Anomalous prefrontal-limbic activation and connectivity in youth at high-risk for bipolar disorder

Towards a neurodevelopmental model of bipolar disorder: a critical review of trait- and state-related functional neuroimaging in adolescents and young adults

Neurodevelopmental mechanisms are increasingly implicated in bipolar disorder (BD), highlighting the importance of their study in young persons. Neuroimaging studies have demonstrated a central role for frontotemporal corticolimbic brain systems that subserve processing and regulation of emotions, and processing of reward in adults with BD. As adolescence and young adulthood (AYA) is a time when fully syndromal BD often emerges, and when these brain systems undergo dynamic maturational changes, the AYA epoch is implicated as a critical period in the neurodevelopment of BD. Functional magnetic resonance imaging (fMRI) studies can be especially informative in identifying the functional neuroanatomy in adolescents and young adults with BD (BDAYA) and at high risk for BD (HR-BDAYA) that is related to acute mood states and trait vulnerability to the disorder. The identification of early emerging brain differences, trait- and state-based, can contribute to the elucidation of the developmental neuropathophysiology of BD, and to the generation of treatment and prevention targets. In this critical review, fMRI studies of BDAYA and HR-BDAYA are discussed, and a preliminary neurodevelopmental model is presented based on a convergence of literature that suggests early emerging dysfunction in subcortical (e.g., amygdalar, striatal, thalamic) and caudal and ventral cortical regions, especially ventral prefrontal cortex (vPFC) and insula, and connections among them, persisting as trait-related features. More rostral and dorsal cortical alterations, and bilaterality progress later, with lateralization, and direction of functional imaging findings differing by mood state. Altered functioning of these brain regions, and regions they are strongly connected to, are implicated in the range of symptoms seen in BD, such as the insula in interoception, precentral gyrus in motor changes, and prefrontal cortex in cognition. Current limitations, and outlook on the future use of neuroimaging evidence to inform interventions and prevent the onset of mood episodes in BDAYA, are outlined.

Lifetime depression and mania/hypomania risk predicted by neural markers in three independent young adult samples during working memory and emotional regulation

Objective markers of pathophysiological processes underlying lifetime depression and mania/hypomania risk can provide biologically informed targets for novel interventions to help prevent the onset of affective disorders in individuals with subsyndromal symptoms. Greater activity within and functional connectivity (FC) between the central executive network (CEN), supporting emotional regulation (ER) subcomponent processes such as working memory (WM), the default mode network (DMN), supporting self-related information processing, and the salience network (SN), is thought to interfere with cognitive functioning and predispose to depressive disorders. Using an emotional n-back paradigm designed to examine WM and ER capacity, we examined in young adults: (1) relationships among activity and FC in these networks and lifetime depression and mania/hypomania risk; (2) the extent to which these relationships were specific to lifetime depression risk versus lifetime mania/hypomania risk; (3) whether findings in a first, Discovery sample n = 101, 63 female, age = 23.85 (2.9) could be replicated in a two independent Test samples of young adults: Test sample 1: n = 90, 60 female, age = 21.7 (2.0); Test sample 2: n = 96, 65 female, age = 21.6 (2.1). The Mood Spectrum Self-Report (MOODS-SR-L) assessed lifetime mania/hypomania risk and depression risk. We showed significant clusters of activity to each contrast in similar locations in the anatomic mask in each Test sample as in the Discovery sample, and, using extracted mean BOLD signal from these clusters as IVs, we showed similar patterns of IV-DV relationships in each Test sample as in the Discovery sample. Specifically, in the Discovery sample, greater DMN activity during WM was associated with greater lifetime depression risk. This finding was specific to depression and replicated in both independent samples (all ps<0.05 qFDR). Greater CEN activity during ER was associated with increased lifetime depression risk and lifetime mania/hypomania risk in all three samples (all ps< 0.05 qFDR). These replicated findings provide promising objective, neural markers to better identify, and guide and monitor early interventions for, depression and mania/hypomania risk in young adults.

Putative Risk Biomarkers of Bipolar Disorder in At-risk Youth

Bipolar disorder is a highly heritable and functionally impairing disease. The recognition and intervention of BD especially that characterized by early onset remains challenging. Risk biomarkers for predicting BD transition among at-risk youth may improve disease prognosis. We reviewed the more recent clinical studies to find possible pre-diagnostic biomarkers in youth at familial or (and) clinical risk of BD. Here we found that putative biomarkers for predicting conversion to BD include findings from multiple sample sources based on different hypotheses. Putative risk biomarkers shown by perspective studies are higher bipolar polygenetic risk scores, epigenetic alterations, elevated immune parameters, front-limbic system deficits, and brain circuit dysfunction associated with emotion and reward processing. Future studies need to enhance machine learning integration, make clinical detection methods more objective, and improve the quality of cohort studies.

Aberrant Neurofunctional Responses During Emotional and Attentional Processing Differentiate ADHD Youth With and Without a Family History of Bipolar I Disorder

OBJECTIVE

To compare neurofunctional responses in emotional and attentional networks of psychostimulant-free ADHD youth with and without familial risk for bipolar I disorder (BD).

METHODS

ADHD youth with (high-risk, HR, n = 48) and without (low-risk, LR, n = 50) a first-degree relative with BD and healthy controls (n = 46) underwent functional magnetic resonance imaging while performing a continuous performance task with emotional distracters. Region-of-interest analyses were performed for bilateral amygdala (AMY), ventrolateral (VLPFC) and dorsolateral (DLPFC) prefrontal cortex, and anterior (ACC) and posterior cingulate cortex (PCC).

RESULTS

Compared with HC, HR, but not LR, exhibited predominantly left-lateralized AMY, VLPFC, DLPFC, PCC, and rostral ACC hyperactivation to emotional distractors, whereas LR exhibited right VLPFC and bilateral dorsal ACC hypoactivation to attentional targets. Regional responses correlated with emotional and attention symptoms.

CONCLUSION

Aberrant neurofunctional responses during emotional and attentional processing differentiate ADHD youth with and without a family history of BD and correlate with relevant symptoms ratings.

Pharmacogenetic Factors Influence Escitalopram Pharmacokinetics and Adverse Events in Youth with a Family History of Bipolar Disorder: A Preliminary Study

Introduction: Escitalopram is an effective and generally well-tolerated antidepressant, but children of parents with bipolar disorder (BD) may be at increased risk for adverse events associated with antidepressants, including increased irritability, restlessness, impulsivity, and manic symptoms. This risk may be influenced by polymorphisms in genes encoding cytochrome P450 enzymes (CYP2C19 or CYP2D6), the serotonin transporter (SLC6A4), and the serotonin receptor 2A subtype (HTR2A). We explored whether gene-drug interactions influence the emergence of adverse events in depressed and/or anxious youth with a family history of BD. Materials and Methods: Children and adolescents aged 12-17 years with a first-degree relative with bipolar I disorder were treated with escitalopram and monitored for adverse effects, underwent pharmacogenetic testing, and provided serum escitalopram levels. Emergence of adverse events was determined by study clinicians, and symptoms were tracked using the Treatment-Emergent Activation and Suicidality Assessment Profile (TEASAP) and Pediatric Adverse Events Rating Scale. Clinical Pharmacogenetics Implementation Consortium guidelines were used to determine CYP2C19 and CYP2D6 phenotypes. Results: Slower CYP2C19 metabolizers had greater dose-normalized 24-hour area under the curve (AUC0-24; p = 0.025), trough concentrations (Ctrough; p = 0.013), and elimination half-lives (t1/2; p < 0.001). CYP2D6 phenotype was not significantly associated with any pharmacokinetic parameter. Slower CYP2D6 metabolizers had increased TEASAP akathisia (p = 0.015) scores. HTR2A A/A and A/G genotypes were associated with increased TEASAP "self-injury, suicidality, and harm to others" subscale scores (p = 0.017). Escitalopram maximum concentration, AUC0-24, CYP2C19 phenotype, and SLC6A4 genotype were not associated with adverse events. Conclusions: CYP2C19 phenotype influences escitalopram pharmacokinetics whereas CYP2D6 phenotype does not. Slower CYP2D6 metabolism was associated with increased akathisia, and HTR2A A/A or A/G genotypes were associated with increased risk of self-harm or harm to others. Larger cohorts are needed to identify associations between genetic test results and antidepressant-associated adverse events. Trial Registration: ClinicalTrials.gov identifier: NCT02553161.

The association of genetic variation in CACNA1C with resting-state functional connectivity in youth bipolar disorder

BACKGROUND

CACNA1C rs1006737 A allele, identified as a genetic risk variant for bipolar disorder (BD), is associated with anomalous functional connectivity in adults with and without BD. Studies have yet to investigate the association of CACNA1C rs1006737 with resting-state functional connectivity (rsFC) in youth BD.

METHODS

Participants included 139 youth with BD-I, -II, or -not otherwise specified, ages 13-20 years, including 27 BD A-carriers, 41 BD non-carriers, 32 healthy controls (HC) A-carriers, and 39 HC non-carriers. Anterior cingulate cortex (ACC), amygdala, and orbitofrontal cortex (OFC) were examined as regions-of-interest in seed-to-voxel analyses. General linear models included main effects of diagnosis and rs1006737, and an interaction term, controlling for age, sex, and race.

RESULTS

We observed a main effect of BD diagnosis on rsFC between the right amygdala and the right occipital pole (p = 0.02), and a main effect of rs1006737 genotypes on rsFC between the right OFC and bilateral occipital cortex (p < 0.001). Two significant BD diagnosis-by-CACNA1C rs1006737 interactions were also identified. The A allele was associated with positive rsFC between the right ACC and right amygdala in BD but negative rsFC in HC (p = 0.01), and negative rsFC between the left OFC and left putamen in BD but positive rsFC in HC (p = 0.01).

CONCLUSION

This study found that the rs1006737 A allele, identified as a genetic risk variant for BD in adults, was differentially associated with rsFC in youth with BD in regions relevant to emotion, executive function, and reward. Future task-based approaches are warranted to better understand brain connectivity in relation to CACNA1C in BD.

The inferior frontal gyrus and familial risk for bipolar disorder

Bipolar disorder (BD) is a familial disorder with high heritability. Genetic factors have been linked to the pathogenesis of BD. Relatives of probands with BD who are at familial risk can exhibit brain abnormalities prior to illness onset. Given its involvement in prefrontal cognitive control and in frontolimbic circuitry that regulates emotional reactivity, the inferior frontal gyrus (IFG) has been a focus of research in studies of BD-related pathology and BD-risk mechanism. In this review, we discuss multimodal neuroimaging findings of the IFG based on studies comparing at-risk relatives and low-risk controls. Review of these studies in at-risk cases suggests the presence of both risk and resilience markers related to the IFG. At-risk individuals exhibited larger gray matter volume and increased functional activities in IFG compared with low-risk controls, which might result from an adaptive brain compensation to support emotion regulation as an aspect of psychological resilience. Functional connectivity between IFG and downstream limbic or striatal areas was typically decreased in at-risk individuals relative to controls, which could contribute to risk-related problems of cognitive and emotional control. Large-scale and longitudinal investigations on at-risk individuals will further elucidate the role of IFG and other brain regions in relation to familial risk for BD, and together guide identification of at-risk individuals for primary prevention.

Global hippocampus functional connectivity as a predictive neural marker for conversion to future mood disorder in unaffected offspring of bipolar disorder parents

OBJECTIVES

Hippocampus-related functional alteration in genetically at-risk individuals may reflect an endophenotype of a mood disorder. Herein, we performed a prospective study to investigate whether baseline hippocampus functional connectivity (FC) in offspring of patients with bipolar disorder (BD) would predict subsequent conversion to mood disorder.

METHODS

Eighty bipolar offspring and 40 matched normal controls (NC) underwent resting state functional MRI (rsfMRI) scanning on a 3.0 Tesla MR scanner. The offspring were subdivided into asymptomatic offspring (AO) (n = 41) and symptomatic offspring (SO) (n = 39) according to whether they manifested subthreshold mood symptoms. After identifying the different hippocampus FCs between the AO and SO, a logistic regression analysis was conducted to investigate whether the baseline hippocampus FCs predicted a future mood disorder during a 6-year follow-up.

RESULTS

We identified seven baseline para/hippocampus FCs that showed differences between AO and SO, which were entered as predictive features in the logistic regressive model. Of the 80 bipolar offspring entering the analysis, the FCs between left hippocampus and left precuneus, and between right hippocampus and left posterior cingulate, showed a discriminative capacity for predicting future mood disorder (area-under-curve, or AUC=75.76 % and 75.00 % respectively), and for predicting BD onset (AUC=77.46 % and 81.63 %, respectively).

CONCLUSIONS

The present findings revealed high predictive utility of the hippocampus resting state FCs for future mood disorder and BD onset in individuals at familial risk. These neural markers can potentially improve early detection of individuals carrying particularly high risk for future mood disorder.

A Double-Blind Randomized Trial to Investigate Mechanisms of Antidepressant-Related Dysfunctional Arousal in Depressed or Anxious Youth at Familial Risk for Bipolar Disorder

Antidepressants are standardly used to treat moderate to severe symptoms of depression and/or anxiety in youth but may also be associated with rare but serious psychiatric adverse events such as irritability, agitation, aggression, or suicidal ideation. Adverse events are especially common in youth with a family history of bipolar disorder (BD) who are at heightened risk for dysfunction in neurobiological systems that regulate emotion and arousal. To further understand this phenomenon, this study will examine (a) baseline risk factors associated with dysfunctional arousal in a sample of youth at high-risk for BD treated with or without an antidepressant, (b) whether antidepressant-related changes in arousal are mediated by changes in prefrontal-limbic circuitry, and (c) whether pharmacogenetic factors influence antidepressant-related changes in arousal. High-risk youth (aged 12-17 years with moderate to severe depressive and/or anxiety symptoms and at least one first-degree relative with bipolar I disorder) will be randomized to receive psychotherapy plus escitalopram or psychotherapy plus placebo. Neuroimaging and behavioral measures of arousal will be collected prior to randomization and at 4 weeks. Samples for pharmacogenetic analysis (serum escitalopram concentration, CYP2C19 metabolizer phenotype, and HTR2A and SLC6A4 genotypes) will be collected at 8 weeks. Youth will be followed for up to 16 weeks to assess change in arousal measures.

Amygdala structure and function in paediatric bipolar disorder and high-risk youth: A systematic review of magnetic resonance imaging findings

OBJECTIVE

Converging evidence from structural and functional magnetic resonance imaging (MRI) studies points to amygdala alteration as crucial in the development of paediatric bipolar disorder (pBP). The high number of recent studies prompted us to comprehensively evaluate findings. We aimed to systematically review structural and functional MRI studies investigating the amygdala in patients with pBP and in youth at high-risk (HR) for developing pBP.

METHODS

We searched PubMed from any time to 25 September 2020 using: 'amygdala AND (MRI OR magnetic resonance imaging) AND bipolar AND (pediatr* OR child OR children OR childhood OR adolescent OR adolescents OR adolescence OR young OR familial OR at-risk OR sibling* OR offspring OR high risk)'. In this review, we adhered to the PRISMA statement.

RESULTS

Amygdala hyperactivity to emotional stimuli is the most commonly reported finding in youth with pBP and HR compared to healthy peers (HC), whereas findings from structural MRI studies are inconsistent.

CONCLUSIONS

Hyperactivation of the amygdala might be an endophenotype of pBP.

Neural correlates of reward processing distinguish healthy youth at familial risk for bipolar disorder from youth at familial risk for major depressive disorder

Youth at familial risk for bipolar disorder (BD-risk) and major depressive disorder (MDD-risk) have aberrant reward processing, a core feature of these mood disorders. Whether BD risk differentiates from MDD risk in reward processing merits further study. We compared neural activation and connectivity during anticipation and outcome of monetary gain and loss during fMRI using the Monetary Incentive Delay (MID) Task among BD-risk (n = 40), MDD-risk (n = 41), and healthy comparison youth (HC) (n = 45), in the absence of any lifetime or current history of psychopathology [mean age 13.09 ± 2.58, 56.3% female]. Participants completed the MID task at baseline and were followed for behavioral and clinical outcomes over 4.37 ± 2.29 years. Region-of-interest (ROI) analyses conducted using anatomically defined thalamus, ventrolateral prefrontal cortex, nucleus accumbens, and putamen seeds showed that relative to MDD-risk and HC, BD-risk had decreased activation of the thalamus during anticipation of monetary gain [F(2,118) = 4.64, p = 0.01 (FDR-corrected p = 0.04)]. Psychophysiological interaction analyses revealed that BD-risk had less connectivity between the thalamus and left middle frontal gyrus (Z > 3.1, p < 0.001) and left-superior temporal gyrus (Z > 3.1, p < 0.05) compared with MDD-risk. Voxelwise, BD-risk had decreased activation in the cerebellum during anticipation and outcome of monetary gain relative to MDD-risk and HC (Z > 3.1, p < 0.001; Z > 3.1, p < 0.01). In BD-risk, decreased thalamic connectivity was associated with increased impulsivity at baseline and reduced prosocial behavior at follow-up. Reduced thalamic activation and connectivity during reward processing may distinguish familial risk for BD from familial risk for MDD and represent early markers of vulnerability that may herald social dysfunction later in adolescence.

Aberrant Neural Response to Social Exclusion Without Significantly Greater Distress in Youth With Bipolar Disorder: Preliminary Findings

BACKGROUND

Little is known about the effects of social exclusion on youth with bipolar disorder (BD). Understanding these effects and the functional neural correlates of social exclusion in youth with BD may establish differences from healthy youth and help identify areas of intervention.

METHODS

We investigated brain function in 19 youth with BD and 14 age and gender matched healthy control (HC) participants while performing Cyberball, an fMRI social exclusion task. Whole brain activation, region-of-interest, and functional connectivity were compared between groups and examined with behavioral measures.

RESULTS

Compared with the HC group, youth with BD exhibited greater activation in the left fusiform gyrus (FFG) during social exclusion. Functional connectivity between the left FFG and the posterior cingulate/precuneus was significantly greater in the HC compared with the BD group. For the HC group only, age and subjective distress during Cyberball significantly predicted mean FFG activation. No significant differences in distress during social exclusion were found between groups.

CONCLUSION

Although preliminary due to small sample size, these data suggest that youth with BD process social exclusion in a manner that focuses on basic visual information while healthy youth make use of past experiences to interpret current social encounters. This difference may account for the social cognitive issues experienced by youth with BD, which can lead to more severe anxiety and mood symptoms.

Neural changes in youth at high risk for bipolar disorder undergoing family-focused therapy or psychoeducation

BACKGROUND

Patients with mood disorders may benefit from psychosocial interventions through changes in brain networks underlying emotion processing. In this study, we used functional magnetic resonance imaging (fMRI) to investigate treatment-related changes in emotion processing networks in youth at familial high risk for bipolar disorder (BD).

METHODS

Youth, ages 9-17, were randomly assigned to family-focused therapy for high-risk youth (FFT-HR) or an active comparison treatment, Enhanced Care (EC). Before and after these 4-month treatments, participants underwent fMRI while viewing happy, fearful, and calm facial expressions. Twenty youth in FFT-HR and 20 in EC were included in analyses of pre- to post-treatment changes in activation across the whole brain. Significant clusters were assessed for correlation with mood symptom improvement.

RESULTS

In the dorsolateral prefrontal cortex (DLPFC), activation increased from pre- to post-treatment in the FFT-HR group and decreased in the EC group. Insula activation decreased in the FFT-HR group and did not change in the EC group. Across both treatments, decreasing activation in the hippocampus and amygdala was correlated with pre- to post-treatment improvement in hypomania, while increasing activation in the DLPFC was correlated with pre- to post-treatment improvement in depression.

DISCUSSION

Psychosocial treatment addresses abnormalities in emotion regulation networks in youth at high risk for BD. Increased prefrontal cortex activation suggests enhanced emotion regulation from pre- to post-treatment with FFT-HR. Improvements in family interactions may facilitate the development of prefrontal resources that provide protection against future mood episodes.

Neural Correlates of Positive Emotion Processing That Distinguish Healthy Youths at Familial Risk for Bipolar Versus Major Depressive Disorder

OBJECTIVE

Familial risk for bipolar disorder (BD) or major depressive disorder (MDD) may lead to differential emotion processing signatures, resulting in unique neural vulnerability.

METHOD

Healthy offspring of a parent with BD (n = 29, "BD-risk") or MDD (n = 44, "MDD-risk") and healthy control youths without any personal or family psychopathology (n = 28, "HC") aged 8 to 17 years (13.64 ± 2.59 years) completed an implicit emotion-perception functional magnetic resonance imaging task. Whole-brain voxelwise and psychophysiological interaction analyses examined neural differences in activation and connectivity during emotion processing. Regression modeling tested for neural associations with behavioral strengths and difficulties and conversion to psychopathology at follow-up (3.71 ± 1.91 years).

RESULTS

BD-risk youth showed significantly reduced bilateral putamen activation, and decreased connectivity between the left putamen and the left ventral anterior cingulate cortex (vACC) and the right posterior cingulate cortex (PCC) during positive-valence emotion processing compared to MDD-risk and HC (Z >2.3; p <.001). Decreased left putamen-right PCC connectivity correlated with subsequent peer problems in BD-risk (β = -2.90; p <.05) and MDD-risk (β = -3.64; p < .05) groups. Decreased left (β = -0.09; p < .05) and right putamen activation (β = -0.07; p = .04) were associated with conversion to a mood or anxiety disorder in BD-risk youths. Decreased left putamen-right PCC connectivity was associated with a higher risk of conversion in BD-risk (HR = 8.28 , p < .01) and MDD-risk (HR = 2.31, p = .02) groups.

CONCLUSION

Reduced putamen activation and connectivity during positive emotion processing appear to distinguish BD-risk youths from MDD-risk and HC youths, and may represent a marker of vulnerability.

Altered Structural and Functional Connectivity Contribute to Rapid Ejaculation: Insights from a Multimodal Neuroimaging Study

Little is known about how the aberrant structural and functional connectivity relates to the rapid ejaculation. Data of diffusion tensor imaging and resting state functional magnetic resonance imaging were acquired from 32 PE patients and 38 healthy controls (HCs). Firstly, we investigated the structural connectivity (SC) disruptions of PE patients using the method of graph theoretical analysis. Brain regions with impaired nodal strength were then defined as regions of interest (ROI). Secondly, the corresponding functional connectivity (FC) changes were explored. Finally, the correlation analyses were performed between brain areas with abnormal connectivity and clinical characteristics. Structural analysis revealed that PE patients had increased nodal strength in the right superior frontal gyrus (dorsolateral), left middle frontal gyrus, right superior frontal gyrus (medial), right superior frontal gyrus (medial orbital) and decreased nodal strength in the left amygdala. FC analysis revealed that PE patients had decreased FC values in the default mode network, visual recognition network and subcortical network, as well as increased FC values in the attention network. Moreover, correlation analysis revealed that the nodal strength of right superior frontal gyrus (dorsolateral) was negatively associated with the intra-vaginal ejaculation latency, while FC values between the left middle frontal gyrus and middle occipital gyrus were positively related to the total scores of the premature ejaculation diagnostic tool (PEDT). Our results indicated that PE might be associated with the abnormal SC of areas in the prefrontal-amygdala pathway and aberrant FC in certain functional brain networks, especially in default mode network.

Changes in Intrinsic Brain Connectivity in Family-Focused Therapy Versus Standard Psychoeducation Among Youths at High Risk for Bipolar Disorder

OBJECTIVE

We compared intrinsic network connectivity in symptomatic youths at high risk (HR) for bipolar disorder (BD) and healthy comparison (HC) youths. In HR youths, we also investigated treatment-related changes in intrinsic connectivity after family-focused therapy for high-risk youths (FFT-HR) vs standardized family psychoeducation.

METHOD

HR youths (N = 34; age 9-17 years; mean 14 years, 56% girls and 44% boys) with depressive and/or hypomanic symptoms and at least 1 first- or second-degree relative with BD I or II were randomly assigned to 4 months of FFT-HR (12 sessions of psychoeducation, communication, and problem-solving skills training) or enhanced care (EC; 3 family and 3 individual psychoeducation sessions). Before and after 4 months of treatment, participants underwent resting state functional magnetic resonance imaging (rs-fMRI). A whole-brain independent component analysis compared rs-fMRI networks in HR youths and 30 age-matched HC youths at a pretreatment baseline. Then we identified pretreatment to posttreatment (4-month) changes in network connectivity in HR youths receiving FFT-HR (n = 16) or EC (n = 18) and correlated these changes with depression improvement.

RESULTS

At baseline, HR youths had greater connectivity between the ventrolateral prefrontal cortex (VLPFC) and the anterior default mode network (aDMN) than did HCs (p = .004). Over 4 months of treatment, FFT-HR-assigned HR youths had increased VLPFC-aDMN connectivity from pre- to posttreatment (p = .003), whereas HR youths in EC showed no significant change over time (p = .11) (treatment by time interaction, t31 = 3.33, 95% CI = 0.27-1.14, p = .002]. Reduction in depression severity over 4 months inversely correlated with enhanced anterior DMN (r = -0.71) connectivity in the FFT-HR but not in the EC (r = -0.07) group (z = -2.17, p = .015).

CONCLUSION

Compared to standard psychoeducation, FFT-HR is associated with stronger connectivity between the VLPFC and aDMN, suggesting possible enhancements of self-awareness, illness awareness, and emotion regulation.

CLINICAL TRIAL REGISTRATION INFORMATION

Early Intervention for Youth at Risk for Bipolar Disorder; https://clinicaltrials.gov/; NCT01483391.

Association between poor tolerability of antidepressant treatment and brain functional activation in youth at risk for bipolar disorder

Objective:

To investigate whether poor antidepressant tolerability is associated with functional brain changes in children and adolescents of parents with bipolar I disorder (at-risk youth).

Methods:

Seventy-three at-risk youth (ages 9-20 years old) who participated in a prospective study and had an available baseline functional magnetic resonance imaging (fMRI) scan were included. Research records were reviewed for the incidence of adverse reactions related to antidepressant exposure during follow-up. The sample was divided among at-risk youth without antidepressant exposure (n=21), at-risk youth with antidepressant exposure and no adverse reaction (n=12), at-risk youth with antidepressant-related adverse reaction (n=21), and healthy controls (n=20). The fMRI task was a continuous performance test with emotional distracters. Region-of-interest mean activation in brain areas of the fronto-limbic emotional circuit was compared among groups.

Results:

Right amygdala activation in response to emotional distracters significantly differed among groups (F_3,66 = 3.1, p = 0.03). At-risk youth with an antidepressant-related adverse reaction had the lowest amygdala activation, while at-risk youth without antidepressant exposure had the highest activation (p = 0.004).

Conclusions:

Decreased right amygdala activation in response to emotional distracters is associated with experiencing an antidepressant-related adverse reaction in at-risk youth. Further studies to determine whether amygdala activation is a useful biomarker for antidepressant-related adverse events are needed.

MRI Insights Into Adolescent Neurocircuitry-A Vision for the Future

Adolescence is the time of onset of many psychiatric disorders. Half of pediatric patients present with comorbid psychiatric disorders that complicate both their medical and psychiatric care. Currently, diagnosis and treatment decisions are based on symptoms. The field urgently needs brain-based diagnosis and personalized care. Neuroimaging can shed light on how aberrations in brain circuits might underlie psychiatric disorders and their development in adolescents. In this perspective article, we summarize recent MRI literature that provides insights into development of psychiatric disorders in adolescents. We specifically focus on studies of brain structural and functional connectivity. Ninety-six included studies demonstrate the potential of MRI to assess psychiatrically relevant constructs, diagnose psychiatric disorders, predict their development or predict response to treatment. Limitations of the included studies are discussed, and recommendations for future research are offered. We also present a vision for the role that neuroimaging may play in pediatrics and primary care in the future: a routine neuropsychological and neuropsychiatric imaging (NPPI) protocol for adolescent patients, which would include a 30-min brain scan, a quality control and safety read of the scan, followed by computer-based calculation of the structural and functional brain network metrics that can be compared to the normative data by the pediatrician. We also perform a cost-benefit analysis to support this vision and provide a roadmap of the steps required for this vision to be implemented.

Serotonergic influence on depressive symptoms and trait anxiety is mediated by negative life events and frontal activation in children and adolescents

Depression and anxiety are common in childhood and adolescence. Even though cardinal symptoms differ, there is a considerable overlap regarding the pathogenic influence of serotonergic innervation, negative life experience, disturbed emotion perception/affect regulation, and impaired neural functioning in the fronto-limbic circuit. In this study, we examined the effect of the 5-HTTLPR/rs25531 genotype on depressive symptoms and trait anxiety under the consideration of the amount of negative life events in healthy children and adolescents (N = 389). In a subsample of 49 subjects, we performed fMRI to add fronto-limbic brain activation as a second interacting factor. Across all subjects, negative life events moderated the influence of the 5-HTTLPR/rs25531 genotype on both depressive symptoms and trait anxiety. In the fMRI subsample, 5-HTTLPR/rs25531 S + S/L_G + S/L_A + L_GL_A + L_GL_G genotype-associated left middle frontal gyrus (MFG) activation mediated the influence of 5-HTTLPR/rs25531 genotype on depressive symptoms, however, only in combination with negative life events. Genetic influence on trait anxiety was predominantly mediated by negative life events; only L_AL_A genotype-specific activation in the right MFG worked as a mediator in combination with negative life events. The present findings hint towards distinct mechanisms mediating the influence of 5-HTTLPR/rs25531 genotype on depressive symptoms and anxiety, with negative life events playing a crucial role in both phenotypes. With regard to depressive symptoms, however, this influence was only visible in combination with MFG activation, whereas, in anxiety, it was independent of brain activation.

Cortico-limbic functional connectivity mediates the effect of early life stress on suicidality in bipolar depressed 5-HTTLPR*s carriers

BACKGROUND

In bipolar disorder (BD) the risk of suicide in adult life can be influenced by the interaction of adverse childhood experiences with the serotonin transporter polymorphism (5-HTTLPR). The cortico-limbic connectivity is a candidate endophenotype for the disorder, also related to suicidality and affected by the 5-HT system.

METHODS

In 64 (*s carriers = 41; l/l = 23) depressed BD patients, we explored the effect of 5-HTTLPR on corticolimbic functional connectivity (FC) during emotional processing, and the role of FC in moderating/mediating the effect of early stressful events on suicidality among 5-HTTLPR groups, by implementing Generalized Structural Equation Model.

RESULTS

5-HTTLPR affects FC between amygdala (Amy) and anterior cingulate cortex (ACC), temporal pole, putamen/thalamus, and precuneus. The short allele was associated to a more inefficient corticolimbic connectivity. In 5-HTTLPR*s carriers, but not in l/l, the Amy-ACC functional coupling mediated the relationship between stress load and current suicidality.

LIMITATIONS

Patients were not drug-naive, and the recruitment took place in a single center, thus raising the possibility of population stratifications. The sample size is relatively small, but our findings can provide the background for replication study in independent and larger datasets.

CONCLUSIONS

Our results confirm the link between the 5-HTT promoter polymorphism and susceptibility to stress in BD, and suggest that cortico-limbic functional connectivity mediates these effects. This pattern could identify a vulnerability factor for the exacerbation of mood episodes after stressful life events particularly relevant in *s carriers.

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.

Eye-gaze processing in the broader bipolar phenotype revealed by electrical neuroimaging

Previous studies have documented atypical brain responses to faces in individuals with bipolar disorder (BD) and in their relatives. In view of previous findings of atypical face processing in youths at risk for BD, the aim of this study was to examine whether BD patients and offspring would show differential activation in networks of the social brain when processing eye-gaze. Data from 18 euthymic BD patients and 18 offspring, as well as 36 age-matched healthy controls, were collected using a delayed face-matching paradigm, event related potentials and electrical neuroimaging methods. The P200 component, which is implicated in facial cues decoding, differentiated the BD groups from their age-matched controls. P200 source reconstruction indicates impairments conveyed by eye-contact in a network involved in experiencing others' social intentions in BD patients (supplementary motor cortex, precentral gyrus, inferior parietal lobe), and the engagement of compensatory prefrontal mechanisms for modulating these functions in BD offspring. When viewing faces that had an averted gaze, BD patients and offspring showed a hypo-activation, compared to controls, particularly in regions involved in experiencing others' feelings (post-central gyrus in BD patients / ventral premotor cortex in offspring). Therefore, the neural mechanism for decoding shifts in eye-gaze may be a familial characteristic of BD.

Neural correlates of emotion processing predict resilience in youth at familial risk for mood disorders

Aberrant face emotion processing has been demonstrated in youth with and at a familial risk for bipolar and major depressive disorders. However, the neurobiological factors related to emotion processing that underlie resilience from youth-onset mood disorders are not well understood. Functional magnetic resonance imaging data during an implicit emotion processing task were collected at baseline from a sample of 50 youth, ages 8-17, who were healthy but also familially at high risk for either bipolar disorder or major depressive disorder, and 24 healthy controls with no family history of psychopathology (HCL). Participants were reevaluated 3 years later and classified into three groups for analysis: high-risk youth who converted to a psychiatric diagnosis (CVT; N = 23), high-risk youth who were resilient from developing any psychopathology (RES; N = 27), and HCL youth (N = 24) who remained healthy at follow-up. For happy > calm faces, the CVT and RES groups had significantly lower activation in the left inferior parietal lobe (IPL), while the RES group had lower activation in the right supramarginal gyrus. For fear > calm faces, the RES group had lower activation in the right precuneus and inferior frontal gyrus (IFG) compared to the CVT group. Connectivity analyses revealed the RES group exhibited higher left IPL connectivity with visual cortical regions for happy > calm faces, and higher IFG connectivity with frontal, temporal, and limbic regions for fear > calm faces. These connectivities were correlated with improvements in prosocial behaviors and global functioning. Our findings suggest that differential activation and connectivity in the IPL, IFG, and precuneus in response to emotional stimuli may represent distinct resilience and risk markers for youth-onset mood disorders.

Neural mechanisms of face emotion processing in youths and adults with bipolar disorder

OBJECTIVES

Little is known about potential differences in the pathophysiology of bipolar disorder (BD) across development. The present study aimed to characterize age-related neural mechanisms of BD.

METHODS

Youths and adults with and without BD (N = 108, age range = 9.8-55.9 years) completed an emotional face labeling task during fMRI acquisition. We leveraged three different fMRI analytic tools to identify age-related neural mechanisms of BD, investigating (a) change in neural responses over the course of the task, (b) neural activation averaged across the entire task, and (c) amygdala functional connectivity.

RESULTS

We found converging Age Group × Diagnosis patterns across all three analytic methods. Compared to healthy youths vs adults, youths vs adults with BD show an altered pattern in response to repeated presentation of emotional faces in medial prefrontal, amygdala, and temporoparietal regions, as well as amygdala-temporoparietal connectivity. Specifically, medial prefrontal and lingual activation decreases over the course of repeated emotional face presentations in healthy youths vs adults but increases in youths with BD compared to adults with BD. Moreover, youths vs adults with BD show less medial prefrontal activation and amygdala-temporoparietal junction connectivity averaged over the task, but this difference is not found for healthy youths vs adults.

CONCLUSION

Although longitudinal confirmation and replication will be necessary, these findings suggest that neural development may be aberrant in BD and that some neural mechanisms mediating BD may differ in adults vs children with the illness.

Neurococognitive and neuroimaging correlates of obesity and components of metabolic syndrome in bipolar disorder: a systematic review

BACKGROUND

Individuals with bipolar disorder (BD) have a higher prevalence of obesity and metabolic syndrome (MetS) compared with the general population. Obesity and MetS are associated with cognitive deficits and brain imaging abnormalities in the general population. Obesity and components of MetS might potentially associate with neuroimaging and neurocognitive findings in BD.

METHODS

A literature search of studies investigating the association between obesity (and other components of MetS) and neurocognitive and neuroimaging findings in BD was conducted. In addition to a systematic review, a random-effects meta-analysis was conducted when sufficient data were available.

RESULTS

Twenty-three studies were included in the current systematic review. Overweight/obese patients were significantly associated with impaired neurocognition compared normal weight individuals with BD (d = 0.37). The most robust association between obesity and cognitive deficits in BD was observed in the cognitive subdomain of executive functions (d = 0.61). There was also evidence for a significant relationship between cognitive impairment in BD and other components of MetS including hypertension, dyslipidemia, and diabetes. Overweight/obese individuals with BD had more pronounced brain imaging abnormalities than normal weight individuals with BD.

CONCLUSIONS

Obesity and related cardiovascular risk factors significantly are associated with more severe cognitive and brain imaging abnormalities in BD. Medical co-morbidities can potentially contribute to functional decline observed in some patients throughout the course of BD.

Cortico-limbic connectivity as a possible biomarker for bipolar disorder: where are we now?

INTRODUCTION

The fronto-limbic network has been suggested as a key circuitry in the pathophysiology and maintenance of bipolar disorder. In the past decade, a disrupted connectivity within prefrontal-limbic structures was identified as a promising candidate biomarker for the disorder. Areas Covered: In this review, the authors examine current literature in terms of the structural, functional and effective connectivity in bipolar disorder, integrating recent findings of imaging genetics and machine learning. This paper profiles the current knowledge and identifies future perspectives to provide reliable and usable neuroimaging biomarkers for bipolar psychopathology in clinical practice. Expert Opinion: The replication and the translation of acquired knowledge into useful and usable tools represents one of the current greatest challenges in biomarker research applied to psychiatry.

Gut Microbiota in Bipolar Depression and Its Relationship to Brain Function: An Advanced Exploration

The mechanism of bipolar disorder is unclear. Growing evidence indicates that gut microbiota plays a pivotal role in mental disorders. This study aimed to find out changes in the gut microbiota in bipolar depression (BD) subjects following treatment with quetiapine and evaluate their correlations with the brain and immune function. Totally 36 subjects with BD and 27 healthy controls (HCs) were recruited. The severity of depression was evaluated with the Montgomery-Asberg depression rating scale (MADRS). At baseline, fecal samples were collected and analyzed by quantitative polymerase chain reaction (qPCR). T lymphocyte subsets were measured to examine immune function. Near-infrared spectroscopy (NIRS) was used to assess brain function. All BD subjects received quetiapine treatment (300 mg/d) for four weeks, following which the fecal microbiota and immune profiles were reexamined. Here, we first put forward the new concept of brain-gut coefficient of balance (B-G_CB), which referred to the ratio of [oxygenated hemoglobin]/(Bifidobacteria to Enterobacteriaceae ratio), to analyze the linkage between the gut microbiota and brain function. At baseline, the CD3⁺ T cell proportion was positively correlated with log₁₀ Enterobacter spp count, whereas the correlativity between the other bacteria and immune profiles were negative. Log₁₀ B-G_CB was positively correlated with CD3⁺ T cell proportion. In subjects with BD, counts of Faecalibacterium prausnitzii, Bacteroides-Prevotella group, Atopobium Cluster, Enterobacter spp, and Clostridium Cluster IV were higher, whereas the log₁₀ (B/E) were lower than HCs (B/E refers to Bifidobacteria to Enterobacteriaceae ratio and represents microbial colonization resistance). After treatment, MADRS scores were reduced, whereas the levels of Eubacterium rectale, Bifidobacteria, and B/E increased. The composition of the gut microbiota and its relationship to brain function were altered in BD subjects. Quetiapine treatment was effective for depression and influenced the composition of gut microbiota in patients. Clinical Trial Registration: http://www.chictr.org.cn/index.aspx, identifier ChiCTR-COC-17011401, URL: http://www.chictr.org.cn/listbycreater.aspx.

Using Cognitive Neuroscience to Improve Mental Health Treatment: A Comprehensive Review

Mental health interventions do not yet offer complete, client-defined functional recovery, and novel directions in treatment research are needed to improve the efficacy of available interventions. One promising direction is the integration of social work and cognitive neuroscience methods, which provides new opportunities for clinical intervention research that will guide development of more effective mental health treatments that holistically attend to the biological, social, and environmental contributors to disability and recovery. This article reviews emerging trends in cognitive neuroscience and provides examples of how these advances can be used by social workers and allied professions to improve mental health treatment. We discuss neuroplasticity, which is the dynamic and malleable nature of the brain. We also review the use of risk and resiliency biomarkers and novel treatment targets based on neuroimaging findings to prevent disability, personalize treatment, and make interventions more targeted and effective. The potential of treatment research to contribute to neuroscience discoveries regarding brain change is considered from the experimental-medicine approach adopted by the National Institute of Mental Health. Finally, we provide resources and recommendations to facilitate the integration of cognitive neuroscience into mental health research in social work.

Regional Cerebral Blood Flow in Mania: Assessment Using 320-Slice Computed Tomography

Objectives: While evidence that episodes of mania in bipolar I are associated with changes in bioenergetic and regional cerebral blood flow (rCBF) and cerebral blood flow velocity (rCBFV), both the regions and the extent of these changes have not yet been defined. Therefore, we determined the pattern of regional cerebral perfusion mania patients and using patients with major depressive disorder (MDD) as positive controls and healthy participants as negative controls. Methods: Twenty participants with mania, together with 22 MDD patients and 24 healthy volunteers, were recruited for this study. On all participants, Transcranial Doppler (TCD) was conducted to measure rCBFV parameters, 320-slice CT was conducted to measure rCBF in the different cerebral artery regions, and hematological parameters were assessed. ANOVA and Pearson's tests were used for the statistical analysis. Results: Our data indicated that rCBF in the medial temporal lobe and hippocampus, especially in the left medial temporal lobe and the right hippocampus, was increased in the mania group compared with the control and MDD groups (p < 0.01). In contrast, rCBF in the medial temporal lobe and hippocampus was decreased in the depression group (p < 0.01) compared with healthy controls. In addition, values of rCBFV in the bilateral internal carotid arteries (ICAs) and middle cerebral arteries (MCA) were increased in mania (p < 0.01) in comparison to the MDD group. Whole blood viscosity and hematocrit as well as red blood cell sedimentation rate remained unchanged in all group (p > 0.05). Conclusions: In mania, rCBF is increased in the medial temporal lobe and hippocampus, with a corresponding increase in rCBFV in the same regions.