White-matter tracts play a pivotal role in transmitting sensory and motor information, facilitating interhemispheric communication and integrating different brain regions. Meanwhile, sensorimotor disturbance is a common symptom in patients with major depressive disorder (MDD). However, the role of aberrant sensorimotor white-matter system in MDD remains largely unknown. Herein, we investigated the topological structure alterations of white-matter morphological brain networks in 233 MDD patients versus 257 matched healthy controls (HCs) from the DIRECT consortium. White-matter networks were derived from magnetic resonance imaging (MRI) data by combining voxel-based morphometry (VBM) and three-dimensional discrete wavelet transform (3D-DWT) approaches. Support vector machine (SVM) analysis was performed to discriminate MDD patients from HCs. The results indicated that the network topological changes in node degree, node efficiency, and node betweenness were mainly located in the sensorimotor superficial white-matter system in MDD. Using network nodal topological properties as classification features, the SVM model could effectively distinguish MDD patients from HCs. These findings provide new evidence to highlight the importance of the sensorimotor system in brain mechanisms underlying MDD from a new perspective of white-matter morphological network.
Humans ; Depressive Disorder, Major/pathology* ; White Matter/pathology* ; Male ; Female ; Support Vector Machine ; Adult ; Magnetic Resonance Imaging ; Middle Aged ; Case-Control Studies ; Sensorimotor Cortex ; Brain

BACKGROUND: Patients with schizophrenia (SCZ) and major depressive disorder (MDD) share significant clinical overlap, although it remains unknown to what extent this overlap reflects shared neural profiles. To identify the shared and specific abnormalities in SCZ and MDD, we performed a whole-brain voxel-based meta-analysis using magnetization transfer imaging, a technique that characterizes the macromolecular structural integrity of brain tissue in terms of the magnetization transfer ratio (MTR). METHODS: A systematic search based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted in PubMed, EMBASE, International Scientific Index (ISI) Web of Science, and MEDLINE for relevant studies up to March 2022. Two researchers independently screened the articles. Rigorous scrutiny and data extraction were performed for the studies that met the inclusion criteria. Voxel-wise meta-analyses were conducted using anisotropic effect size-signed differential mapping with a unified template. Meta-regression was used to explore the potential effects of demographic and clinical characteristics. RESULTS: A total of 15 studies with 17 datasets describing 365 SCZ patients, 224 MDD patients, and 550 healthy controls (HCs) were identified. The conjunction analysis showed that both disorders shared higher MTR than HC in the left cerebellum ( P =0.0006) and left fusiform gyrus ( P =0.0004). Additionally, SCZ patients showed disorder-specific lower MTR in the anterior cingulate/paracingulate gyrus, right superior temporal gyrus, and right superior frontal gyrus, and higher MTR in the left thalamus, precuneus/cuneus, posterior cingulate gyrus, and paracentral lobule; and MDD patients showed higher MTR in the left middle occipital region. Meta-regression showed no statistical significance in either group. CONCLUSIONS The results revealed a structural neural basis shared between SCZ and MDD patients, emphasizing the importance of shared neural substrates across psychopathology. Meanwhile, distinct disease-specific characteristics could have implications for future differential diagnosis and targeted treatment.
Humans ; Depressive Disorder, Major/drug therapy* ; Schizophrenia/pathology* ; Brain/pathology* ; Prefrontal Cortex ; Frontal Lobe ; Magnetic Resonance Imaging/methods*

Major depressive disorder (MDD) is a highly heterogeneous mental disorder, and its complex etiology and unclear mechanism are great obstacles to the diagnosis and treatment of the disease. Studies have shown that abnormal functions of the visual cortex have been reported in MDD patients, and the actions of several antidepressants coincide with improvements in the structure and synaptic functions of the visual cortex. In this review, we critically evaluate current evidence showing the involvement of the malfunctioning visual cortex in the pathophysiology and therapeutic process of depression. In addition, we discuss the molecular mechanisms of visual cortex dysfunction that may underlie the pathogenesis of MDD. Although the precise roles of visual cortex abnormalities in MDD remain uncertain, this undervalued brain region may become a novel area for the treatment of depressed patients.
Humans ; Depressive Disorder, Major/pathology* ; Brain/pathology* ; Antidepressive Agents/therapeutic use* ; Visual Cortex/pathology*

The locus coeruleus (LC) has been studied in major depressive disorder (MDD) and bipolar disorder (BD). A major problem of immunocytochemical studies in the human LC is interference with the staining of the immunocytochemical end-product by the omnipresent natural brown pigment neuromelanin. Here, we used a multispectral method to untangle the two colors: blue immunocytochemical staining and brown neuromelanin. We found significantly increased tyrosine hydroxylase (TH) in the LC of MDD patients-thus validating the method-but not in BD patients, and we did not find significant changes in the receptor tyrosine-protein kinase ErbB4 in the LC in MDD or BD patients. We observed clear co-localization of ErbB4, TH, and neuromelanin in the LC neurons. The different stress-related molecular changes in the LC may contribute to the different clinical symptoms in MDD and BD.
Aged ; Aged, 80 and over ; Bipolar Disorder ; metabolism ; pathology ; Depressive Disorder, Major ; metabolism ; pathology ; Female ; Humans ; Image Processing, Computer-Assisted ; Immunohistochemistry ; methods ; Locus Coeruleus ; metabolism ; pathology ; Male ; Melanins ; metabolism ; Microscopy ; methods ; Middle Aged ; Neurons ; metabolism ; pathology ; Receptor, ErbB-4 ; metabolism ; Sensitivity and Specificity ; Spectrum Analysis ; methods ; Tyrosine 3-Monooxygenase ; metabolism

BACKGROUNDMost previous neuroimaging studies have focused on the structural and functional abnormalities of local brain regions in major depressive disorder (MDD). Moreover, the exactly topological organization of networks underlying MDD remains unclear. This study examined the aberrant global and regional topological patterns of the brain white matter networks in MDD patients.

METHODSThe diffusion tensor imaging data were obtained from 27 patients with MDD and 40 healthy controls. The brain fractional anisotropy-weighted structural networks were constructed, and the global network and regional nodal metrics of the networks were explored by the complex network theory.

RESULTSCompared with the healthy controls, the brain structural network of MDD patients showed an intact small-world topology, but significantly abnormal global network topological organization and regional nodal characteristic of the network in MDD were found. Our findings also indicated that the brain structural networks in MDD patients become a less strongly integrated network with a reduced central role of some key brain regions.

CONCLUSIONSAll these resulted in a less optimal topological organization of networks underlying MDD patients, including an impaired capability of local information processing, reduced centrality of some brain regions and limited capacity to integrate information across different regions. Thus, these global network and regional node-level aberrations might contribute to understanding the pathogenesis of MDD from the view of the brain network.

Adult ; Anisotropy ; Brain ; pathology ; Depressive Disorder, Major ; pathology ; Diffusion Tensor Imaging ; methods ; Female ; Humans ; Male

Our study aimed to establish the relationship between the number of depressive symptoms and the clinical characteristics of major depressive disorder (MDD). This would enable us to predict the clinical significance of the number of depressive symptoms in MDD patients. Using data from the Clinical Research Center for Depression (CRESCEND) study in Korea, 853 patients with DSM-IV MDD were recruited. The baseline and clinical characteristics of groups with different numbers of depressive symptoms were compared using the χ2 test for discrete variables and covariance (ANCOVA) for continuous variables. In addition, the scores of these groups on the measurement tools were compared by ANCOVA after adjusting the potential effects of confounding variables. After adjusting the effects of monthly income and history of depression, a larger number of depressive symptoms indicated higher overall severity of depression (F [4, 756] = 21.458, P < 0.001) and higher levels of depressive symptoms (F [4, 767] = 19.145, P < 0.001), anxiety symptoms (F [4, 765] = 12.890, P < 0.001) and suicidal ideation (F [4, 653] = 6.970, P < 0.001). It also indicated lower levels of social function (F [4, 760] = 13.343, P < 0.001), and quality of life (F [4, 656] = 11.975, P < 0.001). However, there were no significant differences in alcohol consumption (F [4, 656] = 11.975, P < 0.001). The number of depressive symptoms can be used as an index of greater illness burden in clinical psychiatry.
Adult ; Alcohol Drinking ; Analysis of Variance ; Antidepressive Agents/therapeutic use ; Anxiety ; *Depression ; Depressive Disorder, Major/drug therapy/*pathology/psychology ; Female ; Humans ; Male ; Middle Aged ; Quality of Life ; Severity of Illness Index ; Sex Factors ; Suicidal Ideation

In recent years, more attention has been paid to the role of the glutamate transporter 1 (GLT-1, EAAT2) in major depressive disorder (MDD). However, experimental data on brain GLT-1 levels are, to some extent, inconsistent in human postmortem and animal studies. These discrepancies imply that the role of GLT-1 in the pathophysiology of MDD and the action of antidepressants remain obscure. This work was designed to study the impact of chronic unpredictable stress (CUS) for 2 sessions per day for 35 days and four weeks of fluoxetine (FLX) on depressive-like behaviors in rats, as well as the concomitant expression of the GLT-1 protein in the hippocampus. Behavioral changes were assessed by the sucrose preference and open field tests. GLT-1 levels were detected by immunohistchemistry and Western blot analysis. Our study demonstrated that the animals exposed to CUS showed depressive-like behaviors and exhibited a significant decrease in GLT-1 expression in the hippocampus. Chronic FLX treatment reversed the behavioral deficits and the CUS-induced decrease in GLT-1 levels. Taken together, our results support the reduction of GLT-1 in human postmortem studies in MDD and suggest that GLT-1 may be involved in the antidepressant activity of FLX. Our studies further support the notion that GLT-1 is an attractive candidate molecule associated with the fundamental processes of MDD and may be a potential, and novel pharmacological target for the treatment of MDD.
Animals ; Antidepressive Agents, Second-Generation ; pharmacology ; Behavior, Animal ; drug effects ; Brain ; metabolism ; pathology ; Chronic Disease ; Depressive Disorder, Major ; drug therapy ; metabolism ; pathology ; Excitatory Amino Acid Transporter 2 ; metabolism ; Fluoxetine ; pharmacology ; Humans ; Male ; Rats ; Rats, Sprague-Dawley ; Stress, Psychological ; drug therapy ; metabolism ; pathology

A 59-year-old man with a history of major depression was found by his wife to be unconscious and foaming at the mouth. On arrival at the emergency department, the patient was noted to be unresponsive. Computed tomography of the brain showed symmetrical ill-defined areas of hypoattenuation involving the medial aspects of both lentiform nuclei, while magnetic resonance images of the brain showed symmetrical increased signal in the bilateral globi pallidi on diffusion weighted, T2-weighted and fluid attenuated inversion recovery sequences. These findings were those of acute carbon monoxide poisoning. Despite aggressive treatment, the patient's condition continued to deteriorate and he eventually passed away. The various imaging findings of carbon monoxide poisoning in the brain and the differential diagnoses are discussed.
Brain ; diagnostic imaging ; Carbon Monoxide Poisoning ; diagnosis ; diagnostic imaging ; Depressive Disorder, Major ; complications ; Diagnostic Imaging ; Fatal Outcome ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Pulmonary Edema ; pathology ; Radiography, Thoracic ; Suicide, Attempted ; Tomography, X-Ray Computed

BACKGROUNDFunctional imaging studies indicate abnormal activities in cortico-limbic network in depression during either task or resting state. The present work was to explore the abnormal spontaneous activity shown with regional homogeneity (ReHo) in depression by resting-state functional magnetic resonance imaging (fMRI).

METHODSUsing fMRI, the differences of regional brain activity were measured in resting state in depressed vs. healthy participants. Sixteen participants firstly diagnosed with major depressive disorder and 16 controls were scanned during resting state. A novel method based on ReHo was used to detect spontaneous hemodynamic responses across the whole brain.

RESULTSReHo in the left thalamus, left temporal lobe, left cerebellar posterior lobe, and the bilateral occipital lobe was found to be significantly decreased in depression compared to healthy controls in resting state of depression.

CONCLUSIONSAbnormal spontaneous activity exists in the left thalamus, left temporal lobe, left cerebellar posterior lobe, and the bilateral occipital lobe. And the ReHo may be a potential reference in understanding the distinct brain activity in resting state of depression.

Adult ; Case-Control Studies ; Depressive Disorder, Major ; pathology ; Female ; Hemodynamics ; Humans ; Magnetic Resonance Imaging ; methods ; Male ; Middle Aged ; Occipital Lobe ; pathology ; Temporal Lobe ; pathology ; Thalamus ; pathology ; Young Adult

OBJECTIVE: To examine the structural differences in regional gray matter density between a sample of major depressive disorder (MDD) and healthy controls, using the magnetic resonance imaging (MRI) to find the base of pathophysiologic mechanism in depression development. METHODS: A total of 38 MDD patients and 42 healthy subjects enrolled in the MRI scans. Voxel-based morphometry was used to test the difference in gray matter between the 2 groups. RESULTS: The MDD group showed significantly lower gray density than the healthy control group in the right middle frontal gyrus, right superior frontal gyrus, left inferior frontal gyrus and left superior frontal gyrus. However, the healthy control group showed significantly lower gray density than the MDD group in the right precuneus, left anterior central gyrus and right anterior cingutate. CONCLUSION Structural brain abnormalities in MDD patients may be the pathological bases for MDD development.
Adult ; Brain ; pathology ; Case-Control Studies ; Depressive Disorder, Major ; pathology ; Female ; Frontal Lobe ; pathology ; Humans ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging ; Male ; Young Adult