Neuropathic pain, mood, and stress-related disorders: A literature review of comorbidity and co-pathogenesis.

Neuropathic pain can be caused by multiple factors, and its prevalence can reach 10% of the global population. It is becoming increasingly evident that limited or short-lasting response to treatments for neuropathic pain is associated with psychological factors, which include psychiatric comorbidities known to affect quality of life. It is estimated that 60% of patients with neuropathic pain also experience depression, anxiety, and stress symptoms. Altered mood, including stress, can be a consequence of several painful conditions but can also favor pain chronicization when preexisting. Despite the apparent tight connection between clinical pain and mood/stress disorders, the exact physiological mechanisms remain unclear. This review aims to provide an overview of state-of-the-art research on the mechanisms of pain related to the pathophysiology of depression, anxiety, and stress disorders.

The VLPFC-Engaged Voluntary Emotion Regulation: Combined TMS-fMRI Evidence for the Neural Circuit of Cognitive Reappraisal.

A clear understanding of the neural circuit underlying emotion regulation (ER) is important for both basic and translational research. However, a lack of evidence based on combined neuroimaging and neuromodulation techniques calls into question (1) whether the change of prefrontal-subcortical activity intrinsically and causally contributes to the ER effect; and (2) whether the prefrontal control system directly modulates the subcortical affective system. Accordingly, we combined fMRI recordings with transcranial magnetic stimulation (TMS) to map the causal connections between the PFC and subcortical affective structures (amygdala and insula). A total of 117 human adult participants (57 males and 60 females) were included in the study. The results revealed that TMS-induced ventrolateral PFC (VLPFC) facilitation led to enhanced activity in the VLPFC and ventromedial PFC (VMPFC) as well as attenuated activity in the amygdala and insula during reappraisal but not during nonreappraisal (i.e., baseline). Moreover, the activated VLPFC intensified the prefrontal-subcortical couplings via the VMPFC during reappraisal only. This study provides combined TMS-fMRI evidence that downregulating negative emotion involves the prefrontal control system suppressing the subcortical affective system, with the VMPFC serving as a crucial hub within the VLPFC-subcortical network, suggesting an indirect pathway model of the ER circuit. Our findings outline potential protocols for improving ER ability by intensifying the VLPFC-VMPFC coupling in patients with mood and anxiety disorders.SIGNIFICANCE STATEMENT Using fMRI to examine the TMS effect, we uncovered that the opposite neural changes in prefrontal (enhanced) and subcortical (attenuated) regions are not a byproduct of emotion regulation (ER); instead, this prefrontal-subcortical activity per se causally contributes to the ER effect. Furthermore, using TMS to amplify the neural changes within the ER circuit, the "bridge" role of the VMPFC is highlighted under the reappraisal versus nonreappraisal contrast. This "perturb-and-measure" approach overcomes the correlational nature of fMRI data, helping us to identify brain regions that causally support reappraisal (the VLPFC and VMPFC) and those that are modulated by reappraisal (the amygdala and insula). The uncovered ER circuit is important for understanding the neural systems underlying reappraisal and valuable for translational research.

Role of Nociceptin/Orphanin FQ-NOP Receptor System in the Regulation of Stress-Related Disorders.

Nociceptin/orphanin FQ (N/OFQ) is a 17-residue neuropeptide that binds the nociceptin opioid-like receptor (NOP). N/OFQ exhibits nucleotidic and aminoacidics sequence homology with the precursors of other opioid neuropeptides but it does not activate either MOP, KOP or DOP receptors. Furthermore, opioid neuropeptides do not activate the NOP receptor. Generally, activation of N/OFQ system exerts anti-opioids effects, for instance toward opioid-induced reward and analgesia. The NOP receptor is widely expressed throughout the brain, whereas N/OFQ localization is confined to brain nuclei that are involved in stress response such as amygdala, BNST and hypothalamus. Decades of studies have delineated the biological role of this system demonstrating its involvement in significant physiological processes such as pain, learning and memory, anxiety, depression, feeding, drug and alcohol dependence. This review discusses the role of this peptidergic system in the modulation of stress and stress-associated psychiatric disorders in particular drug addiction, mood, anxiety and food-related associated-disorders. Emerging preclinical evidence suggests that both NOP agonists and antagonists may represent a effective therapeutic approaches for substances use disorder. Moreover, the current literature suggests that NOP antagonists can be useful to treat depression and feeding-related diseases, such as obesity and binge eating behavior, whereas the activation of NOP receptor by agonists could be a promising tool for anxiety.

Convergence, preliminary findings and future directions across the four human connectome projects investigating mood and anxiety disorders.

In this paper we provide an overview of the rationale, methods, and preliminary results of the four Connectome Studies Related to Human Disease investigating mood and anxiety disorders. The first study, "Dimensional connectomics of anxious misery" (HCP-DAM), characterizes brain-symptom relations of a transdiagnostic sample of anxious misery disorders. The second study, "Human connectome Project for disordered emotional states" (HCP-DES), tests a hypothesis-driven model of brain circuit dysfunction in a sample of untreated young adults with symptoms of depression and anxiety. The third study, "Perturbation of the treatment resistant depression connectome by fast-acting therapies" (HCP-MDD), quantifies alterations of the structural and functional connectome as a result of three fast-acting interventions: electroconvulsive therapy, serial ketamine therapy, and total sleep deprivation. Finally, the fourth study, "Connectomes related to anxiety and depression in adolescents" (HCP-ADA), investigates developmental trajectories of subtypes of anxiety and depression in adolescence. The four projects use comparable and standardized Human Connectome Project magnetic resonance imaging (MRI) protocols, including structural MRI, diffusion-weighted MRI, and both task and resting state functional MRI. All four projects also conducted comprehensive and convergent clinical and neuropsychological assessments, including (but not limited to) demographic information, clinical diagnoses, symptoms of mood and anxiety disorders, negative and positive affect, cognitive function, and exposure to early life stress. The first round of analyses conducted in the four projects offered novel methods to investigate relations between functional connectomes and self-reports in large datasets, identified new functional correlates of symptoms of mood and anxiety disorders, characterized the trajectory of connectome-symptom profiles over time, and quantified the impact of novel treatments on aberrant connectivity. Taken together, the data obtained and reported by the four Connectome Studies Related to Human Disease investigating mood and anxiety disorders describe a rich constellation of convergent biological, clinical, and behavioral phenotypes that span the peak ages for the onset of emotional disorders. These data are being prepared for open sharing with the scientific community following screens for quality by the Connectome Coordinating Facility (CCF). The CCF also plans to release data from all projects that have been pre-processed using identical state-of-the-art pipelines. The resultant dataset will give researchers the opportunity to pool complementary data across the four projects to study circuit dysfunctions that may underlie mood and anxiety disorders, to map cohesive relations among circuits and symptoms, and to probe how these relations change as a function of age and acute interventions. This large and combined dataset may also be ideal for using data-driven analytic approaches to inform neurobiological targets for future clinical trials and interventions focused on clinical or behavioral outcomes.

The Translational Potential of Non-coding RNAs and Multimodal MRI Data Sets as Diagnostic and Differential Diagnostic Biomarkers for Mood Disorders.

Major Depressive Disorder (MDD) and Bipolar Disorder (BD) have a high prevalence and detrimental socio-economic consequences for the patients and the community. Furthermore, the depressive symptomatology of both disorders is essentially identical, thus rendering the clinical differential diagnosis between the two significantly more difficult considering the concomitant lack of objective biomarkers. Mood disorders are multifactorial disorders the pathophysiology of which includes genetic, epigenetic, neurobiological, neuroimmunological, structural and functional brain alterations, etc. Aberrant genetic variants as well as changed differential expression of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) have been implicated in the pathophysiology of MDD and BD. MiRNAs as well as lncRNAs have regulatory and modulating functions on protein-- coding gene expression thus influencing the remodeling of the architecture, neurotransmission, immunomodulation, etc. in the Central Nervous System (CNS) which are essential in the development of psychiatric disorders including MDD and BD. Moreover, both shared and distinct structural, connectivity, task-related and metabolic features have been observed via functional magnetic resonance imaging and magnetic resonance spectroscopy, suggesting the possibility of a dimensional continuum between the two disorders instead of a categorical differentiation. Aberrant connectivity within and between the Default Mode Network, the Salience Network, Executive Network, etc. as well as dysfunctional emotion, cognitive and executive processing have been associated with mood disorders. Therefore, the aim of this review is to explore a more multidimensional framework in the scientific research of mood disorders, including epigenetic and neuroimaging data in order to shape an outline for their translational capacity in clinical practice.

Verification of a multi-function closed maze for the detection of affective disorder and spatial cognitive impairment in post-weaning socially isolated rats.

OBJECTIVE: To verify a behavioral device for the detection of learning, memory, and affective disorders in post-weaning socially isolated rats. METHODS: We tested the behavioral changes in post-weaning socially isolated rats using a multi-function closed maze, a self-developed behavioral device, against the classical mood disorder detection method, the IntelliCage system and Morris water maze. RESULTS: In the multifunctional closed maze experiment, the spatial learning and memory ability of post-weaning socially isolated rats decreased, which was consistent with the results of the water maze and IntelliCage system. Furthermore, the behavioral changes in the post-weaning socially isolated rats in the multi-function closed maze test were the same as those of the forced swimming and open field tests, indicating that the rats had depression- and anxiety-like behaviors. CONCLUSION: A multi-function closed maze can detect emotional changes, spatial learning ability, and memory ability.

Hippocampal and rostral anterior cingulate blood flow is associated with affective symptoms in chronic traumatic brain injury.

OBJECTIVE: The purpose of this study was to assess cerebral blood flow (CBF) and its association with self-reported symptoms in chronic traumatic brain injury (TBI). PARTICIPANTS: Sixteen participants with mild to severe TBI and persistent self-reported neurological symptoms, 6 to 72 months post-injury were included. For comparison, 16 age- and gender-matched healthy normal control participants were also included. MAIN MEASURES: Regional CBF and brain volume were assessed using pseudo-continuous Arterial Spin Labeling (PCASL) and T1-weighted data respectively. Cognitive function and self-reported symptoms were assessed in TBI participants using the national institutes of health (NIH) Toolbox Cognition Battery and Patient-Reported Outcome Measurement Information System respectively. Associations between CBF and cognitive function, symptoms were assessed. RESULTS: Global CBF and regional brain volumes were similar between groups, but region of interest (ROI) analysis revealed lower CBF bilaterally in the thalamus, hippocampus, left caudate, and left amygdala in the TBI group. Voxel-wise analysis revealed that CBF in the hippocampus, parahippocampus, rostral anterior cingulate, inferior frontal gyrus, and other temporal regions were negatively associated with self-reported anger, anxiety, and depression symptoms. Furthermore, region of interest (ROI) analysis revealed that hippocampal and rostral anterior cingulate CBF were negatively associated with symptoms of fatigue, anxiety, depression, and sleep issues. CONCLUSION: Regional CBF deficit was observed in the group with chronic TBI compared to the normal control (NC) group despite similar volume of cerebral structures. The observed negative correlation between regional CBF and affective symptoms suggests that CBF-targeted intervention may potentially improve affective symptoms and quality of life after TBI, which needs to be assessed in future studies.

Impact of Confinement in Patients under Long-Term Noninvasive Ventilation during the First Wave of the SARS-CoV-2 Pandemic: A Remarkable Resilience.

BACKGROUND: During the first wave of the SARS-CoV-2 pandemic in Switzerland, confinement was imposed to limit transmission and protect vulnerable persons. These measures may have had a negative impact on perceived quality of care and symptoms in patients with chronic disorders. OBJECTIVES: To determine whether patients under long-term home noninvasive ventilation (LTHNIV) for chronic respiratory failure (CRF) were negatively affected by the 56-day confinement (March-April 2020). METHODS: A questionnaire-based survey exploring mood disturbances (HAD), symptom scores related to NIV (S3-NIV), and perception of health-care providers during confinement was sent to all patients under LTHNIV followed up by our center. Symptom scores and data obtained by ventilator software were compared between confinement and the 56 days prior to confinement. RESULTS: Of a total of 100 eligible patients, 66 were included (median age: 66 years [IQR: 53-74]): 35 (53%) with restrictive lung disorders, 20 (30%) with OHS or SRBD, and 11 (17%) with COPD or overlap syndrome. Prevalence of anxiety (n = 7; 11%) and depressive (n = 2; 3%) disorders was remarkably low. Symptom scores were slightly higher during confinement although this difference was not clinically relevant. Technical data regarding ventilation, including compliance, did not change. Patients complained of isolation and lack of social contact. They felt supported by their relatives and caregivers but complained of the lack of regular contact and information by health-care professionals. CONCLUSIONS: Patients under LTHNIV for CRF showed a remarkable resilience during the SARS-CoV-2 confinement period. Comments provided may be helpful for managing similar future health-care crises.

Irritability in Mood Disorders: Neurobiological Underpinnings and Implications for Pharmacological Intervention.

Feeling irritable is a common experience, both in health and disease. In the context of psychiatric illnesses, it is a transdiagnostic phenomenon that features across all ages, and often causes significant distress and impairment. In mood disorders, irritability is near ubiquitous and plays a central role in diagnosis and yet, despite its prevalence, it remains poorly understood. A neurobiological model of irritability posits that, in children and adolescents, it is consequent upon deficits in reward and threat processing, involving regions such as the amygdala and frontal cortices. In comparison, in adults with mood disorders, the few studies that have been conducted implicate the amygdala, orbitofrontal cortices, and hypothalamus; however, the patterns of activity in these areas are at variance with the findings in youth. These age-related differences seem to extend to the neurochemistry of irritability, with links between increased monoamine transmission and irritability evident in adults, but aberrant levels of, and responses to, dopamine in youth. Presently, there are no specific treatments that have significant efficacy in reducing irritability in mood disorders. However, treatments that hold some potential and warrant further exploration include agents that act on serotonergic and dopaminergic systems, especially as irritability may serve as a prognostic indicator for overall clinical responsiveness to specific medications. Therefore, for understanding and treatment of irritability to advance meaningfully, it is imperative that an accurate definition and means of measuring irritability are developed. To achieve this, it is necessary that the subjective experience of irritability, both in health and illness, is better understood. These insights will inform an accurate, comprehensive, and valid interrogation of the qualities of irritability in health and illness, and allow not only a clinical appreciation of the phenomenon, but also a deeper understanding of its important role within the development and manifestation of mood disorders.

Clinical Phenotypes of Behavioral Variant Frontotemporal Dementia by Age at Onset.

BACKGROUND: Behavioral variant frontotemporal dementia (bvFTD) is generally considered a young-onset dementia, although age at onset is highly variable. While several studies indicate clinical differences regarding age at onset, no biomarker validated cohort studies with updated clinical criteria have been performed. OBJECTIVE: We aimed to examine behavior, cognition, and mortality over the full age spectrum in a cohort of bvFTD patients with neuroimaging, genetic, or histopathological confirmation and exclusion of positive Alzheimer's disease biomarkers or severe cerebrovascular damage. METHODS: In total, 315 patients with a clinical diagnosis of probable or definite bvFTD were included from the Amsterdam Dementia Cohort and grouped into quartiles by age-at-diagnosis. Neuropsychiatric symptoms and cognitive functioning were assessed with the neuropsychiatric inventory, the geriatric depression scale and a neuropsychological test battery. Data on mortality was obtained from the Dutch municipal register. Associations between age-at-diagnosis and clinical features and mortality risk were examined. RESULTS: Age-at-diagnosis ranged from 26 to 85 years and established quartiles with mean ages of 52±6, 61±2, 66±2, and 74±3 years. In the total sample, 44.4%exceeded an age of 65 years at time of diagnosis. Earlier age-at-diagnosis was associated with more severe behavioral symptoms, while later age-at-diagnosis was associated with more severe memory impairment. Unexpectedly, mortality risk was not associated with age-at-diagnosis. CONCLUSION: In bvFTD, symptom profile is associated with age-at-diagnosis. This should be taken into account with regard to diagnostics, patient management, and trial design. Additionally, based on our sample, the prevalence of late-onset bvFTD is higher than generally thought.

RNA therapeutics for mood disorders: current evidence toward clinical trials.

INTRODUCTION: Mood disorders are severe yet frequent psychiatric disorders worldwide, comprising major depressive disorder (MDD) and bipolar disorders (BD). Their treatment remains poorly effective. Recently, growing evidence for epigenetic mechanisms has emerged. Consequently, a great interest in a novel pharmacological class arose: RNA therapeutics. AREAS COVERED: We conducted a systematic review of RNA therapeutics -antisense oligonucleotides (ASOs), small interfering RNAs (siRNAs), short hairpin RNAs (shRNAs), and micro-RNA (miRNA) therapeutics- for the treatment of mood disorders studied in pre-clinical animal models listed in PubMed, in clinical trials registered in ClinicalTrials.gov and available on the market by combining literature search and Food and Drug Administration and European Medicine Agency online databases. Eighteen pre-clinical studies investigated the antidepressant effects of RNA therapeutics. However, even though there is an increasing number of marketing authorizations and clinical trials for the past twenty years, no RNA therapeutic has reached the clinical development pipeline for the treatment of psychiatric disorders yet. EXPERT OPINION: Several promising RNA therapeutics have been tested in pre-clinical studies for MDD, whereas no molecule has been developed for BD. There are several issues to address before reaching clinical development and new challenges include stratifying patient population and predicting therapeutic response.

Thyroid Function and Mood Disorders: A Mendelian Randomization Study.

Background: Observational studies suggest that even minor variations in thyroid function are associated with the risk of mood disorders, including major depressive disorder (MDD) and bipolar disorder (BD). However, it is unknown whether these associations are causal or not. We used a Mendelian randomization (MR) approach to investigate causal effects of minor variations in thyrotropin (TSH) and free thyroxine (fT4) levels on MDD and BD risk. Materials and Methods: We performed two-sample MR analyses using data from the largest publicly available genome-wide association studies on normal-range TSH (n = 54,288) and fT4 (n = 49,269) levels, MDD (170,756 cases, 329,443 controls) and BD (20,352 cases, 31,358 controls). Secondary MR analyses investigated the effects of TSH and fT4 levels on specific MDD and BD subtypes. Reverse MR was also performed to assess the effects of MDD and BD on TSH and fT4 levels. Results: There were no associations between genetically predicted TSH and fT4 levels and MDD risk, nor MDD subtypes and minor depressive symptoms. A one standard deviation increase in fT4 levels was nominally associated with an 11% decrease in the overall BD risk (odds ratio [OR] = 0.89, 95% confidence interval [CI] = 0.80-0.98, p = 0.022) and a 13% decrease in the BD type 1 risk (OR = 0.87, CI = 0.75-1.00, p = 0.047). In the reverse direction, genetic predisposition to MDD and BD was not associated with TSH nor fT4 levels. Conclusions: Variations in normal-range TSH and fT4 levels have no effects on the risk of MDD and its subtypes, and neither on minor depressive symptoms. This indicates that depressive symptoms should not be attributed to minor variations in thyroid function. Borderline associations with BD and BD type 1 risks suggest that further clinical studies should investigate the effect of thyroid hormone treatment in BD.

Novel Glutamatergic Modulators for the Treatment of Mood Disorders: Current Status.

The efficacy of standard antidepressants is limited for many patients with mood disorders such as major depressive disorder (MDD) and bipolar depression, underscoring the urgent need to develop novel therapeutics. Both clinical and preclinical studies have implicated glutamatergic system dysfunction in the pathophysiology of mood disorders. In particular, rapid reductions in depressive symptoms have been observed in response to subanesthetic doses of the glutamatergic modulator racemic (R,S)-ketamine in individuals with mood disorders. These results have prompted investigation into other glutamatergic modulators for depression, both as monotherapy and adjunctively. Several glutamate receptor-modulating agents have been tested in proof-of-concept studies for mood disorders. This manuscript gives a brief overview of the glutamate system and its relevance to rapid antidepressant response and discusses the existing clinical evidence for glutamate receptor-modulating agents, including (1) broad glutamatergic modulators ((R,S)-ketamine, esketamine, (R)-ketamine, (2R,6R)-hydroxynorketamine [HNK], dextromethorphan, Nuedexta [a combination of dextromethorphan and quinidine], deudextromethorphan [AVP-786], axsome [AXS-05], dextromethadone [REL-1017], nitrous oxide, AZD6765, CLE100, AGN-241751); (2) glycine site modulators (D-cycloserine [DCS], NRX-101, rapastinel [GLYX-13], apimostinel [NRX-1074], sarcosine, 4-chlorokynurenine [4-Cl-KYN/AV-101]); (3) subunit (NR2B)-specific N-methyl-D-aspartate (NMDA) receptor antagonists (eliprodil [EVT-101], traxoprodil [CP-101,606], rislenemdaz [MK-0657/CERC-301]); (4) metabotropic glutamate receptor (mGluR) modulators (basimglurant, AZD2066, RG1578, TS-161); and (5) mammalian target of rapamycin complex 1 (mTORC1) activators (NV-5138). Many of these agents are still in the preliminary stages of development. Furthermore, to date, most have demonstrated relatively modest effects compared with (R,S)-ketamine and esketamine, though some have shown more favorable characteristics. Of these novel agents, the most promising, and the ones for which the most evidence exists, appear to be those targeting ionotropic glutamate receptors.

The Role of Hypothalamic Inflammation in Diet-Induced Obesity and Its Association with Cognitive and Mood Disorders.

Obesity is often associated with cognitive and mood disorders. Recent evidence suggests that obesity may cause hypothalamic inflammation. Our aim was to investigate the hypothesis that there is a causal link between obesity-induced hypothalamic inflammation and cognitive and mood disorders. Inflammation may influence hypothalamic inter-connections with regions important for cognition and mood, while it may cause dysregulation of the Hypothalamic-Pituitary-Adrenal (HPA) axis and influence monoaminergic systems. Exercise, healthy diet, and glucagon-like peptide receptor agonists, which can reduce hypothalamic inflammation in obese models, could improve the deleterious effects on cognition and mood.

Gender-specific approach in psychiatric diseases: Because sex matters.

In both animals and human beings, males and females differ in their genetic background and hormonally driven behaviour and show sex-related differences in brain activity and response to internal and external stimuli. Gender-specific medicine has been a neglected dimension of medicine for long time, and only in the last three decades it is receiving the due scientific and clinical attention. Research has recently begun to identify factors that could provide a neurobiological basis for gender-based differences in health and disease and to point to gonadal hormones as important determinants of male-female differences. Animal studies have been of great help in understanding factors contributing to sex-dependent differences and sex hormones action. Here we review and discuss evidence provided by clinical and animal studies in the last two decades showing gender (in humans) and sex (in animals) differences in selected psychiatric disorders, namely eating disorders (anorexia nervosa, bulimia nervosa, binge eating disorder), schizophrenia, mood disorders (anxiety, depression, obsessive-compulsive disorder) and neurodevelopmental disorders (autism spectrum disorders, attention-deficit/hyperactivity disorder).

Induced affective states do not modulate effort avoidance.

Recent research reveals that when faced with alternative lines of action, humans tend to choose the less cognitively demanding one, suggesting that cognitive control is intrinsically registered as costly. This idea is further supported by studies showing that the exertion of cognitive control evokes negative affective states. Despite extensive evidence for mood-induced modulations on control abilities, the impact of affective states on the avoidance of cognitive demand is still unknown. Across two well-powered experiments, we tested the hypothesis that negative affective states would increase the avoidance of cognitively demanding tasks. Contrary to our expectations, induced affective states did not modulate the avoidance of demand, despite having an effect on task performance and subjective experience. Altogether, our results indicate that there are limits to the effect of affective signals on cognitive control and that such interaction might depend on specific affective and control settings.

Reduced frontostriatal response to expected value and reward prediction error in remitted monozygotic twins with mood disorders and their unaffected high-risk co-twins.

BACKGROUND: Depressive episodes experienced in unipolar (UD) and bipolar (BD) disorders are characterized by anhedonia and have been associated with abnormalities in reward processes related to reward valuation and error prediction. It remains however unclear whether these deficits are associated with familial vulnerability to mood disorders. METHODS: In a functional magnetic resonance imaging study, we evaluated differences in the expected value (EV) and reward prediction error (RPE) signals in ventral striatum (VS) and prefrontal cortex between three groups of monozygotic twins: affected twins in remission for either UD or BD (n = 53), their high-risk unaffected co-twins (n = 34), and low-risk twins with no family history of mood disorders (n = 25). RESULTS: Compared to low-risk twins, affected twins showed lower EV signal bilaterally in the frontal poles and lower RPE signal bilaterally in the VS, left frontal pole and superior frontal gyrus. The high-risk group did not show a significant change in the EV or RPE signals in frontostriatal regions, yet both reward signals were consistently lower compared with low-risk twins in all regions where the affected twins showed significant reductions. CONCLUSION: Our findings strengthen the notion that reduced valuation of expected rewards and reduced error-dependent reward learning may underpin core symptom of depression such as loss of interest in rewarding activities. The trend reduction in reward-related signals in unaffected co-twins warrants further investigation of this effect in larger samples and prospective follow-up to confirm possible association with increased familial vulnerability to mood disorders.

Affective states influence emotion perception: evidence for emotional egocentricity.

Research in social cognition has shown that our own emotional experiences are an important source of information to understand what other people are feeling. The current study investigated whether individuals project their own affective states when reading other's emotional expressions. We used brief autobiographical recall and audiovisual stimuli to induce happy, neutral and sad transient states. After each emotion induction, participants made emotion judgments about ambiguous faces displaying a mixture of happiness and sadness. Using an adaptive psychophysics procedure, we estimated the tendency to perceive the faces as happy under each of the induced affective states. Results demonstrate the occurrence of egocentric projections, such that faces were more likely judged as happy when participants reported being happy as compared to when they were sad. Moreover, the degree of emotional egocentricity was associated with individual differences in perspective-taking, with smaller biases being observed in individuals with higher disposition to take the perspective of others. Our findings extend previous literature on emotional egocentricity by showing that self-projection occurs when we make emotion attributions based on the other's emotional expressions, and supports the notion that perspective-taking tendencies play a role in the ability to understand the other's affective states.

Retinal structural changes in mood disorders: The optical coherence tomography to better understand physiopathology?

BACKGROUND: Mood disorders are particularly common, disabling conditions. Diagnosis can be difficult as it may involve different pathophysiological assumptions. This could explain why such disorders are resistant to treatment. The retina is part of the central nervous system and shares a common embryonic origin with the brain. Optical coherence tomography (OCT) is an imaging technique for analysing the different layers of the retina. We reviewed studies that examined the retina with OCT in mood disorders. METHODS: We conducted Pubmed search and additional manual research based on the bibliography in each of selected articles. We found and analysed 11 articles relevant to our subject. RESULTS: This literature review confirms that it is possible to use OCT to detect neurodegeneration and neuroinflammation in mood disorders. Their impact is thought to depend on the duration and severity of the disease, and whether it is in acute or chronic stage. The differences seen in studies dealing with depression and those looking at bipolar disorder may reflect the particular characteristics of each disorder. A number of OCT parameters can be proposed as biomarkers of active or chronic inflammation and neurodegeneration. Markers of predisposition to an at-risk mental state are also suggested. LIMITATIONS: The main limitation is selection bias, studies including more varied population would help to confirm and precise these results. CONCLUSION: OCT is thus a particularly promising tool for evaluating some of the etiopathogenetic mechanisms involved in mood disorders. The combination with other approaches could help to find more specific biomarkers.