Bilateral Posterior Cingulate Cortex Research Articles

Neural Basis and Motor Imagery Intervention Methodology Based on Neuroimaging Studies in Children With Developmental Coordination Disorders: A Review.

Although the neural bases of the brain associated with movement disorders in children with developmental coordination disorder (DCD) are becoming clearer, the information is not sufficient because of the lack of extensive brain function research. Therefore, it is controversial about effective intervention methods focusing on brain function. One of the rehabilitation techniques for movement disorders involves intervention using motor imagery (MI). MI is often used for movement disorders, but most studies involve adults and healthy children, and the MI method for children with DCD has not been studied in detail. Therefore, a review was conducted to clarify the neuroscientific basis of the methodology of intervention using MI for children with DCD. The neuroimaging review included 20 magnetic resonance imaging studies, and the neurorehabilitation review included four MI intervention studies. In addition to previously reported neural bases, our results indicate decreased activity of the bilateral thalamus, decreased connectivity of the sensory-motor cortex and the left posterior middle temporal gyrus, bilateral posterior cingulate cortex, precuneus, cerebellum, and basal ganglia, loss of connectivity superiority in the abovementioned areas. Furthermore, reduction of gray matter volume in the right superior frontal gyrus and middle frontal gyrus, lower fractional anisotropy, and axial diffusivity in regions of white matter pathways were found in DCD. As a result of the review, children with DCD had less activation of the left brain, especially those with mirror neurons system (MNS) and sensory integration functions. On the contrary, the area important for the visual space processing of the right brain was activated. Regarding of characteristic of the MI methods was that children observed a video related to motor skills before the intervention. Also, they performed visual-motor tasks before MI training sessions. Adding action observation during MI activates the MNS, and performing visual-motor tasks activates the basal ganglia. These methods may improve the deactivated brain regions of children with DCD and may be useful as conditioning before starting training. Furthermore, we propose a process for sharing the contents of MI with the therapist in language and determining exercise strategies.

Effect of Alzheimer's Disease and Lewy Body Disease on Metabolic Changes.

The relationship among amyloid-β (Aβ) deposition on amyloid positron emission tomography (PET), cortical metabolism on 18F-fluoro-2-deoxy-D-glucose (FDG)-PET, and clinical diagnosis has not been elucidated for both Alzheimer's disease (AD) and Lewy body disease (LBD). We investigated the patterns of cerebral metabolism according to the presence of AD and LBD. A total of 178 subjects were enrolled including 42 pure AD, 32 pure LBD, 34 Lewy body variant AD (LBVAD), 15 LBD with amyloid, 26 AD with dementia with Lewy bodies (DLB), and 29 control subjects. Pure AD, LBVAD, and AD with DLB groups had biomarker-supported diagnoses of typical AD, while pure LBD, LBD with amyloid, and AD with DLB groups had biomarker-supported diagnoses of typical LBD. Typical AD and LBD with amyloid showed amyloid-positivity on 18F-florbetaben (FBB) PET, while typical LBD and LBVAD had abnormalities on dopamine transporter PET. We measured regional patterns of glucose metabolism using FDG-PET and evaluated their relationship with AD and LBD. Compared with control group, typical AD and typical LBD commonly exhibited hypometabolism in the bilateral temporo-parietal junction, precuneus, and posterior cingulate cortex. Typical AD showed an additional hypometabolism in the entorhinal cortex, while patients with dopamine transporter abnormality-supported diagnosis of LBD showed diffuse hypometabolism that spared the sensory-motor cortex. Although the diffuse hypometabolism in LBD also involved the occipital cortex, prominent occipital hypometabolism was only seen in LBD with amyloid group. Combining clinical and metabolic evaluations may enhance the diagnostic accuracy of AD, LBD, and mixed disease cases.

Abnormal Regional Spontaneous Brain Activity and Its Indirect Effect on Spasm Ratings in Patients With Hemifacial Spasm.

PurposeThree classical methods of resting-state functional magnetic resonance imaging (rs-fMRI) were employed to explore the local functional abnormalities and their effect on spasm ratings in hemifacial spasm (HFS) patients.MethodsThirty HFS patients and 30 matched healthy controls (HCs) were recruited. Rs-fMRI data, neurovascular compression (NVC) degree and spasm severity were collected in each subject. Fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and degree centrality (DC) were calculated in the whole brain voxels. Two sample t-tests were performed to investigate group differences of fALFF, ReHo, and DC. Correlation analysis was performed to assess the relationships between the regional brain abnormalities and clinical variables in HFS.ResultsCompared with HCs, HFS patients exhibited increased fALFF in the left precuneus and right posterior cingulate cortex (PCC), together with increased ReHo in the bilateral PCC and bilateral precuneus. Decreased ReHo was observed in the right middle occipital gyrus (MOG), right superior occipital gyrus (SOG), right cuneus, and right angular gyrus (AG) in HFS patients. Moreover, ReHo in the right PCC were positively correlated with NVC degree and spasm severity in HFS patients, respectively. Mediation analysis revealed that increased ReHo in the right PCC regulated the neurovascular compression degree, and further resulted in increased spasm ratings.ConclusionOur study revealed regional brain dysfunctions from different perspectives and an indirect effect of ReHo in right PCC on spasm ratings predominantly through the alteration of NVC.

Tau pathology in posterior DMN is related to aberrant SN‐DMN network connectivity in atypical Alzheimer’s disease

AbstractBackgroundCircumscribed patterns of pathological tau propagation along functional networks have been observed in normal aging and amnestic Alzheimer’s disease (AD), including in two cognition‐relevant networks: the default mode network (DMN) and the salience network (SN). It remains unclear if atypical phenotypes of AD demonstrate a direct relationship between tau and functional connectivity within and between these networks.MethodTwenty‐six amyloid‐positive patients diagnosed with atypical phenotypes of AD (12 PCA, 10 lvPPA, and 4 dysexecutive; mean age = 66 years, 9M/17F) were examined with tau (18F‐AV‐1451) PET and resting state functional MRI (rs‐fMRI). Hub regions within the DMN and SN were defined from the literature within the bilateral posterior cingulate cortex (PCC) and anterior insula (aI), respectively. ROI‐to‐ROI connectivity was calculated to determine within‐ and between‐network connectivity. Bivariate correlation analyses were conducted to determine if the magnitude of partial volume corrected tau PET signal in each network’s hub region was related to the within‐network functional connectivity of the DMN and SN, as well as between the hub regions of the DMN and SN.ResultWe found that higher tau signal in bilateral PCC was associated with diminished DMN connectivity (PCC to posterior angular gyrus) in both hemispheres (left: r = ‐0.50, p = 0.009; right: r = ‐0.47, p = 0.01). We did not observe any relationship between tau and functional connectivity within the SN. Our novel observation was that higher tau signal in the PCC was associated with increased connectivity between the DMN and SN within both hemispheres (left: r = 0.55, p = 0.004; right: r = 0.47, p = 0.02), with some patients demonstrating pathologically positive functional connectivity between the DMN and SN.ConclusionOur findings support the posited relationship between tau pathology and aberrant functional network connectivity reported in aging and amnestic AD by demonstrating that higher tau burden within the PCC is related to fractured DMN connectivity and pathologically increased DMN‐SN connectivity in a group of non‐amnestic AD patients. These findings may help explain how tau deposition in key hub regions of the DMN bring about dysfunctional inter‐network connectivity with the SN, likely contributing to the cognitive and affective dysfunction observed across the clinical spectrum of AD.

Alterations of cortical thickness and gray‐white matter contrast in Alzheimer’s disease and Lewy body‐related cognitive impairment

AbstractBackgroundGray and white matter alteration has been known in patients with neurodegenerative diseases including Alzheimer’s disease‐ (ADCI) and Lewy body‐related cognitive impairment (LBCI). We examined a distinct pattern of cortical thickness (CTH) and gray‐white matter contrast (GWC) alterations in these degenerative neurological diseases. Since the T1‐weighted MRI signal is closely related to myelin content, the GWC may reflect disease‐related alterations of myeloarchitecture along the cortical surface.MethodsT1‐weighted MRIs were obtained from patients (demo‐matched, CDR‐SOB≤9) with ADCI (n=97), LBCI (n=93), and healthy controls (n=37). We measured CTH using the CIVET processing pipeline. GWC was calculated at each vertex as the difference between gray matter (sampled at 50% CTH) and white matter intensity (sampled at 1mm subcortical white matter), then this was normalized by their average. Group differences (controls vs. patients) and correlations (with neuropsychological scores) were examined using general linear models covarying for age, sex, education, intracranial volume, and several vascular risk factors. Results were corrected for multiple comparisons using random field theory p<0.05 (cluster‐forming threshold p=0.001).ResultsPatients with ADCI showed altered CTH in the brain regions typically affected in AD including the bilateral medial temporal, lateral temporo‐parietal, and posterior cingulate cortices. The pattern of GWC alteration was smaller and no change was shown in the lateral temporal lobe (Figure 1A). LBCI patients showed altered CTH in superior frontal, lateral temporal, basal frontal and occipital cortices. The GWC alteration pattern was shown in larger area, notably in the limbic and occipital cortices (Figure 1B). Memory function, in the AD‐spectrum, was more closely associated with CTH, while in the LB‐spectrum, it was more closely with GWC (Figure 2). Frontal/executive function has stronger association with CTH than with GWC in the AD‐spectrum, while the LB‐spectrum showed independent patterns of association in those measures (Figure 3). The visuospatial function was only associated with CTH in AD‐spectrum, and in LB‐spectrum, it was greater in CTH than in GWC (Figure 4).ConclusionsWe demonstrated distinct patterns of CTH and GWC alteration in ADCI and LBCI. Consideration of heterogeneous atrophy patterns may be important when planning prevention and treatment strategies, as they may have different responses to treatment in the disease progression.

Shared and specific dynamics of brain segregation and integration in bipolar disorder and major depressive disorder: A resting-state functional magnetic resonance imaging study

BackgroundWhen bipolar disorder (BD) presents as the depressive state, it is often misdiagnosed as major depressive disorder (MDD). However, few studies have focused on dynamic differences in local brain activity and connectivity between BD and MDD. Therefore, the present study explored shared and specific patterns of abnormal dynamic brain segregation and integration in BD and MDD patients. MethodsBD Patients (n = 106), MDD patients (n = 114), and 130 healthy controls (HCs) underwent resting state functional magnetic resonance imaging (fMRI). We first used a sliding window analysis to evaluate the dynamic amplitude of low-frequency fluctuations (dALFF) and, based on the altered dALFF, further analyzed the dynamic functional connectivity (dFC) using a seed-based approach. ResultsBoth the BD and MDD groups showed decreased temporal variability of the dALFF (less dynamic segregation) in the bilateral posterior cingulate cortex (PCC)/precuneus compared with the HCs. The MDD group showed increased temporal variability of the dALFF (more dynamic segregation) in the left putamen compared with the controls, but there was no significant difference between the BD and HCs. The dFC analysis also showed that both the BD and MDD groups had reduced dFC (less dynamic integration) between the bilateral PCC/ precuneus and the left inferior parietal lobule compared with the HCs. LimitationsThis study was cross-sectional and did not examine data from remitted BD and MDD patients. ConclusionOur findings indicated disrupted dynamic balance between segregation and integration within the default mode network in both BD and MDD. Moreover, we found MDD-specific abnormal brain dynamics in the putamen.

Changed ACC-DMN functional connectivity after acupuncture with deqi for functional dyspepsia treatment: 针刺得气对功能性消化不良患者前扣带回-默认网络功能连接度的影响

ObjectiveTo clarify altered whole brain functional connectivity of the anterior cingulate cortex (ACC) in functional dyspepsia (FD) patients, and then to explore cerebral influence of acupuncture with deqi treating for FD. MethodsThirty-two FD patients and 35 healthy subjects (HS) were firstly scanned by the resting-state blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) to compare differences of ACC-based functional connectivity (FC). Then 32 FD patients were randomized to receive 20 sessions' acupuncture treatment with (n=16) and without deqi (n=16), as well as underwent functional magnetic resonance imaging (fMRI) scans after treatment. After group re-division according to deqi response, changes of ACC subregions-based resting-state FC (rsFC) were compared between the actual with and without deqi group. Two seeds with bilateral of each were selected as regions of interest (ROIs) of the ACC, including two from the dorsal ACC: S2 (BA24) (x=±5,y=2, z=46, r=3.5 mm) and two from the pregenual ACC: I7 (BA24) (x=±5,y=38, z=6, r=3.5 mm). The clinical changes of the Nepean Dyspepsia Index (NDI) that measuring symptoms and quality of life (QOL) were also used to further assess the correlation with ACC subregions rsFC in FD patients. ResultsCompared to HS, FD patients showed significantly increased ACC subregions rsFC with left fusiform gyrus, temporal cortex, hippocampus(HIPP)/amygdala, temporal pole, and right INS, superior occipital gyrus, and bilateral precuneus, superior parietal lobule (SPL), and decreased rsFC with left postcentral/precentral gyrus (PoG/PrG), supplementary motor area (SMA) and right cerebellum. 32 FD patients which were then re-divided into the actual deqi group (n=16) and actual without deqi group (n=16). The decrease of the NDI symptom score(pre-pos) in the actual deqi group was significantly greater than that in the actual without deqi group (P<0.05). Among the two groups, the actual deqi group showed increased ACC subregions rsFC with right SMA and bilateral PrG/PoG, and decreased rsFC with right precuneus, middle occipital gyrus, bilateral posterior cingulate cortex (PCC), HIPP/paraHIPP, angular gyrus and SPL after treatment. In addition, the changed NDI QOL scores(pre-post) of the actual deqi group was significantly positively correlated with their Fisher's transformed Z value of the altered ACC subregion (left I7) rsFC with right SPL(r=-0.597, P=0.04<0.05, FDR corrected P>0.05). ConclusionThe results tested the hypothesis that the advantage of deqi on efficacy is related to affecting the ACC subregions rsFC. It suggested that deqi might participate in the adaptive modulation of disrupted relationship between the ACC subregions and the default mode network (DMN).

Brain functional connectivity during storage based on resting state functional magnetic resonance imaging with synchronous urodynamic testing in healthy volunteers.

The aim of the study was to elucidate the correlation between spatially distinct brain areas with a full bladder from the perspective of functional connectivity using resting-state functional magnetic resonance imaging (rs-fMRI) with simultaneous urodynamic testing in healthy volunteers. The brain regions with full and empty bladders were reported via rs-fMRI using a 3T magnetic resonance system. Then, we identified brain regions that are activated during bladder filling by calculating the amplitude of low-frequency fluctuation (ALFF) values using brain imaging software (DPABI and SPM8) and empirically derived six regions of interest (ROI) from analysis of activation were used as seeds for resting-state functional connectivity (rs-FC) analysis with the rest of the brain to examine differences in the two conditions. Statistical analysis was performed with a paired t-test and statistical significance was defined as a P < 0.01. Twenty-two healthy volunteers (11 men and 11 women) 35-64years of age were enrolled. The rs-fMRI scans of 22 healthy volunteers were analyzed. After motion correction, two subjects were excluded. Meaningful data were obtained on 20 of these subjects. Compared with an empty bladder, functional connection enhancement was noted mainly in the right inferior orbitofrontal cortex and bilateral calcarine gyrus, the left lingual gyrus, left fusiform gyrus, left superior occipital gyrus, right insula, right inferior temporal gyrus, superior parietal lobe, left insula, right lingual gyrus, right fusiform gyrus, left parahippocampal gyrus, right inferior temporal gyrus, superior parietal lobe, left calcarine gyrus, bilateral lingual gyrus, prefrontal cortex, including the middle frontal gyrus and superior frontal gyrus, the right middle temporal gyrus, bilateral posterior cingulate cortex, and right precuneus. The decrease in functional connection was mainly located in the right inferior orbitofrontal cortex, prefrontal cortex, including the superior frontal gyrus, orbitofrontal cortex, and anterior cingulate cortex, the left inferior orbitofrontal cortex, right insula, middle occipital gyrus, angular gyrus, inferior frontal gyrus, right insula, middle temporal gyrus, inferior parietal lobe, middle occipital gyrus, supplementary motor area, superior frontal gyrus, left insula, bilateral posterior cingulate cortex, bilateral precuneus, middle occipital gyrus, and right middle temporal lobe. There were significant changes in the functional connectivity of the brain between full and empty bladders in healthy volunteers, which suggests that the central neural processes involved in storage needs brain areas with integrated control. These findings are strong evidence for physicians to consider brain responses in urine storage and offer the provision of some normative data.

The effect of transcranial direct current stimulation on dysfunction of bilateral posterior cingulate cortex after sleep deprivation: a preliminary study

Objective: To investigate the effects of transcranial direct current stimulation (tDCS) on the disturbance of brain network dysfunction after sleep deprivation (SD). Methods: The experimental design of self-control was used in the study. All 16 subjects received 2 times of 24 h SD with an interval of 3 weeks. After the first normal sleep, 24 h SD and transcranial electrical stimulation (true or false stimulation) intervention (the current magnitude of true and false stimulation was 1 mA, and the action time was 20 min and 2 s, respectively. The intervention experiment lasted for 20 min. ) and the resting magnetic resonance imaging data were collected after the second transcranial electrical stimulation (sham or true stimulation). The resting fMRI data were collected as baseline before SD, the bilateral posterior cingulate cortex in the default mode network was selected as the seed point, and the functional connectivity between the seed points and the whole brain was calculated. Results: Compared with the rest wakefulness, the functional connectivity among bilateral posterior cingulate cortex, bilateral thalamus and hippocampus was increased (P＜0. 01), but connected with the right precuneus, bilateral insula was decreased after 24 h SD (P＜0. 01). Compared with the sham tDCS group, the functional connectivity between left posterior cingulate cortex seed point and right precuneus of tDCS group was increased (P＜0. 01); but decreased with the bilateral thalamus, insula and right cerebral cortex (P＜0. 01). There was a decrease in the functional connectivity among the right posterior cingulate cortex and the bilateral thalamus, right insula, and cerebral cortex(P＜0. 01). Conclusion: 24-hours sleep deprivation can cause functional connection disorder of bilateral posterior cingulate gyrus, and transcranial electrical stimulation can improve the functional connection disorder after sleep deprivation to some extent.

Random Forest Classification of Alcohol Use Disorder Using fMRI Functional Connectivity, Neuropsychological Functioning, and Impulsivity Measures.

Individuals with alcohol use disorder (AUD) are known to manifest a variety of neurocognitive impairments that can be attributed to alterations in specific brain networks. The current study aims to identify specific features of brain connectivity, neuropsychological performance, and impulsivity traits that can classify adult males with AUD (n = 30) from healthy controls (CTL, n = 30) using the Random Forest (RF) classification method. The predictor variables were: (i) fMRI-based within-network functional connectivity (FC) of the Default Mode Network (DMN), (ii) neuropsychological scores from the Tower of London Test (TOLT), and the Visual Span Test (VST), and (iii) impulsivity factors from the Barratt Impulsiveness Scale (BIS). The RF model, with a classification accuracy of 76.67%, identified fourteen DMN connections, two neuropsychological variables (memory span and total correct scores of the forward condition of the VST), and all impulsivity factors as significantly important for classifying participants into either the AUD or CTL group. Specifically, the AUD group manifested hyperconnectivity across the bilateral anterior cingulate cortex and the prefrontal cortex as well as between the bilateral posterior cingulate cortex and the left inferior parietal lobule, while showing hypoconnectivity in long-range anterior–posterior and interhemispheric long-range connections. Individuals with AUD also showed poorer memory performance and increased impulsivity compared to CTL individuals. Furthermore, there were significant associations among FC, impulsivity, neuropsychological performance, and AUD status. These results confirm the previous findings that alterations in specific brain networks coupled with poor neuropsychological functioning and heightened impulsivity may characterize individuals with AUD, who can be efficiently identified using classification algorithms such as Random Forest.

The Specific Impact of Apolipoprotein E Epsilon 2 on Cognition and Brain Function in Cognitively Normal Elders and Mild Cognitive Impairment Patients.

Variants in the apolipoprotein E (APOE) gene play an important role in the development of Alzheimer’s disease (AD). Specifically, the APOE ε4 allele is an established genetic risk factor for AD, while the APOE ε2 allele is a protective factor against AD. However, the mechanism underlying this impact of APOE genotype on the pathogenesis of AD remain unclear. This study sought to investigate the influence of APOE genotype on cognition and neuroimaging features in cognitively normal (CN) elderly individuals and patients with mild cognitive impairment (MCI). A total of 177 participants were selected from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database, including 101 MCI patients and 76 CN individuals. A 2 × 3 (consisting of two groups and three APOE genotypes) analysis of covariance was carried out to measure the influences of diagnosis and APOE genotype on cognition and brain features, assessed based on global functional connectivity density (gFCD) and hippocampal volume. In addition, a mediation analysis was carried out to investigate the indirect influence of neuroimaging features on the relationship between APOE genotype and cognitive performance in the MCI group. This analysis revealed that APOE genotype had an influence on brain function in the bilateral precentral gyrus, right thalamus, and posterior cingulate cortex (PCC). In addition, an interactive influence between diagnosis and APOE genotype was found on general cognition, immediate memory, executive function, hippocampal volume, and gFCD in the right dorsolateral prefrontal cortex and medial prefrontal cortex (MPFC). Finally, this mediation analysis revealed that hippocampal volume and gFCD in the thalamus may mediate the relationship between APOE genotype and cognitive performance in the MCI group. Taken together, our findings provide novel insights into the neural mechanisms underlying the genetically guided pathogenic mechanisms of AD.

Functional Activation Patterns of Deep Brain Stimulation of the Anterior Nucleus of the Thalamus

Deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) is a recently approved therapy for patients with drug-resistant epilepsy. To date, there is a poor understanding of the mechanism of action and lack of invivo biomarkers. We propose a method for investigating the invivo stimulation effects using blood-oxygen-level-dependent (BOLD) magnetic resonance imaging (MRI) and present the brain activation pattern associated with ANT DBS. Two patients undergoing ANT DBS for epilepsy underwent BOLD MRI using a block design after the DBS was programmed to alternate ON/OFF in 30-second blocks. The scanner was triggered using surface electrophysiologic recordings to detect the DBS cycle. Nine total runs were obtained and were analyzed using a general linear model. Active ANT stimulation produced activation within several areas of the brain, including the thalamus, bilateral anterior cingulate and posterior cingulate cortex, precuneus, medial prefrontal cortex, amygdala, ventral tegmental area, hippocampus, striatum, and right angular gyrus. Using block-design BOLD MRI, we were able to show widespread activation resulting from ANT DBS. Overlap with multiple areas of both the default mode and limbic networks was shown, suggesting that these nodes may modulate the effect of seizure control with ANT DBS.

Schizotypy-Related Magnetization of Cortex in Healthy Adolescence Is Colocated With Expression of Schizophrenia-Related Genes

BackgroundGenetic risk is thought to drive clinical variation on a spectrum of schizophrenia-like traits, but the underlying changes in brain structure that mechanistically link genomic variation to schizotypal experience and behavior are unclear. MethodsWe assessed schizotypy using a self-reported questionnaire and measured magnetization transfer as a putative microstructural magnetic resonance imaging marker of intracortical myelination in 68 brain regions in 248 healthy young people (14–25 years of age). We used normative adult brain gene expression data and partial least squares analysis to find the weighted gene expression pattern that was most colocated with the cortical map of schizotypy-related magnetization. ResultsMagnetization was significantly correlated with schizotypy in the bilateral posterior cingulate cortex and precuneus (and for disorganized schizotypy, also in medial prefrontal cortex; all false discovery rate–corrected ps < .05), which are regions of the default mode network specialized for social and memory functions. The genes most positively weighted on the whole-genome expression map colocated with schizotypy-related magnetization were enriched for genes that were significantly downregulated in two prior case-control histological studies of brain gene expression in schizophrenia. Conversely, the most negatively weighted genes were enriched for genes that were transcriptionally upregulated in schizophrenia. Positively weighted (downregulated) genes were enriched for neuronal, specifically interneuronal, affiliations and coded a network of proteins comprising a few highly interactive “hubs” such as parvalbumin and calmodulin. ConclusionsMicrostructural magnetic resonance imaging maps of intracortical magnetization can be linked to both the behavioral traits of schizotypy and prior histological data on dysregulated gene expression in schizophrenia.

Distinguishing between dementia with Lewy bodies and Alzheimer's disease using metabolic patterns

Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) are the 2 most common causes of dementia. We compared the regional metabolism on 18F-fluorodeoxyglucose positron emission tomography (PET) among 21 control subjects and cognitively impaired patients due to DLB (N = 63) and AD (N = 38). All participants underwent 18F-Florbetaben (FBB) PET, and all DLB patients had abnormality on dopamine transporter PET. Both the FBB-positive DLB (N = 38) and FBB-negative DLB (N = 25) groups had increased metabolism in the bilateral central cerebellum, posterior putamen, and somatomotor cortices compared with the control and AD groups. Compared with the control group, the DLB and AD groups commonly exhibited hypometabolism in the bilateral lateral temporal, temporo-parietal junction, posterior cingulate, and precuneus cortices. Both DLB groups had additional hypometabolism in the bilateral thalami and dorsolateral prefrontal cortices, whereas the AD group did in the bilateral entorhinal cortices and hippocampi. Our results suggest that hypermetabolism in the somatomotor cortex, posterior putamen, or central cerebellum could be a useful imaging biomarker for detecting DLB patients, while entorhinal/hippocampal hypometabolism could be a specific biomarker for AD.

The Shared and Specific Dynamics of Brain Segregation and Integration in Bipolar II Disorder and Major Depressive Disorder: A Resting-State Functional Magnetic Resonance Imaging Study

When bipolar disorder (BD) presents as the depressive state, it is often misdiagnosed as major depressive disorder (MDD), which leads to inappropriate treatment, even poor clinical outcomes. However, few studies have focused on dynamic alterations of local brain activity and connectivity directly compared between BD and MDD depression. The present study in order to explore whether BD and MDD patients would show shared and specific patterns of abnormal dynamic brain segregation and integration. Patients with BD II depression (n = 106) and MDD patients (n =114) as well as 130 healthy controls underwent resting‐state functional magnetic resonance imaging (fMRI). We first used sliding window analysis to evaluate the dynamic amplitude of low-frequency fluctuations (dALFF), and then base on the altered dALFF for the further dynamic functional connectivity (dFC) analysis by using seed-based approach. Both BD II and MDD groups showed decreased temporal variability of dALFF (less dynamic segregation) in the bilateral posterior cingulate cortex (PCC)/precuneus compared to HC group. Compared to the HC group, the MDD group showed increased temporal variability of dALFF (more dynamic segregation) in the left putamen, but no significant difference between the BD II and HCs groups. In addition, the seed-voxel dFC analysis show that the BD II and MDD groups also have reduced dFC (less dynamic integration) between the bilateral PCC/ precuneus and the left inferior parietal lobule compared with the HCs group. Our findings indicated similarly disrupted dynamic balance between segregation and integration within the default mode network in both BD and MDD. Moreover, we found MDD-specific abnormal brain dynamics in the putamen. Funding Statement: The study was supported by grants from the National Natural Science Foundation of China (81971597, 81671670, and 81501456); Project in Basic Research and Applied Basic Research in General Colleges and Universities of Guangdong, China (2018KZDXM009); Planned Science and Technology Project of Guangzhou, China (20160402007 and 201604020184). Declaration of Interests: The authors declare that they have no conflict of interests. Ethics Approval Statement: This study was approved by the Ethics Committee of First Affiliated Hospital of Jinan University, Guangzhou, China. All subjects were right handed, they volunteered to participate in the study without coercion, and signed a written informed consent form after a full written and verbal explanation of the study. Two senior clinical psychiatrists confirmed that all subjects had the ability to consent to participate in the examination.

PC-FACS

PC-FACS

Abnormal functional connectivity strength in first-episode, drug-naïve adult patients with major depressive disorder

BackgroundThe pathogenesis of major depressive disorder (MDD) is complicated and equivocal. Previous studies have found an incidence of abnormal changes of neural networks, with plentiful evidence pointing the finger of suspicion firmly at the default mode network (DMN) and cortico-limbic networks. The aim of the present study was to use the approach of functional connectivity strength (FCS) to directly investigate the features of spontaneous brain activity in the case of first-episode, drug-naïve adult patients with MDD at rest. MethodsResting-state functional magnetic resonance imaging (MRI) scans were performed on 23 first-episode drug-naïve major depressive disorder (MDD) patients and 20 healthy controls (HCs). In this study, using graph-theory approaches(FCS), we computed the characteristics of brain connectivity. Simultaneously, we used a series of validated test procedures to evaluate the patients' cognitive function. Subsequently, the results were compared with the peak of FCS value and a correlation analysis was conducted. ResultsCompared with the HCs group, MDD patients showed significantly decreased FCS in bilateral posterior cingulate cortex (PCC)/precuneus and bilateral prefrontal cortex(PFC) and increased FCS in right posterior central gyrus, left thalamus and left temporal lobe. These brain regions belongs to the default-mode network and cortico-limbic networks. Finally, the correlation analyses showed the negative correlation of the FCS values in the left posterior cingulate cortex (PCC)/precuneus and Hamilton Anxiety Rating Scale (HAMA, r = −0.472, p = .023), Stroop Color Word Test-A(SCWT-A, r = −0.451, p = .031), Stroop Color Word Test-B(SCWT-B, r = −0.588, p = .003).Meanwhile, there was negative correlation between the FCS values in the left thalamus and SCWT-A(r = −0.473, p = .023), SCWT-B(r = −0.465, p = .025), SCWTC(r = −0.524, p = .010).In addition, the FCS values in the right PCC has negative correlation with Montgomery Asberg Depression Rating Scale (MADRS) (r = −0.433, p = .039). ConclusionsDMN is an important node of MDD. FCS within the default mode network and cortico-limbic networks in patients with major depressive disorder has been changed in the early stage of MDD. FCS can provide favourable and additional evidence in the investigation of brain pathophysiology and therapy in depression.

Plasma Neurofilament Light Chain Levels Are Associated With Cortical Hypometabolism in Alzheimer Disease Signature Regions.

Neurofilament light chain (NFL) has been recently introduced as a biomarker of early dementia. 18-Fluorodeoxyglucose positron emission tomography (18F-FDG-PET) is a proxy for regional hypometabolism in Alzheimer disease (AD). Globally normalized 18F-FDG-PET values and levels of NFL and tau were obtained from 149 patients with mild cognitive impairment (MCI) from the baseline cohort of the Alzheimer's Disease Neuroimaging Initiative database. We adopted a stepwise partial correlation model using plasma NFL, plasma tau, CSF NFL, and regional cerebral metabolic rate of glucose (CMRGlc) as main variables, and age, sex, and Alzheimer's Disease Rating Scale (ADAS) as covariates. Significant regions were entered into a stepwise multiple regression analysis to investigate the independent correlation of each biomarker to baseline regional CMRGlc and its progression in patients with MCI. Higher baseline CSF NFL levels correlated with hypometabolism in bilateral precuneal and posterior cingulate cortex. After correction for age, sex, and ADAS score, plasma NFL levels correlated with hypometabolism in bilateral parahippocampal and middle temporal gyri. Cortical hypometabolism in bilateral parahippocampal gyri and right fusiform and middle temporal gyri was independently predicted by higher baseline plasma NFL levels in a multiple regression model. Plasma NFL promises to be an early biomarker of cortical hypometabolism in MCI and for MCI progression to AD.

Age-Accelerated Reduction in Cortical Surface Area in United States Service Members and Veterans with Mild Traumatic Brain Injury and Post-Traumatic Stress Disorder.

Despite the prevalence of combat-related mild traumatic brain injury (mTBI) and relatively high incidence of concurrent post-traumatic stress disorder (PTSD), the joint effect of these conditions on the brain is not well understood. Further, few studies in the mTBI or PTSD populations focus on cortical surface area measures, despite known disruptions to cytoarchitecture of the cortex. This study examines the effects of comorbid mTBI and PTSD on age-related surface area changes across the cortex, as compared with a group with mTBI only. While a direct comparison of PTSD versus non-PTSD groups showed little difference on surface area measures, several regions showed a decline in surface area, with increasing age and a significant PTSD-by-age interaction effect, indicating an age-dependent decrease in surface area in those with both mTBI and PTSD. The findings suggest an apparent age-accelerated shrinking of the cortical surface area in some regions when mTBI and PTSD are present, a pattern that was not consistently found in those with mTBI only. Among the several cortical regions with significant age-by-group interactions were bilateral posterior cingulate cortex (left: p = 0.03; right: p = 0.02), isthmus of the cingulate (left: p = 0.016; right: p = 0.001), and lateral orbitofrontal cortex (left: p = 0.038; right: p = 0.02). It is possible that these findings are related to a larger pattern of premature neurodegeneration and age-acceleration noted in those with long-term PTSD.

Ischemic Stroke in Pontine and Corona Radiata: Location Specific Impairment of Neural Network Investigated With Resting State fMRI.

Objective: This study aims to investigate location-specific functional remodeling following ischemic stroke in pons and corona radiata.Methods: This study was approved by the local Institutional Review Board. Written consent was obtained from each of the participants prior to the MRI examination. Thirty six subjects with first ever acute ischemic stroke in pons (PS, n = 15, aged 62.8 ± 11.01 years) or corona radiata (CRS, n = 21, aged 59.33 ± 13.84 years) as well as 30 age and sex matched healthy controls (HC, n = 30, aged 60 ± 6.43 years) were examined with resting state functional magnetic resonance imaging (rs-fMRI). Regional homogeneity (ReHo) and degree centrality (DC) were calculated using a voxel-based approach. Intergroup differences in ReHo and DC were explored using a permutation test with a threshold-free cluster enhancement (PT TFCE, number of permutations = 1,000, family-wise error rate (FWER) < 0.05).Results: ReHo and DC alterations were identified in distributed anatomies for both PS and CRS groups. DC mainly increased in the bilateral anterior and posterior cingulate cortex, the inferior frontal-orbital gyrus, and decreased in the bilateral cuneus, calcarine, and the precuneus, while ReHo mainly decreased in the precentral and the postcentral gyri, inferior parietal lobules, precuneus, posterior cingulate cortex, and the superior occipital gyrus. PS and CRS groups were not significantly different in ReHo or DC (FWER > 0.05).Conclusions: Focal ischemic stroke in pons or corona radiata leads to extensive alterations in the functional network centrality. IS-induced network remodeling is more anatomy-specific than pathway-specific, which may underpin the clinicotopographical profiles during the disease dynamic. Approaches targeting neural pathway and functional connectivity may shed light on a better characterization and management innovation of ischemic stroke.