Appetite decrease is a common symptom in major depressive disorder (MDD). However, published research discussing the cognitive process to food stimuli in MDD patients with decreased appetite is lacking, as are objective indicators to assess their degree of appetitive loss. The current study evaluated the disparities in food-related cognition between healthy controls and MDD patients, explored the brain regions contributing to these changes, and evaluated the potential of event-related potentials for assessing appetite loss severity. A total of 149 subjects (healthy controls, n = 50; MDD patients with decreased appetite, n = 52; MDD patients without appetite change, n = 47) were included in this study. We used the Dimensional Anhedonia Rating Scale (DARS) to measure the degree of appetite decrease, and assessed their alterations in food-related cognition with the late positive potential (LPP). The standardized low-resolution brain electromagnetic tomography (sLORETA) method was used to explore the source activity of the LPP. We found the two groups of MDD patients did not differ in the disease severity, while those with appetite decrease got the lowest DARS food/drink score. And MDD patients with decreased appetite allocated fewer attentional resources to food stimuli with significantly lower LPP amplitude evoked by food in this group. Within depressed patients, LPP source activations were reduced in lingual gyrus, cuneus, inferior and middle occipital lobe, and inferior occipital gyrus in appetite-decreased patients, indicating altered occipital activity may be associated with attentional processing in MDD patients with decreased appetite. And correlation analysis revealed a moderate, positive correlation between LPP amplitude and DARS food/drink score. This study demonstrates the cognitive differences between MDD patients with appetite decrease and without appetite change, and provides a potential biomarker for evaluating the degree of appetite loss in MDD patients experiencing decreased appetite.

Gestational stress can exacerbate postpartum depression (PPD), for which treatment options remain limited. Environmental enrichment (EE) may be a therapeutic intervention for neuropsychiatric disorders, including depression, but the specific mechanisms by which EE might impact PPD remain unknown. Here we examined the behavioral, molecular, and cellular impact of EE in a stable PPD model in rats developed through maternal separation (MS). Maternal rats subjected to MS developed depression-like behavior and cognitive dysfunction together with evidence of significant neuroinflammation including microglia activation, neuronal apoptosis, and impaired synaptic plasticity. Expanding the duration of EE to throughout pregnancy and lactation, we observed an EE-associated reversal of MS-induced depressive phenotypes, inhibition of neuroinflammation and neuronal apoptosis, and improvement in synaptic plasticity in maternal rats. Thus, EE effectively alleviates neuroinflammation, neuronal apoptosis, damage to synaptic plasticity, and consequent depression-like behavior in mother rats experiencing MS-induced PPD, paving the way for new preventive and therapeutic strategies for PPD.

外泌体是一类内吞起源的细胞外囊泡,其携带源细胞的mRNA、非编码RNA、蛋白质、脂质、DNA和其他生物活性物质,并在许多生理过程中发挥作用.在大脑中,外泌体参与突触可塑性、神经元应激反应、细胞间通信和神经发生等过程.外泌体可以穿过血-脑脊液屏障,且含量随其分泌和受体细胞的不同而变化,可以作为神经功能障碍的生物标志物.中枢神经系统的细胞间通讯在大脑生长、发育和内稳态的维持方面发挥重要作用,研究神经源性外泌体可以为疾病诊断和治疗干预提供信息.本文综述神经源性外泌体在中枢神经系统中的作用以及在精神障碍的病理生理学机制.

Early adverse life events (EALs) increase susceptibility to depression and impair cognitive performance, but the physiological mechanisms are still unclear. The target of this article is to clarify the impact of adverse childhood experiences on emotional and cognitive performance from the perspective of the heart–brain axis. We used the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to test cognitive function and the Childhood Trauma Questionnaire (CTQ) to assess adverse childhood experiences. Heart rate variability (HRV) and electroencephalograms (EEG) were acquired at rest. We observed that subjects with depression had experienced more traumatic events during their childhood. Furthermore, they exhibited lower heart rate variability and higher power in the delta, theta, and alpha frequency bands. Moreover, heart rate variability partially mediated the association between childhood trauma exposure and depressive symptoms. Our findings suggested that adverse life events in childhood could influence the development of depression in adulthood, which might be linked to cardiac autonomic dysfunction and altered brain function.

Objectives: To investigate the changes in sleep quality, heart rate variability (HRV) and resting-state electroen-cephalogram (rsEEG) in patients with major depressive disorder (MDD), and to explore whether HRV and rsEEG may be served as more convenient tools to assess sleep quality in MDD patients.Method: We included a total of 91 subjects (46 healthy controls and 45 MDD patients) and compared their sleep quality, HRV and power spectra of rsEEG. Correlation analyses were conducted to discuss the relationship be-tween HRV and seven factors of PSQI. Multiple linear regression model was used to examine whether absolute band power could predict sleep quality in MDD patients.Results: We found higher PSQI scores and lower levels of HRV in depressive individuals compared with healthy controls. In MDD patients, sleep latency was negatively correlated with RMSSD and HF. Delta, theta, and alpha band power of rsEEG were higher in MDD patients. Regression analyses showed delta band power of TP8, as well as theta, alpha band power of AF3 predicts PSQI score of MDD patients.Conclusions: The findings of our study show that some aspects of sleep problems had negative correlations with parasympathetic activity and the regression model supports that the band power of rsEEG may be used as a potential indicator to evaluate the sleep quality in MDD patients. Significance: Cortical hyperarousal may be one of the reasons leading to poor sleep quality of MDD patients. And resting-state EEG can be used as a potential indicator for clinical assessment of MDD patients' sleep quality.

BackgroundsThe neural circuit mechanisms underlying depression remain unclear. Recently optogenetics has gradually gained recognition as a novel technique to regulate the activity of neurons with light stimulation. Scientists are now transferring their focus to the function of brain regions and neural circuits in the pathogenic progress of depression. Deciphering the circuitry mechanism of depressive-like behaviors may help us better understand the symptomatology of depression. However, few studies have summarized current progress on optogenetic researches into the neural circuit mechanisms of depressive-like behaviors.AimsThis review aimed to introduce fundamental characteristics and methodologies of optogenetics, as well as how this technique achieves specific neuronal control with spatial and temporal accuracy. We mainly summarized recent progress in neural circuit discoveries in depressive-like behaviors using optogenetics and exhibited the potential of optogenetics as a tool to investigate the mechanism and possible optimization underlying antidepressant treatment such as ketamine and deep brain stimulation.MethodsA systematic review of the literature published in English mainly from 2010 to the present in databases was performed. The selected literature is then categorized and summarized according to their neural circuits and depressive-like behaviors.ConclusionsMany important discoveries have been made utilizing optogenetics. These findings support optogenetics as a powerful and potential tool for studying depression. And our comprehension to the etiology of depression and other psychiatric disorders will also be more thorough with this rapidly developing technique in the near future.

Objective:To study the alterations of autonomic nervous function in patients with major depression disorder, and to observe the relationship of their gastric electrical activity with the duration of depression, its severity and gastrointestinal symptoms.Methods:Electrogastrography (EGG) was performed before and after a test meal ingestion in 38 depressive patients and 38 healthy control subjects.The severity of depression was evaluated through Hamilton depression scale(HAMD-21) and Beck depression inventory(BDI). Autonomic symptoms were recorded by autonomic nervous symptom-score(ANS-score).Results:The amount of tachygastria in patients with depression before and after test meal were (24.99±1.73)%, (23.66±1.86)% respectively, the amount of tachygastria in healthy controls before and after test meal were(19.80±1.65)%, (15.48±1.50)% respectively.There was a significant group effect ( F(1, 148)=15.6, P=0.0001)) between the two groups.The amount of tachygastria between the two groups before and after test meal were significant different (before test meal P=0.033, after test meal P=0.001). The main power in patients with depression before and after test meal were(21.20±2.71)dB, (20.90±2.66)dB respectively, the main power in healthy controls before and after test meal were(26.45±2.62)dB, (28.94±2.68)dB respectively.There was a significant group effect ( F(1, 148)=6.203, P=0.014) between the two groups.The main power between the two groups after test meal were significant different( P=0.037). The percentage of arrythmia after test meal in patients with gastrointestinal symptoms(5.17±0.56)% was higher than the patients without gastrointestinal symptoms(3.19±0.46)%, the differences were statistically significant( P=0.011). And there was a significant difference ( P=0.029)of the instability coefficient of main power after test meal between the patients with gastrointestinal symptoms (0.44±0.06) and the patients without gastrointestinal symptoms (0.27±0.05). Besides, there was a significant positive correlation between duration of depression and percentage of postprandial tachycardia( r=0.491, P=0.002). Conclusion:Patients with depression have autonomic nerve dysfunction and abnormal gastric motility, which is related to the duration of the disease and whether the patients are accompanied by gastrointestinal symptoms.Electrogastrography can also be used as an index to measure autonomic nervous function in patients with depression.

越来越多的临床证据表明,自主神经系统功能障碍在抑郁障碍中起着重要作用.抑郁障碍患者经常伴有各种躯体症状,主要包括心血管相关症状、失眠、胃肠道不适等;这些可能归因于自主神经系统不平衡,这也通常预示着抑郁程度更严重并且预后更差.本文将系统回顾抑郁障碍患者自主神经功能包括心率变异性及胃动力的改变情况.