Subcortical and ventral prefrontal cortical neural responses to facial expressions distinguish patients with bipolar disorder and major depression

Altered amygdala subregion-related circuits in treatment-naïve post-traumatic stress disorder comorbid with major depressive disorder

Individuals with both post-traumatic stress disorder and major depressive disorder (PTSD+MDD) often show greater social and occupational impairment and poorer treatment response than individuals with PTSD alone. Increasing evidence reveals that the amygdala, a brain region implicated in the pathophysiology of both of these conditions, is a complex of structurally and functionally heterogeneous nuclei. Quantifying the functional connectivity of two key amygdala subregions, the basolateral (BLA) and centromedial (CMA), in PTSD+MDD and PTSD-alone could advance our understanding of the neurocircuitry of these conditions. 18 patients with PTSD+MDD, 28 with PTSD-alone, and 50 trauma exposed healthy controls (TEHC), all from a cohort who survived the same large earthquake in China, underwent resting-state functional magnetic resonance imaging. Bilateral BLA and CMA functional connectivity (FC) maps were created using a seed-based approach for each participant. The analysis of covariance of FC was used to determine between-group differences. A significant interaction between amygdala subregion and diagnostic group suggested that differences in connectivity patterns between the two seeds were mediated by diagnosis. Post-hoc analyses revealed that PTSD+MDD patients showed weaker connectivity between right BLA and (a) left anterior cingulate cortex/supplementary motor area, and (b) bilateral putamen/pallidum, compared with PTSD-alone patients. Higher CMA connectivities left ACC/SMA were also observed in PTSD+MDD compared with PTSD-alone. An inverse relationship between the connectivity of right BLA with right putamen/pallidum and MDD symptoms was found in PTSD+MDD. These findings indicate a relationship between the neural pathophysiology of PTSD+MDD compared with PTSD-alone and TEHC and may inform future clinical interventions.

State representation in mental illness

Reinforcement learning theory provides a powerful set of computational ideas for modeling human learning and decision making. Reinforcement learning algorithms rely on state representations that enable efficient behavior by focusing only on aspects relevant to the task at hand. Forming such representations often requires selective attention to the sensory environment, and recalling memories of relevant past experiences. A striking range of psychiatric disorders, including bipolar disorder and schizophrenia, involve changes in these cognitive processes. We review and discuss evidence that these changes can be cast as altered state representation, with the goal of providing a useful transdiagnostic dimension along which mental disorders can be understood and compared.

Transdiagnostic neural correlates of volitional emotion regulation in anxiety and depression

BACKGROUND

Individuals who suffer from anxiety and/or depression face difficulty in adaptively managing emotional responses, while accumulating evidence suggests impaired emotion regulation is a transdiagnostic feature of psychopathology. Effectual regulation in the context of negative stimuli is characterized by engagement of the prefrontal cortex (PFC) coupled with reduced amygdala reactivity. In anxiety disorders and major depression, PFC underengagement and atypical PFC-amygdala connectivity has been observed, although patient findings based on case-control studies have been mixed with regard to magnitude, locality, and extent of dysfunction. As anxiety disorders and major depression are heterogeneous disorders and frequently comorbid with one another, delineating relationships between reappraise-related substrates and symptoms may advance our understanding of emotion dysregulation in these populations.

METHODS

We examined PFC activation and its functional connectivity (FC) to the amygdala using functional magnetic resonance imaging in a large sample of patients (N = 174) with primary generalized anxiety disorder (n = 47), social anxiety disorder (n = 78), or major depressive disorder (n = 49) during a reappraisal-based emotion regulation task. Comorbidity was permitted and the majority of participants had a concurrent psychiatric illnesses.

RESULTS

Across participants, whole-brain results showed that (1) greater anxiety and depression symptom severity was related to less engagement of the dorsal anterior cingulate cortex (ACC) and (2) less FC between the amygdala and ventrolateral PFC. Results were driven by anxiety, while depression symptoms were not significant.

CONCLUSION

These findings demonstrate that individual differences in anxiety and depression may help explain ACC and PFC dysfunction during emotion regulation observed across anxiety and depressive disorders.

Neural correlates of depression in women across the reproductive lifespan - An fMRI review

INTRODUCTION

Depressive disorders in women emerge largely during transitions in their reproductive aging cycle, which can be attributed to internal endocrine possesses that affect emotion-associated brain circuits. A review was performed to outline the neural basis in depression during female puberty, premenstrual dysphoric disorder (PMDD), postpartum depression disorder (PPD) and perimenopausal depression disorder.

METHODS

For this review, Web of science, Pubmed and PsychInfo databases were searched for functional brain imaging studies addressing reproductive cycle-related mood disorder. The results are summarized and discussed within a broader theoretical framework of major depression disorder (MDD) to determine how reproductive-sensitive phases contribute to affective symptoms and how they relate to the neurobiology of MDD.

RESULTS

Neural activation patterns of all depressive disorders related to female reproductive cycle, except for puberty depression, differ from these observed in MDD. While the PMDD results are widely divergent, the activation patterns in PPD show general hypoactivation in all respects.

LIMITATIONS

Systematic comparisons between the diverse depression disorders are impeded by the heterogeneous experimental protocols used on different samples, reproductive aging stages and depression types.

CONCLUSION

Given that hormonal fluctuations strongly influence the development of a reproductive cycle-related depression, it is possible that the hormonal and neural patterns are indicative of distinct mood disorder with phase specific biotypes, that only show behavioral similarities to MDD. Understanding the similarities and differences in the neural functioning of female cycle-related mood disorders evaluated against MDD might help elucidate the role of neuroendocrine involvement in development of depression in women, and potentially facilitate the search for prevention and treatment approaches for women' reproductive-related depressions.

Combined Processing of Facial and Vocal Emotion in Remitted Patients With Bipolar I Disorder

OBJECTIVES

Bipolar disorder (BD) is associated with impairments in facial emotion and emotional prosody perception during both mood episodes and periods of remission. To expand on previous research, the current study investigated cross-modal emotion perception, that is, matching of facial emotion and emotional prosody in remitted BD patients.

METHODS

Fifty-nine outpatients with BD and 45 healthy volunteers were included into a cross-sectional study. Cross-modal emotion perception was investigated by using two subtests out of the Comprehensive Affective Testing System (CATS).

RESULTS

Compared to control subjects patients were impaired in matching sad (p < .001) and angry emotional prosody (p = .034) to one of five emotional faces exhibiting the corresponding emotion and significantly more frequently matched sad emotional prosody to happy faces (p < .001) and angry emotional prosody to neutral faces (p = .017). In addition, patients were impaired in matching neutral emotional faces to the emotional prosody of one of three sentences (p = .006) and significantly more often matched neutral faces to sad emotional prosody (p = .014).

CONCLUSIONS

These findings demonstrate that, even during periods of symptomatic remission, patients suffering from BD are impaired in matching facial emotion and emotional prosody. As this type of emotion processing is relevant in everyday life, our results point to the necessity to provide specific training programs to improve psychosocial outcomes. (JINS, 2019, 25, 336-342).

Altered amygdala circuits underlying valence processing among manic and depressed phases in bipolar adults

BACKGROUND

Disruptions in affective processing characterize mood disorders, yet the neural mechanisms underlying internal state dependency in affective processes are not well understood. The present work presents a pilot investigation into state dependency among neural circuits known to be involved in processing affective information, by examining acute manic and depressive mood phases in adults with bipolar disorder and major depressive disorder.

METHODS

The present study probed affective processes with a well-validated passive picture-viewing task amongst acutely manic (n = 8) or acutely depressed (bipolar depression: n = 11; major depression: n = 15) mood-disordered adults during functional magnetic resonance imaging .

RESULTS

Beta-series correlation analyses seeded from the amygdala revealed distinct neural circuits distinguished across current mood state rather than diagnostic boundaries. We delineated an amygdala-striatum pathway that distinguished depressed from manic mood phase, rather than between diagnostic boundaries, in processing valenced information. Specifically, we found differences in this neural response to negative, but not positive, images across clinical mood states.

LIMITATIONS

As a preliminary investigation of state-dependent affective processes, the current investigation is predominantly limited by the small sample size. While it provides direction and generates hypotheses for further work, future studies need to replicate and expand the reported effects with larger samples.

CONCLUSIONS

These findings demonstrate the conditions under which mood state-dependent affective processes cut cross traditional diagnostic boundaries, speaking to recent advances in transdiagnostic disease mechanisms, and can guide future work examining the neural mechanisms driving symptomatology in affective disorders.

EEG Based Emotion Recognition by Combining Functional Connectivity Network and Local Activations

OBJECTIVE

Spectral power analysis plays a predominant role in electroencephalogram-based emotional recognition. It can reflect activity differences among multiple brain regions. In addition to activation difference, different emotions also involve different large-scale network during related information processing. In this paper, both information propagation patterns and activation difference in the brain were fused to improve the performance of emotional recognition.

METHODS

We constructed emotion-related brain networks with phase locking value and adopted a multiple feature fusion approach to combine the compensative activation and connection information for emotion recognition.

RESULTS

Recognition results on three public emotional databases demonstrated that the combined features are superior to either single feature based on power distribution or network character. Furthermore, the conducted feature fusion analysis revealed the common characters between activation and connection patterns involved in the positive, neutral, and negative emotions for information processing.

SIGNIFICANCE

The proposed feasible combination of both information propagation patterns and activation difference in the brain is meaningful for developing the effective human-computer interaction systems by adapting to human emotions in the real world applications.

White matter - emotion processing activity relationships in youth offspring of bipolar parents

BACKGROUND

Early detection of Bipolar Disorder (BD) is critical for targeting interventions to delay or prevent illness onset. Yet, the absence of objective BD biomarkers makes accurately identifying at-risk youth difficult. In this study, we examined how relationships between white matter tract (WMT) structure and activity in emotion processing neural circuitry differentiate youth at risk for BD from youth at risk for other psychiatric disorders.

METHODS

Offspring (ages 8-17) of parents with BD (OBP, n = 32), offspring of comparison parents with non-BD psychopathology (OCP, n = 30), and offspring of healthy parents (OHP, n = 24) underwent diffusion tensor and functional magnetic resonance imaging while performing an emotional face processing task. Penalized and multiple regression analyses included GROUP(OBP,OCP)xWMT interactions as main independent variables, and emotion processing activity as dependent variables, to determine significant group differences in WMT-activity relationships.

RESULTS

8 GROUPxWMT interaction variables contributed to 16.5% of the variance in amygdala and prefrontal cortical activity to happy faces. Of these, significant group differences in slopes (inverse for OBP, positive for OCP) existed for the relationship between forceps minor radial diffusivity and rostral anterior cingulate activity (p = 0.014). Slopes remained significantly different in unmedicated youth without psychiatric disorders (p = 0.017) and were moderated by affective lability symptoms (F(1,29) = 5.566, p = 0.036).

LIMITATIONS

Relatively small sample sizes were included.

CONCLUSIONS

Forceps minor radial diffusivity-rostral anterior cingulate activity relationships may reflect underlying neuropathological processes that contribute to affectively labile youth at risk for BD and may help differentiate them from youth at risk for other psychiatric disorders.

Altered Working Memory Processing of Emotion in Adolescents with Dysphoric Symptomatology: An Eye Tracking Study

It has been suggested that altered processing of emotion during cognitive control plays an important role in the etiology of depressive symptoms. The current study investigates the influence of emotional stimuli on working memory (WM) in adolescents with dysphoric symptomatology (DS). Twenty-five adolescents with DS and 40 adolescents with no dysphoric symptomatology (NDS) completed a memory-guided eye movement task. This task assessed the influence of irrelevant affective information on WM processes during high and low cognitive load. Latency analyses showed that, in the high load WM condition, negative distractors disturbed WM performance in adolescents with NDS, but not in adolescents with DS. Accuracy analyses revealed that adolescents with NDS had higher accuracy rates in the presence of positive distractors relative to negative and neutral distractors, and in comparison to adolescents with DS. The findings indicated altered WM performance in the context of emotional distractors in adolescents with DS and may contribute to theoretical knowledge and early prevention of youth depression.

A Dynamical Bifurcation Model of Bipolar Disorder Based on Learned Expectation and Asymmetry in Mood Sensitivity

Bipolar disorder is a common psychiatric dysfunction characterized by recurring episodes of mania and depression. Despite its prevalence, the causes and mechanisms of bipolar disorder remain largely unknown. Recently, theories focusing on the interaction between emotion and behavior, including those based on dysregulation of the so-called behavioral approach system (BAS), have gained popularity. Mathematical models built on this principle predict bistability in mood and do not invoke intrinsic biological rhythms that may arise from interactions between mood and expectation. Here we develop and analyze a model with clinically meaningful and modifiable parameters that incorporates the interaction between mood and expectation. Our nonlinear model exhibits a transition to limit cycle behavior when a mood-sensitivity parameter exceeds a threshold value, signaling a transition to a bipolar state. The model also predicts that asymmetry in response to positive and negative events can induce unipolar depression/mania, consistent with clinical observations. We analyze the model with asymmetric mood sensitivities and show that large unidirectional mood sensitivity can lead to bipolar disorder. Finally, we show how observed effects of lithium- and antidepressant-induced mania can be explained within the framework of our proposed model.

Association of Neuroimaging Measures of Emotion Processing and Regulation Neural Circuitries With Symptoms of Bipolar Disorder in Offspring at Risk for Bipolar Disorder

IMPORTANCE

Bipolar disorder (BD) is difficult to distinguish from other psychiatric disorders. Neuroimaging studies can identify objective markers of BD risk.

OBJECTIVE

To identify neuroimaging measures in emotion processing and regulation neural circuitries and their associations with symptoms specific to youth at risk for BD.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional (August 1, 2011, to July 31, 2017) and longitudinal (February 1, 2013, to November 30, 2017) neuroimaging study performed at the University of Pittsburgh Medical Center compared a sample of 31 offspring of parents with BD (OBP) with 28 offspring of comparison parents with non-BD psychopathologies (OCP) and 21 offspring of healthy parents (OHP); OBP, OCP, and OHP were recruited from the Bipolar Offspring Study and the Longitudinal Assessment of Manic Symptoms Study.

MAIN OUTCOMES AND MEASURES

Group differences in activity and functional connectivity during emotional face processing and n-back task performance in amygdala, dorsolateral and ventrolateral prefrontal cortices (PFC), caudal anterior cingulate cortices (cACC), and rostral anterior cingulate cortices (rACC) neuroimaging measures showing between-group differences and symptom severity (anxiety, affective lability, depression, mania). We hypothesized that elevated amygdala activity and/or lower PFC activity and abnormal amygdala to PFC functional connectivity would distinguish OBP from OCP and OHP, and magnitudes of these abnormalities would positively correlate with elevated symptom severity. We explored associations between changes in neuroimaging and symptom measures over follow-up (mean [SD], 2.9 [1.4] years) in a subset of participants (n = 30).

RESULTS

Eighty participants were included (mean [SD] age, 14.2 (2.1) years; 35 female). Twelve neuroimaging measures explained 51% of the variance in the results of neuroimaging measures overall. Of the 12, 9 showed significant main associations of the group; however, after post hoc analyses and Bonferroni corrections, only 7 showed statistically significant associations between groups (corrected P < .05 for all). Of the 7, 2 showed significant relationships with symptoms. Offspring of parents with BD had greater right rACC activity when regulating attention to happy faces vs OCP (mean [SD] difference, 0.744 [0.249]; 95% CI, 0.134-1.354; P = .01), which positively correlated with affective lability severity (ρ = 0.304; uncorrected P = .006). Offspring of parents with BD had greater amygdala to left cACC functional connectivity when regulating attention to fearful faces vs OCP (mean [SD] difference, 0.493 [0.169]; 95% CI, 0.079-0.908; P = .01). Increases in this measure positively correlated with increases in affective lability over follow-up (r = 0.541; P = .003).

CONCLUSIONS AND RELEVANCE

Greater anterior cingulate cortex activity and functional connectivity during emotion regulation tasks may be specific markers of BD risk. These findings highlight potential neural targets to aid earlier identification of and guide new treatment developments for BD.

Neural correlates of improved recognition of happy faces after erythropoietin treatment in bipolar disorder

OBJECTIVE

Bipolar disorder is associated with impairments in social cognition including the recognition of happy faces. This is accompanied by imbalanced cortico-limbic response to emotional faces. We found that EPO improved the recognition of happy faces in patients with bipolar disorder. This randomized, controlled, longitudinal fMRI study explores the neuronal underpinnings of this effect.

METHOD

Forty-four patients with bipolar disorder in full or partial remission were randomized to eight weekly erythropoietin (EPO; 40 000 IU) or saline (NaCl 0.9%) infusions in a double-blind, parallel-group design. Participants underwent whole-brain fMRI at 3T, mood ratings and blood tests at baseline and week 14. During fMRI, participants viewed happy and fearful faces and performed a gender discrimination task.

RESULTS

Thirty-four patients had complete pre- and post-treatment fMRI data (EPO: N = 18, saline: N = 16). Erythropoietin vs. saline increased right superior frontal response to happy vs. fearful faces. This correlated with improved happiness recognition in the EPO group. Erythropoietin also enhanced gender discrimination accuracy for happy faces. These effects were not influenced by medication, mood, red blood cells or blood pressure.

CONCLUSIONS

Together with previous findings, the present observation suggests that increased dorsal prefrontal attention control is a common mechanism of EPO-associated improvements across several cognitive domains.

Amygdala Activation and Connectivity to Emotional Processing Distinguishes Asymptomatic Patients With Bipolar Disorders and Unipolar Depression

BACKGROUND

Mechanistically based neural markers, such as amygdala reactivity, offer one approach to addressing the challenges of differentiating bipolar and unipolar depressive disorders independently from mood state and acute symptoms. Although emotion-elicited amygdala reactivity has been found to distinguish patients with bipolar depression from patients with unipolar depression, it remains unknown whether this distinction is traitlike and present in the absence of an acutely depressed mood. We addressed this gap by investigating patients with bipolar disorder (BP) and unipolar major depressive disorder (MDD) in remission.

METHODS

Supraliminal and subliminal processing of faces exhibiting threat, sad, happy, and neutral emotions during functional magnetic resonance imaging was completed by 73 participants (23 BP patients and 25 MDD patients matched for age and gender, number of depressive episodes and severity; 25 age- and gender-matched healthy control subjects). We compared groups for activation and connectivity for the amygdala.

RESULTS

BP patients had lower left amygdala activation than MDD patients during supraliminal and subliminal threat, sad, and neutral emotion processing and for subliminal happy faces. BP patients also exhibited lower amygdala connectivity to the insula and hippocampus for threat and to medial orbitofrontal cortex for happy supraliminal and subliminal processing. BP patients also demonstrated greater amygdala-insula connectivity for sad supraliminal and subliminal face processing. Both patient groups were distinct from control subjects across several measures for activation and connectivity.

CONCLUSIONS

Independent of valence or level of emotional awareness, amygdala activation and connectivity during facial emotion processing can distinguish BP patients and MDD patients. These findings provide evidence that this neural substrate could be a potential trait marker to differentiate these two disorders largely independent of illness state.

Cerebral processing of facial emotions in bipolar I and II disorders: An event-related potential study

BACKGROUND

Behavioral results have shown that bipolar disorder patients have impaired recognition of facial emotions, but the detailed information processing of facial emotions in patients with bipolar I (BD I) and II (BD II) disorders remain unknown.

METHODS

We tested the cerebral event-related potentials to the static facial expressions of Neutral, Happiness, Anger and Sadness in 39 adult patients with BD I, 22 BD II, and 54 healthy volunteers. Participants' affective states were measured with the Mood Disorder Questionnaire, the Hypomania Checklist-32, and the Plutchik-van Praag Depression Inventory.

RESULTS

Over-processed right occipitotemporal cortex during N1 time window to Neutral and Happiness, and during P3b window to Sadness were found in BD I; prolonged N1 latencies to Neutral and Happiness, declined P3b amplitude to Sadness, negative correlation between P3b latency to Sadness and depression, and attenuated superior frontal activity during P3b window to Sadness were found in BD II; and the right-side dominance during facial emotion processing were found in both BD I and BD II.

LIMITATIONS

We didn't record the personality traits or medication used in patients, nor included other facial emotions such as fear and disgust.

CONCLUSIONS

When responding to facial emotions, both BD I and BD II showed a right-side processing dominance; BD I displayed enhanced processing in the right occipitotemporal cortex during structural encoding and categorical processing of facial emotions; while BD II displayed generalized impairments, less involvement of superior frontal cortex to negative emotions, and reduced ability to process negative emotions which was associated with depression.

Modulation of negative emotions through anodal tDCS over the right ventrolateral prefrontal cortex

Increasing evidence suggests that the right ventrolateral prefrontal cortex (rVLPFC) plays a critical role in emotion regulation, in particular concerning negative feelings. In the present research, we applied anodal transcranial direct current stimulation (tDCS) over the rVLPFC with a twofold purpose. First, we aimed at exploring the feasibility of modulating the subjective experience of emotions through tDCS in healthy participants. Second, we wanted to assess which specific emotion can be regulated (and which cannot) with this brain stimulation approach. We designed a double-blind, between-subjects, sham-controlled study in which 96 participants watched short video clips eliciting different emotions during anodal or sham tDCS over the rVLPFC. Emotional reactions to each video clip were assessed with self-report scales measuring eight basic emotions. Results showed that, in contrast to the sham condition, tDCS over the rVLPFC reduced the perceived extent of specific negative emotions, namely, fear, anxiety, and sadness, compared to other negative or positive feelings. Overall, these results support the role of rVLPFC in regulating negative emotions, mostly associated with the prevention of dangerous situations (i.e., fear, anxiety, and sadness).

Regional homogeneity and functional connectivity patterns in major depressive disorder, cognitive vulnerability to depression and healthy subjects

BACKGROUND

Cognitive vulnerability to depression (CVD) is a high risk for depressive disorder. Recent studies focus on individuals with CVD to determine the neural basis of major depressive disorder (MDD) neuropathology. However, whether CVD showed specific or similar brain functional activity and connectivity patterns, compared to MDD, remain largely unknown.

METHODS

Here, using resting-state functional magnetic resonance imaging in subjects with CVD, healthy controls (HC) and MDD, regional homogeneity (ReHo) and resting-state functional connectivity (R-FC) analyses were conducted to assess local synchronization and changes in functional connectivity patterns.

RESULTS

Significant ReHo differences were found in right posterior lobe of cerebellum (PLC), left lingual gyrus (LG) and precuneus. Compared to HC, CVD subjects showed increased ReHo in the PLC, which was similar to the difference found between MDD and HC. Compared to MDD patients, CVD subjects showed decreased ReHo in PLC, LG, and precuneus. R-FC analyses found increased functional connections between LG and left inferior parietal lobule, posterior cingulate cortex, and dorsolateral prefrontal cortex in CVD compared to both HC and MDD. Moreover, Regional mean ReHo values were positively correlated with Center for Epidemiologic Studies Depression Scale scores.

CONCLUSION

These analyses revealed that PLC and functional connections between LG and left inferior parietal lobule, posterior cingulate cortex, and dorsolateral prefrontal cortex may be a potential marker for CVD.

Plasma C-reactive protein levels in bipolar depression during cyclooxygenase-2 inhibitor combination treatment

Immune system activation and neuroinflammation appear to play a key role in the pathophysiology and treatment of bipolar depression (BDD). This study is the first to analyze blood levels of the pro-inflammatory biomarker C-reactive protein (CRP) in bipolar disorder patients treated with the cyclooxygenase-2 inhibitor, celecoxib (CBX). In this double-blind study, 47 consenting patients with BDD were randomized to receive either escitalopram (10 mg twice/day) + CBX (200 mg twice/day), or escitalopram (10 mg twice/day) + placebo (twice/day). Plasma CRP levels were measured in both patient groups at baseline, week 4, and week 8, and in a healthy control (HC) group of subjects (N = 35) once. Symptoms were rated using the 17-item Hamilton Depression Scale (HAMD-17). The CBX group had significantly lower HAMD-17 scores vs. placebo at week 4 (P = 0.026) and week 8 (P = 0.002). Therefore, SSRI + CBX is more effective than SSRI + placebo in reversing treatment resistance and augmenting antidepressant response in BDD. Baseline CRP levels were significantly increased amongst BDD patients versus HC subjects, indicating that CRP may be a useful biomarker for BDD (P = 0.044). No significant differences in CRP levels were measured between CBX and placebo groups at baseline (P = 0.156), but by week 8 CRP was significantly decreased in the CBX group vs. placebo (P = 0.003). This indicates reduced inflammation in CBX-treated patients, and that CRP may be a useful biomarker for monitoring treatment response in BDD patients during SSRI + CBX combination treatment. CRP and IL-6 levels were positively correlated in the CBX group, and CRP levels were positively correlated with BMI.

Neuropsychodynamic Approach to Depression: Integrating Resting State Dysfunctions of the Brain and Disturbed Self-Related Processes

A mechanism-based approach was developed focusing on the psychodynamic, psychological and neuronal mechanisms in healthy and depressed persons. In this integrative concept of depression, the self is a core dimension in depression. It is attributed to negative emotions (e.g., failure, guilt). The increased inward focus in depression is connected with a decreased environmental focus. The development of neuropsychodynamic hypotheses of the altered self-reference is based on the investigation of the emotional-cognitive interaction in depressed patients. It may be hypothesized that the increased negative self-attributions—as typical characteristics of an increased self-focus in depression—may result from altered neuronal activity in subcortical-cortical midline structures in the brain, especially from hyperactivity in the cortical-subcortical midline regions and hypoactivity in the lateral regions. The increased resting state activity in depression is especially associated with an increased resting state activity in the default mode network (DMN) and a dysbalance between DMN and executive network (EN) activity. Possible therapeutic consequences of the neuropsychodynamic approach to depression involve the necessary emotional attunement in psychotherapy of depressed patients and the adequate timing of therapeutic interventions. The hypotheses which have been developed in the context of the neuropsychodynamic model of depression may be used for more specific psychotherapeutic interventions, aiming at specific mechanisms of compensation and defence, which are related to the increased resting state activity and the disturbed resting state-stimulus-interaction.

Polymorphisms in the microglial marker molecule CX3CR1 affect the blood volume of the human brain

AIM

CX3CR1, a G-protein-coupled receptor, is involved in various inflammatory processes. Two non-synonymous single nucleotide polymorphisms, V249I (rs3732379) and T280M (rs3732378), are located in the sixth and seventh transmembrane domains of the CX3CR1 protein, respectively. Previous studies have indicated significant associations between T280M and leukocyte functional characteristics, including adhesion, signaling, and chemotaxis, while the function of V249I is unclear. In the brain, microglia are the only proven and widely accepted CX3CR1-expressing cells. This study aimed to specify whether there were specific brain regions on which these two single nucleotide polymorphisms exert their biological impacts through their functional effects on microglia.

METHODS

Associations between the single nucleotide polymorphisms and brain characteristics, including gray and white matter volumes, white matter integrity, resting arterial blood volume, and cerebral blood flow, were evaluated among 1300 healthy Japanese individuals.

RESULTS

The major allele carriers (V249 and T280) were significantly associated with an increased total arterial blood volume of the whole brain, especially around the bilateral precuneus, left posterior cingulate cortex, and left posterior parietal cortex. There were no significant associations between the genotypes and other brain structural indicators.

CONCLUSION

This finding suggests that the CX3CR1 variants may affect arterial structures in the brain, possibly via interactions between microglia and brain microvascular endothelial cells.

Impaired sensory processing measured by functional MRI in Bipolar disorder manic and depressed mood states

Bipolar disorder is characterized by recurring episodes of depression and mania. Defining differences in brain function during these states is an important goal of bipolar disorder research. However, few imaging studies have directly compared brain activity between bipolar mood states. Herein, we compare functional magnetic resonance imaging (fMRI) responses during a flashing checkerboard stimulus between bipolar participants across mood states (euthymia, depression, and mania) in order to identify functional differences between these states. 40 participants with bipolar I disorder and 33 healthy controls underwent fMRI during the presentation of the stimulus. A total of 23 euthymic-state, 16 manic-state, 15 depressed-state, and 32 healthy control imaging sessions were analyzed in order to compare functional activation during the stimulus between mood states and with healthy controls. A reduced response was identified in the visual cortex in both the depressed and manic groups compared to euthymic and healthy participants. Functional differences between bipolar mood states were also observed in the cerebellum, thalamus, striatum, and hippocampus. Functional differences between mood states occurred in several brain regions involved in visual and other sensory processing. These differences suggest that altered visual processing may be a feature of mood states in bipolar disorder. The key limitations of this study are modest mood-state group size and the limited temporal resolution of fMRI which prevents the segregation of primary visual activity from regulatory feedback mechanisms.

Electrocardiographic and Electrooculographic Responses to External Emotions and Their Transitions in Bipolar I and II Disorders

Bipolar disorder has two main types, bipolar I (BD I) and II (BD II), which present different affective states and personality characteristics, they might present different modes of emotional regulation. We hypothesized that the electrocardiogram and electrooculogram to external emotions are different in BD I and BD II. We asked 69 BD I and 54 BD II patients, and 139 healthy volunteers to undergo these tests in response to disgust, erotica, fear, happiness, neutral, and sadness, and their transitions. Their affective states were also measured. The heart rate in BD I was significantly higher under background fear after target neutral. The eyeball movement was quicker in BD I under target happiness after background disgust; in BD I under target sadness after background disgust; and in BD I under background disgust after target neutral. Some electrocardiographic and electrooculographic changes were correlated with affective states in patients. BD I and BD II had different physiological responses to external emotions and their transitions, indicating different pathophysiologies and suggesting different emotional-therapies for BD I and BD II.

Shared facial emotion processing functional network findings in medication-naïve major depressive disorder and healthy individuals: detection by sICA

BACKGROUND

The fundamental mechanism underlying emotional processing in major depressive disorder (MDD) remains unclear. To better understand the neural correlates of emotional processing in MDD, we investigated the role of multiple functional networks (FNs) during emotional stimuli processing.

METHODS

Thirty-two medication-naïve subjects with MDD and 36 healthy controls (HCs) underwent an emotional faces fMRI task that included neutral, happy and fearful expressions. Spatial independent component analysis (sICA) and general linear model (GLM) were conducted to examine the main effect of task condition and group, and two-way interactions of group and task conditions.

RESULTS

In sICA analysis, MDD patients and HCs together showed significant differences in task-related modulations in five FNs across task conditions. One FN mainly involving the ventral medial prefrontal cortex showed lower activation during fearful relative to happy condition. Two FNs mainly involving the bilateral inferior frontal gyrus and temporal cortex, showed opposing modulation relative to the ventral medial prefrontal cortex FN, i.e., greater activation during fearful relative to happy condition. Two remaining FNs involving the fronto-parietal and occipital cortices, showed reduced activation during both fearful and happy conditions relative to the neutral condition. However, MDD and HCs did not show significant differences in expression-related modulations in any FNs in this sample.

CONCLUSIONS

SICA revealed differing functional activation patterns than typical GLM-based analyses. The sICA findings demonstrated unique FNs involved in processing happy and fearful facial expressions. Potential differences between MDD and HCs in expression-related FN modulation should be investigated further.

Reliability of neural activation and connectivity during implicit face emotion processing in youth

Face emotion imaging paradigms are widely used in both healthy and psychiatric populations. Here, in children and adolescents, we evaluate the test-retest reliability of blood oxygenation-level dependent (BOLD) activation and task-based functional connectivity on a widely used implicit face emotion processing task (i.e., gender labeling). Twenty-five healthy youth (M age = 13.97 year s; 60% female) completed two functional magnetic resonance imaging (fMRI) scan sessions approximately two months apart. Participants identified the gender of faces displaying angry, fearful, happy, and neutral emotions. A Bayesian adaptation of the intraclass correlation (ICC) assessed reliability of evoked BOLD activation and amygdala seed-based functional connectivity on task events vs. baseline as well as contrasts between face emotions. For each face emotion vs. baseline, good reliability of activation was demonstrated across key emotion processing regions including middle, medial, and inferior frontal gyri. However, contrasts between face emotions yielded variable results. Contrasts of angry to neutral or happy faces exhibited good reliability of amygdala connectivity to prefrontal regions. Contrasts of fearful to happy faces exhibited good reliability of activation in the anterior cingulate. Findings inform the reproducibility literature and emphasize the need for continued evaluation of task reliability.

Amygdala response to emotional faces in seasonal affective disorder

BACKGROUND

Seasonal affective disorder (SAD) is characterized by seasonally recurring depression. Heightened amygdala activation to aversive stimuli is associated with major depressive disorder but its relation to SAD is unclear. We evaluated seasonal variation in amygdala activation in SAD and healthy controls (HC) using a longitudinal design targeting the asymptomatic/symptomatic phases of SAD. We hypothesized increased amygdala activation to aversive stimuli in the winter in SAD individuals (season-by-group interaction).

METHODS

Seventeen SAD individuals and 15 HCs completed an implicit emotional faces BOLD-fMRI paradigm during summer and winter. We computed amygdala activation (SPM5) to an aversive contrast (angry & fearful minus neutral) and angry, fearful and neutral faces, separately. Season-by-group and main effects were evaluated using Generalized Least Squares. In SAD individuals, we correlated change in symptom severity, assessed with The Hamilton Rating Scale for Depression - Seasonal Affective Disorder version (SIGH-SAD), with change in amygdala activation.

RESULTS

We found no season-by-group, season or group effect on our aversive contrast. Independent of season, SAD individuals showed significantly lower amygdala activation to all faces compared to healthy controls, with no evidence for a season-by-group interaction. Seasonal change in amygdala activation was unrelated to change in SIGH-SAD.

LIMITATIONS

Small sample size, lack of positive valence stimuli.

CONCLUSIONS

Amygdala activation to aversive faces is not increased in symptomatic SAD individuals. Instead, we observed decreased amygdala activation across faces, independent of season. Our findings suggest that amygdala activation to angry, fearful and neutral faces is altered in SAD individuals, independent of the presence of depressive symptoms.

Profiling risk for depressive disorder by circuit, behavior and self-report measures of emotion function

BACKGROUND

Major depressive disorder (MDD) is characterized by maladaptions in affective brain circuitry and in emotion regulation. It remains unknown whether these maladaptions characterize first-degree relatives of probands who are unaffected yet have a higher risk of developing MDD.

METHODS

Participants were 72 unaffected first-degree relatives of probands with MDD and 66 matched non-relative controls. We investigated brain circuit function and self-reported emotion regulation strategies for reappraisal and suppression. During functional magnetic resonance imaging, we probed circuitry relevant to both negative and positive valence systems using facial expressions signaling potential threat, sadness and happiness, presented under both conscious and subliminal viewing conditions. We compared groups using a statistically controlled region of interest (ROI) approach including the amygdala, insula, anterior cingulate cortex (ACC), ventromedial prefrontal cortex and dorsolateral prefrontal cortex. We also used a data-driven cluster analytic approach for characterizing the relatives by their brain function profiles.

RESULTS

As a group, relatives were distinguished by hyper-reactivity of the pregenual ACC during subliminal viewing of threat-related expressions but hypo-activation of the amygdala, insula and dorsal ACC during explicit viewing of the same threat-related expressions and sadness. When considered individually, this brain function profile characterized two-thirds of relatives, and these relatives were also less likely to use reappraisal to regulate negative emotion.

LIMITATIONS

The design was cross-sectional and therefore does not provide direct evidence as to the trait- (versus state-) like profile observed in relatives.

CONCLUSIONS

Familial risk for MDD may involve a disruption to the normal recruitment of neural circuits for appraising salient emotions, both implicit and explicit. Interventions targeting reappraisal strategies for regulating negative emotion may serve to buffer this risk.

The Role of Amygdala in Patients With Euthymic Bipolar Disorder During Resting State

The current study aims to explore the functional changes of the amygdala in patients with euthymic Bipolar Disorder (BD) using resting state fMRI (rs-fMRI). Twenty-one euthymic patients with bipolar disorder and 28 healthy controls participated in this study. Two of the euthymic patients with BD and three of the healthy controls were excluded due to excessive head motion. We found that patients with euthymia (38.79 ± 12.03) show higher fALFF (fractional Amplitude of low-frequency fluctuation) value of the amygdala (t = 2.076, P = 0.044), and lower functional connectivity between the amygdala and supplementary motor area (p < 0.01, GRF corrected) than healthy controls (33.40 ± 8.21). However, euthymic patients did not show a differential activity in ReHo (Regional Homogeneity) and gray matter of the amygdala region as compared to healthy controls. Thus, despite the absence of clinical symptoms in euthymic patients with BD, the amygdala functional activity and its connectivity to other brain regions remain altered. Further investigation of negative emotions and social functioning in euthymic patients with BD are needed and can help pave the way for a better understanding of BD psychopathology.

Brain activation during processing of genuine facial emotion in depression: Preliminary findings

OBJECTIVE

The current study aimed to examine the neural correlates of processing genuine compared with posed emotional expressions, in depressed and healthy subjects using a novel functional magnetic resonance imaging (fMRI) paradigm METHOD: During fMRI scanning, sixteen depressed patients and ten healthy controls performed an Emotion Categorisation Task, whereby participants were asked to distinguish between genuine and non-genuine (posed or neutral) facial displays of happiness and sadness.

RESULTS

Compared to controls, the depressed group showed greater activation whilst processing genuine versus posed facial displays of sadness, in the left medial orbitofrontal cortex, caudate and putamen. The depressed group also showed greater activation whilst processing genuine facial displays of sadness relative to neutral displays, in the bilateral medial frontal/orbitofrontal cortex, left dorsolateral prefrontal cortex, right dorsal anterior cingulate, bilateral posterior cingulate, right superior parietal lobe, left lingual gyrus and cuneus. No differences were found between the two groups for happy facial displays.

LIMITATIONS

Relatively small sample sizes and due to the exploratory nature of the study, no correction was made for multiple comparisons.

CONCLUSION

The findings of this exploratory study suggest that depressed individuals may show a different pattern of brain activation in response to genuine versus posed facial displays of sadness, compared to healthy individuals. This may have important implications for future studies that wish to examine the neural correlates of facial emotion processing in depression.

Blink reflex under external emotional-stimuli in bipolar I and II disorders

Bipolar disorder types I (BD I) and II (BD II) might present different cortico-brainstem circuit dysfunctions under external emotions, which might be reflected by the blink reflex. We therefore invited 32 BD I and 23 BD II patients, and 46 healthy volunteers to answer the Mood Disorder Questionnaire, the Hypomania Checklist-32, and the Plutchik - van Praag Depression inventory, and to undergo the blink reflex test under external emotions (emotional pictures plus sounds) of Disgust, Erotica, Fear, Happiness, and Sadness. Compared to healthy controls, BD I showed prolonged R2/R2' latencies under most emotions, and their PVP scores were negatively correlated with the areas under curve (AUCs) of R2 and R2' under Erotica; and BD II showed reduced R2/R2' AUCs under all emotions. Moreover, R2' AUCs under Disgust, Fear, and Happiness were significantly reduced in BD II than those in BD I. Our results have shown that, irrespective of patients' on-going affective states, the R2/R2' components were delayed in BD I but suppressed in BD II under most external emotions. Our study provides some hints to distinguish the two types of bipolar disorder, referring to the cortico-brainstem circuit dysfunctions under external emotions.

Distinct Associations Between Low Positive Affect, Panic, and Neural Responses to Reward and Threat During Late Stages of Affective Picture Processing

BACKGROUND

Abnormal patterns of attention to threat and reward have been proposed as potential mechanisms of dysfunction in anxiety and mood disorders. However, research on this topic has been inconsistent, perhaps because of both clinical heterogeneity in the samples assessed and measurement of attentional biases that is temporally imprecise.

METHODS

The present study measured transdiagnostic symptoms of anxiety and depression in 205 young adults and recorded affect-modulated event-related potentials in response to task-irrelevant pictures in a speeded response task.

RESULTS

Low positive affect was uniquely associated with reduced modulation of later event-related potentials (i.e., the P300 and the late positive potential) by rewarding images, suggesting deficits in sustained attention to reward. Low positive affect was also associated with a blunted threat-elicited late positive potential. Symptoms of panic were associated with an increased N1 to rewarding images, as well as an increased late positive potential to all picture types.

CONCLUSIONS

These data suggest that dysfunction in neural markers of sustained attention to threat and reward relate in specific ways to transdiagnostic symptom dimensions of anxiety and depression. Moreover, event-related potentials are likely to be useful in investigations of the time course of attentional abnormalities associated with these symptom dimensions.

Differential effects of antidepressant treatment on long-range and short-range functional connectivity strength in patients with major depressive disorder

ABSTARCT

Although we have some basic understanding of the neurochemical mechanisms of the antidepressants, the network-level effect of antidepressant treatment is still not fully understood. This study was conducted to investigate the effects of antidepressant on functional brain networks of patients with major depressive disorder (MDD). We performed resting-state fMRI scans on 20 first-episode drug-naive MDD patients at baseline and after escitalopram medication for 8 weeks. Twenty healthy controls also received MRI scans with an 8-week interval. The graph theory indices, long- and short-range functional connectivity strength (FCS), were computed to characterize the brain connectivity. The analysis of covariance was conducted on FCS maps of patients and controls to obtain the interaction effect of group and time, which indicate treatment-related effect. Following treatment, increased long-range FCS in the bilateral posterior cingulate cortex/precuneus and right thalamus in MDD patients at baseline were reduced. Meanwhile, increased short-range FCS in the bilateral ventromedial prefrontal cortex and left amygdala in patients were reduced, while reduced short-range FCS in the right parahippocampal gyrus was increased. Results suggest that the brain regions associated with negative emotional processing and regulation, and self-referential function could be modulated by escitalopram treatment; long- and short-range FCS are differentially affected by antidepressant.

Reward processing and mood-related symptoms: An RDoC and translational neuroscience perspective

BACKGROUND

Two objectives of the NIMH Research Domain Criteria (RDoC) initiative are to identify (a) mechanisms that are common to multiple psychiatric disorders, and (b) mechanisms that are unique to specific psychiatric symptoms, and that reflect markers of differential risk for these symptoms. With respect to these objectives, a brain-behavior dimension that has received considerable attention and that is directly relevant to the Positive Valence Systems domain of the RDoC initiative involves reward processing.

METHODS

The present review paper first examines the relationship between reward processing and mood-related symptoms from an RDoC perspective. We then place this work in a larger context by examining the relationship between reward processing abnormalities and psychiatric symptoms defined broadly, including mood-related symptoms, schizophrenia, and addiction.

RESULTS

Our review suggests that reward hyposensitivity relates to a subtype of anhedonia characterized by motivational deficits in unipolar depression, and reward hypersensitivity relates to a cluster of hypo/manic symptoms characterized by excessive approach motivation in the context of bipolar disorder. Integrating this perspective with research on reward processing abnormalities in schizophrenia and addiction, we further argue that the principles of equifinality and multifinality may be preferable to a transdiagnostic perspective for conceptualizing the relationship between reward processing and psychiatric symptoms defined broadly.

CONCLUSION

We propose that vulnerability to either motivational anhedonia or approach-related hypo/manic symptoms involve extreme and opposite profiles of reward processing. We further propose that an equifinality and multifinality perspective may serve as a useful framework for future research on reward processing abnormalities and psychiatric symptoms.

Neural complexity as a potential translational biomarker for psychosis

BACKGROUND

The adaptability of the human brain to the constantly changing environment is reduced in patients with psychotic disorders, leading to impaired cognitive functions. Brain signal complexity, which may reflect adaptability, can be readily quantified via resting-state functional magnetic resonance imaging (fMRI) signals. We hypothesized that resting-state brain signal complexity is altered in psychotic disorders, and is correlated with cognitive impairment.

METHODS

We assessed 156 healthy controls (HC) and 330 probands, including 125 patients with psychotic bipolar disorder (BP), 107 patients with schizophrenia (SZ), 98 patients with schizoaffective disorder (SAD) and 230 of their unaffected first-degree relatives (76 BPR, 79 SADR, and 75 SZR) from four sites of the Bipolar-Schizophrenia Network on Intermediate Phenotypes (B-SNIP) consortium. Using multi-scale entropy analysis, we determined whether patients and/or relatives had pathologic differences in complexity of resting-state fMRI signals toward regularity (reduced entropy in all time scales), or toward uncorrelated randomness (increased entropy in fine time scales that decays as the time scale increases) and how these complexity differences might be associated with cognitive impairment.

RESULTS

Compared to HC subjects, proband groups showed either decreased complexity toward regularity or toward randomness. SZ probands showed decreased complexity toward regular signal in hypothalamus, and BP probands in left inferior occipital, right precentral and left superior parietal regions, whereas no brain region with decreased complexity toward regularity was found in SAD probands. All proband groups showed significantly increased brain signal randomness in dorsal and ventral prefrontal cortex (PFC), and unaffected relatives showed no complexity differences in PFC regions. SZ had the largest area of involvement in both dorsal and ventral PFC. BP and SAD probands shared increased brain signal randomness in ventral medial PFC, BP and SZ probands shared increased brain signal randomness in ventral lateral PFC, whereas SAD and SZ probands shared increased brain signal randomness in dorsal medial PFC. Only SZ showed increased brain signal randomness in dorsal lateral PFC. The increased brain signal randomness in dorsal or ventral PFC was weakly associated with reduced cognitive performance in psychotic probands.

CONCLUSION

These observations support the loss of brain complexity hypothesis in psychotic probands. Furthermore, we found significant differences as well as overlaps of pathologic brain signal complexity between psychotic probands by DSM diagnoses, thus suggesting a biological approach to categorizing psychosis based on functional neuroimaging data.

Inhibitory brainstem reflexes under external emotional-stimuli in bipolar I and II disorders

BACKGROUND

Bipolar disorder types I (BD I) and II (BD II) might present different dysfunctions of the cortex and brainstem, as reflected by the second exteroceptive suppression period of temporalis muscle activity (ES2) under different stimuli of external emotions.

METHODS

This study included 30 BD I and 20 BD II patients, and 40 healthy volunteers. All participants were invited to answer the Mood Disorder Questionnaire, the Hypomania Checklist-32, and the Plutchik-van Praag Depression inventory, as well as to undergo the ES2 test under external emotional-stimuli (emotional pictures plus sounds) of Disgust, Erotica, Fear, Happiness, and Sadness.

RESULTS

The scale scores were elevated in both patient groups, but were not correlated with ES2 parameters. Compared to healthy controls, BD I showed prolonged ES2 latency under Erotica, and their perceived happiness and sadness intensities were negatively correlated with the respective ES2 durations, while BD II showed prolonged ES2 latencies under Disgust and Happiness, and shortened ES2 durations under Disgust, Happiness and Sadness. Moreover, ES2 duration under Sadness was significantly shorter in BD II than that in BD I.

CONCLUSIONS

The cortico-brainstem inhibitory dysfunctions in BD I and BD II was different, and this difference was independent of the patient's ongoing emotions. Our study thus provides some hints to distinguish the two types of bipolar disorders.

Biased Facial-Emotion Perception in Mental Health Disorders: A Possible Target for Psychological Intervention?

Our perception of emotion in the faces of others affects our own behavior and mood. Indeed, individuals with mood disorders such as depression and aggression often show biases in facial-emotion perception. Here, we review recent and ongoing research suggesting that biased emotion perception may be on the causal pathway of the onset and maintenance of mood disorders, and hence a potential target for intervention. Simple cognitive-bias modification tasks that change participants’ perception of facial expressions of emotion have shown some promise as a therapeutic technique. We outline further directions for continued research investigating the robustness and clinical impact of emotion-bias modification in real-world settings.

Differential Abnormal Pattern of Anterior Cingulate Gyrus Activation in Unipolar and Bipolar Depression: an fMRI and Pattern Classification Approach

Distinguishing bipolar disorder from major depressive disorder is a major challenge in psychiatric treatment. Consequently, there has been growing interest in identifying neuronal biomarkers of disorder-specific pathophysiological processes to differentiate affective disorders. Thirty-six depressed bipolar patients, 36 depressed unipolar patients, and 36 matched healthy controls (HCs) participated in an fMRI experiment. Emotional faces served as stimuli in a matching task. We investigated neural activation towards angry, fearful, and happy faces focusing on prototypical regions related to emotion processing, ie, the amygdala and the anterior cingulate gyrus (ACG). Furthermore, we employed a whole-brain and a multivariate pattern classification analysis. Unipolar patients showed abnormally reduced ACG activation toward happy and fearful faces compared with bipolar patients and HCs respectively. Furthermore, the whole-brain analysis revealed significantly increased activation in bipolar patients compared with unipolar patients in the fearful condition in the right frontal and parietal cortex. Moreover, the multivariate pattern classification analysis yielded significant classification rates of up to 72% based on ACG activation elicited by fearful faces. Our results question the rather 'amygdalocentric' neurobiological models of mood disorders. We observed patterns of abnormally reduced ventral and supragenual ACG activation, potentially indicating impaired bottom-up emotion processing and automatic emotion regulation specifically in unipolar but not in bipolar individuals.

Impaired cognitive control over emotional material in euthymic bipolar disorder

BACKGROUND

Previous research suggests that bipolar disorder (BD) is characterized by deficits in cognitive control (CC). Impaired CC has been found in high-risk samples and is associated with the maintenance of BD symptoms. It remains unclear, however, whether BD is characterized by a general deficit in CC or by a deficit that is specifically related to the processing of emotional material.

METHODS

The sample consisted of 42 remitted bipolar patients and 39 healthy controls (HC). We examined whether BD individuals display impaired CC when confronted with negative as well as positive material using an arithmetic inhibition task that required inhibition of pictorial stimulus material.

RESULTS

Whereas both groups showed difficulties in exerting CC over negative material, only BD individuals exhibited deficient CC over positive material.

LIMITATIONS

Even though we intended the negative and positive pictures in the arithmetic inhibition task to be similarly arousing, participants in the current study rated the negative compared to the positive pictures as more arousing.

CONCLUSIONS

BD is associated with impaired CC when processing emotional - especially positive - stimuli even when patients are in remission. Possible implications of this deficit especially for emotion regulation are discussed.

Cortico-Striatal-Thalamic Loop Circuits of the Orbitofrontal Cortex: Promising Therapeutic Targets in Psychiatric Illness

Corticostriatal circuits through the orbitofrontal cortex (OFC) play key roles in complex human behaviors such as evaluation, affect regulation and reward-based decision-making. Importantly, the medial and lateral OFC (mOFC and lOFC) circuits have functionally and anatomically distinct connectivity profiles which differentially contribute to the various aspects of goal-directed behavior. OFC corticostriatal circuits have been consistently implicated across a wide range of psychiatric disorders, including major depressive disorder (MDD), obsessive compulsive disorder (OCD), and substance use disorders (SUDs). Furthermore, psychiatric disorders related to OFC corticostriatal dysfunction can be addressed via conventional and novel neurostimulatory techniques, including deep brain stimulation (DBS), electroconvulsive therapy (ECT), repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS). Such techniques elicit changes in OFC corticostriatal activity, resulting in changes in clinical symptomatology. Here we review the available literature regarding how disturbances in mOFC and lOFC corticostriatal functioning may lead to psychiatric symptomatology in the aforementioned disorders, and how psychiatric treatments may exert their therapeutic effect by rectifying abnormal OFC corticostriatal activity. First, we review the role of OFC corticostriatal circuits in reward-guided learning, decision-making, affect regulation and reappraisal. Second, we discuss the role of OFC corticostriatal circuit dysfunction across a wide range of psychiatric disorders. Third, we review available evidence that the therapeutic mechanisms of various neuromodulation techniques may directly involve rectifying abnormal activity in mOFC and lOFC corticostriatal circuits. Finally, we examine the potential of future applications of therapeutic brain stimulation targeted at OFC circuitry; specifically, the role of OFC brain stimulation in the growing field of individually-tailored therapies and personalized medicine in psychiatry.

Decreased Numbers of Somatostatin-Expressing Neurons in the Amygdala of Subjects With Bipolar Disorder or Schizophrenia: Relationship to Circadian Rhythms

BACKGROUND

Growing evidence points to a key role for somatostatin (SST) in schizophrenia (SZ) and bipolar disorder (BD). In the amygdala, neurons expressing SST play an important role in the regulation of anxiety, which is often comorbid in these disorders. We tested the hypothesis that SST-immunoreactive (IR) neurons are decreased in the amygdala of subjects with SZ and BD. Evidence for circadian SST expression in the amygdala and disrupted circadian rhythms and rhythmic peaks of anxiety in BD suggest a disruption of rhythmic expression of SST in this disorder.

METHODS

Amygdala sections from 12 SZ, 15 BD, and 15 control subjects were processed for immunocytochemistry for SST and neuropeptide Y, a neuropeptide partially coexpressed in SST-IR neurons. Total numbers (Nt) of IR neurons were measured. Time of death was used to test associations with circadian rhythms.

RESULTS

SST-IR neurons were decreased in the lateral amygdala nucleus in BD (Nt, p = .003) and SZ (Nt, p = .02). In normal control subjects, Nt of SST-IR neurons varied according to time of death. This pattern was altered in BD subjects, characterized by decreases of SST-IR neurons selectively in subjects with time of death corresponding to the day (6:00 am to 5:59 pm). Numbers of neuropeptide Y-IR neurons were not affected.

CONCLUSIONS

Decreased SST-IR neurons in the amygdala of patients with SZ and BD, interpreted here as decreased SST expression, may disrupt responses to fear and anxiety regulation in these individuals. In BD, our findings raise the possibility that morning peaks of anxiety depend on a disruption of circadian regulation of SST expression in the amygdala.

Amygdala-prefrontal cortex resting-state functional connectivity varies with first depressive or manic episode in bipolar disorder

BACKGROUND

Bipolar disorder (BD) is one of the most complex mental illnesses, characterized by interactive depressive and manic states that are 2 contrary symptoms of disease states. The bilateral amygdala and prefrontal cortex (PFC) appear to play critical roles in BD; however, abnormalities seem to manifest differently in the 2 states and may provide further insight into underlying mechanisms.

METHODS

Sixteen participants with first-episode depressive and 13 participants with first-episode manic states of bipolar disorder as well as 30 healthy control (HC) participants underwent resting-state functional magnetic resonance imaging (fMRI). Resting-state functional connectivity (rsFC) between the bilateral amygdala and PFC was compared among the 3 groups.

RESULTS

Compared with depressive state participants of the BD group, manic state participants of the BD group showed a significant decrease in rsFC between the amygdala and right orbital frontal cortex (p<0.05, corrected). In addition, rsFC between the amygdala and left middle frontal cortex was significantly decreased in depressive and manic state participants of the BD group when compared with the HC group (p<0.05, corrected).

CONCLUSIONS

Our findings suggest that mood state during the first episodes of BD may be related to abnormality in hemispheric lateralization. The abnormalities in amygdala- left PFC functional connectivity might present the trait feature for BD, while deficits in amygdala- right PFC functional connectivity might be specific to manic episode, compared to depressive episode.

Defining biotypes for depression and anxiety based on large-scale circuit dysfunction: a theoretical review of the evidence and future directions for clinical translation

Complex emotional, cognitive and self-reflective functions rely on the activation and connectivity of large-scale neural circuits. These circuits offer a relevant scale of focus for conceptualizing a taxonomy for depression and anxiety based on specific profiles (or biotypes) of neural circuit dysfunction. Here, the theoretical review first outlines the current consensus as to what constitutes the organization of large-scale circuits in the human brain identified using parcellation and meta-analysis. The focus is on neural circuits implicated in resting reflection (default mode), detection of "salience," affective processing ("threat" and "reward"), "attention," and "cognitive control." Next, the current evidence regarding which type of dysfunctions in these circuits characterize depression and anxiety disorders is reviewed, with an emphasis on published meta-analyses and reviews of circuit dysfunctions that have been identified in at least two well-powered case:control studies. Grounded in the review of these topics, a conceptual framework is proposed for considering neural circuit-defined "biotypes." In this framework, biotypes are defined by profiles of extent of dysfunction on each large-scale circuit. The clinical implications of a biotype approach for guiding classification and treatment of depression and anxiety is considered. Future research directions will develop the validity and clinical utility of a neural circuit biotype model that spans diagnostic categories and helps to translate neuroscience into clinical practice in the real world.

Resting State Brain Network Disturbances Related to Hypomania and Depression in Medication-Free Bipolar Disorder

Research on resting functional brain networks in bipolar disorder (BP) has been unable to differentiate between disturbances related to mania or depression, which is necessary to understand the mechanisms leading to each state. Past research has also been unable to elucidate the impact of BP-related network disturbances on the organizational properties of the brain (eg, communication efficiency). Thus, the present work sought to isolate network disturbances related to BP, fractionate these into components associated with manic and depressive symptoms, and characterize the impact of disturbances on network function. Graph theory was used to analyze resting functional magnetic resonance imaging data from 60 medication-free patients meeting the criteria for BP and either a current hypomanic (n=30) or depressed (n=30) episode and 30 closely age/sex-matched healthy controls. Correction for multiple comparisons was carried out. Compared with controls, BP patients evidenced hyperconnectivity in a network involving right amygdala. Fractionation revealed that (hypo)manic symptoms were associated with hyperconnectivity in an overlapping network and disruptions in the brain's 'small-world' network organization. Depressive symptoms predicted hyperconnectivity in a network involving orbitofrontal cortex along with a less resilient global network organization. Findings provide deeper insight into the differential pathophysiological processes associated with hypomania and depression, along with the particular impact these differential processes have on network function.

Increased social anhedonia and reduced helping behaviour in young people with high depressive symptomatology

BACKGROUND

Social anhedonia, the decreased enjoyment of pleasant social experiences, is associated with depression. However, whether social anhedonia in depression affects prosocial behaviours is unclear. The current study aimed to examine how high levels of depressive symptomatology in young people affect responses to usually rewarding social situations, including helping behaviour.

METHODS

We recruited 46 females, 16 scoring high on the Beck Depression Inventory (BDI scores>20, M_age=19; HD) and 30 scoring low (BDI<10, M_age=20; LD). In a social emotion task (SET), participants were presented with social scenarios and asked to rate their expected emotional responses. Subsequently, participants' helping behaviour was measured by dropping a pile of papers near them and recording their responses. Lastly, participants completed the SET again.

RESULTS

The SET at time 1 revealed that HD individuals reported significantly stronger negative (p<.001) and weaker positive (p<.05) emotional responses to social situations than LD subjects. Additionally, all participants showed a significant increase in positive responses (p<.05) on the SET between time 1 and time 2. Moreover, HD subjects were less likely to engage in actual helping behaviour than LD participants.

LIMITATIONS

Limitations of the study are that only females were tested and that no psychiatric screening interview was conducted.

CONCLUSIONS

Our results indicate that young females with high levels of depression symptoms expect to respond less positively to social situations and engage less in helping behaviour compared to those with low depressive symptomatology. Social anhedonia in depression may thus contribute to decreased engagement in rewarding social situations. This, in turn, may lead to social withdrawal and might maintain depression symptoms though a lack of exposure to positive social feedback.

Rethinking the Use of Neutral Faces as a Baseline in fMRI Neuroimaging Studies of Axis-I Psychiatric Disorders

Major Axis-I disorders including major depressive disorder (MDD), bipolar disorder (BD), anxiety disorder, and schizophrenia are associated with a host of aberrations in the way social stimuli are processed. Face perception tasks are often used in neuroimaging research of emotion processing in both healthy and patient populations, and to date, there exists a mounting body of evidence, both behavioral and within the brain, indicating that emotional faces compared to neutral faces are processed abnormally by those with Axis-I disorders relative to healthy control (HC) groups. The use of neutral faces as a "baseline control condition" is predicated on the assumption that neutral faces are processed in the same way HCs and individuals with major Axis-I disorders. In this paper, existing fMRI studies examining the way neutral faces are processed in groups with Axis-I disorders involving socioaffective perception are reviewed. In reviewing available studies, a consistent pattern of results demonstrated that these disorders are associated with abnormal frontolimbic activity in response to neutral faces and in particular within the amygdala and prefrontal regions such as the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) compared to HC groups. Specifically, increased amygdala activation was consistently reported in response to neutral faces in anxiety disorders and schizophrenia. Abnormal medial PFC activity was reported in patients with MDD, and patients with BD exhibit decreased activity in the DLPFC and ACC relative to HCs. In addition, specific suggestions to overcome these obstacles with new research and additional analyses are discussed.

Brain functional effects of psychopharmacological treatments in bipolar disorder

Functional magnetic resonance imaging (fMRI) studies have contributed to the understanding of bipolar disorder. However the effect of medication on brain activation remains poorly understood. We conducted an extensive literature review on PubMed and ScienceDirect to investigate the influence of medication in fMRI studies, including both longitudinal and cross-sectional studies, which aimed at assessing this influence. Although we reported all reviewed studies, we gave greater emphasis to studies with the most robust methodology. One hundred and forty studies matched our inclusion criteria and forty-seven studies demonstrated an effect of pharmacological treatment on fMRI blood oxygen level dependent (BOLD) signal in adults and children with bipolar disorder. Out of these studies, nineteen were longitudinal. Most of cross-sectional studies suffered from methodological bias, due to post-hoc analyses performed on a limited number of patients and did not find any effect of medication. However, both longitudinal and cross-sectional studies showing an impact of treatment tend to suggest that medication prescribed to patients with bipolar disorder mostly influenced brain activation in prefrontal regions, when measured by tasks involving emotional regulation and processing as well as non-emotional cognitive tasks. FMRI promises to elucidate potential new biomarkers in bipolar disorder and could be used to evaluate the effect of new therapeutic compounds. Further research is needed to disentangle the effect of medication and the influence of the changes in mood state on brain activation in patients with bipolar disorder.