Frontal-amygdala connectivity alterations during emotion downregulation in bipolar I disorder

Right ventrolateral and left dorsolateral 10 Hz transcranial magnetic stimulation as an add-on treatment for bipolar I and II depression: a double-blind, randomised, three-arm, sham-controlled study

OBJECTIVES

Despite the clinical importance of bipolar depression (BDE), effective treatment options are still limited. Transcranial magnetic stimulation (rTMS) has proven of moderate efficacy in major depression, but the evidence remains inconclusive for BDE.

METHODS

A 4-week, double-blind, randomised, parallel-group, sham-controlled study (trial ID ISRCTN77188420) explored the benefits of 10 Hz MRI-guided right ventrolateral (RVL) rTMS and left dorsolateral (LDL) rTMS as add-on treatments for BDE. Outcome measures included changes in the Montgomery-Åsberg Depression Rating Scale (MADRS) score, self-assessment, response and remission rates, and side effects.

RESULTS

Sixty patients were randomly assigned to study groups, and forty-six completed the double-blind phase. The mean change from baseline to Week 4 in MADRS was greater in both active groups compared to the sham, yet differences did not achieve significance (RVL vs sham: -4.50, 95%CI -10.63 to 1.64, p = 0.3; LDL vs sham: -4.07, 95%CI -10.24 to 2.10, p = 0.4). None of the other outcome measures yielded significant results.

CONCLUSIONS

While not demonstrating the superiority of either 10 Hz rTMS over sham, with the limited sample size, we can not rule out a moderate yet clinically meaningful effect. Further well-powered studies are essential to elucidate the role of rTMS in managing BDE.

Dysconnectivity of the Nucleus Accumbens and Amygdala in Youths with Thought Problems: A Dimensional Approach

Background: Youths with thought problems (TP) are at risk to develop psychosis and obsessive-compulsive disorder (OCD). Yet, the pathophysiological mechanisms underpinning TP are still unclear. Functional magnetic resonance imaging (fMRI) studies have shown that striatal and limbic alterations are associated with psychosis-like and obsessive-like symptoms in individuals at clinical risk for psychosis, schizophrenia, and OCD. More specifically, nucleus accumbens (NAcc) and amygdala are mainly involved in these associations. The current study aims to investigate the neural correlates of TP in youth populations using a dimensional approach and explore potential cognitive functions and neurotransmitters associated with it. Methods: Seed-to-voxels functional connectivity analyses using NAcc and amygdala as regions-of-interest were conducted with resting-state fMRI data obtained from 1360 young individuals, and potential confounders related to TP such as anxiety and cognitive functions were included as covariates in multiple regression analyses. Replicability was tested in using an adult cohort. In addition, functional decoding and neurochemical correlation analyses were performed to identify the associated cognitive functions and neurotransmitters. Results: The altered functional connectivities between the right NAcc and posterior parahippocampal gyrus, between the right amygdala and lateral prefrontal cortex, and between the left amygdala and the secondary visual area were the best predictors of TP in multiple regression model. These functional connections are mainly involved in social cognition and reward processing. Conclusions: The results show that alterations in the functional connectivity of the NAcc and the amygdala in neural pathways involved in social cognition and reward processing are associated with severity of TP in youths.

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.

The positive and negative emotion functions related to loneliness: a systematic review of behavioural and neuroimaging studies

Loneliness is associated with high prevalences of major psychiatric illnesses such as major depression. However, the underlying emotional mechanisms of loneliness remained unclear. We hypothesized that loneliness originates from both decreases in positive emotional processing and increases in negative emotion processing. To test this, we conducted a systematic review of 29 previous studies (total participants n = 19 560, mean age = 37.16 years, female proportion = 59.7%), including 18 studies that included questionnaire measures of emotions only, and 11 studies that examined the brain correlates of emotions. The main findings were that loneliness was negatively correlated with general positive emotions and positively correlated with general negative emotions. Furthermore, limited evidence indicates loneliness exhibited negative and positive correlations with the brain positive (e.g. the striatum) and negative (e.g. insula) emotion systems, respectively, but the sign of correlation was not entirely consistent. Additionally, loneliness was associated with the structure and function of the brain emotion regulation systems, particularly the prefrontal cortex, but the direction of this relationship remained ambiguous. We concluded that the existing evidence supported a bivalence model of loneliness, but several critical gaps existed that could be addressed by future studies that include adolescent and middle-aged samples, use both questionnaire and task measures of emotions, distinguish between general emotion and social emotion as well as between positive and negative emotion regulation, and adopt a longitudinal design that allows us to ascertain the causal relationships between loneliness and emotion dysfunction. Our findings provide new insights into the underlying emotion mechanisms of loneliness that can inform interventions for lonely individuals.

Unpacking reappraisal: a systematic review of fMRI studies of distancing and reinterpretation

In recent decades, a substantial volume of work has examined the neural mechanisms of cognitive reappraisal. Distancing and reinterpretation are two frequently used tactics through which reappraisal can be implemented. Theoretical frameworks and prior evidence have suggested that the specific tactic through which one employs reappraisal entails differential neural and psychological mechanisms. Thus, we were motivated to assess the neural mechanisms of this distinction by examining the overlap and differentiation exhibited by the neural correlates of distancing (specifically via objective appraisal) and reinterpretation. We analyzed 32 published functional magnetic resonance imaging (fMRI) studies in healthy adults using multilevel kernel density analysis. Results showed that distancing relative to reinterpretation uniquely recruited right bilateral dorsolateral PFC (DLPFC) and left posterior parietal cortex, previously associated with mentalizing, selective attention and working memory. Reinterpretation relative to distancing uniquely recruited left bilateral ventrolateral PFC (VLPFC), previously associated with response selection and inhibition. Further, distancing relative to reinterpretation was associated with greater prevalence of bilateral amygdala attenuation during reappraisal. Finally, a behavioral meta-analysis showed efficacy for both reappraisal tactics. These results are consistent with prior theoretical models for the functional neural architecture of reappraisal via distancing and reinterpretation and suggest potential future applications in region-of-interest specification and neural network analysis in studies focusing on specific reappraisal tactics.

Effect of lithium administration on brain activity under an emotion regulation paradigm in healthy participants: a functional magnetic resonance imaging study

RATIONALE

Emotion regulation (ER) difficulties have been previously described in bipolar disorder (BD). Whilst lithium has been shown to be effective in the treatment of BD, the mechanisms underlying lithium's effect on mood stabilisation remain unclear.

OBJECTIVES

Unravelling lithium's effect on psychological processes impaired in BD, such as ER, could address this translational gap and inform the development of new treatments.

METHODS

This study investigated the neural effects of lithium (800mg) on ER in 33 healthy volunteers in a double-blind between-groups design, randomised to lithium (n=17) or placebo (n=16) for 11 days. At treatment completion, participants underwent 3-Tesla fMRI scan whilst performing an ER task.

RESULTS

Reappraisal reduced negative affect across groups and led to the expected increase in frontal brain activity. Participants receiving lithium showed (1) decreased activation in prefrontal and posterior parietal cortices and connectivity between the fronto-limbic network (Z>2.3, p<0.05 corrected); and (2) increased activity in the right superior temporal gyrus (Z>3.1, p<0.05 corrected) and connectivity between the right medial temporal gyrus (MTG) and left middle frontal gyrus (Z>2.3, p<0.05 corrected) during reappraisal. Further effects of lithium were found in response to negative picture presentation, whereby an anticorrelation was found between the left amygdala and the frontal cortex, and greater connectivity between the right MTG and the bilateral medial prefrontal cortex extending into the paracingulate gyrus, compared to placebo (Z>2.3, p < 0.05 corrected).

CONCLUSIONS

These results show a potential effect of lithium on ER through its effects on activity and connectivity, and further elaborate the neural underpinnings of cognitive reappraisal. Future work should investigate longer term effects of lithium on ER in BD, ultimately benefitting the development of novel and more effective treatments.

Association Between the Fronto-Limbic Network and Cognitive and Emotional Functioning in Individuals With Bipolar Disorder: A Systematic Review and Meta-analysis

Importance

Individuals with bipolar disorder (BD) experience cognitive and emotional dysfunctions. Various brain circuits are implicated in BD but have not been investigated in a meta-analysis of functional magnetic resonance imaging (fMRI) studies.

Objective

To investigate the brain functioning of individuals with BD compared with healthy control individuals in the domains of emotion processing, reward processing, and working memory.

Data Sources

All fMRI experiments on BD published before March 2020, as identified in a literature search of PubMed, Embase, Web of Science, Cochrane Library, PsycInfo, Emcare, Academic Search Premier, and ScienceDirect. The literature search was conducted on February 21, 2017, and March 2, 2020, and data were analyzed from January 2021 to January 2022.

Study Selection

fMRI experiments comparing adult individuals with BD and healthy control individuals were selected if they reported whole-brain results, including a task assessing at least 1 of the domains. In total, 2320 studies were screened, and 253 full-text articles were evaluated.

Data Extraction and Synthesis

A total of 49 studies were included after selection procedure. Coordinates reporting significant activation differences between individuals with BD and healthy control individuals were extracted. Differences in brain region activity were tested using the activation likelihood estimation method.

Main Outcomes and Measures

A whole-brain meta-analysis evaluated whether reported differences in brain activation in response to stimuli in 3 cognitive domains between individuals with BD and healthy control individuals were different.

Results

The study population included 999 individuals with BD (551 [55.2%] female) and 1027 healthy control individuals (532 [51.8%] female). Compared with healthy control individuals, individuals with BD showed amygdala and hippocampal hyperactivity and hypoactivation in the inferior frontal gyrus during emotion processing (20 studies; 324 individuals with BD and 369 healthy control individuals), hyperactivation in the orbitofrontal cortex during reward processing (9 studies; 195 individuals with BD and 213 healthy control individuals), and hyperactivation in the ventromedial prefrontal cortex and subgenual anterior cingulate cortex during working memory (20 studies; 530 individuals with BD and 417 healthy control individuals). Limbic hyperactivation was only found during euthymia in the emotion and reward processing domains; abnormalities in frontal cortex activity were also found in individuals with BD with mania and depression.

Conclusions and Relevance

This systematic review and meta-analysis revealed evidence for activity disturbances in key brain areas involved in cognitive and emotion processing in individuals with BD. Most of the regions are part of the fronto-limbic network. The results suggest that aberrations in the fronto-limbic network, present in both euthymic and symptomatic individuals, may be underlying cognitive and emotional dysfunctions in BD.

Emotion regulation in bipolar disorder type-I: multivariate analysis of fMRI data

BACKGROUND

Bipolar disorder type-I (BD-I) patients are known to show emotion regulation abnormalities. In a previous fMRI study using an explicit emotion regulation paradigm, we compared responses from 19 BD-I patients and 17 matched healthy controls (HC). A standard general linear model-based univariate analysis revealed that BD patients showed increased activations in inferior frontal gyrus when instructed to decrease their emotional response as elicited by neutral images. We implemented multivariate pattern recognition analyses on the same data to examine if we could classify conditions within-group as well as HC versus BD.

METHODS

We reanalyzed explicit emotion regulation data using a multivariate pattern recognition approach, as implemented in PRONTO software. The original experimental paradigm consisted of a full 2 × 2 factorial design, with valence (Negative/Neutral) and instruction (Look/Decrease) as within subject factors.

RESULTS

The multivariate models were able to accurately classify different task conditions when HC and BD were analyzed separately (63.24%-75.00%, p = 0.001-0.012). In addition, the models were able to correctly classify HC versus BD with significant accuracy in conditions where subjects were instructed to downregulate their felt emotion (59.60%-60.84%, p = 0.014-0.018). The results for HC versus BD classification demonstrated contributions from the salience network, several occipital and frontal regions, inferior parietal lobes, as well as other cortical regions, to achieve above-chance classifications.

CONCLUSIONS

Our multivariate analysis successfully reproduced some of the main results obtained in the previous univariate analysis, confirming that these findings are not dependent on the analysis approach. In particular, both types of analyses suggest that there is a significant difference of neural patterns between conditions within each subject group. The multivariate approach also revealed that reappraisal conditions provide the most informative activity for differentiating HC versus BD, irrespective of emotional valence (negative or neutral). The current results illustrate the importance of investigating the cognitive control of emotion in BD. We also propose a set of candidate regions for further study of emotional control in BD.

Disrupted white matter network of brain structural connectomes in bipolar disorder patients revealed by q-ball imaging

BACKGROUND

Structural and functional brain changes have been found to be associated with altered emotion and cognition in patients with bipolar disorder (BD). Widespread microstructural white matter abnormalities have been observed using traditional structural imaging in BD. q-Ball imaging (QBI) and graph theoretical analysis (GTA) improve the specificity and sensitivity and high accuracy of fiber tracking. We applied QBI and GTA to investigate and compare the structural connectivity alterations and network alterations in patients with and without BD.

METHODS

Sixty-two patients with BD and 62 healthy controls (HCs) completed a MR scan. We evaluated the group differences in generalized fractional anisotropy (GFA) and normalized quantitative anisotropy (NQA) values by voxel-based statistical analysis with QBI. We also evaluated the group differences in topological parameters of GTA and subnetwork interconnections in network-based statistical analysis (NBS).

RESULTS

The QBI indices in the BD group were significantly lower than those in the HC group in the corpus callosum, cingulate gyrus, and caudate. The GTA indices indicated that the BD group demonstrated less global integration and higher local segregation than the HC group, but they retained small-world properties. NBS evaluation showed that the majority of the more connected subnetworks in BD occurred in thalamo-temporal/parietal connectivity.

CONCLUSION

Our findings supported white matter integrity with network alterations in BD.

Neural responses during down-regulation of negative emotion in patients with recently diagnosed bipolar disorder and their unaffected relatives

BACKGROUND

Aberrant emotion regulation has been posited as a putative endophenotype of bipolar disorder (BD). We therefore aimed to compare the neural responses during voluntary down-regulation of negative emotions in a large functional magnetic resonance imaging study of BD, patients' unaffected first-degree relatives (URs), and healthy controls (HCs).

METHODS

We compared neural activity and fronto-limbic functional connectivity during emotion regulation in response to aversive v. neutral pictures in patients recently diagnosed with BD (n = 78) in full/partial remission, their URs (n = 35), and HCs (n = 56).

RESULTS

Patients showed hypo-activity in the left dorsomedial, dorsolateral, and ventrolateral prefrontal cortex (DMPFC and DLPFC) during emotion regulation while viewing aversive pictures compared to HCs, with URs displaying intermediate neural activity in these regions. There were no significant differences between patients with BD and HCs in functional connectivity from the amygdala during emotion regulation. However, exploratory analysis indicated that URs displayed more negative amygdala-DMPFC coupling compared with HCs and more negative amygdala-cingulate DLPFC coupling compared to patients with BD. At a behavioral level, patients and their URs were less able to dampen negative emotions in response aversive pictures.

CONCLUSIONS

The findings point to deficient recruitment of prefrontal resources and more negative fronto-amygdala coupling as neural markers of impaired emotion regulation in recently diagnosed remitted patients with BD and their URs, respectively.

The Neural Processes in Food Decision-making and their Effect on Daily Diet Management in Successful and Unsuccessful Restrained Eaters

This study aimed to explore the neural mechanisms underlying food decision making in unsuccessful restrained eaters (US-REs) and successful restrained eaters (S-REs). During a functional magnetic resonance imaging scan, participants were required to choose between pairs of high- and low-calorie foods under the following conditions: the congruent condition (choose between high- and low-calorie foods with the same level of tastiness) and incongruent condition (choose between high-calorie foods tastier than the corresponding low-calorie foods). Subsequently, the participants' diets were monitored for one week. The behavioral results showed that US-REs (n = 28) chose more high-calorie foods than S-REs (n = 26); in contrast, S-REs spent more time in choosing for the incongruent than the congruent condition. The fMRI results found that US-REs exhibited more activity in reward regions (caudate and thalamus) than S-REs in the congruent condition. In the incongruent condition, S-REs showed stronger functional connectivity between the conflict-monitoring region (anterior cingulate cortex) and inhibitory-control regions (inferior frontal gyrus [IFG] and medial frontal gyrus) than US-REs. In both the conditions, increased activation of the insula, putamen, middle frontal gyrus, and IFG could predict increased food intake among US-REs in the following week. Furthermore, in both the conditions, increased IFG activation could predict decreased food cravings among S-REs during the following week. Our results suggest that US-REs have a strong reward response to food. Compared to US-REs, S-REs are more guided more by the goal of weight control, and exhibit strong functional connections between the conflict-monitoring and inhibitory-control regions. Therefore, eating enjoyment and weight-control goals influence restrained eating in daily life.

The longitudinal trajectory of emotion regulation and associated neural activity in patients with bipolar disorder: A prospective fMRI study

OBJECTIVES

Impaired emotion regulation is a key feature of bipolar disorder (BD) that presents during acute mood episodes and in remission. The neural correlates of voluntary emotion regulation seem to involve deficient prefrontal top-down regulation already at BD illness onset. However, the trajectory of aberrant neuronal activity during emotion regulation in BD is unclear.

METHODS

We investigated neural activity during emotion regulation in response to aversive pictures from the International Affective Picture System in patients with recently diagnosed BD (n = 43) in full or partial remission and in healthy controls (HC) (n = 38) longitudinally at baseline and 16 months later.

RESULTS

Patients with BD exhibited stable hypo-activity in the left dorsomedial prefrontal cortex (DMPFC) and right dorsolateral prefrontal cortex (DLPFC) and impaired emotion regulation compared to HC over the 16 months follow-up time. More DLPFC hypo-activity during emotion regulation correlated with less successful down-regulation (r = 0.16, p = 0.045), more subsyndromal depression (r = -0.18, p = 0.02) and more functional impairment (r = -0.24, p = 0.002), while more DMPFC hypo-activity correlated with less efficient emotion regulation (r = 0.16, p = 0.048). Finally, more DMPFC hypo-activity during emotion regulation at baseline was associated with an increased likelihood of subsequent relapse during the 16 months follow-up time (β = -2.26, 95% CI [0.01; 0.99], p = 0.048).

CONCLUSION

The stable DLPFC and DMPFC hypo-activity during emotion regulation represents a neuronal trait-marker of persistent emotion regulation difficulties in BD. Hypo-activity in the DMPFC may contribute to greater risk of relapse.

Assessment of the validity and feasibility of a novel virtual reality test of emotion regulation in patients with bipolar disorder and their unaffected relatives

BACKGROUND

Emotion dysregulation has been suggested as an endophenotype of bipolar disorder (BD). Neuroimaging studies show aberrant neural activity during emotion regulation in remitted patients with BD and their unaffected first-degree relatives (UR) compared to healthy controls (HC). However, behavioural studies produce conflicting - generally negative findings - possibly due to limited sensitivity and ecological validity of current behavioural paradigms.

METHODS

This study aimed to explore emotion regulation in BD (n = 30) and UR (n = 26) relative to HC (n = 47) by using a novel emotion regulation task in virtual reality (VR). Participants were instructed to either react naturally to, or dampen, their emotional response to highly positive or highly negative scenarios presented in first-person 360-degree spherically camera-recorded VR environments. Participants also completed a more traditional computerised task of emotion regulation for comparison purposes.

RESULTS

Patients with BD exhibited difficulties with down-regulating their negative emotions in the VR paradigm compared to HC and UR (ps ≤ .04), whereas UR did not differ from HC (p = .97). There was no emotion regulation difference between groups in the more traditional computerised task (ps ≥ .40).

LIMITATIONS

The small sample size limits generalisability.

CONCLUSIONS

The results suggest trait-related reduced ability to down-regulate negative emotions in BD patients compared to HC in the VR paradigm, but not in the more traditional task of emotion regulation. This may indicate that VR provides a more sensitive measure relative to traditional paradigms. The findings provided no support for aberrant emotional regulation as an endophenotype of BD given the normal emotion regulation performance in UR.

Decreased cortical gyrification in patients with bipolar disorder

BACKGROUND

An aberrant neural connectivity has been known to be associated with bipolar disorder (BD). Local gyrification may reflect the early neural development of cortical connectivity and has been studied as a possible endophenotype of psychiatric disorders. This study aimed to investigate differences in the local gyrification index (LGI) in each cortical region between patients with BD and healthy controls (HCs).

METHODS

LGI values, as measured using FreeSurfer software, were compared between 61 patients with BD and 183 HCs. The values were also compared between patients with BD type I and type II as a sub-group analysis. Furthermore, we evaluated whether there was a correlation between LGI values and illness duration or depressive symptom severity in patients with BD.

RESULTS

Patients with BD showed significant hypogyria in various cortical regions, including the left inferior frontal gyrus (pars opercularis), precentral gyrus, postcentral gyrus, superior temporal cortex, insula, right entorhinal cortex, and both transverse temporal cortices, compared to HCs after the Bonferroni correction (p < 0.05/66, 0.000758). LGI was not associated with clinical factors such as illness duration, depressive symptom severity, and lithium treatment. No significant differences in cortical gyrification according to the BD subtype were found.

CONCLUSIONS

BD appears to be characterized by a significant regionally localized hypogyria, in various cortical areas. This abnormality may be a structural and developmental endophenotype marking the risk for BD, and it might help to clarify the etiology of BD.

Neural underpinnings of emotion regulation subgroups in remitted patients with recently diagnosed bipolar disorder

Neuroimaging studies of bipolar disorder (BD) generally involve comparison with healthy controls (HC), which may mask neurobiological variability within the disorder. This study aims to assess the neural underpinnings of potential subgroups of BD patients based on functional activity in the emotion regulation network and its relation to illness characteristics and relapse risk. Eighty-seven remitted patients with recently diagnosed BD and 66 HC underwent functional magnetic resonance imaging (fMRI) while performing an emotion regulation task. Patients were re-assessed with clinical interviews after 16 (±5) months. Data-driven hierarchical cluster analysis was employed to investigate 'neuronal subgroups' of patients based on their neuronal activity in a pre-defined emotion regulation network. Relations between neuronal subgroups and illness characteristics and relapse rates were examined. Patients were allocated into two subgroups. Subgroup 1 (n=62, 75%) was characterized by exaggerated bilateral amygdala reactivity but normal prefrontal and temporo-parietal activation. Subgroup 2 (n= 22, 25%) showed widespread hypo-activity within all emotion regulation regions. Both subgroups were less successful at down-regulating their emotions than HC (F(2,146)=5.33, p=.006, η_p²=.07). Patients in subgroup 2 had a history of more and longer mixed episodes (ps≤.01). Importantly, heightened amygdala activity across all patients was associated with increased risk of relapse during a 16-month follow-up period (β=3.36, 95% CI [1.49;550.35], N=60, p=.03). The identified neuronal subgroups of patients with either amygdala hyper-activity or broad network hypo-activity during emotion regulation points to neurobiological heterogeneity among remitted patients with BD. Heightened amygdala reactivity may be a neuronal target for personalized treatments to prevent relapse.

Neural functional connectivity changes to psychosocial stress in young adults with bipolar disorder and preliminary associations with clinical trajectories

BACKGROUND

Stress-related mechanisms are implicated in the pathophysiology of bipolar disorder and may contribute to heterogeneity in illness course. Yet, there is a lack of study investigating the neural mechanisms underlying the stress response in this condition. This study investigated changes in amygdala activation and functional connectivity in response to acute psychosocial stress in young adults with bipolar disorder and explored relations with clinical phenotype and prospective mood symptoms.

METHODS

42 young adults [19 with bipolar disorder, age_mean  ± SD =21.4 ± 2.2 years] completed a modified version of the Montreal Imaging Stress Task. Amygdala activation and functional connectivity with prefrontal cortex (PFC) regions of interest was calculated for control and stress conditions. Main effects of group, condition, and group by condition interaction on amygdala activation and connectivity were modeled. A subset of bipolar participants completed 1-year follow-up assessments. Relations between neural responses to stress with concurrent substance use and prospective mood symptoms were explored.

RESULTS

There were no between-group differences in amygdala activation or functional connectivity during the control condition. Increased right amygdala-right rostral PFC (rPFC) functional connectivity to stress was observed in bipolar disorder, compared to typically developing controls. In bipolar disorder, greater increase in right amygdala-right rPFC functional connectivity to stress was associated with less frequent cannabis use, and prospectively with shorter duration and lower severity of depression symptoms over follow-up.

CONCLUSION

Results from this preliminary study suggest differences in frontolimbic functional connectivity responses to stress in young adults with bipolar disorder and associations with cannabis use and prospective mood symptoms.

Neural network of bipolar disorder: Toward integration of neuroimaging and neurocircuit-based treatment strategies

Bipolar disorder (BD) is a complex psychiatric disorder characterized by dysfunctions in three domains including emotional processing, cognitive processing, and psychomotor dimensions. However, the neural underpinnings underlying these clinical profiles are not well understood. Based on the reported data, we hypothesized that (i) the core neuropathology in BD is damage in fronto-limbic network, which is associated with emotional dysfunction; (ii) changes in intrinsic brain network, such as sensorimotor network, salience network, default-mode network, central executive network are associated with impaired cognition function; and (iii) beyond the dopaminergic-driven basal ganglia-thalamo-cortical motor circuit modulated by other neurotransmitter systems, such as serotonin (subcortical-cortical modulation), the sensorimotor network and related motor function modulated by other non-motor networks such as the default-mode network are involved in psychomotor function. In this review, we propose a neurocircuit-based clinical characteristics and taxonomy to guide the treatment of BD. We draw on findings from neuropsychological and neuroimaging studies in BD and link variations in these clinical profiles to underlying neurocircuit dysfunctions. We consider pharmacological, psychotherapy, and neuromodulatory treatments that could target those specific neurocircuit dysfunctions in BD. Finally, it is suggested that the methods of testing the neurocircuit-based taxonomy and important limitations to this approach should be considered in future.

The local neural markers of MRI in patients with temporal lobe epilepsy presenting ictal panic: A resting resting-state postictal fMRI study

OBJECTIVES

Temporal lobe epilepsy (TLE) is one of the most common focal epilepsies. Some patients with TLE have ictal panic (IP), which is often confused with panic attack (PA) in panic disorder (PD). Previous studies have described temporal lobe epilepsy with ictal panic (TLEIP), but the specific mechanisms remain unclear. Here, we used resting-state functional magnetic resonance imaging (rs-fMRI) to investigate local brain abnormalities in patients with TLEIP and tried to find neural markers to explore the mechanism of IP in patients with TLE.

METHODS

A total of 40 patients with TLE, including 28 patients with TLE and 12 patients with TLEIP along with 30 age- and gender-matched healthy controls were included. We collected clinical/physiological/neuropsychological and rs-fMRI data. Fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and degree centrality (DC) were calculated. ANOVA was used to find different areas and t-tests used to compare differences among fALFF, ReHo, and DC. Correlation analyses explored the relationship between local brain abnormalities and patient characteristics.

RESULTS

No significant differences in age and gender were found among the three groups, nor were there differences in education level, Montreal Cognitive Assessment (MOCA) and Hamilton Anxiety Scale (HAMA) between the TLEIP and TLE groups. All the onset sites of patients with TLEIP were on the right. In addition to fear, other symptoms observed included nausea, palpitations, rising epigastric sensation, and dyspnea. There were no correlations between duration of IP and HAMA (p = 0.659). Moreover, all IP durations were <2 min and most <1 min. Compared to the HCs group, the ReHo value of the TLEIP group in the right middle frontal gyrus was significantly decreased (GRF correction, two-tailed, voxel level P < 0.005, cluster level P < 0.05). Compared to the HCs and TLE groups, the DC value of the TLEIP group in the left middle temporal gyrus (MTG) was significantly increased (GRF correction, two-tailed, voxel level P < 0.005, cluster level P < 0.05). No regions showed any significant fALFF difference between HCs and TLE groups (GRF correction, two-tailed, voxel level P < 0.005, cluster level P < 0.05).

CONCLUSIONS

This research describes local brain abnormalities in patients with TLE presenting as IP. These results will be preliminarily conducive to understand the seizure mechanism of IP in patients with TLE, find out the MRI neural markers, and to further explore the neurophysiological mechanisms of IP in patients with TLE.

Acute neurofunctional effects of escitalopram during emotional processing in pediatric anxiety: a double-blind, placebo-controlled trial

Anxiety disorders are the most common mental disorders in adolescents. However, only 50% of pediatric patients with anxiety disorders respond to the first-line pharmacologic treatments-selective serotonin reuptake inhibitors (SSRIs). Thus, identifying the neurofunctional targets of SSRIs and finding pretreatment or early-treatment neurofunctional markers of SSRI treatment response in this population is clinically important. We acquired pretreatment and early-treatment (2 weeks into treatment) functional magnetic resonance imaging during a continuous processing task with emotional and neutral distractors in adolescents with generalized anxiety disorder (GAD, N = 36) randomized to 8 weeks of double-blind escitalopram or placebo. Generalized psychophysiological interaction analysis was conducted to examine the functional connectivity of the amygdala while patients viewed emotional pictures. Full-factorial analysis was used to investigate the treatment effect of escitalopram on amygdala connectivity. Correlation analyses were performed to explore whether pretreatment and early (week 2) treatment-related connectivity were associated with treatment response (improvement in anxiety) at week 8. Compared to placebo, escitalopram enhanced emotional processing speed and enhanced negative right amygdala-bilateral ventromedial prefrontal cortex (vmPFC) and positive left amygdala-right angular gyrus connectivity during emotion processing. Baseline amygdala-vmPFC connectivity and escitalopram-induced increased amygdala-angular gyrus connectivity at week 2 predicted the magnitude of subsequent improvement in anxiety symptoms. These findings suggest that amygdala connectivity to hubs of the default mode network represents a target of acute SSRI treatment. Furthermore, pretreatment and early-treatment amygdala connectivity could serve as biomarkers of SSRI treatment response in adolescents with GAD. The trial registration for the study is ClinicalTrials.gov Identifier: NCT02818751.

Reduced prefrontal cortex response to own vs. unknown emotional infant faces in mothers with bipolar disorder

Motherhood involves functional brain adaptations within a broad neural network purported to underlie sensitive caregiving behavior. Bipolar disorder (BD) is associated with aberrant brain response to emotional faces within a similar network, which may influence BD mothers' sensitivity to infant faces. This functional magnetic resonance imaging (fMRI) study aimed to investigate whether mothers with BD display aberrant neural responses to own infant faces compared to healthy mothers. Twenty-six mothers with BD in remission and 35 healthy mothers underwent fMRI during which they viewed happy and distressed still facial photographs of their own and of unknown infants. After the scan, mothers viewed the pictures again on a computer screen and rated the intensity of infants' facial emotions and their own emotional response to infant face images. Mothers with BD displayed lower left dorsolateral prefrontal cortex (dlPFC) response compared to healthy mothers to own vs. unknown infant faces specifically and abnormal positive functional connectivity between the left and right amygdala and prefrontal regions. BD mothers further displayed stronger deactivation of precuneus and occipital regions to all happy vs. distressed infant faces. After the scan, they rated their infants' distress and own response to their infants' distressed faces less negatively than healthy mothers. Blunted dlPFC response and aberrant fronto-limbic connectivity while viewing own infant faces and less negative ratings of own infants' distress in BD mothers may affect their responses to their own infants in real-life mother-infant interactions.

Emotional Reactivity, Emotion Regulation, and Social Emotions in Affective Disorders

Abstract. Affective disorders, specifically Major Depressive Disorder and Bipolar Disorders, show high prevalence, relapse rates, and a high likelihood to develop a chronic course. For the past two decades, research has investigated the neural correlates of emotion processing and emotion regulation in patients with affective disorders. Putative underlying causal mechanisms of dysregulated affect have been informed by knowledge from the intersection of neuroimaging and clinical psychology. More recent investigations also consider processing the role of mostly negative, self-blaming social emotions, which have been linked to treatment resistance and, hence, provide a prolific target for intervention. Several psychotherapeutic treatment approaches already focus on emotion, and here specific knowledge about the mechanisms underlying persistent changes in affect bears the potential to improve the treatment of affective disorders. In this narrative review, we delineate why and how our insights into the neural correlates of emotion processing and regulation can be applied to the treatment of patients with affective disorders.

Multivariate alterations in insula - Medial prefrontal cortex linked to genetics in 12q24 in schizophrenia

The direct effect of genetic variations on clinical phenotypes within schizophrenia (SZ) remains elusive. We examined the previously identified association of reduced gray matter concentration in the insula - medial prefrontal cortex and a quantitative trait locus located in 12q24 in a SZ dataset. The main analysis was performed on 1461 SNPs and 830 participants. The highest contributing SNPs were localized in five genes including TMEM119, which encodes a microglial marker, that is associated with neuroinflammation and Alzheimer's disease. The gene set in 12q4 may partially explain brain alterations in SZ, but they may also relate to other psychiatric and developmental disorders.

In search of convergent regional brain abnormality in cognitive emotion regulation: A transdiagnostic neuroimaging meta-analysis

Ineffective use of adaptive cognitive strategies (e.g., reappraisal) to regulate emotional states is often reported in a wide variety of psychiatric disorders, suggesting a common characteristic across different diagnostic categories. However, the extent of shared neurobiological impairments is incompletely understood. This study, therefore, aimed to identify the transdiagnostic neural signature of disturbed reappraisal using the coordinate‐based meta‐analysis (CBMA) approach. Following the best‐practice guidelines for conducting neuroimaging meta‐analyses, we systematically searched PubMed, ScienceDirect, and Web of Science databases and tracked the references. Out of 1,608 identified publications, 32 whole‐brain neuroimaging studies were retrieved that compared brain activation in patients with psychiatric disorders and healthy controls during a reappraisal task. Then, the reported peak coordinates of group comparisons were extracted and several activation likelihood estimation (ALE) analyses were performed at three hierarchical levels to identify the potential spatial convergence: the global level (i.e., the pooled analysis and the analyses of increased/decreased activations), the experimental‐contrast level (i.e., the analyses of grouped data based on the regulation goal, stimulus valence, and instruction rule) and the disorder‐group level (i.e., the analyses across the experimental‐contrast level focused on increasing homogeneity of disorders). Surprisingly, none of our analyses provided significant convergent findings. This CBMA indicates a lack of transdiagnostic convergent regional abnormality related to reappraisal task, probably due to the complex nature of cognitive emotion regulation, heterogeneity of clinical populations, and/or experimental and statistical flexibility of individual studies.

Assessment of the neuronal underpinnings of cognitive impairment in bipolar disorder with a picture encoding paradigm and methodological lessons learnt

BACKGROUND

Mood disorders are often associated with persistent cognitive impairments. However, pro-cognitive treatments are essentially lacking. This is partially because of poor insight into the neurocircuitry abnormalities underlying these deficits and their change with illness progression.

AIMS

This functional magnetic resonance imaging (fMRI) study investigates the neuronal underpinnings of cognitive impairments and neuronal change after mood episodes in remitted patients with bipolar disorder (BD) using a hippocampus-based picture encoding paradigm.

METHODS

Remitted patients with BD (n=153) and healthy controls (n=52) were assessed with neuropsychological tests and underwent fMRI while performing a strategic picture encoding task. A subgroup of patients (n=43) were rescanned after 16 months. We conducted data-driven hierarchical cluster analysis of patients' neuropsychological data and compared encoding-related neuronal activity between the resulting neurocognitive subgroups. For patients with follow-up data, effects of mood episodes were assessed by comparing encoding-related neuronal activity change in BD patients with and without episode(s).

RESULTS

Two neurocognitive subgroups were revealed: 91 patients displayed cognitive impairments while 62 patients were cognitively normal. No neuronal activity differences were observed between neurocognitive subgroups within the dorsal cognitive control network or hippocampus. However, exploratory whole-brain analysis revealed lower activity within a small region of middle temporal gyrus in impaired patients, which significantly correlated with poorer neuropsychological performance. No changes were observed in encoding-related neuronal activity or picture recall accuracy with the occurrence of mood episode(s) during the follow-up period.

CONCLUSION

Memory encoding fMRI paradigms may not capture the neuronal underpinnings of cognitive impairment or effects of mood episodes.

Neural basis of implicit cognitive reappraisal in panic disorder: an event-related fMRI study

Background

Panic disorder (PD) is thought to be related with deficits in emotion regulation, especially in cognitive reappraisal. According to the cognitive model, PD patients’ intrinsic and unconscious misappraisal strategies are the cause of panic attacks. However, no studies have yet been performed to explore the underlying neuromechanism of cognitive reappraisal that occur on an unconscious level in PD patients.

Methods

Twenty-six patients with PD and 25 healthy controls (HC) performed a fully-verified event-block design emotional regulation task aimed at investigating responses of implicit cognitive reappraisal during an fMRI scan. Participants passively viewed negatively valanced pictures that were beforehand neutrally, positively, or adversely portrayed in the task.

Results

Whole-brain analysis of fMRI data showed that PD patients exhibited less activation in the right dorsolateral prefrontal cortex (dlPFC) and right dorsomedial prefrontal cortex (dmPFC) compared to HC, but presented greater activation in parietal cortex when negative pictures were preceded by positive/neutral vs negative descriptions. Simultaneously, interactive effects of Group × Condition were observed in the right amygdala across both groups. Furthermore, activation in dlPFC and dmPFC was is negatively correlated to severity of anxiety and panic in PD when negative images were preceded by non-negative vs negative descriptions.

Conclusions

Emotional dysregulation in PD is likely the result of deficient activation in dlPFC and dmPFC during implicit cognitive reappraisal, in line with impaired automatic top-down regulation. Correlations between severity of anxiety and panic attack and activation of right dlPFC and dmPFC suggest that the failure to engage prefrontal region during implicit cognitive reappraisal might be associated wtih the severity of anxiety and panic; such functional patterns might be the target of possible treatments.

Neurocognitive correlates of working memory and emotional processing in postpartum psychosis: an fMRI study

BACKGROUND

Postpartum psychosis (PP) is a severe postpartum disorder. While working memory and emotional processing-related brain function are consistently impaired in psychoses unrelated to the puerperium, no studies have investigated them in PP.

METHODS

Twenty-four women at risk of developing PP (11 developed an episode - PE; 13 remained well - NPE) and 20 healthy postpartum women completed two functional magnetic resonance imaging tasks within a year of delivery: working memory (n-back) and emotional face recognition (fearful faces). We compared women at-risk of PP to controls, as well as NPE, PE, and controls to test for potential effects of a PP episode occurrence.

RESULTS

Women at-risk of PP and PE showed hyperactivation of lateral visual areas, precuneus, and posterior cingulate during the n-back task. The at-risk group as a whole, as well as the PE and NPE groups, showed hyperconnectivity of the right dorsolateral prefrontal cortex (DLPFC) with various parieto-occipito-temporo-cerebellar regions compared to controls during several n-back conditions. Increases in connectivity between the right DLPFC and ipsilateral middle temporal gyrus were observed in the PE group compared to NPE during 2-back. During the fearful faces task, at-risk women as a group showed hyperactivation of fronto-cingulo-subcortical regions, and hypoconnectivity between the left amygdala and ipsilateral occipito-parietal regions compared to controls. No significant performance differences were observed.

CONCLUSIONS

These results present preliminary evidence of a differential nature of functional brain abnormalities in PP compared to the typically observed reduced connectivity with the DLPFC in psychoses unrelated to puerperium, such as bipolar disorder.

Amygdala hyperconnectivity in the paranoid state: A transdiagnostic study

BACKGROUND

Paranoia significantly contributes to social impairments across clinical diagnoses, and amygdala dysfunction has been identified as a neurobiological marker of paranoia among individuals with schizophrenia. Therefore, we aimed to investigate amygdala functional connectivity (FC) in paranoia across diagnoses.

METHODS

Forty-five patients with recent history of clinically significant paranoid ideation and a current DSM-5 diagnosis of any disorder underwent resting-state functional magnetic resonance imaging either in a paranoid (N = 23) or non-paranoid (N = 22) state. Amygdala FC were compared between paranoid and non-paranoid patients. Supplemental correlation analyses between amygdala FC and paranoia score were performed separately in patients and a non-equivalent healthy control (HC; N = 60) group.

RESULTS

Increased FC was found between right amygdala and the prefrontal cortex (PFC) [bilateral medial superior frontal gyrus, anterior cingulate, medial frontal gyrus, the triangular part and the opercular part of the inferior frontal gyrus (IFG); right orbital part of IFG], the frontal cortex (bilateral median cingulate, left precentral gyrus), and subcortical areas (right insula) in the paranoid group compared with the non-paranoid group. No significant between-group differences were observed in left amygdala FC. FC between right amygdala and PFC and frontal cortex was positively correlated with paranoia in patient and HC groups.

CONCLUSION

Paranoia is associated with right amygdala hyperconnectivity with PFC, frontal cortex, and insula. This hyperconnectivity was evident regardless of diagnosis and therefore identify a likely transdiagnostic neural mechanism, which may help to identify treatment targets that could potentially improve the social functioning of individuals with clinical diagnoses.

Neural function during emotion regulation and future depressive symptoms in youth at risk for affective disorders

Affective disorders (AD, including bipolar disorder, BD, and major depressive disorder) are severe recurrent illnesses. Identifying neural markers of processes underlying AD development in at-risk youth can provide objective, "early-warning" signs that may predate onset or worsening of symptoms. Using data (n = 34) from the Bipolar Offspring Study, we examined relationships between neural response in regions supporting executive function, and those supporting self-monitoring, during an emotional n-back task (focusing on the 2-back face distractor versus the 0-back no-face control conditions) and future depressive and hypo/manic symptoms across two groups of youth at familial risk for AD: Offspring of parents with BD (n = 15, age = 14.15) and offspring of parents with non-BD psychopathology (n = 19, age = 13.62). Participants were scanned and assessed twice, approximately 4 years apart. Across groups, less deactivation in the mid-cingulate cortex during emotional regulation (Rate Ratio = 3.07(95% CI:1.09-8.66), χ²(1) = 4.48, p = 0.03) at Time-1, and increases in functional connectivity from Time-1 to 2 (Rate Ratio = 1.45(95% CI:1.15-1.84), χ²(1) = 8.69, p = 0.003) between regions that showed deactivation during emotional regulation and the right caudate, predicted higher depression severity at Time-2. Both effects were robust to sensitivity analyses controlling for clinical characteristics. Decreases in deactivation between Times 1 and 2 in the right putamen tail were associated with increases in hypo/mania at Time-2, but this effect was not robust to sensitivity analyses. Our findings reflect neural mechanisms of risk for worsening affective symptoms, particularly depression, in youth across a range of familial risk for affective disorders. They may serve as potential objective, early-warning signs of AD in youth.

Antagonism between brain regions relevant for cognitive control and emotional memory facilitates the generation of humorous ideas

The ability to generate humor gives rise to positive emotions and thus facilitate the successful resolution of adversity. Although there is consensus that inhibitory processes might be related to broaden the way of thinking, the neural underpinnings of these mechanisms are largely unknown. Here, we use functional Magnetic Resonance Imaging, a humorous alternative uses task and a stroop task, to investigate the brain mechanisms underlying the emergence of humorous ideas in 24 subjects. Neuroimaging results indicate that greater cognitive control abilities are associated with increased activation in the amygdala, the hippocampus and the superior and medial frontal gyrus during the generation of humorous ideas. Examining the neural mechanisms more closely shows that the hypoactivation of frontal brain regions is associated with an hyperactivation in the amygdala and vice versa. This antagonistic connectivity is concurrently linked with an increased number of humorous ideas and enhanced amygdala responses during the task. Our data therefore suggests that a neural antagonism previously related to the emergence and regulation of negative affective responses, is linked with the generation of emotionally positive ideas and may represent an important neural pathway supporting mental health.

Deficits in explicit emotion regulation in bipolar disorder: a systematic review

Background

This study aimed to compile and synthesize studies investigating explicit emotion regulation in patients with bipolar disorder and individuals at risk of developing bipolar disorder. The importance of explicit emotion regulation arises from its potential role as a marker for bipolar disorders in individuals at risk and its potent role in therapy for bipolar disorder patients.

Methods

To obtain an exhaustive compilation of studies dealing specifically with explicit emotion regulation in bipolar disorder, we conducted a systematic literature search in four databases. In the 15 studies we included in our review, the emotion-regulation strategies maintenance, distraction, and reappraisal (self-focused and situation-focused) were investigated partly on a purely behavioral level and partly in conjunction with neural measures. The samples used in the identified studies included individuals at increased risk of bipolar disorder, patients with current affective episodes, and patients with euthymic mood state.

Results

In summary, the reviewed studies' results indicate impairments in explicit emotion regulation in individuals at risk for bipolar disorder, patients with manic and depressive episodes, and euthymic patients. These deficits manifest in subjective behavioral measures as well as in neural aberrations. Further, our review reveals a discrepancy between behavioral and neural findings regarding explicit emotion regulation in individuals at risk for bipolar disorders and euthymic patients. While these groups often do not differ significantly in behavioral measures from healthy and low-risk individuals, neural differences are mainly found in frontostriatal networks.

Conclusion

We conclude that these neural aberrations are a potentially sensitive measure of the probability of occurrence and recurrence of symptoms of bipolar disorders and that strengthening this frontostriatal route is a potentially protective measure for individuals at risk and patients who have bipolar disorders.

Investigating neural circuits of emotion regulation to distinguish euthymic patients with bipolar disorder and major depressive disorder

BACKGROUND

Up to 40% of patients with bipolar disorder (BD) are initially diagnosed as having major depressive disorder (MDD), and emotional lability is a key aspect of both sets of mood disorders. However, it remains unknown whether differences in the regulation of emotions through cognitive reappraisal may serve to distinguish BD and MDD. Therefore, we examined this question in euthymic BD and MDD patients.

METHODS

Thirty-eight euthymic BD, 33 euthymic MDD and 37 healthy control (HC) participants, matched for age, gender and depression severity, engaged in an emotion regulation (ER) cognitive reappraisal task during an fMRI scan were examined. Participants either reappraised (Think condition) or passively watched negative (Watch condition) or neutral (Neutral condition) pictures and rated their affect. Activation and connectivity analyses were used to examine group differences in reappraisal (Think vs Watch) and reactivity (Watch vs Neutral) conditions in ER-specific neural circuits.

RESULTS

Irrespective of group, participants rated most negatively the images during the Watch condition relative to Think and Neutral conditions, and more negatively to Think relative to Neutral. Notably, BD participants exhibited reduced subgenual anterior cingulate activation (sgACC) relative to MDD during reappraisal, but exhibited greater sgACC activation relative to MDD during reactivity, whereas MDD participants elicited greater activation in right amygdala relative to BD during reactivity. We found no group differences in task-related connectivity.

CONCLUSIONS

Euthymic BD and MDD patients engage differential brain regions to process and regulate emotional information. These differences could serve to distinguish the clinical groups and provide novel insights into the underlying pathophysiology of BD.

Altered frontal cortex functioning in emotion regulation and hopelessness in bipolar disorder

OBJECTIVES

Emotion regulation difficulties precipitate and exacerbate acute mood symptoms in individuals with bipolar disorder (BD), and contribute to suicidal behavior. However, few studies have examined regional brain responses in explicit emotion regulation during acute BD mood states, or hopelessness, a major suicide risk factor. We assessed brain responses during explicit emotion regulation, and their relationship with hopelessness, in acutely symptomatic and euthymic individuals with BD.

METHODS

Functional MRI data were obtained from individuals with BD who were either in acute negative (BD-A; n = 24) or euthymic (BD-E; n = 24) mood states, and from healthy volunteers (HV; n = 55), while participants performed a paradigm that instructed them to downregulate their responses to fearful (EmReg-Fear) and happy (EmReg-Happy) facial stimuli. Emotion regulation-related differences in brain responses during negative and euthymic BD states, as well as their associations with negative affective symptoms (hopelessness and depression), were examined.

RESULTS

Decreased responses were observed in ventral and dorsal frontal regions, including medial orbitofrontal (mOFC) and dorsal anterior cingulate cortices, during EmReg-Fear across symptomatic and euthymic states in participants with BD relative to HVs. The lowest responses were observed in the BD-A group. Across BD participants, negative associations were observed between mOFC responses and hopelessness, particularly due to loss of motivation. Differences were not significant during EmReg-Happy.

CONCLUSIONS

Lesser emotion regulation-related ventral and dorsal frontal engagement in BD could represent a trait abnormality that worsens during acute negative states. The reduced mOFC engagement in BD during explicit regulation of negative emotions may contribute to hopelessness particularly in the context of diminished motivation.

Gender-related difference in altered fractional amplitude of low-frequency fluctuations after electroacupuncture on primary insomnia patients: A resting-state fMRI study

BACKGROUND

Primary insomnia (PI) is defined as a sleep disorder with no definite cause or inducement. Electroacupuncture, a treatment of inserting needles into specific points on the body surface and applying electrical stimulation, has been proved effective in treating PI with minimal adverse effects. However, the influence of gender difference on the clinical treatment efficacy of electroacupuncture for PI patients remains unclear. Therefore, we designed a clinical trial to compare the clinical treatment efficacy of electroacupuncture for PI patients with different genders. The research on the mechanism of electroacupuncture suggested it could modulate the sleep and wakefulness by activating or deactivating brain regions via a needling/tactile somatosensory specific stimulus. Therefore, we also designed a resting-state functional magnetic resonance imaging (rs-fMRI) study to detect the spontaneous brain activity of PI patients before and after the electroacupuncture treatment.

METHOD

Thirty PI patients were recruited to accept 5-week electroacupuncture treatment on HT-7. Athens Insomnia Scale (AIS) and Pittsburgh sleep quality index (PSQI) questionnaires were used to evaluate the clinical treatment efficacy. Rs-fMRI was employed to observe the spontaneous brain activity in the resting state at the baseline and after 5 weeks of electroacupuncture treatment, which was measured by the fractional amplitude of low-frequency fluctuations (fALFF).

RESULT

The AIS and PSQI scores were significantly decreased both in the female PI group and the male PI group after treatment. The decreased PSQI of female patients was significantly more than that of male patients (p < .05). The gender-related difference in the cerebral response to electroacupuncture was mainly in posterior cingulate and supramarginal gyrus.

CONCLUSION

There is a gender-related difference in the clinical treatment efficacy of electroacupuncture for PI patients, and female patients may benefit more from electroacupuncture. Gender-related differences in the cerebral response to electroacupuncture may be one of the factors affecting clinical treatment efficacy.

Altered functional activity in bipolar disorder: A comprehensive review from a large-scale network perspective

BACKGROUND

Growing literature continues to identify brain regions that are functionally altered in bipolar disorder. However, precise functional network correlates of bipolar disorder have yet to be determined due to inconsistent results. The overview of neurological alterations from a large-scale network perspective may provide more comprehensive results and elucidate the neuropathology of bipolar disorder. Here, we critically review recent neuroimaging research on bipolar disorder using a network-based approach.

METHODS

A systematic search was conducted on studies published from 2009 through 2019 in PubMed and Google Scholar. Articles that utilized functional magnetic resonance imaging technique to examine altered functional activity of major regions belonging to a large-scale brain network in bipolar disorder were selected.

RESULTS

A total of 49 studies were reviewed. Within-network hypoconnectivity was reported in bipolar disorder at rest among the default mode, salience, and central executive networks. In contrast, when performing a cognitive task, hyperconnectivity among the central executive network was found. Internetwork functional connectivity in the brain of bipolar disorder was greater between the salience and default mode networks, while reduced between the salience and central executive networks at rest, compared to control.

CONCLUSION

This systematic review suggests disruption in the functional activity of large-scale brain networks at rest as well as during a task stimuli in bipolar disorder. Disrupted intra- and internetwork functional connectivity that are also associated with clinical symptoms suggest altered functional connectivity of and between large-scale networks plays an important role in the pathophysiology of bipolar disorder.

Basolateral Amygdala but Not Medial Prefrontal Cortex Contributes to Chronic Fluoxetine Treatments for PTSD Symptoms in Mice

Do chronic fluoxetine treatments reduced footshock-induced posttraumatic stress disorder (PTSD) symptoms, including fear and comorbid depression, in the situational reminder phase? Moreover, are the subareas of the medial prefrontal cortex (mPFC), including the cingulate cortex 1 (Cg1), prelimbic cortex (PrL), infralimbic cortex (IL), and basolateral amygdala (BLA), involved in the fluoxetine amelioration of PTSD symptoms? These two crucial issues were addressed in the present study. All mice were injected with chronic fluoxetine or normal saline treatments for the adaptation (14 days), footshock fear conditioning (1 day), and situational reminder (3 days) phases. After adaptation, the mice were subjected to footshock (2 mA, 10 seconds) or nonfootshock and stayed 2 min in a footshock box for 2 min for fear conditioning. Later, they were placed in the footshock box for 2 min in the situational reminder phase. In the final session of the situational reminder phase, a forced swimming test (FST) and immunohistochemical staining were conducted. The results indicated that footshock induced fear and comorbid depression. Meanwhile, chronic fluoxetine treatments reduced fear and depression behaviors. The Cg1, PrL, IL, and BLA were seemingly to increase c-Fos expression after footshock-induced PTSD symptoms in the situational reminder phase. The fluoxetine treatments reduced only the BLA's c-Fos expression. The findings suggest that BLA contributes to the fluoxetine amelioration of PTSD symptoms; however, the mPFC, including the Cg1, PrL, and IL, did not mediate PTSD symptoms' amelioration stemming from fluoxetine. The present data might help us to further understand the neural mechanism of fluoxetine treatments in PTSD symptoms.

No Words for Feelings? Not Only for My Own: Diminished Emotional Empathic Ability in Alexithymia

The present study has been designed to disentangle cognitive and emotional dimensions of empathy in a group of mentally healthy and highly alexithymic individuals (ALEX, n = 24) and well-matched controls (n = 26) through questionnaire Interpersonal Reactivity Index (IRI) and Multifaceted Empathy Task (MET) used during the fMRI and after the fMRI. Simultaneously, Skin Conductance Response (SCR) has been acquired as an implicit measure of emotional reaction. Results show an impaired emotional empathic ability in alexithymic individuals, with lower levels of SCR and higher activation in prefrontal brain regions such as the ventrolateral prefrontal cortex (VLPFC) and inferior frontal gyrus (IFG). Cognitive empathy was not impaired in the alexithymic group and the results were accompanied by a higher activation left IFG. The study leads to the conclusion that alexithymia does not only involve a diminished ability to identify and describe one's own emotions. Furthermore, it is related to a deeper disability of emotion regulation, which becomes visible through impaired emotional concern for others and higher levels of personal distress.

Drum training induces long-term plasticity in the cerebellum and connected cortical thickness

It is unclear to what extent cerebellar networks show long-term plasticity and accompanied changes in cortical structures. Using drumming as a demanding multimodal motor training, we compared cerebellar lobular volume and white matter microstructure, as well as cortical thickness of 15 healthy non-musicians before and after learning to drum, and 16 age matched novice control participants. After 8 weeks of group drumming instruction, 3 ×30 minutes per week, we observed the cerebellum significantly changing its grey (volume increase of left VIIIa, relative decrease of VIIIb and vermis Crus I volume) and white matter microstructure in the inferior cerebellar peduncle. These plastic cerebellar changes were complemented by changes in cortical thickness (increase in left paracentral, right precuneus and right but not left superior frontal thickness), suggesting an interplay of cerebellar learning with cortical structures enabled through cerebellar pathways.

Neural Subtypes of Euthymic Bipolar I Disorder Characterized by Emotion Regulation Circuitry

BACKGROUND

Current diagnostic strategy for bipolar disorders relies on symptomological classification. Yet, responses to both pharmacological and psychotherapeutic treatments vary widely, suggesting that underlying neuropathological differences are not well defined by current nosology. Classifying patients with bipolar disorder based on emotion regulation network (ERN) activation may account for some of the heterogeneity within the disorder.

METHODS

Euthymic participants diagnosed with bipolar I disorder (n = 86) and healthy subjects (n = 80) underwent functional magnetic resonance imaging scans while engaged in emotional reappraisal of negative stimuli. After determining average regional activations in key network regions, we applied agglomerative hierarchical clustering to identify subtypes of bipolar disorder. Next, we examined relations among neural subtypes, demographic variables, and mood symptoms.

RESULTS

Analyses revealed two primary neural subtypes of euthymic bipolar I disorder participants. The first subtype, ERN cluster 1, was characterized by increased amygdala activation and slightly increased ventrolateral prefrontal and subgenual cingulate activation, whereas ERN cluster 2 was defined by decreased amygdala activation with wider-spread prefrontal activation. Cluster 1 was associated with a higher number of hospitalizations for depression (odds ratio = 1.30, 95% confidence interval = 1.02-1.64) and later onset of manic episodes (odds ratio = 1.06, 95% confidence interval = 1.00-21.13) than cluster 2. ERN clusters of healthy subjects differed from bipolar disorder clusters and were defined by differential activation of the prefrontal cortex. ERN clusters of healthy subjects, which differed from bipolar disorder clusters, were defined by differential activation of the prefrontal cortex.

CONCLUSIONS

Emotion regulation circuitry can distinguish neurobiological subtypes of bipolar disorder in the euthymic state. These subtypes, which are differentially associated with indices of illness severity and subsyndromal affective symptoms, may help to inform relapse risk and more personalized treatment approaches.

Daily-life affective instability in emotional distress disorders is associated with function and structure of posterior parietal cortex

Affective instability (i.e., large and frequent shifts in negative emotions) is a key emotion dysregulation symptom in emotional distress disorders and can be reliably and validly assessed using ambulatory assessment. However, no study has examined whether affective instability is associated with brain function and structure. Using multimodal neuroimaging and ambulatory assessment, we examined associations between functional activation and cortical structure with ambulatory-assessed affective instability in emotional distress disorders (n = 27). Increased daily life-affective instability was associated with decreased neural activation on an emotion regulation task in a left inferior parietal region consistently associated with emotion regulation. Daily-life affective instability was also associated with hypogyria in this same left inferior parietal region, with hypogyria extending into additional posterior parietal regions. This study found evidence that daily-life affective instability was associated with both functionstructure of the posterior parietal cortex, a key attentional control region involved in emotion regulation.

Transcranial magnetic stimulation demonstrates a role for the ventrolateral prefrontal cortex in emotion perception

The lateral prefrontal cortex, a region with both structural and functional connectivity to the amygdala, has been consistently implicated in the downregulation of subcortical-generated emotional responses. Although previous work has demonstrated that the ventral lateral prefrontal cortex (vlPFC) is important to emotion processing, no study has interrupted vlPFC function in order to test is role in emotion perception. In the current study, we acutely disrupted vlPFC function in twenty healthy adult participants by administering sham stimulation and transcranial magnetic stimulation (TMS), in randomized order, during performance of an emotional perception task. During sham stimulation, participants demonstrated increased perceptual sensitivity for happy faces compared to angry faces. Disruption of the vlPFC eliminated this difference: in this condition, perceptual sensitivity did not differ between happy and angry faces. Reaction times and response bias did not differ between emotions or TMS conditions. This pattern of perceptual bias is consistent with effects observed in a wide range of affective disorders, in which vlPFC dysfunction has also been reported. This study provides insight into a possible mechanism through which the vlPFC may contribute to emotion perception.

Distinct temporal brain dynamics in bipolar disorder and schizophrenia during emotion regulation

BACKGROUND

Disturbances in emotion regulation (ER) are characteristic of both patients with bipolar disorder (BD) and schizophrenia (SZ). We investigated the temporal dynamics of brain activation during cognitive ER in BD and SZ to understand the contribution of temporal characteristics of disturbed ER to their unique and shared symptomatology.

METHOD

Forty-six participants performed an ER-task (BD, n = 15; SZ, n = 16; controls, n = 15) during functional magnetic resonance imaging, in which they were instructed to use cognitive reappraisal techniques to regulate their emotional responses. Finite impulse response modeling was applied to estimate the temporal dynamics of brain responses during cognitive reappraisal (v. passive attending) of negative pictures. Group, time, and group × time effects were tested using multivariate modeling.

RESULTS

We observed a group × time interaction during ER in the ventrolateral prefrontal cortex (VLPFC), supplementary motor area (SMA) and inferior occipital gyrus. Patients with SZ demonstrated initial hyper-activation of the VLPFC and SMA activation that was not sustained in later regulatory phases. Response profiles in the inferior occipital gyrus in SZ showed abnormal activation in the later phases of regulation. BD-patients showed general blunted responsivity in these regions.

CONCLUSIONS

These results suggest that ER-disturbances in SZ are characterized by an inefficient initialization and failure to sustain regulatory control, whereas in BD, a failure to recruit regulatory resources may represent initial deficits in formulating adequate representations of the regulatory needs. This may help to further understand how ER-disturbances give rise to symptomatology of BD and SZ.

Sex differences and brain development during puberty and adolescence

Sex differences in behavior, and whether these behavioral differences are related to sex differences in brain development, has been a longstanding topic of debate. Presumably, sex differences can provide critically important leads for explaining the etiology of various illnesses that show (i) large sex differences in prevalence and (ii) have an origin before or during adolescence. The general aim of this chapter is to provide an overview of scientific studies on sex differences in normative brain and behavioral development across puberty and adolescence, including the (sex) hormone-driven transition phase of puberty. Moreover, we describe the literature on brain and behavioral development in gender dysphoria, a severe and persistent incongruence between the self-identified gender and the assigned sex at birth. From the literature it becomes clear there is evidence for a specific link between pubertal maturation and developmental changes in arousal, motivation, and emotion. However, this link is rather similar between boys and girls. Moreover, although there is substantial evidence for sex differences in mean brain structure, these have not always been linked to sex differences in behavior, cognition, or psychopathology. Furthermore, there is little evidence for sex differences in brain development and thus, studies so far have been unable to explain sex differences in cognition. Suggestions for future research and methodologic considerations are provided.

Bipolar limbic expression of auto-immune thyroid targets: thyroglobulin and thyroid-stimulating hormone receptor

The associations between thyroid auto-immunity and neuro-psychiatric disorders are well-documented. However, there exists limited literature specifically linking auto-immune thyroid disease (AITD) to bipolar disorder (BD). Thus, we investigated the likely association between Hashimoto's disease and BD through the extra-thyroidal localisation of thyroid-stimulating hormone receptor (TSH-R) and thyroglobulin (TG) in limbic regions of normal and bipolar human adult brain. Further, we hypothesised that changes in thyroid expression in bipolar limbic cortex may contribute to mood dysregulation associated with BD. Immuno-chemistry and in-situ PCR were used to localise TSH-R/TG within the amygdala, cingulate gyrus and frontal cortex of normal (n = 5) and bipolar (n = 5) brains. Reverse-transcriptase qPCR provided fold-change differences in TSH-R gene expression. The results demonstrated reduced thyroid protein expression in bipolar limbic regions; these novel results correlate with other neuro-imaging reports that describe reduced cortico-limbic tissue volumes and neuro-physiological activity during BD. We also demonstrated TG-like proteins exclusive to bipolar amygdala neurons, and which relates to previous neuro-imaging studies of amygdala hyperactivity and enhanced emotional sensitivity in BD. Indeed, reduced TSH-R/TG in limbic regions may predispose to, or bear relevance in the pathophysiology of mood dysregulation and symptoms of BD. Further, we attribute mood dysregulation in BD to limbic-derived TSH-R, which probably provides potential targets for thyroid auto-immune factors during Hashimoto's disease. Consequently, this may lead to inactivated and/or damaged neurons. The neuro-pathology of diminished neuronal functioning or neuronal atrophy suggests a novel neuro-degeneration mechanism in BD.

Low working memory capacity in euthymic bipolar I disorder: No relation to reappraisal on emotion regulation

BACKGROUND

Emotion regulation (ER) applies behavioral and cognitive strategies to modify the appearance and intensity of emotions. Working memory capacity (WMC) plays an important role in the ER process, particularly through its influence on the efficiency of ER strategies.

METHODS

We investigated interactions between WMC and three ER strategies, namely cognitive reappraisal, expressive suppression, and rumination, in 43 euthymic patients with bipolar I disorder and 48 healthy control subjects. We used the Korean versions of the Operation Span Task, Emotion Regulation Questionnaire, Ruminative Response Scale, and Difficulties in Emotion Regulation Scale.

RESULTS

WMC modulated the efficacy of cognitive reappraisal in healthy controls with high WMC, but not in patients with bipolar disorder. There were no significant interactions between WMC and expressive suppression or rumination in either group.

LIMITATIONS

These include the small sample size, use of neutral words to evaluate negative emotion, use of self-administered questionnaires, and relatively high cut-off for the definition of euthymic states. A number of uncontrolled factors may have influenced our results including patients' duration of remission, number of episodes, psychiatric family history, and current psychiatric medications.

CONCLUSIONS

Our findings suggest that working memory does not function effectively in the reappraisal process during ER in patients with bipolar disorder. This may indicate that top-down regulation of emotion is impaired in bipolar disorder. Cognitive interventions aimed at improving ER in such patients may be ineffective.

Attentional engagement increases inferior frontal gyrus activity and mutes limbic activity in pediatric bipolar disorder: Meta-analyses of fMRI studies

OBJECTIVES

Attention deficit has been shown to exist in adult and pediatric bipolar disorder across the life span. Given that emotion dysregulation is central to bipolar disorder, this study hypothesizes that emotional circuitry regions are altered along with anomalies in the attentional systems during cognitive deployment in bipolar disorder.

METHODS

An activation likelihood estimation meta-analysis of attentional activities using GingerALE software was completed for adult and pediatric bipolar disorder populations in all published studies till December 2017. The meta-analysis of all fMRI studies included a total of ten pediatric studies (comprised of pediatric bipolar disorder (PBD) and typically developing (TD) groups) and nine adult patient studies (comprised of adult bipolar disorder (ABD) and healthy control (HC) groups).

RESULTS

While engaged in attentional tasks, increased activation was seen in inferior frontal gyrus with decreased activation in limbic regions in subjects with PBD, relative to TD. Differential patterns of underactivity were also noted in the dorsal attentional system i.e., frontostriatal circuit (dorsolateral prefrontal cortex, anterior cingulate cortex, right lentiform nucleus and right globus pallidus) in PBD patients relative to the TD. However, we did not see any significant differences between the adult groups i.e., ABD vs. HC.

CONCLUSIONS

In PBD, deploying attentional system potentially improves the fronto-limbic affective circuitry function, despite impaired dorsal attentional system i.e., fronto-striatal circuitry. In contrast, these neural correlates underlying attentional engagement appeared to be not significant in adult BD.

LIMITATIONS

We examined the PBD vs. TD and the ABD vs. HC separately instead of four-way contrast (dual meta-analytic study). Also, attentional tasks were not unidimensional and tend to capture selective and sustained attention along with response inhibition, thereby recruiting multiple brain circuits.

Near-infrared spectroscopy reveals neural perception of vocal emotions in human neonates

Processing affective prosody, that is the emotional tone of a speaker, is fundamental to human communication and adaptive behaviors. Previous studies have mainly focused on adults and infants; thus the neural mechanisms underlying the processing of affective prosody in newborns remain unclear. Here, we used near-infrared spectroscopy to examine the ability of 0-to-4-day-old neonates to discriminate emotions conveyed by speech prosody in their maternal language and a foreign language. Happy, fearful, and angry prosodies enhanced neural activation in the right superior temporal gyrus relative to neutral prosody in the maternal but not the foreign language. Happy prosody elicited greater activation than negative prosody in the left superior frontal gyrus and the left angular gyrus, regions that have not been associated with affective prosody processing in infants or adults. These findings suggest that sensitivity to affective prosody is formed through prenatal exposure to vocal stimuli of the maternal language. Furthermore, the sensitive neural correlates appeared more distributed in neonates than infants, indicating a high-level of neural specialization between the neonatal stage and early infancy. Finally, neonates showed preferential neural responses to positive over negative prosody, which is contrary to the "negativity bias" phenomenon established in adult and infant studies.

From the microscope to the magnet: Disconnection in schizophrenia and bipolar disorder

White matter (WM) abnormalities have implicated schizophrenia (SZ) and bipolar disorder (BD) as disconnection syndromes, yet the extent to which these abnormalities are shared versus distinct remains unclear. Diffusion tensor imaging (DTI) studies yield a putative measure of WM integrity while neuropathological studies provide more specific microstructural information. We therefore systematically reviewed all neuropathological (n = 12) and DTI (n = 11) studies directly comparing patients with SZ and BD. Most studies (18/23) reported no difference between patient groups. Changes in oligodendrocyte density, myelin staining and gene, protein and mRNA expression were found in SZ and/or BD patients as compared to healthy individuals, while DTI studies showed common alterations in thalamic radiations, uncinate fasciculus, corpus callosum, longitudinal fasciculus and corona radiata. Altogether, findings suggest shared disconnectivity in SZ and BD, which are likely related to their considerable overlap. Above all, neuroimaging findings corroborated neuropathological findings in the prefrontal cortex, demonstrating the utility of integrating multiple methodologies. Focusing on clinical dimensions over disease entities will advance our understanding of disconnectivity and help inform preventive medicine.

Development of Amygdala Functional Connectivity During Infancy and Its Relationship With 4-Year Behavioral Outcomes

BACKGROUND

The amygdala represents a core node in the human brain's emotional signal processing circuitry. Given its critical role, both the typical and atypical functional connectivity patterns of the amygdala have been extensively studied in adults. However, the development of amygdala functional connectivity during infancy is less well studied; thus, our understanding of the normal growth trajectory of key emotion-related brain circuits during a critical period is limited.

METHODS

In this study, we used resting-state functional magnetic resonance imaging (N = 233 subjects with 334 datasets) to delineate the spatiotemporal dynamics of amygdala functional connectivity development during the first 2 years of life. Their relationships with 4-year emotional (i.e., anxiety and inhibitory self-control parent report measures) and cognitive (i.e., IQ) behavioral outcomes were also assessed using multivariate modeling.

RESULTS

Our results revealed nonlinear growth of amygdala functional connectivity during the first 2 years of life, featuring dramatic synchronization during the first year followed by moderate growth or fine tuning during the second year. Importantly, functional connectivity growth during the second year had significant behavioral implications exemplified by multiple significant predictions of 4-year emotional and cognitive developmental outcomes.

CONCLUSIONS

The delineation of the spatiotemporal dynamics of amygdala functional connectivity development during infancy and their associations with 4-year behavioral outcomes may provide new references on the early emergence of both typical and atypical emotion processing capabilities.