Modulation of transcutaneous auricular vagus nerve stimulation on default mode network in patients with primary insomnia / 中国针灸

OBJECTIVE@#To explore the modulation of transcutaneous auricular vagus nerve stimulation (taVNS) on default mode network (DMN) in patients with primary insomnia (PI).@*METHODS@#A total of 22 PI patients (one patient dropped off and two patients were excluded) were included and treated with taVNS. The bilateral auricular points of Xin (CO15) and Shen (CO10) were selected and treated with disperse-dense wave at frequency of 4 Hz/20 Hz, the intensity was based on the patient's tolerance. taVNS was given once in the morning and once in the evening for 30 minutes each time. The treatment lasted for at least 5 days a week for 4 weeks. At the same time, 16 healthy subjects matched with gender and age were recruited. The Pittsburgh sleep quality index (PSQI) score was evaluated before and after treatment in PI patients. The resting-state functional magnetic resonance imaging (rs-fMRI) data of PI patients before and after treatment and healthy subjects at baseline period were collected to observe the effect of taVNS on the functional connection (FC) between posterior cingulate cortex (PCC) and whole brain.@*RESULTS@#After treatment, the total score of PSQI in PI patients was lower than that before treatment (P<0.01). Compared with healthy subjects, the FC of the left PCC was increased either with the left orbital superior frontal gyrus or with left middle frontal gyrus (P<0.001), and the FC between right PCC and left middle frontal gyrus was increased in PI patients before treatment (P<0.001). Compared before treatment, the FC between left PCC and left middle frontal gyrus was decreased (P<0.05), and the FC of the right PCC was decreased either with the right medial prefrontal cortex or with the left middle frontal gyrus in PI patients after treatment (P<0.001, P<0.01).@*CONCLUSION@#taVNS can modulate the FC between anterior and posterior DMN, and between DMN and cognitive control network of PI patients, which may be one of the brain effect mechanisms of taVNS in the treatment of PI patients.

Distinct Neural Correlates of Executive Function by Amyloid Positivity and Associations with Clinical Progression in Mild Cognitive Impairment

PURPOSE: This study aimed to identify the neural basis of executive function (EF) in amnestic mild cognitive impairment (aMCI) according to beta-amyloid (Aβ) positivity. Furthermore, we explored if the identified brain areas could serve as predictors for clinical progression. MATERIALS AND METHODS: We included individuals with aMCI using data from [¹⁸F]-florbetapir-positron emission tomography (PET), fluorodeoxyglucose-PET, and EF scores, as well as follow-up clinical severity scores at 1 and 5 years from baseline from the Alzheimer's Disease Neuroimaging Initiative database. The correlations between EF score and regional cerebral glucose metabolism (rCMglc) were analyzed separately for aMCI with low Aβ burden (aMCI Aβ−, n=230) and aMCI with high Aβ burden (aMCI Aβ+, n=268). Multiple linear regression analysis was conducted to investigate the associations between rCMglc and clinical progression. RESULTS: Longitudinal courses differed between aMCI Aβ− and aMCI Aβ+ groups. On average, aMCI Aβ− subjects maintained their level of clinical severity, whereas aMCI Aβ+ subjects showed progression. EF impairment in aMCI Aβ− was related to the anterior cingulate cortex (ACC), whereas that in aMCI Aβ+ was related to Alzheimer's Disease-vulnerable brain regions. ACC and the posterior cingulate cortex were associated with clinical progression in aMCI Aβ− and aMCI Aβ+, respectively. CONCLUSION: Our findings suggest that although MCI subjects showed similar behavioral phenotypes at the time of diagnosis, EF and further progression were associated with different brain regions according to Aβ burden. Clarification of the etiologies and nature of EF impairment in aMCI are critical for disease prognosis and management.

Dysfunctional Social Reinforcement Processing in Disruptive Behavior Disorders: An Functional Magnetic Resonance Imaging Study

OBJECTIVE: Prior functional magnetic resonance imaging (fMRI) work has revealed that children/adolescents with disruptive behavior disorders (DBDs) show dysfunctional reward/non-reward processing of non-social reinforcements in the context of instrumental learning tasks. Neural responsiveness to social reinforcements during instrumental learning, despite the importance of this for socialization, has not yet been previously investigated. METHODS: Twenty-nine healthy children/adolescents and 19 children/adolescents with DBDs performed the fMRI social/non-social reinforcement learning task. Participants responded to random fractal image stimuli and received social and non-social rewards/non-rewards according to their accuracy. RESULTS: Children/adolescents with DBDs showed significantly reduced responses within the caudate and posterior cingulate cortex (PCC) to non-social (financial) rewards and social non-rewards (the distress of others). Connectivity analyses revealed that children/adolescents with DBDs have decreased positive functional connectivity between the ventral striatum (VST) and the ventromedial prefrontal cortex (vmPFC) seeds and the lateral frontal cortex in response to reward relative to non-reward, irrespective of its sociality. In addition, they showed decreased positive connectivity between the vmPFC seed and the amygdala in response to non-reward relative to reward. CONCLUSION: These data indicate compromised reinforcement processing of both non-social rewards and social non-rewards in children/adolescents with DBDs within core regions for instrumental learning and reinforcement-based decision-making (caudate and PCC). In addition, children/adolescents with DBDs show dysfunctional interactions between the VST, vmPFC, and lateral frontal cortex in response to rewarded instrumental actions potentially reflecting disruptions in attention to rewarded stimuli.

Magnetic resonance spectroscopy study of the left posterior cingulate cortex in type 2 diabetic encephalopathy patients / 实用放射学杂志

Objective To analyze the changes of metabolites in the left posterior cingulate cortex (PCC)in patients with type 2 diabetes mellitus (T2DM),diabetic encephalopathy(DE)and healthy control(HC),to discuss the pathogenesis and to provide the biological information for the early diagnosis of DE.Methods 46 patients with clinical diagnosis of T2DM and 26 matched HC were received single-voxel MRS on the left PCC using Siemens Verio 3.0T MR scanner.Participants were divided into two groups based on MoCA scoring criteria and diabetic retinopathy,including DM group (n=31)and DE group (n=15).All T2DM patients were received fasting blood glucose,glycated hemoglobin (HbAlc)and other clinical labortory tests before MR scans.SPSS 21.0 software package was used for statistical analysis.Results (1)Ins and Ins/Cr were increased gradually in DE compared with HC and DM groups(P＜0.05).(2) NAA/Ins ratio in DE group was significant lower than that in DM and HC group,but no significant difference was observed between DM and DE groups(P＞0.05).No significant differences exsited in NAA/Cr among these three groups(P＞0.05).Conclusion MRS can be more sensitive to detect DE patients on the left PCC-related metabolic abnormalities and help DE with early screening and preliminary clinical diagnosis.The increase Ins/Cr in the left PCC area is more sensitive to the brain injury of T2DM and can refelect the progress degree.It is necessary to expand the sample size to verify its diagnostic efficacy and early warning of the brain injury.

Abnormal Effective Connectivity of the Anterior Forebrain Regions in Disorders of Consciousness / 神经科学通报·英文版

A number of studies have indicated that disorders of consciousness result from multifocal injuries as well as from the impaired functional and anatomical connectivity between various anterior forebrain regions. However, the specific causal mechanism linking these regions remains unclear. In this study, we used spectral dynamic causal modeling to assess how the effective connections (ECs) between various regions differ between individuals. Next, we used connectome-based predictive modeling to evaluate the performance of the ECs in predicting the clinical scores of DOC patients. We found increased ECs from the striatum to the globus pallidus as well as from the globus pallidus to the posterior cingulate cortex, and decreased ECs from the globus pallidus to the thalamus and from the medial prefrontal cortex to the striatum in DOC patients as compared to healthy controls. Prediction of the patients' outcome was effective using the negative ECs as features. In summary, the present study highlights a key role of the thalamo-basal ganglia-cortical loop in DOCs and supports the anterior forebrain mesocircuit hypothesis. Furthermore, EC could be potentially used to assess the consciousness level.

Changes of resting-state default-mode network functional connectivity in patients with treatment-resistant depression / 中国医学影像技术

Objective To explore the difference of resting-state default-mode network functional connectivity in patients with treatment-resistant depression (TRD) and in healthy subjects. Methods Ten patients with TRD and 12 healthy control subjects underwent 440 s fMRI scans while resting quietly. Functional connectivity analysis was used to isolate the default mode network in each subject. Group maps of the default-mode network were generated and compared between the two groups. A within-group analysis was performed in the depressed group to explore effects of depression refractoriness on network functional connectivity. Results Functional connectivity of both side of middle temporal gyrus, rectal gyrus, precuneus gray matter, left orbital gyrus, right inferior parietal lobule, and post cingulate gyrus in TRD group weakened compared with that of the control subjects. Conclusion There are resting default network connection weakening in multiple brain areas in TRD patients, which may lead to self-control and emotional behavior abnormal in patients.