Cerebral responses to emotional expressions and the development of social anxiety disorder: a preliminary longitudinal study

Pre-COVID resting-state brain activity in the fusiform gyrus prospectively predicts social anxiety alterations during the pandemic

BACKGROUND

Social anxiety (SA) has been linked to the coronavirus disease 2019 (COVID-19) pandemic, but the neurobiopsychological mechanisms underlying this relationship remain unclear. This study aimed to elucidate the neurofunctional markers for COVID-induced SA development and the potential role of COVID-related posttraumatic stress symptoms (PTSS) in the brain-SA alterations link.

METHODS

Before the COVID-19 pandemic (T1), 100 general college students underwent resting-state magnetic resonance imaging and behavioral tests. During the period of community-level outbreaks (T2), these students were re-contacted to undergo follow-up behavioral assessments.

RESULTS

Whole-brain correlation and prediction analyses found that pre-pandemic spontaneous neural activity (measured by fractional amplitude of low-frequency fluctuations) in the right fusiform gyrus (FG) was positively correlated to SA alterations (T2 - T1). Mediation analyses revealed that COVID-specific PTSS mediated the effects of right FG on SA alterations.

LIMITATIONS

The results should be interpreted carefully because only one-session neuroimaging data in a sample of normal adults were included.

CONCLUSIONS

The results provide evidence for neurofunctional markers of COVID-induced SA and may help develop targeted brain-based interventions that reduce SA.

A Mobile Application Adjunct to Augment Cognitive-Behavioral Group Therapy for Adolescents with Social Anxiety: Feasibility and Acceptability Results from the Wiring Adolescents with Social Anxiety via Behavioral Interventions Pilot Trial

Objective: Cognitive-Behavioral Group Therapy (CBGT) is an established treatment for Social Anxiety (SA). However, diagnostic recovery rate is only 20.5% in CBGT, and up to 50% of patients remain symptomatic posttreatment. Using videocalls to deliver digital CBGT (dCBGT) is feasible, cost-effective, and efficacious. Yet, the impact of dCBGT on social functioning remains limited, as dCBGT does not offer opportunities for monitoring cognition and behavior in social situations. Wiring Adolescents with Social Anxiety via Behavioral Interventions (WASABI), a clinician-assisted application that uses ecological momentary assessments (EMAs), cognitive bias tests, and clinical self-reports, was investigated as an adjunct to dCBGT. Methods: A prospective, parallel arm, double-blind randomized controlled trial was employed in 24 SA adolescents randomly assigned to dCBGT versus dCBGT plus WASABI. Results: Study completion rates (83%) and exit survey data indicated that WASABI is feasible and acceptable. Engagement with EMAs varied from four to 244 EMAs completed per person. Cognitive bias tests and clinical self-reports were completed at least weekly by 53% and 69% of participants, respectively. While standard tests did not reveal statistically significant differences between dCBGT plus WASABI and dCBGT alone, effect sizes were greater for dCBGT plus WASABI on symptom severity, social skills, and functioning. Conclusions: Despite the small sample, preliminary results suggest that WASABI is feasible, acceptable, and may be an effective augmentation tool for treating SA in teenagers.

Positive valence systems in youth anxiety development: A scoping review

Research on pathophysiological mechanisms supporting anxiety development in youth has traditionally focused on the role of threat systems. However, emerging research suggests that the positive valence system (PVS) may also play a strong and unique role in the development and maintenance of anxiety during childhood and adolescence. To better understand the connection between the PVS and anxiety, this scoping review describes current research spanning multiple units of analysis (i.e., self-report, behavior, neural circuits) linking child and adolescent anxiety and risk for anxiety to various PVS constructs (i.e., positive affect, reward responsiveness, reward learning and decision-making). After screening, 78 peer-reviewed articles and dissertations published between 1998 and May 2021 were included in a qualitative review. Though some consistencies in the literature were found, such as high neural reactivity to incentive anticipation in youth at temperamental risk for social anxiety and blunted positive affect in youth with social anxiety disorder, the literature is largely inconsistent. Inconsistencies could be related to the small number of similar studies, small and homogenous study samples, and variability in methodologies employed in this research. It cannot be confirmed whether findings linking PVS constructs to anxiety are unique to anxiety symptoms or better accounted for by co-occurring depressive symptoms. This review concludes with recommendations for robust future research in this area.

Genetics of social anxiety disorder: a systematic review

Social anxiety disorder (SAD) is a common psychiatric disorder, often associated with avoidant temperament. Research studies have implicated a strong genetic architecture of SAD. We have conducted a systematic review on the genetics of SAD and yielded 66 articles. In general, prior research studies have focused on the serotonin transporter, oxytocin receptor, brain-derived neurotrophic factor and catechol-O-methyltransferase genes. Mixed and inconsistent results have been reported. Additional approaches and phenotypes have also been investigated, including pharmacogenetics of treatment response, imaging genetics and gene-environment interactions. Future directions warrant further international collaborative efforts, deep-phenotyping of clinical characteristics including consistent and reliable measurement-based symptom severity, and larger sample sizes to ensure sufficient power for stratification due to the heterogeneity of this chronic and often debilitating condition.

ENIGMA-anxiety working group: Rationale for and organization of large-scale neuroimaging studies of anxiety disorders

Anxiety disorders are highly prevalent and disabling but seem particularly tractable to investigation with translational neuroscience methodologies. Neuroimaging has informed our understanding of the neurobiology of anxiety disorders, but research has been limited by small sample sizes and low statistical power, as well as heterogenous imaging methodology. The ENIGMA-Anxiety Working Group has brought together researchers from around the world, in a harmonized and coordinated effort to address these challenges and generate more robust and reproducible findings. This paper elaborates on the concepts and methods informing the work of the working group to date, and describes the initial approach of the four subgroups studying generalized anxiety disorder, panic disorder, social anxiety disorder, and specific phobia. At present, the ENIGMA-Anxiety database contains information about more than 100 unique samples, from 16 countries and 59 institutes. Future directions include examining additional imaging modalities, integrating imaging and genetic data, and collaborating with other ENIGMA working groups. The ENIGMA consortium creates synergy at the intersection of global mental health and clinical neuroscience, and the ENIGMA-Anxiety Working Group extends the promise of this approach to neuroimaging research on anxiety disorders.

Imaging the socially-anxious brain: recent advances and future prospects

Social anxiety disorder (SAD) is serious psychiatric condition with a genetic background. Insight into the neurobiological alterations underlying the disorder is essential to develop effective interventions that could relieve SAD-related suffering. In this expert review, we consider recent neuroimaging work on SAD. First, we focus on new results from magnetic resonance imaging studies dedicated to outlining biomarkers of SAD, including encouraging findings with respect to structural and functional brain alterations associated with the disorder. Furthermore, we highlight innovative studies in the field of neuroprediction and studies that established the effects of treatment on brain characteristics. Next, we describe novel work aimed to delineate endophenotypes of SAD, providing insight into the genetic susceptibility to develop the disorder. Finally, we outline outstanding questions and point out directions for future research.

Interactions between the combined genotypes of 5-HTTLPR and BDNF Val66Met polymorphisms and parenting on adolescent depressive symptoms: A three-year longitudinal study

BACKGROUND

The importance of multiple genes-environment interaction (G × E) has been highlighted in studies on depressive symptoms. 5-HTTLPR and BDNF Val66Met polymorphisms, with functional interconnection, have been implicated in the pathophysiology of depressive symptoms. However, little is understood about whether the interaction of 5-HTTLPR, BDNF Val66Met and parenting fits better with the epistatic or cumulative manner.

METHODS

865 adolescents (T1: M_age = 12.32, 50.2% girls) were included in a three-year interval longitudinal design. Standardized questionares about parenting and depressive symptoms were collected. Saliva samples were collected for genotyping.

RESULTS

Neither the concurrent nor longitudinal interaction of 5-HTTLPR, BDNF Val66Met and parenting (G × G × E) showed significant effects on depressive symptoms. The interaction between cumulative genotypes and positive parenting (CG × E) was significant, with the strong differential susceptibility model, for depressive symptoms concurrently but not longitudinally after statistical correction. Adolescents who carried 3 (i.e. SS and Val/Met, L allele and Val/Val) and 4 (i.e. SS and Val/Val), not 1 (i.e. L allele and Met/Met) or 2 cumulative susceptibility alleles (i.e. SS and Met/Met, L allele and Val/Met), reported fewer depressive symptoms if they had experienced higher levels of positive parenting, and more symptoms under lower levels of positive parenting.

LIMITATIONS

This study did not examine the 5-HTTLPR triallelic (rs25531) marker and did not include an external sample.

CONCLUSIONS

The combined effects of 5-HTTLPR and BDNF Val66Met polymorphisms functioned in a manner of cumulative rather than epistatic in response to positive parenting on early adolescent depressive symptoms.

A systematic review of treatments targeting cognitive biases in socially anxious adolescents: Special Section on "Translational and Neuroscience Studies in Affective Disorders" Section Editor, Maria Nobile MD, PhD

BACKGROUND

Adolescence is a period of brain plasticity that is affected by social and affective stimuli. Adaptive neurodevelopmental changes in the context of complex social situations may precipitate or exacerbate cognitive biases (i.e., attention and/or interpretation biases) and predispose at-risk individuals to symptoms of social anxiety.

METHODS

This systematic review followed the PRISMA guidelines. Nine adolescent studies were examined including 3 studies using Cognitive Bias Modification Training (CBMT) to target attention biases (CBMT-A), 3 studies using CBMT to target interpretation biases (CBMT-I), and 3 aimed at reducing both attention and interpretation biases.

RESULTS

The studies of CBMT-A alone did not find significant effects on cognitive and clinical outcomes. However, studies of CBMT-I alone showed some improvement in interpretation bias. The combination of CBMT-A and CBMT-I appeared promising in reducing both attentionl and interpretation biases.

LIMITATIONS

The paucity of studies and the heterogeneity across studies (e.g., format of CBMT, assessment measures) limit the calculation of overall effect sizes and the examination of predictors, moderators, and mediators of outcome.

CONCLUSIONS

Technology-driven interventions such as CBMT have the potential to extend treatments outside the clinic setting and to augment current therapies for social anxiety. Further research is needed to develop CBMT procedures that optimize learning in group and real-world settings and to identify predictors of treatment response. Understanding the neural correlates of response to CBMT may help identify future targets for intervention.

Role of rumination in the relationship between metacognition and shyness

AIM

To explore the association between metacognitive beliefs, rumination and shyness in a non-clinical sample of adults.

METHODS

One hundred and three healthy subjects from the general population were enrolled in the study. Shyness was evaluated using the Revised Cheek and Buss Shyness Scale, rumination was assessed using the Ruminative Response Scale, metacognition was evaluated using the Meta-Cognitions Questionnaire 30, and anxiety levels were measured using the State Trait Anxiety Inventory form Y. Correlation analyses, mediation models and 95% bias-corrected and accelerated (BCaCI) bootstrapped analyses were performed. Mediation analyses were adjusted for sex and anxiety.

RESULTS

Shyness, rumination and metacognition were significantly correlated (P < 0.05). The relationship between metacognition and shyness was fully mediated by rumination (Indirect effect: 0.20; 95% BCaCI: 0.08-0.33).

CONCLUSION

These findings suggest an association between metacognition and shyness. Rumination mediated the relationship between metacognition and shyness, suggesting that rumination could be a cognitive strategy for shy people. Future research should explore the relationship between these constructs in more depth.

When change is the only constant: The promise of longitudinal neuroimaging in understanding social anxiety disorder

Longitudinal studies offer a unique window into developmental change. Yet, most of what we know about the pathophysiology of psychiatric disorders is based on cross-sectional work. Here, we highlight the importance of adopting a longitudinal approach in order to make progress towards identifying the neurobiological mechanisms of social anxiety disorder (SAD). Using examples, we illustrate how longitudinal data can uniquely inform SAD etiology and timing of interventions. The brain's inherently adaptive quality requires that we model risk correlates of disorders as dynamic in their expression. Developmental theories regarding timing of environmental events, cascading effects and (mal)adaptations of the developing brain will be crucial components of comprehensive, integrative models of SAD. We close by discussing analytical considerations when working with longitudinal, developmental data.

Salience network response to changes in emotional expressions of others is heightened during early adolescence: relevance for social functioning

Adolescence is a unique developmental period when the salience of social and emotional information becomes particularly pronounced. Although this increased sensitivity to social and emotional information has frequently been considered with respect to risk behaviors and psychopathology, evidence suggests that increased adolescent sensitivity to social and emotional cues may confer advantages. For example, greater sensitivity to shifts in the emotions of others is likely to promote flexible and adaptive social behavior. In this study, a sample of 54 children and adolescents (age 8-19 years) performed a delayed match-to-sample task for emotional faces while undergoing fMRI scanning. Recruitment of the anterior cingulate and anterior insula when the emotion of the probe face did not match the emotion held in memory followed a quadratic developmental pattern that peaked during early adolescence. These findings indicate meaningful developmental variation in the neural mechanisms underlying sensitivity to changes in the emotional expressions. Across all participants, greater activation of this network for changes in emotional expression was associated with less social anxiety and fewer social problems. These results suggest that the heightened salience of social and emotional information during adolescence may confer important advantages for social behavior, providing sensitivity to others' emotions that facilitates flexible social responding.

The ventromedial hypothalamic nucleus plays an important role in anxiolytic-like effect of neuropeptide S

Neuropeptide S (NPS), the endogenous neuropeptide ligand of NPSR, has been reported to regulate anxiety-related behavior involved in multiple brain regions, including amygdale, locus coeruleus and Barrington's nucleus. However, little research has been conducted on the anxiolytic-like behaviors of NPS on the hypothalamus, which was an important area in defensive behavior. Here, we investigated a role of hypothalamus in anxiolytic-like behaviors of NPS. We found that NPSR protein of mouse distributed mainly in the ventromedial hypothalamus (VMH). And in the single prolonged stress model (SPS), the results showed that NPS mRNA of the mice exposed to SPS was significantly higher than control, while NPSR mRNA was remarkable lower than control in hypothalamus. Further studies found that NPS intra-VMH infusion dose-dependently (1, 10 and 100pmol) induced anxiolytic effects, using elevated plus maze and open field tests. These anxiolytic effects could be blocked by NPSR antagonist (SHA68), but not by picrotoxin (a GABA_A receptor antagonist) and sacolfen (a GABA_B receptor antagonist). Meanwhile, our data showed that the expression of c-Fos was significantly increased in VMH after NPS delivered into the lateral ventricles. These results cast a new light on the hypothalamic nucleus in the anxiolytic-like effect of NPS system.

Reappraising Preclinical Models of Separation Anxiety Disorder, Panic Disorder, and CO2 Sensitivity: Implications for Methodology and Translation into New Treatments

Separation anxiety applies to multiple forms of distress responses seen in mammals during postnatal development, including separation from a caregiver. Childhood separation anxiety disorder is an important risk factor for developing panic disorder in early adulthood, and both conditions display an increased sensitivity to elevated CO₂ concentrations inhaled from the air. By interfacing epidemiological, genetic, and physiological knowledge with preclinical animal research models, it is possible to decipher the mechanisms that are central to separation anxiety and panic disorders while also suggesting possible therapies. Preclinical research models allow for environmentally controlled studies of early interferences with parental care. These models have shown that different forms of early maternal separation in mice and rats induce elevated CO₂ respiratory sensitivity, an important biomarker of separation anxiety and panic disorders. In mice, this is likely due to gene-environment interactions that affect multiple behavioural and physical phenotypes after exposure to this early adversity. Although several questions regarding the causal mechanism of separation anxiety and panic disorder remain unanswered, the identification and improved understanding of biomarkers that link these mental health conditions under the guise of preclinical research models in conjunction with human longitudinal cohort studies can help resolve these issues.

Imaging genetics in neurodevelopmental psychopathology

Neurodevelopmental disorders are defined by highly heritable problems during development and brain growth. Attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorders (ASDs), and intellectual disability (ID) are frequent neurodevelopmental disorders, with common comorbidity among them. Imaging genetics studies on the role of disease-linked genetic variants on brain structure and function have been performed to unravel the etiology of these disorders. Here, we reviewed imaging genetics literature on these disorders attempting to understand the mechanisms of individual disorders and their clinical overlap. For ADHD and ASD, we selected replicated candidate genes implicated through common genetic variants. For ID, which is mainly caused by rare variants, we included genes for relatively frequent forms of ID occurring comorbid with ADHD or ASD. We reviewed case-control studies and studies of risk variants in healthy individuals. Imaging genetics studies for ADHD were retrieved for SLC6A3/DAT1, DRD2, DRD4, NOS1, and SLC6A4/5HTT. For ASD, studies on CNTNAP2, MET, OXTR, and SLC6A4/5HTT were found. For ID, we reviewed the genes FMR1, TSC1 and TSC2, NF1, and MECP2. Alterations in brain volume, activity, and connectivity were observed. Several findings were consistent across studies, implicating, for example, SLC6A4/5HTT in brain activation and functional connectivity related to emotion regulation. However, many studies had small sample sizes, and hypothesis-based, brain region-specific studies were common. Results from available studies confirm that imaging genetics can provide insight into the link between genes, disease-related behavior, and the brain. However, the field is still in its early stages, and conclusions about shared mechanisms cannot yet be drawn.

Shared genetic influences among childhood shyness, social competences, and cortical responses to emotions

Visual event-related potentials (ERPs) evoked by facial expressions are useful to map socioemotional responses among shy children and to predict transition into social phobia. We investigated the sources of covariation among childhood shyness, social competences, and ERPs to other children's happy, neutral, and angry expressions. Electrophysiological and twin analyses examined the phenotypic and etiological association among an index of childhood shyness, an index of social competences, and ERP responses to facial expressions in 200 twins (mean age=9.23years). Multivariate twin analyses showed that the covariation among shyness, social competences, and a composite of a frontal late negative component occurring around 200-400ms in response to happy, neutral, and angry expressions could be entirely explained by shared genetic factors. A coherent causal structure links childhood shyness, social competences, and the cortical responses to facial emotions. A common genetic substrate can explain the interrelatedness of individual differences for childhood shyness, social competences, and some associated electrophysiological responses to socioemotional signals.

Developmental psychopathology in an era of molecular genetics and neuroimaging: A developmental neurogenetics approach

The emerging field of neurogenetics seeks to model the complex pathways from gene to brain to behavior. This field has focused on imaging genetics techniques that examine how variability in common genetic polymorphisms predict differences in brain structure and function. These studies are informed by other complimentary techniques (e.g., animal models and multimodal imaging) and have recently begun to incorporate the environment through examination of Imaging Gene × Environment interactions. Though neurogenetics has the potential to inform our understanding of the development of psychopathology, there has been little integration between principles of neurogenetics and developmental psychopathology. The paper describes a neurogenetics and Imaging Gene × Environment approach and how these approaches have been usefully applied to the study of psychopathology. Six tenets of developmental psychopathology (the structure of phenotypes, the importance of exploring mechanisms, the conditional nature of risk, the complexity of multilevel pathways, the role of development, and the importance of who is studied) are identified, and how these principles can further neurogenetics applications to understanding the development of psychopathology is discussed. A major issue of this piece is how neurogenetics and current imaging and molecular genetics approaches can be incorporated into developmental psychopathology perspectives with a goal of providing models for better understanding pathways from among genes, environments, the brain, and behavior.

Dynamic changes in amygdala activation and functional connectivity in children and adolescents with anxiety disorders

Anxiety disorders are associated with abnormalities in amygdala function and prefrontal cortex-amygdala connectivity. The majority of functional magnetic resonance imaging studies have examined mean group differences in amygdala activation or connectivity in children and adolescents with anxiety disorders relative to controls, but emerging evidence suggests that abnormalities in amygdala function are dependent on the timing of the task and may vary across the course of a scanning session. The goal of the present study was to extend our knowledge of the dynamics of amygdala dysfunction by examining whether changes in amygdala activation and connectivity over scanning differ in pediatric anxiety disorder patients relative to typically developing controls during an emotion processing task. Examining changes in activation over time allows for a comparison of how brain function differs during initial exposure to novel stimuli versus more prolonged exposure. Participants included 34 anxiety disorder patients and 19 controls 7 to 19 years old. Participants performed an emotional face-matching task during functional magnetic resonance imaging scanning, and the task was divided into thirds in order to examine change in activation over time. Results demonstrated that patients exhibited an abnormal pattern of amygdala activation characterized by an initially heightened amygdala response relative to controls at the beginning of scanning, followed by significant decreases in activation over time. In addition, controls evidenced greater context-modulated prefrontal cortex-amygdala connectivity during the beginning of scanning relative to patients. These results indicate that differences in emotion processing between the groups vary from initial exposure to novel stimuli relative to more prolonged exposure. Implications are discussed regarding how this pattern of neural activation may relate to altered early-occurring or anticipatory emotion-regulation strategies and maladaptive later-occurring strategies in children and adolescents with anxiety disorders.

Social anxiety disorder in adolescence: How developmental cognitive neuroscience findings may shape understanding and interventions for psychopathology

Social anxiety disorder represents a debilitating condition that has large adverse effects on the quality of social connections, educational achievement and wellbeing. Age-of-onset data suggests that early adolescence is a developmentally sensitive juncture for the onset of social anxiety. In this review, we highlight the potential of using a developmental cognitive neuroscience approach to understand (i) why there are normative increases in social worries in adolescence and (ii) how adolescence-associated changes may 'bring out' neuro-cognitive risk factors for social anxiety in a subset of individuals during this developmental period. We also speculate on how changes that occur in learning and plasticity may allow for optimal acquisition of more adaptive neurocognitive strategies through external interventions. Hence, for the minority of individuals who require external interventions to target their social fears, this enhanced flexibility could result in more powerful and longer-lasting therapeutic effects. We will review two novel interventions that target information-processing biases and their neural substrates via cognitive training and visual feedback of neural activity measured through functional magnetic resonance imaging.

Annual research review: Towards a developmental neuroscience of atypical social cognition

As a starting point for our review we use a developmental timeline, starting from birth and divided into major developmental epochs defined by key milestones of social cognition in typical development. For each epoch, we highlight those developmental disorders that diverge from the normal developmental pattern, what is known about these key milestones in the major disorders affecting social cognition, and any available research on the neural basis of these differences. We relate behavioural observations to four major networks of the social brain, that is, Amygdala, Mentalizing, Emotion and Mirror networks. We focus on those developmental disorders that are characterized primarily by social atypicality, such as autism spectrum disorder, social anxiety and a variety of genetically defined syndromes. The processes and aspects of social cognition we highlight are sketched in a putative network diagram, and include: agent identification, emotion processing and empathy, mental state attribution, self-processing and social hierarchy mapping involving social ‘policing’ and in-group/out-group categorization. Developmental disorders reveal some dissociable deficits in different components of this map of social cognition. This broad review across disorders, ages and aspects of social cognition leads us to some key questions: How can we best distinguish primary from secondary social disorders? Is social cognition especially vulnerable to developmental disorder, or surprisingly robust? Are cascading notions of social development, in which early functions are essential stepping stones or building bricks for later abilities, necessarily correct?

A meta-analysis and scoping review of social cognition performance in social phobia, posttraumatic stress disorder and other anxiety disorders

Social cognition deficits are observed in a variety of psychiatric illnesses. However, data concerning anxiety disorders are sparse and difficult to interpret. This meta-analysis aims at determining if social cognition is affected in social phobia (SP) or posttraumatic stress disorder (PTSD) compared to non-clinical controls and the specificity of such deficits relatively to other anxiety disorders. The scoping review aims to identify research gaps in the field. Forty studies assessing mentalizing, emotion recognition, social perception/knowledge or attributional style in anxiety disorders were included, totalizing 1417 anxious patients and 1321 non-clinical controls. Results indicate distinct patterns of social cognition impairments: people with PTSD show deficits in mentalizing (effect size d = -1.13) and emotion recognition (d = -1.6) while other anxiety disorders including SP showed attributional biases (d = -0.53 to d = -1.15). The scoping review identified several under investigated domains of social cognition in anxiety disorders. Some recommendations are expressed for future studies to explore the full range of social cognition in anxiety disorders and allow direct comparisons between different disorders.

Neuroimaging studies of pediatric social anxiety: paradigms, pitfalls and a new direction for investigating the neural mechanisms

Social Anxiety Disorder (SAD) is a common and debilitating condition that typically manifests in adolescence. Here we describe cognitive factors engaged by brain-imaging tasks, which model the peer-based social interactions that evoke symptoms of SAD. We then present preliminary results from the Virtual School paradigm, a novel peer-based social interaction task. This paradigm is designed to investigate the neural mechanisms mediating individual differences in social response flexibility and in participants' responses to uncertainty in social contexts. We discuss the utility of this new paradigm for research on brain function and developmental psychopathology.

Linear association between social anxiety symptoms and neural activations to angry faces: from subclinical to clinical levels

Social anxiety disorder (SAD), which is characterized by the fear of being rejected and negatively evaluated, involves altered brain activation during the processing of negative emotions in a social context. Although associated temperament traits, such as shyness or behavioral inhibition, have been studied, there is still insufficient knowledge to support the dimensional approach, which assumes a continuum from subclinical to clinical levels of social anxiety symptoms. This study used functional magnetic resonance imaging (fMRI) to examine the neural bases of individual differences in social anxiety. Our sample included participants with both healthy/subclinical as well as clinical levels of social anxiety. Forty-six participants with a wide range of social anxiety levels performed a gender decision task with emotional facial expressions during fMRI scanning. Activation in the left anterior insula and right lateral prefrontal cortex in response to angry faces was positively correlated with the level of social anxiety in a regression analysis. The results substantiate, with a dimensional approach, those obtained in previous studies that involved SAD patients or healthy and subclinical participants. It may help to refine further therapeutic strategies based on markers of social anxiety.

Serotonin transporter genotype impacts amygdala habituation in youth with autism spectrum disorders

Failure of the amygdala to habituate, or decrease response intensity, to repeatedly presented faces may be one mechanism by which individuals with autism spectrum disorders (ASD) develop and maintain social symptoms. However, genetic influences on habituation in ASD have not been examined. We hypothesized that serotonin transporter-linked promoter region (5-HTTLPR) genotype affects change in amygdala response to repeated sad faces differently in individuals with ASD vs healthy controls. Forty-four youth with ASD and 65 controls aged 8-19 years were genotyped and underwent an event-related functional magnetic resonance imaging scan where they identified the gender of emotional faces presented for 250 ms. The first half of the run was compared with the second half to assess habituation. 5-HTTLPR genotype influences amygdala habituation to sad faces differently for individuals with ASD vs controls. The genotype-by-diagnosis-by-run half interaction was driven by individuals with ASD and low expressing genotypes (S/S, S/L(G) and L(G)/L(G)), who trended toward sensitization (increase in amygdala activation) and whose habituation scores significantly differed from individuals with ASD and higher expressing genotypes (L(A)/L(A), S/L(A) and L(A)/L(G)) as well as controls with low expressing genotypes. Our results show that amygdala response to social stimuli in ASD, which may contribute to social symptoms, is genetically influenced.

Age-related effect of serotonin transporter genotype on amygdala and prefrontal cortex function in adolescence

The S and LG alleles of the serotonin transporter-linked polymorphic region (5-HTTLPR) lower serotonin transporter expression. These low-expressing alleles are linked to increased risk for depression and brain activation patterns found in depression (increased amygdala activation and decreased amygdala-prefrontal cortex connectivity). Paradoxically, serotonin transporter blockade relieves depression symptoms. Rodent models suggest that decreased serotonin transporter in early life produces depression that emerges in adolescence, whereas decreased serotonin transporter that occurs later in development ameliorates depression. However, no brain imaging research has yet investigated the moderating influence of human development on the link between 5-HTTLPR and effect-related brain function. We investigated the age-related effect of 5-HTTLPR on amygdala activation and amygdala-prefrontal cortex connectivity using a well-replicated probe, an emotional face task, in children and adolescents aged 9-19 years. A significant genotype-by-age interaction predicted amygdala activation, such that the low-expressing genotype (S/S and S/LG ) group showed a greater increase in amygdala activation with age compared to the higher expressing (LA /LA and S/LA ) group. Additionally, compared to the higher expressing group, the low-expressing genotype group exhibited decreased connectivity between the right amygdala and ventromedial prefrontal cortex with age. Findings indicate that low-expressing genotypes may not result in the corticolimbic profile associated with depression risk until later adolescence.