Is a lack of disgust something to fear? A functional magnetic resonance imaging facial emotion recognition study in euthymic bipolar disorder patients

Neuroimaging Changes in the Sensorimotor Network and Visual Network in Bipolar Disorder and Their Relationship with Genetic Characteristics

Objective: Patients with bipolar disorder (BD) may exhibit common and significant changes in brain activity across different networks. Our aim was to investigate the changes in functional connectivity (FC) within different brain networks in BD, as well as their neuroimaging homogeneity, heterogeneity, and genetic variation. Methods: In this study, we analyzed the seed points and whole-brain FC of the sensorimotor network (SMN) and visual network (VN) in 83 healthy controls (HCs) and 77 BD patients, along with their genetic neuroimaging associations. Results: The results showed that, compared to HCs, BD patients exhibited abnormal FC in the SMN and VN brain regions. However, after three months of treatment, there were no significant differences in SMN and VN FC in the brain regions of the patients compared to pre-treatment levels. Enrichment analysis indicated that genes associated with changes in FC were shared among different SMN seed points, but no shared genes were found among VN seed points. Conclusions: In conclusion, changes in SMN FC may serve as a potential neuroimaging marker in BD patients. Our genetic neuroimaging association analysis may help to comprehensively understand the molecular mechanisms underlying FC changes in BD patients.

Error monitoring and response inhibition in adolescents with bipolar disorders: An ERP study

Cognitive control develops throughout adolescence, a high-risk period for bipolar disorders (BD) onset. Despite neurobehavioral abnormalities in adults with BD, there is minimal research investigating deviations in cognitive control in adolescents with BD. Cognitive control involves numerous processes. Identifying the specific neural abnormalities in adolescent BD could provide precise targets for novel interventions that improve illness outcomes. The present study administered a Go/No-Go (GNG) task to 98 adolescents (44 BD; 54 controls) to activate response inhibition and error processes and recorded EEG for event-related potentials (ERPs) analysis. Stimulus-locked N2 and P3 (response inhibition) and response-locked error-related negativity (ERN; early error detection) and error positivity (Pe; conscious error detection) were analyzed. Adolescents with BD had attenuated Pe mean amplitudes following failed inhibition trials. There were no group differences in other ERP amplitudes, including N2, P3, and ERN. The pattern of findings implicates conscious error detection impairment in adolescents with BD, without support for deficits in more automatic, earlier error detection. Impaired conscious error detection in adolescents with BD may be an early expression of BD pathophysiology and a possible intervention target for cognitive rehabilitation. Further studies are needed to examine Pe in BD across the lifetime.

Structural and functional disruption of subcortical limbic structures related with executive function in pediatric bipolar disorder

BACKGROUND

Impaired cognition has been demonstrated in pediatric bipolar disorder (PBD). The subcortical limbic structures play a key role in PBD. However, alternations of anatomical and functional characteristics of subcortical limbic structures and their relationship with neurocognition of PBD remain unclear.

METHODS

Thirty-six PBD type I (PBD-I) (15.36 ± 0.32 years old), twenty PBD type II (PBD-II) (14.80 ± 0.32 years old) and nineteen age-gender matched healthy controls (HCs) (14.16 ± 0.36 years old) were enlisted. Primarily, the volumes of the subcortical limbic structures were obtained and differences in the volumes were evaluated. Then, these structures served as seeds of regions of interest to calculate the voxel-wised functional connectivity (FC). After that, correlation analysis was completed between volumes and FC of brain regions showing significant differences and neuropsychological tests.

RESULTS

Compared to HCs, both PBD-I and PBD-II patients showed a decrease in the Stroop color word test (SCWT) and digit span backward test scores. Compared with HCs, PBD-II patients exhibited a significantly increased volume of right septal nuclei, and PBD-I patients presented increased FC of right nucleus accumbens and bilateral pallidum, of right basal forebrain with right putamen and left pallidum. Both the significantly altered volumes and FC were negatively correlated with SCWT scores.

SIGNIFICANCE

The study revealed the role of subcortical limbic structural and functional abnormalities on cognitive impairments in PBD patients. These may have far-reaching significance for the etiology of PBD and provide neuroimaging clues for the differential diagnosis of PBD subtypes.

CONCLUSIONS

Distinctive features of neural structure and function in PBD subtypes may contribute to better comprehending the potential mechanisms of PBD.

Advances in functional MRI research in bipolar disorder: from the perspective of mood states

Bipolar disorder is characterised by recurrent and alternating episodes of mania/hypomania and depression. Current breakthroughs in functional MRI techniques have uncovered the functional neuroanatomy of bipolar disorder. However, the pathophysiology underlying mood instability, mood switching and the development of extreme mood states is less well understood. This review presents a comprehensive overview of current evidence from functional MRI studies from the perspective of mood states. We first summarise the disrupted brain activation patterns and functional connectivity that have been reported in bipolar disorder, irrespective of the mood state. We next focus on research that solely included patients in a single mood state for a better understanding of the pathophysiology of bipolar disorder and research comparing patients with different mood states to dissect mood state-related effects. Finally, we briefly summarise current theoretical models and conclude this review by proposing potential avenues for future research. A comprehensive understanding of the pathophysiology with consideration of mood states could not only deepen our understanding of how acute mood episodes develop at a neurophysiological level but could also facilitate the identification of biological targets for personalised treatment and the development of new interventions for bipolar disorder.

Functional connectivity of the cerebellar vermis in bipolar disorder and associations with mood

Purpose

Studies of the neural underpinnings of bipolar type I disorder have focused on the emotional control network. However, there is also growing evidence for cerebellar involvement, including abnormal structure, function, and metabolism. Here, we sought to assess functional connectivity of the cerebellar vermis with the cerebrum in bipolar disorder and to assess whether connectivity might depend on mood.

Methods

This cross-sectional study enrolled 128 participants with bipolar type I disorder and 83 control comparison participants who completed a 3 T magnetic resonance imaging (MRI) study, which included anatomical as well as resting state Blood Oxygenation Level Dependent (BOLD) imaging. Functional connectivity of the cerebellar vermis to all other brain regions was assessed. Based on quality control metrics of the fMRI data, 109 participants with bipolar disorder and 79 controls were included in the statistical analysis comparing connectivity of the vermis. In addition, the data was explored for the potential impacts of mood, symptom burden, and medication in those with bipolar disorder.

Results

Functional connectivity between the cerebellar vermis and the cerebrum was found to be aberrant in bipolar disorder. The connectivity of the vermis was found to be greater in bipolar disorder to regions involved in motor control and emotion (trending), while reduced connectivity was observed to a region associated with language production. In the participants with bipolar disorder, past depression symptom burden affected connectivity; however, no effects of medication were observed. Functional connectivity between the cerebellar vermis and all other regions revealed an inverse association with current mood ratings.

Conclusion

Together the findings may suggest that the cerebellum plays a compensatory role in bipolar disorder. The proximity of the cerebellar vermis to the skull may make this region a potential target for treatment with transcranial magnetic stimulation.

Effect of high-definition transcranial direct current stimulation on improving depression and modulating functional activity in emotion-related cortical-subcortical regions in bipolar depression

Preliminary studies have suggested that transcranial direct current stimulation (tDCS) is effective for bipolar depression, However, brain correlates of the depression alleviating are unclear. To determine the efficacy and safety of tDCS as an add-on treatment for patients with bipolar depression and further to identify the effect of tDCS on the resting-state brain activities, we recruited fifty patients with bipolar depression to complete the double-blind, sham-controlled and randomized clinical trial. Fourteen sessions of tDCS were performed once a day for 14 days. The anode was placed over F3 with return electrodes placed at FP1, FZ, C3 and F7. Regional homogeneity (ReHo) was examined on 50 patients with bipolar depression before and after 14-day active or sham tDCS. Patients in the active group showed significantly superior alleviating the depression symptoms compared with those receiving sham. The active group after 14-day active tDCS showed increased ReHo values in the orbitofrontal cortex and middle frontal gyrus and decreased ReHo values in subcortical structures including hippocampus, parahippocampa gyrus, amygdala, putamen and lentiform nucleus. The reduction of depression severity showed positive correlation of increased ReHo values in the orbitofrontal cortex and middle frontal gyrus and negative correlation of altered ReHo values in the putamen and lentiform. TDCS was an effective and safe add-on intervention for this small bipolar depression sample. The reduction of depression induced by tDCS is associated with a modulation of neural synchronization in the cortical and subcortical structures (ReHo values) within an emotion-related brain network.

Limbic and cortical regions as functional biomarkers associated with emotion regulation in bipolar disorder: A meta-analysis of neuroimaging studies

BACKGROUND

Bipolar disorder (BD) is a psychiatric disorder characterized by episodes of depression and mania, associated with impaired emotion processing. Several functional MRI (fMRI) studies have been used to investigate the structural and functional alteration in BD. Here, we aim to investigate the current fMRI findings of brain activation during emotion-regulation tasks between BD patients and healthy controls (HC).

METHODS

A systematic search through PubMed database for fMRI studies on bipolar patients and HC yielded 685 studies. We performed an activation likelihood estimation (ALE) on 21 studies for emotion regulation in BD patients and HC. Furthermore, we performed subgroup analyses for task performances in response time and accuracy between bipolar patients and HC.

RESULTS

The total sample included 21 fMRI studies, comprising 543 BD patients, compared to 565 HC. ALE maps for emotion-related tasks showed hyperactivation in BD patients in the caudate, amygdala, precentral gyrus, middle frontal gyri, and sub-gyrus. Whereas hypoactivation was seen in the inferior frontal gyrus and anterior cingulate gyrus.

LIMITATIONS

We could not apply a correction for p-value thresholds, as it needs large number of foci. Second, functional abnormalities were investigated for adult BD patients only, as BD patients have functional differences correlated with age.

CONCLUSIONS

Our results showed that limbic and cortical regions can represent a potential biomarker for the diagnosis and management of BD, by showing clustered brain regions of abnormal patterns of increased activation between BD patients and HC.

Functional Connectivity of the Cerebellar Vermis in Bipolar Disorder and Associations with Mood

Purpose

Studies of the neural underpinnings of bipolar type I disorder have focused on the emotional control network. However, there is also growing evidence for cerebellar involvement, including abnormal structure, function, and metabolism. Here, we sought to assess functional connectivity of the cerebellum with the cerebrum in bipolar disorder and to assess whether any effects might depend on mood.

Methods

This cross-sectional study enrolled 128 participants with bipolar type I disorder and 83 control comparison participants who completed a 3T MRI scan, which included anatomical imaging as well as resting state BOLD imaging. Functional connectivity of the cerebellar vermis to all other brain regions was assessed. Based on quality control metrics of the fMRI data, 109 participants with bipolar disorder and 79 controls were used to in the statistical analysis comparing connectivity of the vermis as well as associations with mood. Potential impacts of medications were also explored.

Results

Functional connectivity of the cerebellar vermis in bipolar disorder was found to differ significantly between brain regions known to be involved in the control of emotion, motor function, and language. While connections with emotion and motor control areas were significantly stronger in bipolar disorder, connection to a region associated language production was significantly weaker. In the participants with bipolar disorder, ratings of depression and mania were inversely associated with vermis functional connectivity. No effect of medications on these connections were observed.

Conclusion

Together the findings suggest cerebellum may play a compensatory role in bipolar disorder and when it can no longer fulfill this role, depression and mania develop. The proximity of the cerebellar vermis to the skull may make this region a potential target for treatment with transcranial magnetic stimulation.

Distinct brain activity alterations of treatment for bipolar disorders with psychotherapy and drug therapy: activation likelihood estimation meta-analysis

BACKGROUNDS

Many studies suggest that both psychotherapy and drug therapy are effective in the treatment of bipolar disorders (BDs). However, the pathophysiology of both types of intervention has not been established definitively.

METHODS

An activation likelihood estimation meta-analysis was performed to identify the distinct brain activity alterations between psychotherapy and drug therapy for the treatment of BDs. Articles were identified by searching databases including PubMed, Embase, Cochrane Library, and Web of Science databases. Eligible studies on BDs were published up until 10 June 2021.

RESULTS

21 studies were included and we conducted a meta-analysis for different therapies and imaging tasks. After receiving psychotherapy, BD patients showed increased activation in the inferior frontal gyrus (IFG) and superior temporal gyrus. While after taking drug therapy, BD patients displayed increased activation in the anterior cingulate cortex, medial frontal gyrus, IFG, and decreased activation in the posterior cingulate cortex. The regions of brain activity changes caused by psychotherapy were mostly focused on the frontal areas, while drug therapy mainly impacted on the limbic areas. Different type of tasks also affected brain regions which were activated.

CONCLUSIONS

Our comprehensive meta-analysis indicates that these two treatments might have effect on BD in their own therapeutic modes. Psychotherapy might have a top-down effect, while drug therapy might have a bottom-up effect. This study may contribute to differential diagnosis of BDs and would be helpful to finding more accurate neuroimaging biomarkers for BD treatment.

Associations of emotion recognition, loneliness, and social functioning in euthymic patients with bipolar disorder

Emotion recognition deficit is related to impaired community functioning. Loneliness is also associated with impaired social performance. However, the way in which emotion recognition and loneliness may contribute to social functioning remains unclear in euthymic patients with bipolar disorder. We aimed to examine emotion recognition ability in Han Chinese euBD patients relative to healthy controls (HCs) and to investigate the associations between emotion recognition, loneliness, and social functioning. Thirty-nine HCs and 46 euthymic BD patients completed an emotion recognition task and nonsocial cognitive measures related to executive function and attention. The UCLA loneliness scale and Social Performance Scale were administered to evaluate psychological loneliness and social functioning, respectively. We observed lower emotion recognition accuracy, higher loneliness, and poorer social functioning in the BD patients after adjustment for demographic data. Loneliness was negatively associated with global social functioning in both the BD and HC groups. Higher loneliness and lower emotion recognition accuracy were associated with poorer social functioning in euthymic BD in different subdomains. Our study confirmed a subtle impairment of emotion recognition ability in euthymic BD. Loneliness impacts globally on social functioning, while emotion recognition ability may affect specific subdomains of social functioning in euthymic BD. Alleviation of loneliness and enhancement of social cognition might improve social functioning in BD patients.

Common and distinct neurofunctional representations of core and social disgust in the brain: Coordinate-based and network meta-analyses

Disgust represents a multifaceted defensive-avoidance response. On the behavioral level, the response includes withdrawal and a disgust-specific facial expression. While both serve the avoidance of pathogens, the latter additionally transmits social-communicative information. Given that common and distinct brain representation of the primary defensive-avoidance response (core disgust) and encoding of the social-communicative signal (social disgust) remain debated, we employed neuroimaging meta-analyses to (1) determine brain systems generally engaged in disgust processing, and (2) segregate common and distinct brain systems for core and social disgust. Disgust processing, in general, engaged a bilateral network encompassing the insula, amygdala, occipital and prefrontal regions. Core disgust evoked stronger reactivity in left-lateralized threat detection and defensive response network including amygdala, occipital and frontal regions, while social disgust engaged a right-lateralized superior temporal-frontal network involved in social cognition. Anterior insula, inferior frontal and fusiform regions were commonly engaged during core and social disgust, suggesting a shared neurofunctional basis. We demonstrate a common and distinct neural basis of primary disgust responses and encoding of associated social-communicative signals.

Emotion Processing Deficit in Euthymic Bipolar Disorder: A Potential Endophenotype

BACKGROUND

Emotion processing deficits have been described in patients with bipolar disorder (BD) and are considered one of the core cognitive abnormalities in BD with endophenotype potential. However, the literature on specific impairments in emotion processing cognitive strategies (directive/cortical/higher versus intuitive/limbic/lower) in euthymic adult BD patients and healthy first-degree relatives/high-risk (HR) subjects in comparison with healthy controls (HCs) is sparse.

METHODS

We examined facial emotion recognition deficits (FERD) in BD (N = 30), HR (N = 21), and HC (N = 30) matched for age (years), years of education, and sex using computer-administered face emotions-Matching And Labeling Task (eMALT).

RESULTS

The three groups were significantly different based on labeling accuracy scores for fear and anger (FA) (P < 0.001) and sad and disgust (SD) (P < 0.001). On post-hoc analysis, HR subjects exhibited a significant deficit in the labeling accuracy of FA facial emotions (P < 0.001) compared to HC. The BD group was found to have significant differences in all FA (P = 0.004) and SD (P = 0.003) emotion matching as well as FA (P = 0.001) and SD (P < 0.001) emotion labeling accuracy scores.

CONCLUSIONS

BD in remission exhibits FERD in general, whereas specific labeling deficits of fear and anger emotions, indicating impaired directive higher order aspect of emotion processing, were demonstrated in HR subjects. This appears to be a potential endophenotype. These deficits could underlie the pathogenesis in BD, with possible frontolimbic circuitry impairment. They may have potential implications in functional recovery and prognosis of BD.

Facial emotion recognition and its association with quality of life and socio-occupational functioning in patients with bipolar disorder and their first-degree relatives

INTRODUCTION

Facial emotion recognition deficits (FERD) are common even in the remitted phase of bipolar disorder (BD). Research regarding FERD in first-degree relatives is inconclusive. This study aimed to assess the facial emotion recognition in remitted patients of bipolar disorder and first-degree relatives(FDR) in comparison with healthy controls. Correlation between FERD and quality of life and socio-occupational functioning was also assessed.

METHODS

It was an observational, cross-sectional study done at a tertiary hospital in India. Study population (n = 75) included remitted patients of bipolar disorder (n = 27), first-degree relatives of BD patients (FDR) (n = 20) and healthy controls (HC) (n = 28). Facial emotion recognition, social and occupational functioning, and quality of life (QoL) was measured using Tool for Recognition of Emotions in Neuropsychiatric Disorders, Social & Occupational Functioning Assessment Scale and World Health Organization Quality of Life-Bref, respectively, in all the participants.

RESULTS

The BD group did significantly worse in facial emotion recognition in comparison to FDR and HC groups (p < 0.001). Emotion recognition of fear, anger, surprise, and happy were most affected. FDR did not vary significantly from HC in facial emotion recognition. Lower scores on facial emotion recognition were associated with lower QoL in the social domain(p = 0.006) and poorer socio- occupational functioning scores (p = 0.01), but it was not significant within the BD group.

CONCLUSION

FERD is seen in remitted patients of bipolar disorder but not in the first -degree relatives. FERD affects social quality of life and functioning. Poorer social functioning in remitted patients of bipolar disorder might be multifactorial and cannot be attributed solely to FERD.

Cortical Thickness and Surface Area Abnormalities in Bipolar I and II Disorders

OBJECTIVE

Although bipolar II disorder (BD II) is not simply a mitigated form of bipolar I disorder (BD I), their neurobiological differences have not been elucidated. The present study aimed to explore cortical thickness (CT) and surface area (SA) in patients with BD I and BD II and healthy controls (HCs) to investigate the shared and unique neurobiological mechanisms of BD subtypes.

METHODS

We enrolled 30 and 44 patients with BD I and BD II, respectively, and 100 HCs. We evaluated CT and SA using FreeSurfer and estimated differences in CT and SA among the three groups (BD I vs. BD II vs. HC). We adjusted for age, sex, educational level, and intracranial volume as confounding factors.

RESULTS

We found widespread cortical thinning in the bilateral frontal, temporal, and occipital regions; cingulate gyrus; and insula in patients with BD. Alterations in SA, including increased SA of the pars triangularis and decreased SA of the insula, were noted in patients with BD. Overall, we found BD II patients demonstrated decreased SA in the right long insula compared to BD I patients.

CONCLUSION

Our results suggest that decreased SA in the right long insula is crucial for differentiating BD subtypes.

Asymmetrical alterations of grey matter among psychiatric disorders: A systematic analysis by voxel-based activation likelihood estimation

Schizophrenia (SZ), bipolar disorder (BD) and major depression disorder (MDD) have been regarded as highly diverged independent entities in current psychiatric diagnosis. However, ample new evidence suggests that they may have common biological traits. Neuroimaging studies showed that psychiatric disorders might associated with altered grey matter (GM) asymmetry compared to controls; however, the degree to which SZ, BD and MDD have common and/or distinct asymmetrical alterations in GM is still ambiguous. In this study, we analysed 169 voxel-based studies (including 3517 SZ patients, 1575 BD patients, 3280 MDD patients and 9733 controls) using activation likelihood estimation (ALE) meta-analysis to systematically review the existence of similar GM atrophy and asymmetrical alteration patterns among these psychiatric disorders, and the functional association between behaviour domains and topological alterations. We found that the right parahippocampal gyrus and left superior frontal gyrus showed commonly altered GM volume across all three illnesses, but did not identify common asymmetrical alteration. The asymmetrical alteration with leftward bias appeared in SZ and bipolar disorder at different locations, but more asymmetrical alteration with rightward bias appeared in MDD. Moreover, these changes have been confirmed to be associate with several symptoms and may have roles in functional networks. Our findings support the existence of common neurobiological damnification in these psychiatric disorders and provides valuable insights for the neural commonalties among different psychiatric disorders based on a large sample size.

Structural neuroimaging phenotypes of a novel multi-gene risk score in youth bipolar disorder

BACKGROUND

Bipolar disorder (BD) is among the most heritable psychiatric disorders, particularly in early-onset cases, owing to multiple genes of small effect. Here we examine a multi-gene risk score (MGRS), to address the gap in multi-gene research in early-onset BD.

METHODS

MGRS was derived from 34 genetic variants relevant to neuropsychiatric diseases and related systemic processes. Multiple MGRS were calculated across a spectrum of inclusion p-value thresholds, based on allelic associations with BD. Youth participants (123 BD, 103 healthy control [HC]) of European descent were included, of which 101 participants (58 BD, 43 HC) underwent MRI T1-weighted structural neuroimaging. Hierarchical regressions examined for main effects and MGRS-by-diagnosis interaction effects on 6 regions-of-interest (ROIs). Vertex-wise analysis also examined MGRS-by-diagnosis interactions.

RESULTS

MGRS based on allelic association p≤0.60 was most robust, explaining 6.8% of variance (t(226)=3.46, p=.001). There was an MGRS-by-diagnosis interaction effect on ventrolateral prefrontal cortex surface area (vlPFC; β=.21, p=.0007). Higher MGRS was associated with larger vlPFC surface area in BD vs. HC. There were 8 significant clusters in vertex-wise analyses, primarily in fronto-temporal regions, including vlPFC.

LIMITATIONS

Cross-sectional design, modest sample size.

CONCLUSIONS

There was a diagnosis-by-MGRS interaction effect on vlPFC surface area, a region involved in emotional processing, emotional regulation, and reward response. Vertex-wise analysis also identified several clusters overlapping this region. This preliminary study provides an example of an approach to imaging-genetics that is intermediate between candidate gene and genome-wide association studies, enriched for genetic variants with established relevance to neuropsychiatric diseases.

Time-Frequency Characterization of Resting Brain in Bipolar Disorder during Euthymia-A Preliminary Study

The goal of this paper is to investigate the baseline brain activity in euthymic bipolar disorder (BD) patients by comparing it to healthy controls (HC) with the use of a variety of resting state functional magnetic resonance imaging (rs-fMRI) analyses, such as amplitude of low frequency fluctuations (ALFF), fractional ALFF (f/ALFF), ALFF-based functional connectivity (FC), and r egional homogeneity (ReHo). We hypothesize that above-mentioned techniques will differentiate BD from HC indicating dissimilarities between the groups within different brain structures. Forty-two participants divided into two groups of euthymic BD patients (n = 21) and HC (n = 21) underwent rs-fMRI evaluation. Typical band ALFF, slow-4, slow-5, f/ALFF, as well as ReHo indexes were analyzed. Regions with altered ALFF were chosen as ROI for seed-to-voxel analysis of FC. As opposed to HC, BD patients revealed: increased ALFF in left insula; increased slow-5 in left middle temporal pole; increased f/ALFF in left superior frontal gyrus, left superior temporal gyrus, left middle occipital gyrus, right putamen, and bilateral thalamus. There were no significant differences between BD and HC groups in slow-4 band. Compared to HC, the BD group presented higher ReHo values in the left superior medial frontal gyrus and lower ReHo values in the right supplementary motor area. FC analysis revealed significant hyper-connectivity within the BD group between left insula and bilateral middle frontal gyrus, right superior parietal gyrus, right supramarginal gyrus, left inferior parietal gyrus, left cerebellum, and left supplementary motor area. To our best knowledge, this is the first rs-fMRI study combining ReHo, ALFF, f/ALFF, and subdivided frequency bands (slow-4 and slow-5) in euthymic BD patients. ALFF, f/ALFF, slow-5, as well as REHO analysis revealed significant differences between two studied groups. Although results obtained with the above methods enable to identify group-specific brain structures, no overlap between the brain regions was detected. This indicates that combination of foregoing rs-fMRI methods may complement each other, revealing the bigger picture of the complex resting state abnormalities in BD.

Cortical activity measured by functional near infrared spectroscopy during a theory of mind task in subjects with schizophrenia, bipolar disorder and healthy controls

Theory of Mind (ToM) deficits interfere in social cognitive functioning in schizophrenia (SCZ) and are increasingly recognized to do so in bipolar disorder (BD), however their clinical and neurobiological correlates remain unclear. This study represents the first direct comparison of subjects with SCZ (N = 26), BD (N = 26) and healthy controls (N = 33) in cortical activity during the Reading the Mind in the Eyes Task (RMET) using functional Near Infrared Spectroscopy (fNIRS) with the control condition (CC) involving gender identification via the same stimuli. The three groups were compared with a comprehensive ToM battery and assessed in terms of the relationship of ToM performance with clinical symptoms, insight and functioning. The controls scored higher than the SCZ and BD groups in ToM assessments, with SCZ group showing the worse performance in terms of meta-representation and empathy. The SCZ group ToM scores inversely correlated with negative symptom severity and positively correlated with insight; BD group ToM scores negatively correlated with subclinical mania symptoms and projected functioning. Cortical activity was higher during the ToM condition compared to the CC in the pre-motor and supplementary-motor cortices, middle and superior temporal gyri, and the primary somatosensory cortex. Group x Condition interaction was detected whereby activity was higher during the ToM condition among controls with no detected difference between SCZ and BD groups. The results suggest that ToM is represented similarly in cortical activity in SCZ and BD compared to healthy controls pointing to possible neurobiological convergence of SCZ and BD in underlying impairments of social cognition.

The activity and connectivity of the facial emotion processing neural circuitry in bipolar disorder: a systematic review

BACKGROUND

Facial emotion processing abnormalities may be a trait feature of bipolar disorder (BD). These social cognitive impairments may be due to alterations in the neural processing of facial affective information in visual ("core"), and limbic and prefrontal ("extended") networks, however, the precise neurobiological mechanism(s) underlying these symptoms are unclear.

METHODS

We conducted a systematic review to appraise the literature on the activity and connectivity of the facial emotion processing neural circuitry in BD. Two reviewers undertook a search of the electronic databases PubMed, Scopus and PsycINFO, to identify relevant literature published since inception up until September 2019. Study eligibility criteria included; BD participants, neuroimaging, and facial emotion processing tasks.

RESULTS

Out of an initial yield of 6121 articles, 66 were eligible for inclusion in this review. We identified differences in neural activity and connectivity within and between occipitotemporal, limbic, and prefrontal regions, in response to facial affective stimuli, in BD compared to healthy controls.

LIMITATIONS

The methodologies used across studies varied considerably.

CONCLUSIONS

The findings from this review suggest abnormalities in both the activity and connectivity of facial emotion processing neural circuitry in BD. It is recommended that future research aims to further define the connectivity and spatiotemporal course of neural events within and between occipitotemporal, limbic, and prefrontal regions.

Social cognition in siblings of patients with bipolar disorders

BACKGROUND

Identifying people at risk of developing bipolar disorder (BD) using endophenotypes is of recent interest. Few studies on social cognition in first-degree relatives of patients with BD have shown inconsistent findings. This study aimed to evaluate the social cognitive deficits (SCD) and its correlates among siblings of patients with BD.

METHODOLOGY

In this cross-sectional study, patients of BD (n = 32), their siblings (n = 32), and healthy control (HC) subjects (n = 38) matched for age, gender, and education were evaluated on social cognition rating tools in Indian setting and neurocognitive tests (color trail test, Wisconsin card sorting test [WCST], and Hopkin's verbal learning test [HVLT]).

RESULTS

When the siblings of patients with BD were compared with patients with BD and the HCs, siblings (mean 0.6 [standard deviation [SD]: 0.2]) performed worse than the HCs (mean 0.9 [SD: 0.1]) (P ≤ 0.001) on the Faux pas composite index. Compared to HCs, siblings performed worse on all the subtests of HVLT (Trial delayed) (P < 0.001) and WCST (total correct, total errors, and conceptual responses) (P < 0.001).

CONCLUSION

Presence of elevated level of SCD among siblings, especially the Faux pas composite index in comparison to HCs, imply that these are stable traits, which are more often present in the patients and at risk individuals. This implies that SCD can be considered as another important endophenotype for BD.

Microsaccadic modulation evoked by emotional events

Saccadic eye movements can allude to emotional states and visual attention. Recent studies have shown that microsaccadic responses (i.e., small fixational eye movements) reflect advanced brain activity during attentional and cognitive tasks. Moreover, the microsaccadic activity related to emotional attention provides new insights into this field. For example, emotional pictures attenuate the microsaccadic rate, and microsaccadic responses to covert attention occur in the direction opposite to a negative emotional target. However, the effects of various emotional events on microsaccadic activity remain debatable. This review introduces visual attention and eye movement studies that support findings on the modulation of microsaccadic responses to emotional events, comparing them with typical microsaccadic responses. This review also discusses the brain neuronal mechanisms governing microsaccadic responses to the attentional shifts triggered by emotion-related stimuli. It is hard to reveal the direct brain pathway of the microsaccadic modulation, especially in advanced (e.g., sustained anger, envy, distrust, guilt, frustration, delight, attraction, trust, and love), but also in basic human emotions (i.e., anger, disgust, fear, happiness, sadness, and surprise). However, non-human primates and human studies can uncover the possible brain pathways of emotional attention and microsaccades, thus providing future research directions. In particular, the facilitated (or reduced) attention is common evidence that microsaccadic activities change under a variety of social modalities (e.g., cognition, music, mental illness, and working memory) that elicit emotions and feelings.

Facial emotion recognition deficits in patients with bipolar disorder and their healthy parents

BACKGROUND

There is evidence on deficits in facial emotion recognition (FER) in patients with bipolar disorder (BD), and these deficits may be present in individuals with genetic risk for BD. This study investigated facial emotion identification and discrimination abilities in patients with BD, their parents, and healthy controls.

MATERIALS AND METHODS

This study included 38 patients with bipolar I disorder and 30 healthy controls for patients as well as 30 healthy mothers and 30 healthy fathers of these patients and 30 healthy controls who matched the mothers and fathers for age, gender, and education (total 188 participants). Facial Emotion Identification and Discrimination Tests were applied to all participants; the Hamilton Depression Rating Scale and Young Mania Rating Scale were applied to patients and their control group.

RESULTS

Facial Emotion Identification and Discrimination Test scores of patients and their parents were reasonably lower than their matching control groups. Moreover, we found that difficulty in FER affected more emotions in mothers than in fathers and mothers performed significantly worse than patients in the identification of angry and embarrassed faces.

CONCLUSION

These findings indicate that parents of patients with BD have impairment with recognizing facial emotions and suggest that there may be an association between FER of patients with BD and that of their mothers.

Emotional memory in bipolar disorder: Impact of multiple episodes and childhood trauma

BACKGROUND

Emotional memory is a critical amygdala-dependent cognitive function characterized by enhanced memory for emotional events coupled with retrograde amnesia. Our study aims to assess the influence of bipolar disorder (BD), trauma, and the number of mood episodes on emotional memory.

METHODS

53 subjects (33 euthymic patients with BD and 20 healthy controls) answered a clinical assessment, childhood trauma questionnaire (CTQ), and an emotional memory test composed of lists of nouns, including neutral words, one emotional (E), one preceding (E-1) and one following word (E + 1). We assessed for the influence of type, position, diagnosis, trauma, and number of mood episodes in word recall using generalized estimating equations.

RESULTS

Controlling for neutral words, BD had a higher recall for E-1 (p = 0.038) and a trend for a higher recall of E (p = 0.055). There was no difference between patients with and without trauma. Patients with BD who suffered multiple mood episodes had a higher recall of E compared to patients with fewer episodes (p = 0.016).

LIMITATIONS

Cross-sectional design and small sample size.

CONCLUSION

Our results indicate dysfunction in emotional memory in patients with BD, particularly after multiple mood episodes. While we expected an impaired emotional memory, patients with BD showed an increased recall for emotional stimuli and events preceding them. Childhood trauma does not seem to interfere with emotional memory changes in patients with BD. Emotional memory enhancement seems to be a promising marker of progression in BD.

The Insular Subregions Topological Characteristics of Patients With Bipolar Depressive Disorder

The insular cortex appears to have a crucial role in emotional processing and cognitive control in bipolar disorder (BD). However, most previous studies focused on the entire insular region of BD, neglecting the topological profile of its subregions. Our study aimed to investigate its subregion topological characteristics using the resting-state functional connectivity (rsFC) in patients with BD on depression episode. The magnetic resonance imaging (MRI) data of 28 depressed BD patients and 28 age- and gender-matched healthy controls (HCs) were acquired. We observed that compared to HCs, depressed patients with BD exhibited significantly decreased rsFC between the right ventral anterior insula (vAI) and the left middle temporal gyrus/the right angular, the right dorsal anterior insula (dAI) and the left precuneus, as well as the right posterior insula and the right lingual gyrus. Furthermore, hyperconnectivity was observed between the left dAI and the left medial frontal gyrus, as well as right dAI and left superior temporal gyrus in BD depression. However, no significant group effect was observed between aberrant FC patterns and clinical variables. These findings revealed the functional connectivity patterns of insular subregions for the depressed BD patients, suggesting the potential neural substrate of insular subregions involved in depressive episode of BD. Hence, these results may provide a neural substrate for the potential treatment target of BD on depression episode.

Abnormal Connectivity Within Anterior Cortical Midline Structures in Bipolar Disorder: Evidence From Integrated MRI and Functional MRI

Background: Aberrant functional and structural connectivity across multiple brain networks have been reported in bipolar disorder (BD). However, most previous studies consider the functional and structural alterations in isolation regardless of their possible integrative relationship. The present study aimed to identify the brain connectivity alterations in BD by capturing the latent nexus in multimodal neuroimaging data. Methods: Structural and resting-state images were acquired from 83 patients with BD and 94 healthy controls (HCs). Combined with univariate methods conducted to detect the dysconnectivity in BD, we also employed a semi-multimodal fusion framework fully utilizing the interrelationship between the two modalities to distinguish patients from HCs. Moreover, one-way analysis of variance was adopted to explore whether the detected dysconnectivity has differences across stages of patients with BD. Results: The semi-multimodal fusion framework distinguished patients from HCs with 81.47% accuracy, 85.42% specificity, and 74.75% sensitivity. The connection between the anterior cingulate cortex (ACC) and superior medial prefrontal cortex (sMPFC) contributed the most to BD diagnosis. Consistently, the univariate method also identified that this ACC-sMPFC functional connection significantly decreased in BD patients compared to HCs, and the significant order of the dysconnectivity is: depressive episode < HCs and remission episode < HCs. Conclusions: Our findings, by adopting univariate and multivariate analysis methods, shed light on the decoupling within the anterior midline brain in the pathophysiology of BD, and this decoupling may serve as a trait marker for this disease.

Two patterns of anterior insular cortex functional connectivity in bipolar disorder and schizophrenia

OBJECTIVES

Bipolar disorder (BD) and schizophrenia (SZ) share structural abnormalities in the anterior insula cortex (AIC). The AIC appears to have a crucial role in emotional processing and regulation and cognitive control in BD and SZ.

METHODS

Forty-six participants with BD, 68 with SZ and 66 healthy controls (HC) underwent functional magnetic resonance imaging scanning. Resting-state functional connectivity (rsFC) from AIC subregions (ventral and dorsal) was compared among the three groups.

RESULTS

Compared to HC group, both BD and SZ groups exhibited increased rsFC from the ventral AIC (vAIC) and dorsal AIC (dAIC) to bilateral frontal pole and thalamus, the left middle frontal gyrus and the hippocampus. Meanwhile, the BD group demonstrated increased rsFC from the vAIC to the perigenual anterior cingulate cortex, the SZ group presented increased rsFC from the vAIC and dAIC to the right caudate. Compared with the BD group, the SZ group showed significantly increased rsFC from the vAIC and dAIC to the left middle frontal gyrus.

CONCLUSIONS

The shared AIC rsFC abnormalities in both BD and SZ support the importance of the AIC in the common pathophysiology of BD and SZ. There were also disorder-specific features of AIC rsFC, which might implicate potential avenues for differentiating during the early stages.

Structural imaging biomarkers for bipolar disorder: Meta-analyses of whole-brain voxel-based morphometry studies

BACKGROUND

Bipolar disorder (BD) is a common and destructive psychiatric illness worldwide. Although it is known that BD is associated with morphological abnormalities of the brain, the regions implicated in BD remain unclear. Therefore, we aimed to update current knowledge on potential structural imaging biomarkers of BD.

METHODS

Studies published up to January 31, 2018, were identified by a comprehensive literature search of PubMed, EBSCO, and BrainMap voxel-based morphometry (VBM) database. Whole-brain VBM studies that examined gray matter (GM) abnormalities of group comparisons between BD and healthy controls (HC) and reported results as coordinates in a standard reference space were included. Different meta-analyses were performed by activation likelihood estimation (ALE) algorithm.

RESULTS

A total of 46 studies with 56 experiments, including 1720 subjects and 268 foci were included. Seven different meta-analyses were calculated separately across experiments reporting decreased or increased GM volume among BD, BDΙ, BD-adults, and BD-youths groups. Fifteen regions of significantly different GM volume between four groups and HC were identified. There were extensive GM deficits in the prefrontal and temporal cortex, and enlargements in the putamen, cingulate cortex, and precuneus.

CONCLUSIONS

The results revealed that the thinning of prefrontal cortex was a key region in the pathophysiology of BD. The enlargement of the cingulate cortex may be implicated in a compensatory mechanism. It underscored important differences between BD-adults and BD-youths and specific biomarkers of three subgroups.

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.

Using an emotional saccade task to characterize executive functioning and emotion processing in attention-deficit hyperactivity disorder and bipolar disorder

Despite distinct diagnostic criteria, attention-deficit hyperactivity disorder (ADHD) and bipolar disorder (BD) share cognitive and emotion processing deficits that complicate diagnoses. The goal of this study was to use an emotional saccade task to characterize executive functioning and emotion processing in adult ADHD and BD. Participants (21 control, 20 ADHD, 20 BD) performed an interleaved pro/antisaccade task (look toward vs. look away from a visual target, respectively) in which the sex of emotional face stimuli acted as the cue to perform either the pro- or antisaccade. Both patient groups made more direction (erroneous prosaccades on antisaccade trials) and anticipatory (saccades made before cue processing) errors than controls. Controls exhibited lower microsaccade rates preceding correct anti- vs. prosaccade initiation, but this task-related modulation was absent in both patient groups. Regarding emotion processing, the ADHD group performed worse than controls on neutral face trials, while the BD group performed worse than controls on trials presenting faces of all valence. These findings support the role of fronto-striatal circuitry in mediating response inhibition deficits in both ADHD and BD, and suggest that such deficits are exacerbated in BD during emotion processing, presumably via dysregulated limbic system circuitry involving the anterior cingulate and orbitofrontal cortex.

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.

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.

Functional Dysconnection of the Inferior Frontal Gyrus in Young People With Bipolar Disorder or at Genetic High Risk

BACKGROUND

Bipolar disorder (BD) is characterized by a dysregulation of affect and impaired integration of emotion with cognition. These traits are also expressed in probands at high genetic risk of BD. The inferior frontal gyrus (IFG) is a key cortical hub in the circuits of emotion and cognitive control, and it has been frequently associated with BD. Here, we studied resting-state functional connectivity of the left IFG in participants with BD and in those at increased genetic risk.

METHODS

Using resting-state functional magnetic resonance imaging we compared 49 young BD participants, 71 individuals with at least one first-degree relative with BD (at-risk), and 80 control subjects. We performed between-group analyses of the functional connectivity of the left IFG and used graph theory to study its local functional network topology. We also used machine learning to study classification based solely on the functional connectivity of the IFG.

RESULTS

In BD, the left IFG was functionally dysconnected from a network of regions, including bilateral insulae, ventrolateral prefrontal gyri, superior temporal gyri, and the putamen (p < .001). A small network incorporating neighboring insular regions and the anterior cingulate cortex showed weaker functional connectivity in at-risk than control participants (p < .006). These constellations of regions overlapped with frontolimbic regions that a machine learning classifier selected as predicting group membership with an accuracy significantly greater than chance.

CONCLUSIONS

Functional dysconnectivity of the IFG from regions involved in emotional regulation may represent a trait abnormality for BD and could potentially aid clinical diagnosis.

Emotion processing and psychosocial functioning in euthymic bipolar disorder

OBJECTIVE

To examine emotion processing in euthymic bipolar patients (EBP) compared to healthy controls. In addition, to determine whether or not there is an association between emotion processing and psychosocial functioning.

MATERIAL AND METHODS

A sample of 60 EBP and 60 healthy controls matched for age, gender, education level, and premorbid intelligence were studied. All subjects were assessed using the MATRICS Consensus Cognitive Battery (MCCB) and two additional executive function measures: the Trail Making Test-Part B and the Stroop Test. Emotion processing was examined using the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT). Psychosocial functioning was assessed using the Functional Assessment Short Test (FAST).

RESULTS

Euthymic bipolar patients obtained lower scores than controls in all MSCEIT measures except for the using emotions branch. Likewise, EBP obtained a worse performance than healthy controls in all neurocognitive domains. Correlation between MSCEIT strategic area measures and FAST total score was found (r = -0.311; P < 0.016). Regression analysis showed that residual depressive symptomatology explains a 9.1% of the variance in functional outcome. MSCEIT strategic area score explained an additional 8.6%. Neurocognition did not increase the percentage of the variance explained by emotion processing.

CONCLUSIONS

Euthymic bipolar patients exhibit deficits in emotion processing. Emotion processing is associated with social functioning in these patients.

Interhemispheric functional disconnection because of abnormal corpus callosum integrity in bipolar disorder type II

BACKGROUND

A significantly lower fractional anisotropy (FA) value has been shown in anterior parts of the corpus callosum in patients with bipolar disorder.

AIMS

We investigated the association between abnormal corpus callosum integrity and interhemispheric functional connectivity (IFC) in patients with bipolar disorder.

METHODS

We examined the association between FA values in the corpus callosum (CC-FA) and the IFC between homotopic regions in the anterior cortical structures of bipolar disorder (n=16) and major depressive disorder (n=22) patients with depressed or euthymic states.

RESULTS

We found a positive correlation between the CC-FA and IFC values between homotopic regions of the ventral prefrontal cortex and insula cortex, and significantly lower IFC between these regions in bipolar disorder patients.

CONCLUSIONS

The abnormal corpus callosum integrity in bipolar disorder patients is relevant to the IFC between homotopic regions, possibly disturbing the exchange of emotional information between the cerebral hemispheres resulting in emotional dysregulation.

DECLARATION OF INTEREST

None.

COPYRIGHT AND USAGE

© The Royal College of Psychiatrists 2016. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license.

Socio-demographic and Clinical Correlates of Facial Expression Recognition Disorder in the Euthymic Phase of Bipolar Patients

OBJECTIVE

Bipolar patients show social cognitive disorders. The objective of this study is to review facial expression recognition (FER) disorders in bipolar patients (BP) and explore clinical heterogeneity factors that could affect them in the euthymic phase: socio-demographic level, clinical and changing characteristics of the disorder, history of suicide attempt, and abuse.

METHOD

Thirty-four euthymic bipolar patients and 29 control subjects completed a computer task of explicit facial expression recognition and were clinically evaluated.

RESULTS

Compared with control subjects, BP patients show: a decrease in fear, anger, and disgust recognition; an extended reaction time for disgust, surprise and neutrality recognition; confusion between fear and surprise, anger and disgust, disgust and sadness, sadness and neutrality. In BP patients, age negatively affects anger and neutrality recognition, as opposed to education level which positively affects recognizing these emotions. The history of patient abuse negatively affects surprise and disgust recognition, and the number of suicide attempts negatively affects disgust and anger recognition.

CONCLUSIONS

Cognitive heterogeneity in euthymic phase BP patients is affected by several factors inherent to bipolar disorder complexity that should be considered in social cognition study.

The ANK3 gene and facial affect processing: An ERP study

ANK3 is one of the most promising candidate genes for bipolar disorder (BD). A polymorphism (rs10994336) within the ANK3 gene has been associated with BD in at least three genome-wide association studies of BD [McGuffin et al., 2003; Kieseppä, 2004; Edvardsen et al., 2008]. Because facial affect processing is disrupted in patients with BD, the current study aimed to explore whether the BD risk alleles are associated with the N170, an early event-related potential (ERP) component related to facial affect processing. We collected data from two independent samples of healthy individuals (Ns = 83 and 82, respectively) to test the association between rs10994336 and an early event-related potential (ERP) component (N170) that is sensitive to facial affect processing. Repeated-measures analysis of covariance in both samples consistently revealed significant main effects of rs10994336 genotype (Sample I: F (1, 72) = 7.24, P = 0.009; Sample II: F (1, 69) = 11.81, P = 0.001), but no significant interaction of genotype × electrodes (Ps > 0.05) or genotype × emotional conditions (Ps > 0.05). These results suggested that rs10994336 was linked to early ERP component reflecting facial structural encoding during facial affect processing. These results shed new light on the brain mechanism of this risk SNP and associated disorders such as BD. © 2016 Wiley Periodicals, Inc.

Brain networks modulated by subthalamic nucleus deep brain stimulation

Deep brain stimulation of the subthalamic nucleus is an established treatment for the motor symptoms of Parkinson's disease. Given the frequent occurrence of stimulation-induced affective and cognitive adverse effects, a better understanding about the role of the subthalamic nucleus in non-motor functions is needed. The main goal of this study is to characterize anatomical circuits modulated by subthalamic deep brain stimulation, and infer about the inner organization of the nucleus in terms of motor and non-motor areas. Given its small size and anatomical intersubject variability, functional organization of the subthalamic nucleus is difficult to investigate in vivo with current methods. Here, we used local field potential recordings obtained from 10 patients with Parkinson's disease to identify a subthalamic area with an analogous electrophysiological signature, namely a predominant beta oscillatory activity. The spatial accuracy was improved by identifying a single contact per macroelectrode for its vicinity to the electrophysiological source of the beta oscillation. We then conducted whole brain probabilistic tractography seeding from the previously identified contacts, and further described connectivity modifications along the macroelectrode's main axis. The designated subthalamic 'beta' area projected predominantly to motor and premotor cortical regions additional to connections to limbic and associative areas. More ventral subthalamic areas showed predominant connectivity to medial temporal regions including amygdala and hippocampus. We interpret our findings as evidence for the convergence of different functional circuits within subthalamic nucleus' portions deemed to be appropriate as deep brain stimulation target to treat motor symptoms in Parkinson's disease. Potential clinical implications of our study are illustrated by an index case where deep brain stimulation of estimated predominant non-motor subthalamic nucleus induced hypomanic behaviour.

Facial emotion recognition in euthymic patients with bipolar disorder and their unaffected first-degree relatives

BACKGROUND

Facial emotion recognition (FER) is an important task associated with social cognition because facial expression is a significant source of non-verbal information that guides interpersonal relationships. Increasing evidence suggests that bipolar disorder (BD) patients present deficits in FER and these deficits may be present in individuals at high genetic risk for BD. The aim of this study was to evaluate the occurrence of FER deficits in euthymic BD patients, their first-degree relatives, and healthy controls (HC) and to consider if these deficits might be regarded as an endophenotype candidate for BD.

METHODS

We studied 23 patients with DSM-IV BD type I, 22 first-degree relatives of these patients, and 27 HC. We used the Penn Emotion Recognition Tests to evaluate tasks of FER, emotion discrimination, and emotional acuity. Patients were recruited from outpatient facilities at the Institute of Psychiatry of the University of Sao Paulo Medical School, or from the community through media advertisements, had to be euthymic, with age above 18years old and a diagnosis of DSM-IV BD type I.

RESULTS

Euthymic BD patients presented significantly fewer correct responses for fear, and significantly increased time to response to recognize happy faces when compared with HC, but not when compared with first-degree relatives. First-degree relatives did not significantly differ from HC on any of the emotion recognition tasks.

CONCLUSION

Our results suggest that deficits in FER are present in euthymic patients, but not in subjects at high genetic risk for BD. Thus, we have not found evidence to consider FER as an endophenotype candidate for BD.

Facial recognition deficits as a potential endophenotype in bipolar disorder

Bipolar disorder (BD) is considered a highly heritable and genetically complex disorder. Several cognitive functions, such as executive functions and verbal memory have been suggested as promising candidates for endophenotypes. Although there is evidence for deficits in facial emotion recognition in individuals with BD, studies investigating these functions as endophenotypes are rare. The current study investigates emotion recognition as a potential endophenotype in BD by comparing 36 BD participants, 24 of their 1st degree relatives and 40 healthy control participants in a computerised facial emotion recognition task. Group differences were evaluated using repeated measurement analysis of co-variance with age as a covariate. Results revealed slowed emotion recognition for both BD and their relatives. Furthermore, BD participants were less accurate than healthy controls in their recognition of emotion expressions. We found no evidence of emotion specific differences between groups. Our results provide evidence for facial recognition as a potential endophenotype in BD.

Functional dysconnection in the prefrontal-amygdala circuitry in unaffected siblings of patients with bipolar I disorder

OBJECTIVES

Bipolar I disorder (BD) is a highly heritable disorder characterized by mood swings between high-energy and low-energy states. Amygdala hyperactivity and cortical inhibitory hypoactivity [e.g., of the dorsolateral prefrontal cortex (dlPFC)] have been found in patients with BD, as evidenced by their abnormal resting-state functional connectivity (FC) and glucose utilization (GU). However, it has not been determined whether functional abnormalities of the dlPFC-amygdala circuit exist in unaffected, healthy siblings of the patients with BD (BDsib).

METHODS

Twenty euthymic patients with BD, 20 unaffected matching BDsib of the patient group, and 20 well-matched healthy control subjects were recruited. We investigated seed-based FC (seeds: dlPFC) with resting-state functional magnetic resonance imaging and GU in the regions of interest (e.g., dlPFC and amygdala) using (18) F-fluorodeoxyglucose positron emission tomography.

RESULTS

The FC in the dlPFC (right)-amygdala circuit was statistically abnormal in patients with BD and BDsib, but only the patients with BD demonstrated hypoactive GU bilaterally in the dlPFC and hyperactive GU bilaterally in the amygdala. Facilitating differentiation between the BD groups, the altered FC between dlPFC (right) and amygdala (left) was even more prominent in the patients with BD (p < 0.05).

CONCLUSIONS

There was a dysfunctional connection with intact GU in the dlPFC-amygdala circuit of the BDsib, which highlights the vulnerability in families with BD. Diminished top-down control from the bilateral dlPFC, which prevents adequate inhibition of limbic hyperactivity, might mediate the development of BD.

Late-onset recurrent mania as a manifestation of Wallenberg syndrome: a case report and review of the literature

OBJECTIVE

The aim of the present case report was to describe the late onset of recurrent mania in a patient after ischemic injury to the cerebellum and dorsolateral medulla.

METHODS

We studied an 86-year-old male with no prior psychiatric history who developed recurrent episodes of mania following a brain stroke. Additionally, he had neurological symptom constellation typical of Wallenberg syndrome.

RESULTS

Magnetic resonance imaging of the brain revealed infarction in the inferomedial right cerebellar hemisphere and the right dorsolateral medulla in the right posterior inferior cerebellar artery (PICA) distribution. He was successfully managed with a combination of antipsychotic and mood-stabilizer medications.

CONCLUSIONS

Post-stroke mania may be one of the rare manifestations of Wallenberg syndrome. This case adds to the emerging literature on cerebellar involvement in mood regulation and pathology of mania.

A voxel-based morphometry study of gray matter correlates of facial emotion recognition in bipolar disorder

Facial emotion recognition (FER) is one of the many cognitive deficits reported in bipolar disorder (BD) patients. The aim of this study was to investigate neuroanatomical correlates of FER impairments in BD type I (BD-I). Participants comprised 21 euthymic BD-I patients without Axis I DSM IV-TR comorbidities and 21 healthy controls who were assessed using magnetic resonance imaging and the Penn Emotion Recognition Test (ER40). Preprocessing of images used DARTEL (diffeomorphic anatomical registration through exponentiated Lie algebra) for optimized voxel-based morphometry in SPM8. Compared with healthy subjects, BD-I patients performed poorly in on the ER40 and had reduced gray matter volume (GMV) in the left orbitofrontal cortex, superior portion of the temporal pole and insula. In the BD-I group, the statistical maps indicated a direct correlation between FER on the ER40 and right middle cingulate gyrus GMV. Our findings are consistent with the previous studies regarding the overlap of multiple brain networks of social cognition and BD neurobiology, particularly components of the anterior-limbic neural network.

Changes in absolute theta power in bipolar patients during a saccadic attention task

The present study analyzed absolute theta power (ATP) in brain areas involved with attention in the three phase of BD while the patients performing a saccadic attention task. We hypothesized that patients in depression and mania states show a higher ATP compared to euthymic patients, since a higher ATP is indicative of attention deficit. We analyzed the frontal (F7, F3, Fz, F4 and F8) and central (C3, Cz and C4) areas. Thirty bipolar patients were enrolled in this study. The subjects performed a saccadic attention task while their brain activity pattern was recorded using quantitative electroencephalography (20 channels). Our results showed a main effect for group over C3, C4, Cz, F7, F4, F8 electrodes, and a main effect for moment over Cz, F7, F8 electrodes. These results indicate that both task and groups produce changes in theta activity in distinct cortical areas that participate in the organization of attention. Our results therefore demonstrate that, although it is well established in the literature that theta has a relevant role in the attention process, it is necessary to deepen the investigations to better understand the specifics of theta during visual processing tasks that have a demand for attention.

Empathy, but not mimicry restriction, influences the recognition of change in emotional facial expressions

The current study addressed the hypothesis that empathy and the restriction of facial muscles of observers can influence recognition of emotional facial expressions. A sample of 74 participants recognized the subjective onset of emotional facial expressions (anger, disgust, fear, happiness, sadness, surprise, and neutral) in a series of morphed face photographs showing a gradual change (frame by frame) from one expression to another. The high-empathy (as measured by the Empathy Quotient) participants recognized emotional facial expressions at earlier photographs from the series than did low-empathy ones, but there was no difference in the exploration time. Restriction of facial muscles of observers (with plasters and a stick in mouth) did not influence the responses. We discuss these findings in the context of the embodied simulation theory and previous data on empathy.

The neurocognitive functioning in bipolar disorder: a systematic review of data

BACKGROUND

During the last decades, there have been many different opinions concerning the neurocognitive function in Bipolar disorder (BD). The aim of the current study was to perform a systematic review of the literature and to synthesize the data in a comprehensive picture of the neurocognitive dysfunction in BD.

METHODS

Papers were located with searches in PubMed/MEDLINE, through June 1st 2015. The review followed a modified version of the recommendations of the Preferred Items for Reporting of Systematic Reviews and Meta-Analyses statement.

RESULTS

The initial search returned 110,403 papers. After the deletion of duplicates, 11,771 papers remained for further evaluation. Eventually, 250 were included in the analysis.

CONCLUSION

The current review supports the presence of a neurocognitive deficit in BD, in almost all neurocognitive domains. This deficit is qualitative similar to that observed in schizophrenia but it is less severe. There are no differences between BD subtypes. Its origin is unclear. It seems it is an enduring component and represents a core primary characteristic of the illness, rather than being secondary to the mood state or medication. This core deficit is confounded (either increased or attenuated) by the disease phase, specific personal characteristics of the patients (age, gender, education, etc.), current symptomatology and its treatment (especially psychotic features) and long-term course and long-term exposure to medication, psychiatric and somatic comorbidity and alcohol and/or substance abuse.

Volumetric, cortical thickness and white matter integrity alterations in bipolar disorder type I and II

BACKGROUND

Bipolar disorder (BD) is a debilitating psychiatric disorder affecting millions of people worldwide with mean time to diagnosis estimated to be at least 10 years. Whilst many brain imaging studies have compared those with BD to controls, few have attempted to investigate differences between BD Type I and II and matched controls.

METHODS

Thirty-one patients with BD (16 Type I and 15 Type II) and 31 matched healthy controls were MRI brain scanned with conventional T1-weighted and diffusion tensor imaging methods.

RESULTS

There was significantly reduced regional brain volume and thickness among the BD subjects, but also between BD Type I when compared to Type II. White matter integrity also differed between the groups and BD severity correlated significantly with regional brain volume and thickness.

LIMITATIONS

Future investigations will consider length of time each BD patient had been diagnosed with BD, as well as assessing controls for family history of psychiatric illness, specifically BD. Similarly, genetic assessment will be conducted as well.

CONCLUSIONS

These findings suggest that there are not only regional brain volumetric, thickness and white matter integrity differences between BD and matched controls, but also between those with BD Type I and Type II, such that reduced regional brain volume may underlie BD Type I whereas white matter integrity is more altered in BD Type II.