Research on depression recognition based on brain function network / 生物医学工程学杂志

Traditional depression research based on electroencephalogram (EEG) regards electrodes as isolated nodes and ignores the correlation between them. So it is difficult to discover abnormal brain topology alters in patients with depression. To resolve this problem, this paper proposes a framework for depression recognition based on brain function network (BFN). To avoid the volume conductor effect, the phase lag index is used to construct BFN. BFN indexes closely related to the characteristics of "small world" and specific brain regions of minimum spanning tree were selected based on the information complementarity of weighted and binary BFN and then potential biomarkers of depression recognition are found based on the progressive index analysis strategy. The resting state EEG data of 48 subjects was used to verify this scheme. The results showed that the synchronization between groups was significantly changed in the left temporal, right parietal occipital and right frontal, the shortest path length and clustering coefficient of weighted BFN, the leaf scores of left temporal and right frontal and the diameter of right parietal occipital of binary BFN were correlated with patient health questionnaire 9-items (PHQ-9), and the highest recognition rate was 94.11%. In addition, the study found that compared with healthy controls, the information processing ability of patients with depression reduced significantly. The results of this study provide a new idea for the construction and analysis of BFN and a new method for exploring the potential markers of depression recognition.

Research on characteristics of brain functional network in stroke patients during convalescent period under transcranial direct current stimulation / 生物医学工程学杂志

Transcranial direct current stimulation (tDCS) is an emerging non-invasive brain stimulation technique. However, the rehabilitation effect of tDCS on stroke disease is unclear. In this paper, based on electroencephalogram (EEG) and complex network analysis methods, the effect of tDCS on brain function network of stroke patients during rehabilitation was investigated. The resting state EEG signals of 31 stroke rehabilitation patients were collected and divided into stimulation group (16 cases) and control group (15 cases). The Pearson correlation coefficients were calculated between the channels, brain functional network of two groups were constructed before and after stimulation, and five characteristic parameters were analyzed and compared such as node degree, clustering coefficient, characteristic path length, global efficiency, and small world attribute. The results showed that node degree, clustering coefficient, global efficiency, and small world attributes of brain functional network in the tDCS group were significantly increased, characteristic path length was significantly reduced, and the difference was statistically significant (

Functional Connectivities in Right Hemisphere for Post-stroke Aphasia: Based on Dual Stream Model / 中国康复理论与实践

Objective:To study the effect of right brain language network in post-stroke aphasia (PSA) patients with left hemisphere injury. Methods:From December, 2018 to June, 2019, twelve PSA patients with left hemisphere injury, and twelve matched healthy controls were recruited to accept rest-state functional magnetic resonance imaging (f-MRI) scan, and analyzed the characteristics of right brain function network with Dual Stream model. Results:There were two patients lost. Compared with the controls, for dorsolateral lingual pathway, the functional connections increased from superior marginal gyrus to middle frontal gyrus and inferior frontal gyrus of trigone in the patients, while those decreased from posterior central gyrus to inferior frontal gyrus of insula. For ventral lingual pathway, the functional connection increased from angular gyrus to orbital inferior frontal gyrus. For ventral and dorsolateral double-pathway, the functional connections increased from temporal lobe to lenticular pallidum and angular gyrus, from caudate nucleus to inferior frontal gyrus of insula, from lenticular putamen nucleus to middle frontal gyrus and trigonometry, while it decreased from superior marginal gyrus and temporal lobe to inferior frontal gyrus of insula. There was a negative correlation between the functional connection from inferior frontal gyrus to lenticular putamen and repeating (r = -0.720, P < 0.05), between the functional connection from inferior frontal gyrus to the caudate nucleus to speaking and repeating (r < -0.696, P < 0.05). In terms of network index, there were significant differences between the patients and the controls in both local and global indexes for language key brain area in right brain (|t| > 2.143, P < 0.05). Conclusion:The functional network has reorganized in right hemisphere of PSA patients. However, the increase of connection between language critical cortex and subcortical nuclei may play a role in improvement of language function.

Small-world networks analysis of leukoaraiosis: a rest-state functional MRI study / 中华行为医学与脑科学杂志

Objective To explore the effect of leukoaraiosis (LA) on the efficiency of the brain function network and to analyze the features of the "small world" network with graph theory method.Methods This study involved 34 LA patients from the Department of Neurology,Beijing Tiantan hospital,Capital Medical University from January 2014 to September 2015 and 23 age-and sex-matched healthy controls(NC group).All participants underwent the neurocognitive tests including M MSE,MoCA and clinical dementia rating(CDR).The subjects were divided into LA with cognitive normal group (CN) (n=11) and LA patients with vascular cognitive impairment-non dementia group(VCIND) (n=23).Functional MRI (fMRI) was employed at resting state.And then,the functional network establishment and small-world network metrics (characteristic clustering coefficient and path length) were computed using graph analytical methods.Results In the range of 0.05 ≤ Kcost ≤ 0.5,the functional networks fitted the definition of small-worldness in LA (CN),LA(VCIND) and NC groups(δ＞1).The Lambda of group LA(CN) and LA (VCIND) were smaller than that of NC group at each threshold,and more closing to 1.The gamma of group LA(CN) were higher than that of NC group at each threshold.While the gamma of group LA(VCIND)were lower than that of NC group at each threshold.The sigma of group LA(CN) were higher than that of NC group at each threshold.Conclusion The LA patients exhibit abnormal small-world network properties.And compared with HCs,small world properties in LA (CN) patients have been increased,while that in LA (VCIND) patients have been reduced,which manifested that the altered topological properties may be responsible for cognitive dysfunction in LA patients.