Neural substrates of negativity bias in women with and without major depression

Inflammation-related abnormal dynamic brain activity correlates with cognitive impairment in first-episode, drug-naïve major depressive disorder

BACKGROUND

Cognitive impairment is common in major depressive disorder (MDD) and potentially linked to inflammation-induced alterations in brain function. However, the relationship between inflammation, dynamic brain activity, and cognitive impairment in MDD remains unclear.

METHODS

Fifty-seven first-episode, drug-naïve MDD patients and sixty healthy controls underwent fMRI scanning. Dynamic amplitude of low-frequency fluctuations (dALFF) and dynamic functional connectivity (dFC) were measured using the sliding window method. Plasma IL - 6 levels and cognitive function were assessed using enzyme-linked immunosorbent assay (ELISA) and the Repeated Battery for Assessment of Neuropsychological Status (RBANS), respectively.

RESULTS

MDD patients exhibited decreased dALFF in the bilateral inferior temporal gyrus (ITG), right inferior frontal gyrus, opercular part (IFGoperc), and bilateral middle occipital gyrus (MOG). Regions of dALFF associated with IL-6 included right ITG (r = -0.400/p = 0.003), left ITG (r = -0.381/p = 0.004), right IFGoperc (r = -0.342/p = 0.011), and right MOG (r = -0.327/p = 0.016). Furthermore, IL-6-related abnormal dALFF (including right ITG: r = 0.309/p = 0.023, left ITG: r = 0.276/p = 0.044) was associated with attention impairment. These associations were absent entirely in MDD patients without suicidal ideation. Additionally, IL-6 levels were correlated with dFC of specific brain regions.

LIMITATIONS

Small sample size and cross-sectional study design.

CONCLUSIONS

Inflammation-related dALFF was associated with attention impairment in MDD patients, with variations observed among MDD subgroups. These findings contribute to the understanding of the intricate relationship between inflammation, dynamic brain activity and cognitive impairments in MDD.

Influence of Internet Use on Happiness in China: Mediating Effects of Environmental Quality Perception and Moderating Role of Sense of Environmental Security

This study aims to comprehensively examine the effects of different types of Internet use and happiness while considering the mediating role of environmental quality perception and the moderating role of a sense of environmental security. Drawing on the uses and gratifications theory, negativity bias, and social cognitive theory, the study investigates the mediating role of environmental quality perception and the moderating role of environmental security in the above relationship. Using data from 3162 respondents in the 2021 Chinese Social Survey (CSS) and Structural Equation Modeling (SEM), the study finds that Internet use for information and educational purposes significantly enhances happiness, with environmental quality perception acting as a mediator. Moreover, a moderating effect of environmental security was observed in the relationship between Internet use for educational purposes and national environmental quality perception. Specifically, the interaction between study-related Internet use and the sense of environmental security significantly and positively predicted national environmental quality perception. These findings highlight the complex interaction between Internet use, environmental factors, and happiness, offering insights into policy interventions aimed at improving Internet access and environmental awareness to enhance public mental health outcomes in China.

The impact of Internet use and involvement on residents' attitudes to healthcare in China: A propensity score matching analysis

The recent surge in Internet growth has significantly altered how residents obtain health information and services, underscoring the need to investigate its impact on healthcare perceptions. However, current studies often fail to distinguish between Internet use and involvement, as well as the diverse range of healthcare stakeholders, resulting in incomplete and inconsistent understanding. To address this, this study utilized data from the 2018 China Family Panel Study (CFPS 2018), categorizing attitudes toward healthcare into three dimensions: doctor trust, satisfaction with medical institutions, and perception of systemic healthcare issues. Employing propensity score matching (PSM) to control for thirteen confounding variables, this study examined the Internet's impact on public attitudes toward healthcare among similar demographic, psychological, and health-related variables. Results revealed that both Internet use and involvement affect residents' attitudes toward healthcare to some extent, with involvement having a more pronounced effect. While Internet use increased the perception of systemic healthcare issues, Internet involvement enhanced doctor trust, yet reduced satisfaction with medical institutions and exaggerated the perception of systemic healthcare issues. These findings have significant theoretical and practical implications. They enhance the comprehension of diverse levels and purposes of Internet use, thereby advancing our knowledge of its multi-faced influence on public attitudes toward healthcare. Furthermore, they offer insights for medical institutions to improve service quality, assist Internet media in optimizing information delivery, and illuminate the implications for residents who effectively use the Internet to assess health information.

Estimating heterogeneous effects of internet use on environmental knowledge: Taking population heterogeneity into consideration

The recent decades have witnessed the rise of digital media; as an essential informal way of environmental education, the internet has become an important source where public acquire environmental knowledge. The current study investigates the heterogeneous treatment effects of internet use on environmental knowledge across members of the Chinese population. Based on a nationwide survey in China, the propensity score approach, a series of statistical techniques that are often used in the counterfactual framework to understand the causal relationship between an intervention and an outcome, is employed to adjust for population heterogeneity and to estimate heterogeneous treatment effects. The findings reveal highly significant positive associations between internet access/use and environmental knowledge. More importantly, this study shows that individuals who are least likely to access the internet benefit most from the knowledge returns to internet access and use, indicating a positive outlook for the potential of the digital media to narrow the environmental knowledge gap.

Aberrant brain entropy in posttraumatic stress disorder comorbid with major depressive disorder during the coronavirus disease 2019 pandemic

Aim

Previously, neuroimaging studies on comorbid Posttraumatic-Major depression disorder (PTSD-MDD) comorbidity found abnormalities in multiple brain regions among patients. Recent neuroimaging studies have revealed dynamic nature on human brain activity during resting state, and entropy as an indicator of dynamic regularity may provide a new perspective for studying abnormalities of brain function among PTSD-MDD patients. During the COVID-19 pandemic, there has been a significant increase in the number of patients with PTSD-MDD. We have decided to conduct research on resting-state brain functional activity of patients who developed PTSD-MDD during this period using entropy.

Methods

Thirty three patients with PTSD-MDD and 36 matched TCs were recruited. PTSD and depression symptoms were assessed using multiple clinical scales. All subjects underwent functional magnetic resonance imaging (fMRI) scans. And the brain entropy (BEN) maps were calculated using the BEN mapping toolbox. A two-sample t-test was used to compare the differences in the brain entropy between the PTSD-MDD comorbidity group and TC group. Furthermore, correlation analysis was conducted between the BEN changes in patients with PTSD-MDD and clinical scales.

Results

Compared to the TCs, PTSD-MDD patients had a reduced BEN in the right middle frontal orbital gyrus (R_MFOG), left putamen, and right inferior frontal gyrus, opercular part (R_IFOG). Furthermore, a higher BEN in the R_MFOG was related to higher CAPS and HAMD-24 scores in the patients with PTSD-MDD.

Conclusion

The results showed that the R_MFOG is a potential marker for showing the symptom severity of PTSD-MDD comorbidity. Consequently, PTSD-MDD may have reduced BEN in frontal and basal ganglia regions which are related to emotional dysregulation and cognitive deficits.

Does Internet Use Aggravate Public Distrust of Doctors? Evidence from China

The internet has exacerbated the spillover of medical information, and changes in the quantity, quality, and scope of information supply also affect public trust in doctors, which is of great significance to the construction of a harmonious physician–patient relationship. The objective of this study is to explore the relationship between internet use and residents’ trust in doctors using data from the China Family Panel Studies for 2018. The empirical investigation utilizes an endogenous switching regression model (ESR) to overcome the endogeneity bias. Our results indicate that internet use is negatively associated with residents’ trust in doctors (β = 0.07, p < 0.05). Specifically, the patient trust of internet users is nearly 7 percent less than that of non-internet users. Nevertheless, residents with higher dependence on traditional media such as television, newspapers, magazines and radio as an information channel show stronger patient trust. Finally, the results of the subsample analysis indicate a need to focus on older and less-educated residents, who are more vulnerable and more likely to be affected.

The influence of smartphone use on conservation agricultural practice: Evidence from the extension of rice-green manure rotation system in China

Although the impact of smartphone use has aroused widespread public interest, its effect on promoting conservation agriculture has never been revealed. We developed an integrated model to explain the scientific question of how smartphone use influence farmers' behavior of adopting a conservation agricultural practice-rice-green manure rotation system (RGRS). Based on a sample set containing 934 respondents, the causal chain was estimated by using the PLS-SEM with bootstrapping. The results showed that smartphone use directly contributes to farmers' RGRS adoption behavior, which provides new evidence for promoting the popularization of intelligent terminals in rural China. Another finding was that, perceived environmental degradation threats and environmental services of RGRS mediated the relationship between smartphone use and farmers' adoption behavior. This discovery provides us with enlightenment that knowledge related to environmental degradation and environmental services of RGRS can be imported into smartphone Apps commonly used by farmers to increase information exposure, raise environmental awareness and regulate farmer behavior. Besides, smartphone use reduced farmers' satisfaction with governmental support for RGRS, which adversely affected farmers' RGRS adoption behavior. Surprisingly, we found that the use of some traditional media helped to improve farmers' satisfaction. Therefore, policymakers should not ignore the role of traditional media while making use of smartphone-based information tools. These results can help policymakers better understand the contribution of smartphone use to conservation agriculture, and inform the development of supportive policies.

Altered Brain Function and Causal Connectivity Induced by Repetitive Transcranial Magnetic Stimulation Treatment for Major Depressive Disorder

Objective

Repetitive transcranial magnetic stimulation (rTMS) can effectively improve depression symptoms in patients with major depressive disorder (MDD); however, its mechanism of action remains obscure. This study explored the neuralimaging mechanisms of rTMS in improving depression symptoms in patients with MDD.

Methods

In this study, MDD patients with first-episode, drug-naive (n = 29) and healthy controls (n = 33) were enrolled. Depression symptoms before and after rTMS treatment were assessed using the Hamilton Depression Rating Scale (HAMD-17). Resting-state functional magnetic resonance imaging (rs-fMRI) data were collected both before and after the treatment. Changes in the brain function after the treatment were compared using the following two indices: the amplitude of the low-frequency fluctuation (ALFF) and regional homogeneity (ReHo), which are sensitive for evaluating spontaneous neuronal activity. The brain region with synchronous changes was selected as the seed point, and the differences in the causal connectivity between the seed point and whole brain before and after rTMS treatment were investigated via Granger causality analysis (GCA).

Results

Before treatment, patients with MDD had significantly lower ALFF in the left superior frontal gyrus (p < 0.01), higher ALFF in the left middle frontal gyrus and left precuneus (p < 0.01), and lower ReHo in the left middle frontal and left middle occipital gyri (p < 0.01) than the values observed in healthy controls. After the rTMS treatment, the ALFF was significantly increased in the left superior frontal gyrus (p < 0.01) and decreased in the left middle frontal gyrus and left precuneus (p < 0.01). Furthermore, ReHo was significantly increased in the left middle frontal and left middle occipital gyri (p < 0.01) in patients with MDD. Before treatment, GCA using the left middle frontal gyrus (the brain region with synchronous changes) as the seed point revealed a weak bidirectional causal connectivity between the middle and superior frontal gyri as well as a weak causal connectivity from the inferior temporal to the middle frontal gyri. After treatment, these causal connectivities were strengthened. Moreover, the causal connectivity from the inferior temporal gyrus to the middle frontal gyri negatively correlated with the total HAMD-17 score (r = −0.443, p = 0.021).

Conclusion

rTMS treatment not only improves the local neural activity in the middle frontal gyrus, superior frontal gyrus, and precuneus but also strengthens the bidirectional causal connectivity between the middle and superior frontal gyri and the causal connectivity from the inferior temporal to the middle frontal gyri. Changes in these neuroimaging indices may represent the neural mechanisms underlying rTMS treatment in MDD.

Clinical Trial Registration

This study was registered in the Chinese Clinical Trial Registry (Registration number: ChiCTR1800019761).

Abnormal neural activities in adults and youths with major depressive disorder during emotional processing: a meta-analysis

BACKGROUND

Abnormal neural activities during emotional processing have been found in both adults and youths with major depressive disorder. However, findings were inconsistent in each group and cannot be compared to each other.

METHODS

We first identified neuroimaging experiments that revealed abnormal neural activities during emotional processing in patients with major depressive disorder published from January 1997 to January 2019. Then we conducted voxel-wise meta-analyses on adult and youth patients separately and compared the two age groups using direct meta-comparison.

RESULTS

Fifty-four studies comprising 1141 patients and 1242 healthy controls were identified. Both adult and youth patients showed abnormal neural activities in anterior cingulate cortex, insula, superior and middle temporal gyrus, and occipital cortex compared to healthy controls. However, hyperactivities in the superior and middle frontal gyrus, amygdala, and hippocampus were only observed in adult patients, while hyperactivity in the striatum was only found in youth patients compared to controls. In addition, compared with youths, adult patients exhibited significantly greater abnormal activities in insula, middle frontal gyrus, and hippocampus, and significantly lower abnormal activities in middle temporal gyrus, middle occipital gyrus, lingual gyrus, and striatum.

CONCLUSIONS

The common alterations confirmed the negative processing bias in major depressive disorder. Both adult and youth patients were suggested to have disturbed emotional perception, appraisal, and reactivity. However, adult patients might be more subject to the impaired appraisal and reactivity processes, while youth patients were more subject to the impaired perception process. These findings help us understand the progressive pathophysiology of major depressive disorder.

Effects of negativity bias on amygdala and anterior cingulate cortex activity in short and long emotional stimulation paradigms

Recent functional studies have reported that amygdala and anterior cingulate cortex (ACC) dysfunction is a reproducible and good biomarker of major depressive disorder. When we use the activation of these regions as biomarkers of major depressive disorder, a short and simple stimulation paradigm could be preferable to reduce the burden on patients. However, negativity bias, which is the phenomenon by which negative stimuli are processed noticeably faster than positive stimuli, might affect the activation of these regions in the short and simple stimulation paradigm. Few studies have reported the relationship between the length of the stimulation paradigm and activation in the amygdala and ACC from the viewpoint of negativity bias. The purpose of this study was to assess the effects of negativity bias on the amygdala and ACC as a result of manipulating the stimulation paradigm (short-simple vs. long-complex conditions) on presenting pleasant and unpleasant pictures. Image analyses showed that the amygdala was activated during unpleasant picture presentation, regardless of the task length, but no activation was observed during pleasant picture presentation under the short-simple condition. The ACC was deactivated in both the short-simple and long-complex conditions. Region of interest analyses showed that the effect of negativity bias was prominent for the amygdala in the short-simple condition and for the ACC in the long-complex condition. In conclusion, the effects of negativity bias depend on neural regions, including the amygdala and ACC, and therefore, we should consider these effects while designing stimulation paradigms.

Ketamine Normalizes the Structural Alterations of Inferior Frontal Gyrus in Depression

Background

Ketamine is a novel fast-acting antidepressant. Acute ketamine treatment can reverse microstructure deficits and normalize functional alterations in the brain, but little is known about the impacts of ketamine on brain volumes in individuals with depression.

Methods

We used 3 T magnetic resonance imaging (MRI) and tensorbased morphological methods to investigate the regional volume differences for 29 healthy control (HC) subjects and 21 subjects with major depressive disorder (MDD), including 10 subjects with comorbid post-traumatic stress disorder (PTSD). All the subjects participated in MRI scanning before and 24 h post intravenous ketamine infusion. The effects of acute ketamine administration on HC, MDD, and MDD/PTSD groups were examined separately by whole-brain voxel-wise t-tests.

Results

Our data showed smaller volume of inferior frontal gyrus (IFG, opercular part) in MDD and MDD/PTSD subjects compared to HC, and a significant correlation between opercular IFG volume and depressive severity in MDD subjects only. Ketamine administration normalized the structural alterations of opercular IFG in both MDD and MDD/PTSD groups, and significantly improved depressive and PTSD symptoms. Twenty-four hours after a single ketamine infusion, there were two clusters of voxels with volume changes in MDD subjects, including significantly increased volumes of opercular IFG. No significant structural alterations were found in the MDD/PTSD or HC groups.

Conclusion

These findings provide direct evidence that acute ketamine administration can normalize structural alterations associated with depression and highlight the importance of IFG in the guidance of future therapeutic targets.

Internet use and individuals' environmental quality evaluation: Evidence from China

Identifying factors that influence the public's environmental quality perception is conducive to environmental protection and risk management. By employing data from the Chinese Social Survey (CGSS) and the ordinary least squares (OLS) method, the present study aims to explore the associations between Internet use and Chinese residents' environmental quality evaluation. The results show that, compared with non-netizens, netizens have a higher negative evaluation of environmental quality, which supports the negativity bias theory, namely, that netizens pay more attention to negative news related to environmental pollution on the Internet. Further study suggests that the impact of Internet use on environmental quality evaluation is heterogeneous across different categories of environmental issues and populations: Internet use has greater effects on risk perception of environmental issues that are closely related to residents' lives. In addition, Internet use has a greater negative impact on environmental quality evaluation for older people and rural residents. Finally, this paper utilizes a substitution variable method, propensity score matching (PSM) and quantile regression to conduct the robustness check.

Ecological micro-expression recognition characteristics of young adults with subthreshold depression

The micro-expression (ME) processing characteristics of patients with depression has been studied but has not been investigated in people with subthreshold depression. Based on this, by adopting the ecological MEs recognition paradigm, this study aimed to explore ME recognition in people with subthreshold depression. A 4 (background expression: happy, neutral, sad and fearful) × 4 (ME: happy, neutral, sad, and fearful) study was designed; two groups of participants (experimental group with subthreshold depression vs. healthy control group, 32 participants in each group) were asked to complete the ecological ME recognition task, and the corresponding accuracy (ACC) and reaction time (RT) were analyzed. Results: (1) Under different background conditions, recognizing happy MEs had the highest ACC and shortest RT. (2) There was no significant difference in the ACC and RT between experimental and control groups. (3)In different contexts, individuals with subthreshold depression tended to misjudge neutral, sad, and fearful MEs as happy, while neutral MEs were misjudged as sad and fearful. (4) The performance of individuals with subthreshold depression in the ecological ME recognition task were influenced by the type of ME; they showed highest ACC and shortest RT when recognizing happy MEs (vs. the other MEs). Conclusions: (1) The performance of individuals’ ecological ME recognition were influenced by the background expression, and this embodied the need for ecological ME recognition. (2) Individuals with subthreshold depression showed normal ecological ME recognition ability. (3) In terms of misjudgment, individuals with subthreshold depression showed both positive and negative bias, when completing the ecological ME recognition task. (4) Compared with the other MEs, happy MEs showed an advantage recognition effect for individuals with subthreshold depression who completed the ecological ME recognition task.

Intrinsic Functional Network Connectivity Is Associated With Clinical Symptoms and Cognition in Late-Life Depression

BACKGROUND

Late-life depression (LLD) has been associated with alterations in intrinsic functional networks, best characterized in the default mode network (DMN), cognitive control network (CCN), and salience network. However, these findings often derive from small samples, and it is not well understood how network findings relate to clinical and cognitive symptomatology.

METHODS

We studied 100 older adults (n = 79 with LLD, n = 21 nondepressed) and collected resting-state functional magnetic resonance imaging, clinical measures of depression, and performance on cognitive tests. We selected canonical network regions for each intrinsic functional network (DMN, CCN, and salience network) as seeds in seed-to-voxel analysis. We compared connectivity between the depressed and nondepressed groups and correlated connectivity with depression severity among depressed subjects. We then investigated whether the observed connectivity findings were associated with greater severity of common neuropsychiatric symptoms or poorer cognitive performance.

RESULTS

LLD was characterized by decreased DMN connectivity to the frontal pole, a CCN region (Wald χ²₁ = 22.33, p < .001). No significant group differences in connectivity were found for the CCN or salience network. However, in the LLD group, increased CCN connectivity was associated with increased depression severity (Wald χ²₁ > 20.14, p < .001), greater anhedonia (Wald χ²₁ = 7.02, p = .008) and fatigue (Wald χ²₁ = 6.31, p = .012), and poorer performance on tests of episodic memory (Wald χ²₁ > 4.65, p < .031), executive function (Wald χ²₁ = 7.18, p = .007), and working memory (Wald χ²₁ > 4.29, p < .038).

CONCLUSIONS

LLD is characterized by differences in DMN connectivity, while CCN connectivity is associated with LLD symptomology, including poorer performance in several cognitive domains.

Neural predictors of emotional inertia in daily life

Assessing emotional dynamics in the brain offers insight into the fundamental neural and psychological mechanisms underlying emotion. One such dynamic is emotional inertia-the influence of one's emotional state at one time point on one's emotional state at a subsequent time point. Emotion inertia reflects emotional rigidity and poor emotion regulation as evidenced by its relationship to depression and neuroticism. In this study, we assessed changes in cerebral blood flow (CBF) from before to after an emotional task and used these changes to predict stress, positive and negative emotional inertia in daily life events. Cerebral blood flow changes in the lateral prefrontal cortex (lPFC) predicted decreased non-specific emotional inertia, suggesting that the lPFC may feature a general inhibitory mechanism responsible for limiting the impact that an emotional state from one event has on the emotional state of a subsequent event. CBF changes in the ventromedial prefrontal cortex and lateral occipital cortex were associated with positive emotional inertia and negative/stress inertia, respectively. These data advance the blossoming literature on the temporal dynamics of emotion in the brain and on the use of neural indices to predict mental health-relevant behavior in daily life.

Comparison of Ecological Micro-Expression Recognition in Patients with Depression and Healthy Individuals

Previous studies have focused on the characteristics of ordinary facial expressions in patients with depression, and have not investigated the processing characteristics of ecological micro-expressions (MEs, i.e., MEs that presented in different background expressions) in these patients. Based on this, adopting the ecological MEs recognition paradigm, this study aimed to comparatively evaluate facial ME recognition in depressed and healthy individuals. The findings of the study are as follows: (1) background expression: the accuracy (ACC) in the neutral background condition tended to be higher than that in the fear background condition, and the reaction time (RT) in the neutral background condition was significantly longer than that in other backgrounds. The type of ME and its interaction with the type of background expression could affect participants’ ecological MEs recognition ACC and speed. Depression type: there was no significant difference between the ecological MEs recognition ACC of patients with depression and healthy individuals, but the patients’ RT was significantly longer than that of healthy individuals; and (2) patients with depression judged happy MEs that were presented against different backgrounds as neutral and judged neutral MEs that were presented against sad backgrounds as sad. The present study suggested the following: (1) ecological MEs recognition was influenced by background expressions. The ACC of happy MEs was the highest, of neutral ME moderate and of sadness and fear the lowest. The response to the happy MEs was significantly shorter than that of identifying other MEs. It is necessary to conduct research on ecological MEs recognition; (2) the speed of patients with depression in identifying ecological MEs was slower than of healthy individuals; indicating that the patients’ cognitive function was impaired; and (3) the patients with depression showed negative bias in the ecological MEs recognition task, reflecting the lack of happy ME recognition ability and the generalized identification of sad MEs in those patients.

Nicotine and networks: Potential for enhancement of mood and cognition in late-life depression

Late-life depression is characterized by both lower mood and poor cognitive performance, symptoms that often do not fully respond to current antidepressant medications. Nicotinic acetylcholine receptor (nAChR) agonists such as nicotine may serve as a novel therapeutic approach for this population. Both preclinical and preliminary clinical studies suggest that nAChR agonists can improve depressive behavior in animal models and improve mood in depressed individuals. Substantial literature also supports that nAChR agonists benefit cognitive performance, particularly in older populations. These potential benefits may be mediated by the effects of nAChR stimulation on neural network function and connectivity. Functional neuroimaging studies detail effects of nAChR agonists on the default mode network, central-executive network, and salience network that may oppose or reverse network changes seen in depression. We propose that, given the existent literature and the clinical presentation of late-life depression, nicotine or other nAChR agonists may have unique therapeutic benefits in this population and that clinical trials examining nicotine effects on mood, cognition, and network dynamics in late-life depression are justified.

THE POSITIVITY OFFSET THEORY OF ANHEDONIA IN SCHIZOPHRENIA

Prior studies have concluded that schizophrenia patients are not anhedonic because they do not report reduced experience of positive emotion to pleasant stimuli. The current study challenged this view by applying quantitative methods validated in the Evaluative Space Model of emotional experience to test the hypothesis that schizophrenia patients evidence a reduction in the normative "positivity offset" (i.e., the tendency to experience higher levels of positive than negative emotional output when stimulus input is absent or weak). Participants included 76 schizophrenia patients and 60 healthy controls who completed an emotional experience task that required reporting the level of positive emotion, negative emotion, and arousal to photographs. Results indicated that although schizophrenia patients evidenced intact capacity to experience positive emotion at high levels of stimulus input, they displayed a diminished positivity offset. Reductions in the positivity offset may underlie volitional disturbance, limiting approach behaviors toward novel stimuli in neutral environments.

The negativity bias predicts response rate to Behavioral Activation for depression

BACKGROUND AND OBJECTIVES

This treatment study investigated the extent to which asymmetric dimensions of affective responding, specifically the positivity offset and the negativity bias, at pretreatment altered the rate of response to Behavioral Activation treatment for depression.

METHOD

Forty-one depressed participants were enrolled into 16 weekly sessions of BA. An additional 36 lifetime healthy participants were evaluated prospectively for 16 weeks to compare affective responding between healthy and remitted patients at post-treatment. All participants were assessed at Weeks 0, 8 and 16 using repeated measures, involving a structured clinical interview for DSM-IV Axis I disorders, questionnaires, and a computerized task designed to measure affective responses to unpleasant, neutral, and pleasant images.

RESULTS

The negativity bias at pre-treatment predicted the rate of response to BA, while the positivity offset did not.

LIMITATIONS

Only one treatment condition was used in this study and untreated depressed participants were not enrolled, limiting our ability to compare the effect of BA.

CONCLUSIONS

Baseline negativity bias may serve as a signal for patients to engage in and benefit from the goal-directed BA strategies, thereby accelerating rate of response.

Altered neuronal spontaneous activity correlates with glutamate concentration in medial prefrontal cortex of major depressed females: An fMRI-MRS study

BACKGROUND

Major depressive disorder (MDD) is twice more prevalent in females than in males. Yet, there have only been a few studies on the functional brain activity in female MDD patients and the detailed mechanisms underlying their neurobiology merit further investigations. In the present work, we used combined fMRI-MRS methods to investigate the altered intrinsic neuronal activity and its association with neurotransmitter concentration in female MDD patients.

METHODS

The whole brain amplitude of low frequency fluctuation (ALFF) analysis using resting state functional magnetic resonance imaging (fMRI) was performed to explore the alteration of intrinsic neuronal signals in MDD females (n=11) compared with female healthy controls (n=11). With a specific interest in the medial prefrontal cortex (mPFC) area, we quantified the concentration of amino acid neurotransmitters including GABA ((r-aminobutyric acid)), Glu (Glutamate), and Glx (Glutamate + Glutamine) using (1)H-MRS technology. Moreover, we conducted Pearson correlation analysis between the ALFF value and neurotransmitter concentration to find out the functional-biochemical relation in mPFC area. The relationship between the metabolites concentration and MDD symptomatology was also examined through Spearman correlation analysis.

RESULTS

We found that the female MDD patients showed increased neuronal spontaneous activity in left medial prefrontal cortex (mPFC) and left middle frontal cortex, with decreased ALFF level in right putamen and right middle temporal cortex (p<0.01, Alphasim corrected). The ALFF in mPFC was shown positively correlated with Glu concentration in female MDD patients (r=0.67, p=0.023). The Glu concentration in mPFC was positively correlated with patients HAMA scores (r=0.641, p=0.033).

LIMITATIONS

The relatively small sample size, metabolite information acquired only in mPFC and not all patients were unmedicated are the major limitations of our study.

CONCLUSIONS

Using combined fMRI-MRS methods, we found increased spontaneous neuronal activity was correlated with Glu concentration in mPFC of female MDD patients. Other regions including left middle frontal gyrus, right putamen and middle temporal gyrus also showed altered spontaneous neuronal activities. The abnormal intrinsic neuronal activities in fronto-cortical regions shed light on the pathogenesis underlying MDD females. The multimodal resting-state neuroimaging technique served as a useful tool for functional-biochemical investigation of MDD pathophysiology.

Twice the negativity bias and half the positivity offset: Evaluative responses to emotional information in depression

BACKGROUND AND OBJECTIVES

Humans have the dual capacity to assign a slightly pleasant valence to neutral stimuli (the positivity offset) to encourage approach behaviors, as well as to assign a higher negative valence to unpleasant images relative to the positive valence to equally arousing and extreme pleasant images (the negativity bias) to facilitate defensive strategies. We conducted an experimental psychopathology study to examine the extent to which the negativity bias and the positivity offset differ in participants with and without major depression..

METHOD

Forty-one depressed and thirty-six healthy participants were evaluated using a structured clinical interview for DSM-IV Axis I disorders, questionnaires, and a computerized task designed to measure implicit affective responses to unpleasant, neutral, and pleasant stimuli.

RESULTS

The negativity bias was significantly higher and the positivity offset was significantly lower in depressed relative to healthy participants..

LIMITATIONS

Entry criteria enrolling medication-free participants with minimal DSM-IV comorbidity may limit generalizability of the findings.

CONCLUSIONS

This study advances our understanding of the positive and negative valence systems in depression, highlighting the irregularities in the positive valence system..