Resting-state Neural Networks and Granger Causal Connectivity for Patients with Cognitive Impairment Associated with Leukoaraiosis / 中国康复理论与实践

Objective:To compare the difference in resting state networks among leukoaraiosis (LA) patients with or without mild cognitive impairment, and healthy controls, as well as the functional connectivity under Granger causality analysis (GCA). Methods:Subjects aged 40 to 80 years, including 34 LA-MCI patients, 15 LA patients with normal cognition and 33 healthy controls, accepted resting-state functional magnetic resonance imaging. Independent component analysis was used to separate functional brain networks, and difference of activation was determined with two sample t-test. GCA was used to analyze effective connectivity of these functional networks. Results:Eight resting state networks were obtained, including default mode network, motor network, medial visual network, lateral visual network, right-memory network, left-memory network, auditory network and executive network. Activation was different among three groups. Effective connectivity of RSNs was also different among three groups. Conclusion:Components of the resting state networks keep changing as LA progressing. Activation decreases as patients' cognition impaired. The direction and strength of connections remodel.

Cortical Thickness of Resting State Networks in the Brain of Male Patients with Alcohol Dependence

OBJECTIVES: It is well known that problem drinking is associated with alterations of brain structures and functions. Brain functions related to alcohol consumption can be determined by the resting state functional connectivity in various resting state networks (RSNs). This study aims to ascertain the alcohol effect on the structures forming predetermined RSNs by assessing their cortical thickness. METHODS: Twenty-six abstinent male patients with alcohol dependence and the same number of age-matched healthy control were recruited from an inpatient mental hospital and community. All participants underwent a 3T MRI scan. Averaged cortical thickness of areas constituting 7 RSNs were determined by using FreeSurfer with Yeo atlas derived from cortical parcellation estimated by intrinsic functional connectivity. RESULTS: There were significant group differences of mean cortical thicknesses (Cohen's d, corrected p) in ventral attention (1.01, < 0.01), dorsal attention (0.93, 0.01), somatomotor (0.90, 0.01), and visual (0.88, 0.02) networks. We could not find significant group differences in the default mode network. There were also significant group differences of gray matter volumes corrected by head size across the all networks. However, there were no group differences of surface area in each network. CONCLUSIONS: There are differences in degree and pattern of structural recovery after abstinence across areas forming RSNs. Considering the previous observation that group differences of functional connectivity were significant only in networks related to taskpositive networks such as dorsal attention and cognitive control networks, we can explain recovery pattern of cognition and emotion related to the default mode network and the mechanisms for craving and relapse associated with task-positive networks.

Dysconnectivity of multiple resting-state networks in patients with schizophrenia with auditory verbal hallucinations / 中国心理卫生杂志

Objective:To explore the traits of functional connectivity of resting-state networks in patients of schizophrenia with auditory verbal hallucinations (AVH) by using independent component analysis (ICA).Methods:All patients were met the Diagnostic and Statistical Mannal of Mental Disorders,Fourth Edition,Text Revision (DSM-IV-TR) diagnostic criteria for schizophrenia.Thirty schizophrenia patients with frequent AVH (AVH),24 schizophrenia patients without AVH (non-AVH) and 60 healthy controls (HC) matching with age and gender were analyzed by resting functional magnetic resonance imaging.The AVH were assessed by using Hoffman auditory hallucination scale.By using ICA,auditory network (AUN),language network (LAN),salience network (SAN),right front-parietal network (RFP) and default mode network (DMN) were selected as interesting networks for further analyses.Covariance analysis was used to compare the activity and functional connectivity of multiple resting state networks between three groups,and correlation analysis was used to evaluate the relations between abnormalities of brain and the severity of hallucination.Results:Compared to non-AVH,AVH group showed increased activity in left superior temporal gyrus (STG) and left postcentral gyrus (LPG) in the AUN,and showed decreased activity in right anterior cingulate cortex (ACC) in the SAN (P ＜ 0.05,FDR corrected).The severity of AVH group was associated with activity of the left STG (r =0.43,P ＜0.05) and the right ACC (r =-0.48,P ＜0.01).Furthermore,compared to non-AVH group,there were decreased connectivity between LAN and AUN [(-0.29 ±0.21) vs.(-0.16 ± 0.17),P ＜ 0.05,uncorrected],decreased connectivity between SAN and LAN [(-0.09 ± 0.22) vs.(-0.06 ± 0.18),P ＜ 0.05,uncorrected],increased connectivity between SAN and AUN [(0.30 ± 0.18) vs.(0.15 ± 0.24),P ＜ 0.05,uncorrected] in AVH group.Conclusion:There may be aberrant functional connectivities of AUN,LAN and SAN in schizophrenia patients with frequent AVH,and the occurrence of AVH seems to be related to brain areas involved in language production,speech perception and self-monitoring.