability, both the FE-SCZ and SIB-SCZ had decreased cluster coefficients and local efficiency, and decreased nodal efficiency in the right medial superior frontal gyrus and right medial orbital superior frontal gyrus compared with the healthy controls. With respect to disease expression, only the FE-SCZ group showed decreased or increased global, subnetwork, and nodal connectivity in broader brain regions compared with the healthy controls.

Conclusion: Difference in the topological properties of brain structural connectivity not only reflect the underlying mechanism of vulnerability but also that of resilience to schizophrenia. Alteration in the brain structural connectivity associating with resilience and disease expression may contribute to the onset of SCZ.
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http://dx.doi.org/10.1016/j.pnpbp.2020.109917DOI Listing
July 2020

Altered properties of brain white matter structural networks in patients with nasopharyngeal carcinoma after radiotherapy.

Brain Imaging Behav 2020 Dec;14(6):2745-2761

Center for the Study of Applied Psychology & MRI Center, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, People's Republic of China.

Previous neuroimaging studies revealed radiation-induced brain injury in patients with nasopharyngeal carcinoma (NPC) in the years after radiotherapy (RT). These injuries may be associated with structural and functional alterations. However, differences in the brain structural connectivity of NPC patients at different times after RT, especially in the early-delayed period, remain unclear. We acquired diffusion tensor imaging (DTI) data from three groups of NPC patients, 25 in the pre-RT (before RT) group, 22 in the early-delayed (1-6 months) period (post-RT-ED) group, and 33 in the late-delayed (>6 months) period (post-RT-LD) group. Then, we constructed brain white matter (WM) structural networks and used graph theory to compare their between-group differences. The NPC patients in the post-RT-ED group showed decreased global properties when compared with the pre-RT group. We also detected the nodes with between-group differences in nodal parameters. The nodes that differed between the post-RT-ED and pre-RT groups were mainly located in the default mode (DMN) and central executive networks (CEN); those that differed between the post-RT-LD and pre-RT groups were located in the limbic system; and those that differed between the post-RT-LD and post-RT-ED groups were mainly in the DMN. These findings may indicate that radiation-induced brain injury begins in the early-delayed period and that a reorganization strategy begins in the late-delayed period. Our findings may provide new insight into the pathogenesis of radiation-induced brain injury in normal-appearing brain tissue from the network perspective.
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http://dx.doi.org/10.1007/s11682-019-00224-2DOI Listing
December 2020

The left inferior longitudinal fasciculus supports orthographic processing: Evidence from a lesion-behavior mapping analysis.

Brain Lang 2020 02 20;201:104721. Epub 2019 Dec 20.

State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, China. Electronic address:

Orthographic processing is a critical stage in visual word recognition. However, the white-matter pathways that support this processing are unclear, as prior findings might have been confounded by impure behavioral measures, potential structural reorganization of the brain, and limited sample sizes. To address this issue, we investigated the correlations between the integrity of 20 major tracts in the whole brain and the pure orthographic index across 67 patients with short-term brain damage. The integrity of the tracts was measured by the lesion volume percentage and the mean fractional anisotropy value. The orthographic index was calculated as the residual of the orthographic tasks after regressing out corresponding nonorthographic tasks and the orthographic factor from the principal component analysis (PCA) on the basis of four orthographic tasks. We found significant correlations associated with the left inferior longitudinal fasciculus (ILF), even after controlling for the influence of potential confounding variables. These observations strengthen evidence for the vital role of the left ILF in orthographic processing.
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http://dx.doi.org/10.1016/j.bandl.2019.104721DOI Listing
February 2020

Abnormal dynamic properties of functional connectivity in disorders of consciousness.

Neuroimage Clin 2019 5;24:102071. Epub 2019 Nov 5.

Center for the Study of Applied Psychology and MRI Center, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, South China Normal University, Guangzhou 510631, China. Electronic address:

Resting-state functional magnetic resonance imaging (rs-fMRI) is widely used to research abnormal functional connectivity (FC) in patients with disorders of consciousness (DOC). However, most studies assumed steady spatial-temporal signal interactions between distinct brain regions during the scan period. The aim of this study was to explore abnormal dynamic functional connectivity (dFC) in DOC patients. After excluding 26 patients' data that failed to meet the requirements of imaging quality, we retained 19 DOC patients (12 with unresponsive wakefulness syndrome and 7 in a minimally conscious state, diagnosed with the Coma Recovery Scale-Revised [CRS-R]) for the dFC analysis. We used the sliding windows approach to construct dFC matrices. Then these matrices were clustered into distinct states using the k-means clustering algorithm. We found that the DOC patients showed decreased dFC in the sensory and somatomotor networks compared with the healthy controls. There were also significant differences in temporal properties, the mean dwell time (MDT) and the number of transitions (NT), between the DOC patients and the healthy controls. In addition, we also used a hidden Markov model (HMM) to test the robustness of the results. With the connectome-based predictive modeling (CPM) approach, we found that the properties of abnormal dynamic network can be used to predict the CRS-R scores of the patients after severe brain injury. These findings may contribute to a better understanding of the abnormal brain networks in DOC patients.
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http://dx.doi.org/10.1016/j.nicl.2019.102071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6881656PMC
September 2020

Abnormalities of intrinsic regional brain activity in first-episode and chronic schizophrenia: a meta-analysis of resting-state functional MRI

J Psychiatry Neurosci 2020 01;45(1):55-68

From the Medical Imaging Center, First Affiliated Hospital of Jinan University, Guangzhou China (Gong, Luo, Chen, Huang, Wang); the Department of Radiology, Six Affiliated Hospital of Sun Yat-sen University, Guangzhou, China (Gong); the Department of Applied Psychology, Guangdong University of Foreign Studies, Guangzhou, China (Wang); the School of Psychology, Institute of Brain Research and Rehabilitation (IBRR), Center for the Study of Applied Psychology & MRI Center, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, South China Normal University, Guangzhou China (Huang, Huang).

Background: Resting-state functional MRI (fMRI) studies have provided much evidence for abnormal intrinsic brain activity in schizophrenia, but results have been inconsistent.

Methods: We conducted a meta-analysis of whole-brain, resting-state fMRI studies that explored differences in amplitude of low-frequency fluctuation (ALFF) between people with schizophrenia (including first episode and chronic) and healthy controls.

Results: A systematic literature search identified 24 studies comparing a total of 1249 people with schizophrenia and 1179 healthy controls. Overall, patients with schizophrenia displayed decreased ALFF in the bilateral postcentral gyrus, bilateral precuneus, left inferior parietal gyri and right occipital lobe, and increased ALFF in the right putamen, right inferior frontal gyrus, left inferior temporal gyrus and right anterior cingulate cortex. In the subgroup analysis, patients with first-episode schizophrenia demonstrated decreased ALFF in the bilateral inferior parietal gyri, right precuneus and left medial prefrontal cortex, and increased ALFF in the bilateral putamen and bilateral occipital gyrus. Patients with chronic schizophrenia showed decreased ALFF in the bilateral postcentral gyrus, left precuneus and right occipital gyrus, and increased ALFF in the bilateral inferior frontal gyri, bilateral superior frontal gyrus, left amygdala, left inferior temporal gyrus, right anterior cingulate cortex and left insula.

Limitations: The small sample size of our subgroup analysis, predominantly Asian samples, processing steps and publication bias could have limited the accuracy of the results.

Conclusion: Our comprehensive meta-analysis suggests that findings of aberrant regional intrinsic brain activity during the initial stages of schizophrenia, and much more widespread damage with the progression of disease, may contribute to our understanding of the progressive pathophysiology of schizophrenia.
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http://dx.doi.org/10.1503/jpn.180245DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6919918PMC
January 2020

Representation of human spatial navigation responding to input spatial information and output navigational strategies: An ALE meta-analysis.

Neurosci Biobehav Rev 2019 08 12;103:60-72. Epub 2019 Jun 12.

Centre for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, PR China. Electronic address:

Spatial navigation is a crucial ability involving the interplay of multiple cognitive processes and is related to input spatial information (such as landmarks and orientation cues) and output navigational strategies (such as route-based and map-based). It is still not clear where is the spatial navigation system and whether these tasks evoke different activation patterns in human brain. Thus, we analyzed the reported brain activations of 33 related functional neuroimaging studies by using activation likelihood estimation (ALE) meta-analyses. Statistical analysis revealed a navigational system including the hippocampus, parahippocampal place area (PPA), retrosplenial complex (RSC), occipital place area (OPA), and insula. More likely, landmarks activate the left secondary motor cortex (SMC), whereas orientation cues activate the right somatosensory associative cortex (SAC). Although no region showed stronger activation likelihood in route- than map-based navigation, the map-based navigation had stronger activation likelihood in the right SAC than route-based navigation. These findings revealed the brain representation of spatial navigational system and suggested that different parts of this system are involved with the specific navigational tasks.
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http://dx.doi.org/10.1016/j.neubiorev.2019.06.012DOI Listing
August 2019

Abnormal intrinsic brain functional network dynamics in unmedicated depressed bipolar II disorder.

J Affect Disord 2019 06 1;253:402-409. Epub 2019 May 1.

Center for the Study of Applied Psychology & MRI Center, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, Institute of Brain Research and Rehabilitation, South China Normal University, Guangzhou 510631, China. Electronic address:

Background: Previous studies analyzed brain functional connectivity (FC) based on resting-state fMRI (RS-fMRI) data to reveal the neuropathology of bipolar disorder (BD) and suggested that their FC alterations are at widespread network-level. However, few studies have analyzed the dynamic functional network connectivity (dFNC) in BD. Thus, we aimed to reveal the dFNC properties of BD in this study.

Methods: The RS-fMRI data were collected from 51 unmedicated depressed BD II patients and 50 healthy controls. We analyzed the dFNC properties by using an independent component analysis, sliding window correlation, k-means clustering, and graph theory methods.

Results: The intrinsic brain FNC could be clustered into three configuration states, one with sparse connections between all functional networks (State 1), another with negative correlations between the salience network, cerebellum, basal ganglia and the sensory networks (State 2), and a third with negative correlations between the default mode network and the other functional networks (State 3). The BD patients had increased time in State 2, decreased time in State 3, and increased transition number between states. And the time spent in State 2 was positively correlated with the HDRS24 score in the BD patients. In addition, the BD patients had increased dynamic variance in the small-world properties of FNC.

Limitations: This study did not examine data from BD patients in other episodes and other BD types.

Conclusions: This study detected abnormal dFNC properties in BD, which indicated their FNC unstability and provided new insights into the neuropathology of their affective and cognitive deficits.
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http://dx.doi.org/10.1016/j.jad.2019.04.103DOI Listing
June 2019

Abnormal dynamic functional network connectivity in unmedicated bipolar and major depressive disorders based on the triple-network model.

Psychol Med 2020 02 14;50(3):465-474. Epub 2019 Mar 14.

School of Psychology, Institute of Brain Research and Rehabilitation (IBRR), Center for the Study of Applied Psychology & MRI Center, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, South China Normal University, Guangzhou510631, China.

Background: Previous studies have analyzed brain functional connectivity to reveal the neural physiopathology of bipolar disorder (BD) and major depressive disorder (MDD) based on the triple-network model [involving the salience network, default mode network (DMN), and central executive network (CEN)]. However, most studies assumed that the brain intrinsic fluctuations throughout the entire scan are static. Thus, we aimed to reveal the dynamic functional network connectivity (dFNC) in the triple networks of BD and MDD.

Methods: We collected resting state fMRI data from 51 unmedicated depressed BD II patients, 51 unmedicated depressed MDD patients, and 52 healthy controls. We analyzed the dFNC by using an independent component analysis, sliding window correlation and k-means clustering, and used the parameters of dFNC state properties and dFNC variability for group comparisons.

Results: The dFNC within the triple networks could be clustered into four configuration states, three of them showing dense connections (States 1, 2, and 4) and the other one showing sparse connections (State 3). Both BD and MDD patients spent more time in State 3 and showed decreased dFNC variability between posterior DMN and right CEN (rCEN) compared with controls. The MDD patients showed specific decreased dFNC variability between anterior DMN and rCEN compared with controls.

Conclusions: This study revealed more common but less specific dFNC alterations within the triple networks in unmedicated depressed BD II and MDD patients, which indicated their decreased information processing and communication ability and may help us to understand their abnormal affective and cognitive functions clinically.
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http://dx.doi.org/10.1017/S003329171900028XDOI Listing
February 2020

Spatially Overlapping Regions Show Abnormal Thalamo-frontal Circuit and Abnormal Precuneus in Disorders of Consciousness.

Brain Topogr 2019 05 1;32(3):445-460. Epub 2019 Feb 1.

Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, People's Republic of China.

Understanding the neural mechanisms of disorders of consciousness (DOC) is essential for estimating the conscious level and diagnosing DOC patients. Although previous studies reported brain functional connectivity (FC) and spontaneous neural activity patterns associated with consciousness, the relationship between them remains unclear. In this study, we identified the abnormal brain regions in DOC patients by performing voxel-wise FC strength (FCS) and fractional amplitude of low-frequency fluctuations (fALFF) analyses on resting-state functional magnetic resonance imaging data of 15 DOC patients and 24 healthy controls. Furthermore, we detected spatial intersections between two measures and estimated the correlations between either the FCS or the fALFF and the subscales of the Coma Recovery Scale-Revised (CRS-R). We found that the right superior frontal gyrus, left thalamus and right precuneus in which the DOC patients had a lower local FCS and fALFF than healthy controls, are coincident with regions of the mesocircuit model. In the right precuneus, the local FCS/fALFF was significantly positively correlated with the oromotor and motor scores/motor score of the CRS-R. Our findings may indicate that the co-occurrent pattern of spontaneous neural activity and functional connectivity in the thalamo-frontal circuit and the precuneus are associated with motor function in DOC patients.
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http://dx.doi.org/10.1007/s10548-018-0693-0DOI Listing
May 2019

Common and specific altered amplitude of low-frequency fluctuations in Parkinson's disease patients with and without freezing of gait in different frequency bands.

Brain Imaging Behav 2020 Jun;14(3):857-868

Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, South China Normal University, Guangzhou, 510631, People's Republic of China.

Freezing of gait (FOG), a disabling symptom of Parkinson's disease (PD), severely affects PD patients' life quality. Previous studies found neuropathologies in functional connectivity related to FOG, but few studies detected abnormal regional activities related to FOG in PD patients. In the present study, we analyzed the amplitude of low-frequency fluctuations (ALFF) to detect brain regions showing abnormal activity in PD patients with FOG (PD-with-FOG) and without FOG (PD-without-FOG). As different frequencies of neural oscillations in brain may reflect distinct brain functional and physiological properties, we conducted this study in three frequency bands, slow-5 (0.01-0.027 Hz), slow-4 (0.027-0.073 Hz), and classical frequency band (0.01-0.08 Hz). We acquired rs-fMRI data from 18 PD-with-FOG patients, 18 PD-without-FOG patients, and 17 healthy controls, then calculated voxel-wise ALFF across the whole brain and compared ALFF among the three groups in each frequency band. We found: (1) in slow-5, both PD-with-FOG and PD-without-FOG patients showed lower ALFF in the bilateral putamen compared to healthy controls, (2) in slow-4, PD-with-FOG patients showed higher ALFF in left inferior temporal gyrus (ITG) and lower ALFF in right middle frontal gyrus (MFG) compared to either PD-without-FOG patients or healthy controls, (3) in classical frequency band, PD-with-FOG patients also showed higher ALFF in ITG compared to either PD-without-FOG patients or healthy controls. Furthermore, we found that ALFF in MFG and ITG in slow-4 provided the highest classification accuracy (96.7%) in distinguishing PD-with-FOG from PD-without-FOG patients by using a stepwise multivariate pattern analysis. Our findings indicated frequency-specific regional spontaneous neural activity related to FOG, which may help to elucidate the pathogenesis of FOG.
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http://dx.doi.org/10.1007/s11682-018-0031-xDOI Listing
June 2020

Eyes Closed Elevates Brain Intrinsic Activity of Sensory Dominance Networks: A Classifier Discrimination Analysis.

Brain Connect 2019 03;9(2):221-230

1 Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, South China Normal University, Guangzhou, China.

Brain neocortex is usually dominated by visual input (with eyes open [EO]), whereas this visual predominance could be reduced by closing eyes. Cutting off visual input from the eyes (with eyes closed [EC]) would also benefit other sensory performance; however, the neural basis underlying the state-switching remains unclear. In this study, we investigated the brain intrinsic activity of either the EO or EC states by using the resting-state functional magnetic resonance imaging data from 22 healthy participants. The 10 resting-state networks (RSNs) of these participants were explored by the independent component analysis method. Within each RSN, various network parameters (i.e., the amplitude of low-frequency fluctuation, the voxel-wise weighted degree centrality, and the RSN-wise functional connectivity) were measured to depict the brain intrinsic activity properties underlying the EO and EC states. Taking these brain intrinsic activity properties as discriminative features in a linear classifier, we found that the EO and EC states could be effectively classified using the intrinsic properties of the sensory dominance networks and the salience network (SN). Further analysis showed that the brain intrinsic activity within the sensory dominance networks was constantly overwhelmed during the EC state relative to that in the EO state. The SN might play a key role as a switcher between state-switching. Therefore, this study indicated that the brain intrinsic activity in the sensory dominance networks would be enhanced with EC, which might improve other sensory-relative task performance.
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http://dx.doi.org/10.1089/brain.2018.0644DOI Listing
March 2019

Shared and specific functional connectivity alterations in unmedicated bipolar and major depressive disorders based on the triple-network model.

Brain Imaging Behav 2020 Feb;14(1):186-199

Center for the Study of Applied Psychology & MRI Center, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, Institute of Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, China.

Bipolar disorder (BD) is frequently misdiagnosed as major depressive disorder (MDD) in clinical practice, especially during depressive episodes. A unifying triple-network model, involving the default mode network (DMN), central executive network (CEN) and salience network (SN), has been proposed to explain the neural physiopathology of psychiatric and neurological disorders. Although several studies revealed shared and specific alterations between BD and MDD in key regions of DMN, CEN, and SN, and a few studies used different measures to detect detailed alterations in the triple networks in BD and MDD, their shared and specific patterns of altered functional connectivity (FC) in the triple networks has remained unclear. In this study, we acquired resting-state fMRI (R-fMRI) data from 38 unmedicated BD and 35 unmedicated MDD patients during depressive episodes along with 47 healthy controls. We first determined the spatially independent components of the DMN, SN, and CEN by using independent component analysis (ICA); then we estimated the inter-ROI and inter-network FC for each group. By comparing the differences between the three groups, we obtained the following results: (1) both the BD and MDD patients showed shared weaker intra-network FC in the left mPFC and right precuneus within the DMN as well as weaker inter-ROI FC between the left AI and right AI compared with the healthy controls; (2) the BD had weaker while the MDD had stronger intra-network FC in the right dlPFC within the rCEN as well as stronger inter-ROI FC between the right dlPFC and right ANG compared with the healthy controls; (3) the BD showed specific, stronger inter-ROI FC between the left PPC and right AI as well as stronger inter-network FC between the lCEN and SN compared with either the MDD or the control group. Our findings provide new information for understanding the neural physiopathology and clinical symptoms of depressed BD and MDD patients.
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http://dx.doi.org/10.1007/s11682-018-9978-xDOI Listing
February 2020
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