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BackgroundDepression is a common comorbid psychiatric symptom in patients with Alzheimer’s disease (AD), and the prevalence of depression is higher among people with AD compared with healthy older adults. Comorbid depression in AD may increase the risk of cognitive decline, impair patients’ function, and reduce their quality of life. However, the mechanisms of depression in AD remain unclear. Here, our aim was to identify neurometabolic characteristics in the brain that are associated with depression in patients with mild AD.MethodsThirty-seven patients were evaluated using the Neuropsychiatric Inventory (NPI) and Hamilton Depression Rating Scale (HAMD-17), and divided into two groups: 17 AD patients with depression (D-AD) and 20 non-depressed AD patients (nD-AD). Using proton magnetic resonance spectroscopy, we characterized neurometabolites in the anterior cingulate gyrus (ACG) of D-AD and nD-AD patients.ResultsCompared with nD-AD patients, D-AD patients showed lower N-acetylaspartate/creatine (NAA/Cr) and higher myo-inositol/creatine (mI/Cr) in the left ACG. NPI score correlated with NAA/Cr and mI/Cr in the left ACG, while HAMD correlated with NAA/Cr.ConclusionsOur findings show neurometabolic alterations in D-AD patients. Thus, D-AD pathogenesis may be attributed to abnormal activity of neurons and glial cells in the left ACG.

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Background: Recent research suggests that abnormalities in the habenula (HB), a core area of the brain that transmits reward information, may be a determinant of depression. However, it is not clear whether the functional connectivity (FC) pattern of the mild cognitive impairment (MCI) with and without depression symptoms is abnormal. Methods:In this study, we used resting-state functional magnetic resonance imaging (fMRI) to examine the FC pattern of the HB in MCI patients with depression symptoms (D-MCI). We acquired fMRI data from 54 subjects on a 3T MRI. Subjects collected included 16 patients with D-MCI, 18 patients with MCI with no depression, and 20 healthy controls. One way ANCOVA and post hoc t-test were used to compare the difference in FC strength between the three groups. Results:The D-MCI group had altered FC between the left HB and the right superior temporal gyrus, right inferior frontal gyrus/opercular part, and right middle frontal gyrus. The D-MCI group had increased FC between the right HB and precuneus.Conclusions: These results suggest that the dysfunction of the HB-Default model network might be involved in the neural mechanism underlying depression in MCI.

Background The aim of the present study was to explore the brain active characteristics of patients with irritable bowel syndrome with diarrhea (IBS-D) using resting-state functional magnetic resonance imaging technology. Methods Thirteen IBS-D patients and fourteen healthy controls (HC) were enrolled. All subjects underwent head MRI examination during resting state. A voxel-based analysis of fractional amplitude of low frequency fluctuation (fALFF) maps between IBS-D and HC was performed using a two-sample t-test. The relationship between the fALFF values in abnormal brain regions and the scores of Symptom Severity Scale (IBS-SSS) were analyzed using Pearson correlation analysis. Results Compared with HC, IBS-D patients had lower fALFF values in the left medial superior frontal gyrus and higher fALFF values in the left hippocampus and right precuneus. There was a positive correlation between the duration scores of IBS-SSS and fALFF values in the right precuneus. Conclusion The altered fALFF values in the medial superior frontal gyri, left hippocampus and right precuneus revealed changes of intrinsic neuronal activity, further revealing the abnormality of gut-brain axis of IBS-D.