Changes in default network topology properties of brain function in maintenance dialysis patients with end-stage renal disease with cognitive impairment / 中华行为医学与脑科学杂志

Objective:To investigate the relationship between the changes of default network topology properties of brain function and cognitive function in patients with end-stage renal disease (ESRD).Methods:A total of 31 patients with ESRD were enrolled in the Department of Nephrology, Changzhou Second Hospital Affiliated to Nanjing Medical University from January 2019 to December 2020, and 18 healthy persons were included in the same period as the control group.The cognitive function was evaluated with the Montreal cognitive assessment (MoCA) and trail making tests, and then the subjects were examined by resting-state functional magnetic resonance imaging (rs-fMRI). After preprocessing, the brain functional network was constructed and the topology properities of the network were calculated.The SPSS 20.0 software was used for statistical analysis.Independent sample t-test, chi square test and Pearson correlation analysis were used for data statistics. Results:(1) The score of MoCA in the ESRD group(23.37±1.77) was significantly lower than that in the healthy control group(27.94±1.13)( t=9.537, P<0.001). (2) The levels of Eglobal, Elocal, Cp and Sigma in ESRD group ((0.129±0.025), (0.148±0.040), (0.188±0.046), (1.593±0.650)) were significantly lower than those in healthy control group ((0.160±0.040), (0.212±0.024), (0.276±0.049), (2.004±0.864))( t=3.591, 7.474, 7.058, 2.034, all P<0.05). The Lp value of the ESRD group (8.131±1.905) was significantly higher than that of the control group (6.777±2.150)( t=2.583, P< 0.05). The node efficiency values of bilateral dorsolateral superior frontal gyrus, left middle frontal gyrus, bilateral posterior cingulate gyrus, right hippocampus, left superior marginal gyrus, bilateral angular gyrus and bilateral cuneate anterior lobe in ESRD group ((0.133±0.071), (0.201±0.047), (0.211±0.106), (0.175±0.066), (0.276±0.113), (0.122±0.146), (0.042±0.075), (0.171±0.027), (0.154±0.078), (0.240±0.095), (0.161±0.056))were lower than those in the healthy control group((0.312±0.075), (0.289±0.091), (0.277±0.132), (0.284±0.053), (0.368±0.063), (0.231±0.227), (0.120±0.162), (0.296±0.064), (0.310±0.186), (0.318±0.066), (0.286±0.103))( t=2.107-9.436, all P<0.05). (3)Pearson correlation analysis showed that the node efficiency values of bilateral posterior cingulate gyrus and right hippocampus in ESRD group were positively correlated with the score of MoCA( r=0.36, 0.49, 0.53, all P<0.05). Conclusion:The topological structure of brain functional network is abnormal in ESRD patients, which can affect the cognitive function of patients.

Seed-Based Resting-State Functional MRI for Presurgical Localization of the Motor Cortex: A Task-Based Functional MRI-Determined Seed Versus an Anatomy-Determined Seed

OBJECTIVE: For localization of the motor cortex, seed-based resting-state functional MRI (rsfMRI) uses the contralateral motor cortex as a seed. However, research has shown that the location of the motor cortex could differ according to anatomical variations. The purpose of this study was to compare the results of rsfMRI using two seeds: a template seed (the anatomically expected location of the contralateral motor cortex) and a functional seed (the actual location of the contralateral motor cortex determined by task-based functional MRI [tbfMRI]). MATERIALS AND METHODS: Eight patients (4 with glioma, 3 with meningioma, and 1 with arteriovenous malformation) and 9 healthy volunteers participated. For the patients, tbfMRI was performed unilaterally to activate the healthy contralateral motor cortex. The affected ipsilateral motor cortices were mapped with rsfMRI using seed-based and independent component analysis (ICA). In the healthy volunteer group, both motor cortices were mapped with both-hands tbfMRI and rsfMRI. We compared the results between template and functional seeds, and between the seed-based analysis and ICA with visual and quantitative analysis. RESULTS: For the visual analysis, the functional seed showed significantly higher scores compared to the template seed in both the patients (p = 0.002) and healthy volunteers (p < 0.001). Although no significant difference was observed between the functional seed and ICA, the ICA results showed significantly higher scores than the template seed in both the patients (p = 0.01) and healthy volunteers (p = 0.005). In the quantitative analysis, the functional seed exhibited greater similarity to tbfMRI than the template seed and ICA. CONCLUSION: Using the contralateral motor cortex determined by tbfMRI as a seed could enhance visual delineation of the motor cortex in seed-based rsfMRI.

Changes in the Laterality of Functional Connectivity Associated with Tinnitus: Resting-State fMRI Study

PURPOSE: One of the suggested potential mechanisms of tinnitus is an alteration in perception in the neural auditory pathway. The aim of this study was to investigate the difference in laterality in functional connectivity between tinnitus patients and healthy controls using resting state functional MRI (rs-fMRI). MATERIALS AND METHODS: Thirty-eight chronic tinnitus subjects and 45 age-matched healthy controls were enrolled in this study. Connectivity was investigated using independent component analysis, and the laterality index map was calculated based on auditory (AN) and dorsal attention (DAN), default mode (DMN), sensorimotor, salience (SalN), and visual networks (VNs). The laterality index (LI) of tinnitus subjects was compared with that of normal controls using region-of-interest (ROI) and voxel-based methods and a two-sample unpaired t-test. Pearson correlation was conducted to assess the associations between the LI in each network and clinical variables. RESULTS: The AN and VN showed significant differences in LI between the two groups in ROI analysis (P < 0.05), and the tinnitus group had clusters with significantly decreased laterality of AN, SalN, and VN in voxel-based comparisons. The AN was positively correlated with tinnitus distress (tinnitus handicap inventory), and the SalN was negatively correlated with symptom duration (P < 0.05). CONCLUSION: The results of this study suggest that various functional networks related to psychological distress can be modified by tinnitus, and that this interrelation can present differently on the right and left sides, according to the dominance of the network.

Brain Regional Homogeneity Changes in Cirrhotic Patients with or without Hepatic Encephalopathy Revealed by Multi-Frequency Bands Analysis Based on Resting-State Functional MRI

OBJECTIVE: To investigate brain regional homogeneity (ReHo) changes of multiple sub-frequency bands in cirrhotic patients with or without hepatic encephalopathy using resting-state functional MRI. MATERIALS AND METHODS: This study recruited 46 cirrhotic patients without clinical hepatic encephalopathy (noHE), 38 cirrhotic patients with clinical hepatic encephalopathy (HE), and 37 healthy volunteers. ReHo differences were analyzed in slow-5 (0.010−0.027 Hz), slow-4 (0.027−0.073 Hz), and slow-3 (0.073−0.198 Hz) bands. Routine analysis of (0.010−0.080 Hz) band was used as a benchmark. Associations of abnormal ReHo values in each frequency band with neuropsychological scores and blood ammonia level were analyzed. Pattern classification analyses were conducted to determine whether ReHo differences in each band could differentiate the three groups of subjects (patients with or without hepatic encephalopathy and healthy controls). RESULTS: Compared to routine analysis, more differences between HE and noHE were observed in slow-5 and slow-4 bands (p 12, overall corrected p < 0.05). Sub-frequency band analysis also showed that ReHo abnormalities were frequency-dependent (overall corrected p < 0.05). In addition, ReHo abnormalities in each sub-band were correlated with blood ammonia level and neuropsychological scores, especially in the left inferior parietal lobe (overall corrected p < 0.05 for all frequency bands). Pattern classification analysis demonstrated that ReHo differences in lower slow-5 and slow-4 bands (both p < 0.05) and higher slow-3 band could differentiate the three groups (p < 0.05). Compared to routine analysis, ReHo features in slow-4 band obtained better classification accuracy (89%). CONCLUSION: Cirrhotic patients showed frequency-dependent changes in ReHo. Sub-frequency band analysis is important for understanding HE and clinical monitoring.

Functional connectivity of the fronto-striatal circuitry in patients with bulimia nervosa based on resting-state fMRI / 中华行为医学与脑科学杂志

Objective To explore the functional connectivity (FC) of the fronto-striatal circuitry in patients with bulimia nervosa (BN) based on the resting-state fMRI and its correlation with the inhibitory function.Methods 27 medication-naive female patients with BN and 27 age-and education-matched female healthy control subjects were included in the study.All the subjects performed a stop signal task (SST) and underwent the resting-state fMRI scan,separately.The FC between striatal subregions and the frontal cortex was analyzed.Results Compared with healthy controls,FC between the right ventral rostral putamen (VRP) and the right supplementary motor areas (SMA) decreased (MNI coordinate:x =3,y =-15,z =51,K =27) in patients with BN.And the FC was also decreased between the right VRP and premotor area(PM) (MNI coordinate:x =27,y =0,z =57,K =44).FC between bilateral dorsal caudal putamen (DCP) (MNI coordinate:x=21,y=-6,z=48,K=43) and the right PM(MNI coordinate:x=21,y=-12,z=57,K=24) was decreased in patients with BN (P＜0.05,Alphasim corrected,voxel P＜0.005,clusters ≥ 20 voxels).FC between the right VRP and right SMA was negatively correlated with the stop signal reaction time (SSRT) in patients with BN (r=-0.595,P=0.004).The FC between right DCP and right PM was positively correlated with the impulsivity regulation subscale scores of the Eating Disorder Inventory-Ⅱ in patients with BN(r=0.483,P=0.023).Conclusion There is disrupted FC between the striatum and motor cortex in medication-naive female patients with BN based on resting-state fMRI,which may be related to impaired inhibitory control in patients with BN.

A resting-state functional MRI study on brain control of bladder storage function / 中华泌尿外科杂志

Objective In order to observe central responses during naturally occurring urinary bladder storage in healthy subjects,we examined brain areas that control strong bladder sensation by resting-state functional magnetic resonance imaging (rs-fMRI).Methods 44 healthy subjects (19 men and 25 women,between 22 and 50 years of age) were screened in the study from October 2014 to October 2016.All subjects were right-handed and scanned twice under the following two conditions:empty bladder (bladder volume ＜ 10 ml)and full bladder (‘strong desire to void’,bladder volume between 200 and 400 ml)without the use of filling with a catheter.Brain imaging softwares (SPM8,DPABI,REST) were adopted to analyze the difference in brain-blood perfusion between these two conditions.Voxel-based analysis of the regional homogeneity (ReHo) was performed to analyze rs-fMRI data including the main excitatory regions and inhibitory areas,peak value (X-axis,Y-axis,Z-axis),clusters size (active volume unit:number of voxel),T value (the excitatory and inhibitory extent of brain active regions).Results The rs-fMRI scans of 44 healthy subjects were analyzed.Nine subjects were excluded because of excessive head movements of more than 1.5 mm and 1.5° in rotation.Data sets were obtained from 35 subjects in two states of bladder,empty bladder and strong desires to void.Increased activity during strong desire to void was observed in the prefrontal cortex (PFC),anterior cingulate cortex (ACC),hypothalamus,temporal lobes and left caudate nucleus.Conclusions There are significant changes in the brain's ReHo during the strong sensation to void.The results suggest that the PFC,the ACC,hypothalamus,temporal lobes and left caudate nucleus play a role in the cerebral control of bladder storage without artificial bladder filling in healthy people.

Improved Diagnostic Accuracy of Alzheimer's Disease by Combining Regional Cortical Thickness and Default Mode Network Functional Connectivity: Validated in the Alzheimer's Disease Neuroimaging Initiative Set

OBJECTIVE: To identify potential imaging biomarkers of Alzheimer's disease by combining brain cortical thickness (CThk) and functional connectivity and to validate this model's diagnostic accuracy in a validation set. MATERIALS AND METHODS: Data from 98 subjects was retrospectively reviewed, including a study set (n = 63) and a validation set from the Alzheimer's Disease Neuroimaging Initiative (n = 35). From each subject, data for CThk and functional connectivity of the default mode network was extracted from structural T1-weighted and resting-state functional magnetic resonance imaging. Cortical regions with significant differences between patients and healthy controls in the correlation of CThk and functional connectivity were identified in the study set. The diagnostic accuracy of functional connectivity measures combined with CThk in the identified regions was evaluated against that in the medial temporal lobes using the validation set and application of a support vector machine. RESULTS: Group-wise differences in the correlation of CThk and default mode network functional connectivity were identified in the superior temporal (p < 0.001) and supramarginal gyrus (p = 0.007) of the left cerebral hemisphere. Default mode network functional connectivity combined with the CThk of those two regions were more accurate than that combined with the CThk of both medial temporal lobes (91.7% vs. 75%). CONCLUSION: Combining functional information with CThk of the superior temporal and supramarginal gyri in the left cerebral hemisphere improves diagnostic accuracy, making it a potential imaging biomarker for Alzheimer's disease.

Rs-fMRI changes of posterior cingulate cortex in type 2 diabetes mellitus patients with cognitive im-pairment / 中华行为医学与脑科学杂志

Objective To investigate the resting?state functional alteration in posterior cingulate cortex ( PCC) in Type 2 diabetes ( T2DM) patients with cognitive impairment and to determine the relation?ship of rs?fMRI changes with cognitive decline. Methods Resting?state functional magnetic resonance ima?ging was performed T2DM patients with impaired cognition ( n=19) and healthy control subjects ( n=20) . The amplitude of low frequency fluctuations ( ALFF) and regional homogeneity ( ReHo) values were calcu?lated in left PCC to represent the spontaneous brain activity. Using left PCC as a seed region,the functional connectivity of the whole brain was mapped. In addition,correlation analysis was conducted among ALFF,Re?Ho,and neuropsychological test scores. Results The ALFF values of left PCC (0.72±0.37) was decreased compared with the control group(1.09±0.46),but the ReHo value(1.12±0.10)was not significantly changed compared with control group (1.14±0.11). The functional connectivity was decreased with the left medial temporal lobe,left superior and middle temporal gyrus,right superior frontal gyrus,and right supplementary motor area ( SMA) ,while it was increased with the left middle frontal gyrus,inferior frontal gyrus and right cerebella. MoCA scores were positively correlated with the ALFF values of left PCC. Conclusion In resting state,the spontaneous activity and functional connectivity of PCC is altered in T2DM patients with cognitive impairement;and the function of PCC contributes to the cognitive decline associated with T2DM.The decrease of ALFF value of PCC may help to detect the cognitive decline of T2DM.

The study of low frequency fluctuation in the resting state between short-term heroin and methamphetamine abusers after withdrawal / 实用放射学杂志

Objective To investigate the differences of low frequency fluctuation (ALFF)in the resting state between short-term heroin and methamphetamine abusers after withdrawal.Methods Sixteen male short-term heroin abusers and fourteen male short-term methamphetamine abusers were performed the functional magnetic resonance imaging (fMRI).The differences of ALFF be-tween the two groups were performed with preprocessing softwares.Threshold was set to 0.05.Results Compared with metham-phetamine-dependent patients,heroin-dependent patients showed increased ALFF in the left side of the lingual gyrus and the left ton-sil of cerebellum and decreased ALFF in the left side of the brain stem,midbrain and the left side of the cerebellar vermis.Conclusion There are differences between the short-term heroin and methamphetamine abusers in the function of the brain,mainly involving the brain regions associating with cognition and affection.

Stroke Connectome and Its Implications for Cognitive and Behavioral Sequela of Stroke / 대한뇌졸중학회지

Systems-based approaches to neuroscience, using network analysis and the human connectome, have been adopted by many researchers by virtue of recent progress in neuroimaging and computational technologies. Various neurological disorders have been evaluated from a network perspective, including stroke, Alzheimer's disease, Parkinson's disease, and traumatic brain injury. Until now, dynamic processes after stroke and during recovery were investigated through multimodal neuroimaging techniques. Many studies have shown disruptions in structural and functional connectivity, including in large-scale neural networks, in patients with stroke sequela such as motor weakness, aphasia, hemianopia, neglect, and general cognitive dysfunction. A connectome-based approach might shed light on the underlying mechanisms of stroke sequela and the recovery process, and could identify candidates for individualized rehabilitation programs. In this review, we briefly outline the basic concepts of structural and functional connectivity, and the connectome. Then, we explore current evidence regarding how stroke lesions cause changes in connectivity and network architecture parameters. Finally, the clinical implications of perspectives on the connectome are discussed in relation to the cognitive and behavioral sequela of stroke.