Individual differences in emotion-cognition interactions: emotional valence interacts with serotonin transporter genotype to influence brain systems involved in emotional reactivity and cognitive control

A neural model of vulnerability and resilience to stress-related disorders linked to differential susceptibility

Expert opinion remains divided concerning the impact of putative risk factors on vulnerability to depression and other stress-related disorders. A large body of literature has investigated gene by environment interactions, particularly between the serotonin transporter polymorphism (5-HTTLPR) and negative environments, on the risk for depression. However, fewer studies have simultaneously investigated the outcomes in both negative and positive environments, which could explain some of the inconclusive findings. This is embodied by the concept of differential susceptibility, i.e., the idea that certain common gene polymorphisms, prenatal factors, and traits make some individuals not only disproportionately more susceptible and responsive to negative, vulnerability-promoting environments, but also more sensitive and responsive to positive, resilience-enhancing environmental conditions. Although this concept from the field of developmental psychology is well accepted and supported by behavioral findings, it is striking that its implementation in neuropsychiatric research is limited and that underlying neural mechanisms are virtually unknown. Based on neuroimaging studies that examined how factors mediating differential susceptibility affect brain function, we posit that environmental sensitivity manifests in increased salience network activity, increased salience and default mode network connectivity, and increased salience and central executive network connectivity. These changes in network function may bring about automatic exogenous attention for positive and negative stimuli and flexible attentional set-shifting. We conclude with a call to action; unraveling the neural mechanisms through which differential susceptibility factors mediate vulnerability and resilience may lead us to personalized preventive interventions.

Mindfulness video game improves connectivity of the fronto-parietal attentional network in adolescents: A multi-modal imaging study

Mindfulness training has been shown to improve attention and change the underlying brain substrates in adults. Most mindfulness training programs involve a myriad of techniques, and it is difficult to attribute changes to any particular aspect of the program. Here, we created a video game, Tenacity, which models a specific mindfulness technique – focused attention on one’s breathing – and assessed its potential to train an attentional network in adolescents. A combined analysis of resting state functional connectivity (rs-FC) and diffusion tensor imaging (DTI) yielded convergent results – change in communication within the left fronto-parietal network after two weeks of playing Tenacity compared to a control game. Rs-FC analysis showed greater connectivity between left dorsolateral prefrontal cortex (dlPFC) and left inferior parietal cortex (IPC) in the Tenacity group. Importantly, changes in left dlPFC – IPC rs-FC and changes in structural connectivity of the white matter tract that connects these regions –left superior longitudinal fasiculus (SLF) – were associated with changes in performance on an attention task. Finally, changes in left dlPFC – IPC rs-FC correlated with the change in left SLF structural connectivity as measured by fractional anisotropy (FA) in the Tenacity group only.

Thought Control Ability Moderates the Effect of Mind Wandering on Positive Affect via the Frontoparietal Control Network

Mind wandering is a phenomenon that involves thoughts shifting away from a primary task to the process of dealing with other personal goals. A large number of studies have found that mind wandering can predict negative emotions, but researchers have seldom focused on the positive role of mind wandering. The current study aimed to explore the relationships among mind wandering, emotions and thought control ability, which is the ability to inhibit one's own unpleasant or unwanted intrusive thoughts. Here, we collected resting-state functional magnetic resonance imaging (rsfMRI) data from 368 participants who completed a set of questionnaires involving mind wandering, thought control ability and positive or negative emotions. The results revealed that (1) rsfMRI connectivity features related to thought control ability and mind wandering could divide individuals into two groups: HMW (high mind-wandering) group and LMW (low mind-wandering) group. The HMW group scored lower in thought control ability (TCA), higher in negative emotion (NE) and lower in positive emotion (PE) than the LMW group. (2) TCA moderated the association between MW and positive affect (PA). (3) Two groups exhibited different segregation within key nodes (SWKN) of the frontoparietal control network (FPCN), and the subsequent analysis showed that the SWKN of the FPCN was negatively correlated with PA. These findings indicate that TCA moderates the effect of mind wandering on affect via the FPCN, which may have important implications for our understanding of the positive role of mind wandering.

Genetic and Environmental Associations Among Executive Functions, Trait Anxiety, and Depression Symptoms in Middle Age

Multiple executive functions (EFs) are associated with trait anxiety and depression symptoms, but it is unclear how genetic and/or environmental factors account for these associations, and if they are explained by general variance underlying multiple EFs (i.e., Common EF). In this study, 1207 male twins completed seven EF tasks and measures of trait anxiety and depression symptoms at average age 62. The Common EF factor was associated with both anxiety (r= -.25) and depression symptoms (r= -.35). Anxiety and depression had near complete genetic overlap (r g=.96). Genetic influences shared with depression accounted for 83% of the phenotypic correlation between anxiety and Common EF. For depression, the phenotypic correlation with Common EF was explained by genetic influences shared with anxiety (69%), but also nonshared environmental influences distinct from anxiety (20%). These results suggest that genetic influences on Common EF play a role in the observed genetic overlap between anxiety and depression.

Associations between genetic risk, functional brain network organization and neuroticism

Neuroticism and genetic variation in the serotonin-transporter (SLC6A4) and catechol-O-methyltransferase (COMT) gene are risk factors for psychopathology. Alterations in the functional integration and segregation of neural circuits have recently been found in individuals scoring higher on neuroticism. The aim of the current study was to investigate how genetic risk factors impact functional network organization and whether genetic risk factors moderate the association between neuroticism and functional network organization. We applied graph theory analysis on resting-state fMRI data in a sample of 120 women selected based on their neuroticism score, and genotyped two polymorphisms: 5-HTTLPR (S-carriers and L-homozygotes) and COMT (rs4680-rs165599; COMT risk group and COMT non-risk group). For the 5-HTTLPR polymorphism, we found that subnetworks related to cognitive control show less connections with other subnetworks in S-carriers compared to L-homozygotes. The COMT polymorphism moderated the association between neuroticism and functional network organization. We found that neuroticism was associated with lower efficiency coefficients in visual and somatosensory-motor subnetworks in the COMT risk group compared to the COMT non-risk group. The findings of altered topology of specific subnetworks point to different cognitive-emotional processes that may be affected in relation to the genetic risk factors, concerning emotion regulation in S-carriers (5-HTTLPR) and emotional salience processing in COMT risk carriers.

The interaction between 5-HTTLPR and stress exposure influences connectivity of the executive control and default mode brain networks

We recently reported that the serotonin transporter polymorphism 5-HTTLPR moderates the relation between stress exposure and attention-deficit/hyperactivity disorder (ADHD) severity. This gene-environment interaction (GxE) has been previously tied to the processing of emotional stimuli, which is increasingly recognized to be a key factor in ADHD-related impairment. The executive control and default mode brain networks play an important role in the regulation of emotion processing, and altered connectivity of these networks has also been associated with ADHD. We therefore investigated whether resting-state connectivity of either of these networks mediates the relation of 5-HTTLPR and stress exposure with ADHD severity. Resting-state functional magnetic resonance imaging, genetic, and stress exposure questionnaire data was available for 425 adolescents and young adults (average age 17.2 years). We found that 5-HTTLPR S-allele carriers showed a more negative relation between stress exposure and connectivity of the executive control network than L-allele homozygotes, specifically in the pre/postcentral gyrus, striatum, and frontal pole. In the default mode network, we found a positive association between the GxE and supramarginal gyrus connectivity. Connectivity of either network did not significantly mediate the effect of this GxE on ADHD. Opposite effects of stress exposure on connectivity in the executive and default mode networks may contribute to findings that stress exposure is associated with lowered cognitive control and heightened levels of rumination and worrying, for S-allele carriers but not L-allele homozygotes. When combined, these effects on connectivity of both networks may relate to the emotional problems seen in individuals with ADHD.

ADRA2B deletion variant and enhanced cognitive processing of emotional information: A meta-analytical review

This meta-analytical review examines whether a deletion variant in ADRA2B, a gene that encodes α_2B adrenoceptor in the regulation of norepinephrine availability, influences cognitive processing of emotional information in human observers. Using a multilevel modeling approach, this meta-analysis of 16 published studies with a total of 2752 participants showed that ADRA2B deletion variant was significantly associated with enhanced perceptual and cognitive task performance for emotional stimuli. In contrast, this genetic effect did not manifest in overall task performance when non-emotional content was used. Furthermore, various study-level factors, such as targeted cognitive processes (memory vs. attention/perception) and task procedures (recall vs. recognition), could moderate the size of this genetic effect. Overall, with increased statistical power and standardized analytical procedures, this meta-analysis has established the contributions of ADRA2B to the interactions between emotion and cognition, adding to the growing literature on individual differences in attention, perception, and memory for emotional information in the general population.

Situation Awareness Performance in Healthy Young Adults Is Associated With a Serotonin Transporter Gene Polymorphism

Background Situation awareness (SA) is defined in three levels: SA1 is the perception of the elements in a specific context, SA2 is the comprehension of their meaning, and SA3 is the projection of their status. Purpose To analyze the possible association of a genetic polymorphism in the serotonin transporter ( SLC6A4) gene and performance on the Situational Awareness test (SAtest). Methods SAtest was applied to a sample of 230 healthy Colombian subjects, using the Psychology Experiment Building Language platform and a functional polymorphism in the SLC6A4 gene was genotyped by polymerase chain reaction. Results In the SA1 level, s/s genotype carriers had worse accuracy, in comparison with s/l and l/l genotypes. At SA2 level, l/l genotype carriers had better accuracy than s/s and s/l individuals and that in the SA3 level, l/l carriers also had better accuracy. These associations were significant after correction for multiple testing. Conclusions It is possible that l/l carriers have a better ability to perceive and focus their attention on the elements of their environment and to have the capacity to understand and predict what will happen with those elements. This is the first genetic study of SA performance in healthy participants. Additional investigations of other genes could contribute to the understanding of the molecular correlates of SA in healthy subjects and in neuropsychiatric patients.

SLC6A3 Is Associated With Relational Aggression in Children

Abstract. Understanding the genetic influence on aggressive behavior in children is one way to understand pathways to the development of aggression in adults. While aggression is likely under some environmental influence, it is also likely under some genetic influence. Overt aggression associates with a variety of genes including dopaminergic and serotonergic genes. Dopaminergic and serotonergic genes are known to be associated with overt aggression. However, little is known regarding the genetic pathways associated with relational aggression. Detecting genetic associates of relational aggression is important to eventually understand pathways to socially aggressive behaviors in children. Therefore, we attempted to determine if relational aggression was also associated with dopaminergic and serotonergic genes. We invited the parents of 327 children to complete a modified version of the MacArthur Health and Behavior Questionnaire (HBQ-P), which has a subscale for relational aggression. We used logistic regression models that predicted relational aggression after controlling for covariates. One genetic predictor was added at a time until there was no model improvement. The covariates were overt aggression scores obtained from the HBQ-P and age. The final (best) model included as a significant predictor of relational aggression one single nucleotide polymorphisms (SNP) on SLC6A3 (rs2617605) and the covariates.

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.

Face and emotion expression processing and the serotonin transporter polymorphism 5-HTTLPR/rs22531

Face cognition, including face identity and facial expression processing, is a crucial component of socio-emotional abilities, characterizing humans as highest developed social beings. However, for these trait domains molecular genetic studies investigating gene-behavior associations based on well-founded phenotype definitions are still rare. We examined the relationship between 5-HTTLPR/rs25531 polymorphisms - related to serotonin-reuptake - and the ability to perceive and recognize faces and emotional expressions in human faces. For this aim we conducted structural equation modeling on data from 230 young adults, obtained by using a comprehensive, multivariate task battery with maximal effort tasks. By additionally modeling fluid intelligence and immediate and delayed memory factors, we aimed to address the discriminant relationships of the 5-HTTLPR/rs25531 polymorphisms with socio-emotional abilities. We found a robust association between the 5-HTTLPR/rs25531 polymorphism and facial emotion perception. Carriers of two long (L) alleles outperformed carriers of one or two S alleles. Weaker associations were present for face identity perception and memory for emotional facial expressions. There was no association between the 5-HTTLPR/rs25531 polymorphism and non-social abilities, demonstrating discriminant validity of the relationships. We discuss the implications and possible neural mechanisms underlying these novel findings.

5-HTTLPR Expression Outside the Skin: An Experimental Test of the Emotional Reactivity Hypothesis in Children

Background

There is increasing evidence that variation in the promoter region of the serotonin transporter gene SLC6A4 (i.e., the 5-HTTLPR polymorphism) moderates the impact of environmental stressors on child psychopathology. Emotional reactivity −the intensity of an individual’s response to other’s emotions− has been put forward as a possible mechanism underlying these gene-by-environment interactions (i.e., G×E). Compared to children homozygous for the L-allele (LL-genotypes), children carrying an S-allele (SS/SL-genotypes), specifically when they have been frequently exposed to negative emotions in the family environment, might be more emotionally reactive and therefore more susceptible to affective environmental stressors. However, the association between 5-HTTLPR and emotional reactivity in children has not yet been empirically tested. Therefore, the goal of this study was to test this association in a large-scale experiment.

Methods

Children (N = 521, 52.5% boys, Mage = 9.72 years) were genotyped and randomly assigned to happy, angry or neutral dynamic facial expressions and vocalizations. Motor and affective emotional reactivity were assessed through children’s self-reported negative and positive affect (n = 460) and facial electromyography activity (i.e., fEMG: the zygomaticus or “smile” muscle and the corrugator or “frown” muscle, n = 403). Parents reported on their negative and positive parenting behaviors.

Results

Children mimicked and experienced the emotion they were exposed to. However, neither motor reactivity nor affective reactivity to these emotions depended on children’s 5-HTTLPR genotype: SS/SL-genotypes did not manifest any stronger response to emotional stimuli than LL-genotypes. This finding remained the same when taking the broader family environment into account, controlling for kinship, age, gender and genetic ancestry, and when including a tri-allelic factor.

Conclusions

We found no evidence for an association between the 5-HTTLPR polymorphism and children’s emotional reactivity. This finding is important, in discounting one potential underlying endophenotype of G×E between the 5-HTTLPR and affective environmental stressors.

Ovarian steroids regulate gene expression in the dorsal raphe of old female macaques

With extended life spans in modern humans, menopause has become a significant risk factor for depression, anxiety, loss of cognitive functions, weight gain, metabolic disease, osteoporosis, cardiovascular disease, and neurodegenerative diseases. Clinical studies have found beneficial neural effects of ovarian steroid hormone therapy (HT) during the menopausal transition and data are emerging that it can be continued long term. To further understand molecular underpinnings of the clinical studies, we used quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) to examine gene expression in the serotonergic dorsal raphe of old (>18 years) rhesus macaques, focusing on genes related to depression, cellular resilience, and neurodegenerative diseases. The animals were ovariectomized (Ovx, surgically menopausal) and subjected to either estradiol or estradiol plus progesterone HT, or to placebo, starting 2 months after Ovx and continuing for ∼ 4 years. Significant changes were observed in 36 of 48 genes examined that encode proteins supporting serotonin neurotransmission, synapse assembly, glutamate neurotransmission, DNA repair, chaperones, ubiquinases and transport motors, as well as genes encoding proteins that have potential to delay the onset of neuropathologies. The data reveal important gene targets for chronic HT that contribute to neural health. Alternatively, the loss of ovarian steroids may lead to loss of functions at the gene level that contribute to many of the observable neural deficits after menopause.

5-HTTLPR differentially predicts brain network responses to emotional faces

The effects of the 5-HTTLPR polymorphism on neural responses to emotionally salient faces have been studied extensively, focusing on amygdala reactivity and amygdala-prefrontal interactions. Despite compelling evidence that emotional face paradigms engage a distributed network of brain regions involved in emotion, cognitive and visual processing, less is known about 5-HTTLPR effects on broader network responses. To address this, we evaluated 5-HTTLPR differences in the whole-brain response to an emotional faces paradigm including neutral, angry and fearful faces using functional magnetic resonance imaging in 76 healthy adults. We observed robust increased response to emotional faces in the amygdala, hippocampus, caudate, fusiform gyrus, superior temporal sulcus and lateral prefrontal and occipito-parietal cortices. We observed dissociation between 5-HTTLPR groups such that LA LA individuals had increased response to only angry faces, relative to neutral ones, but S' carriers had increased activity for both angry and fearful faces relative to neutral. Additionally, the response to angry faces was significantly greater in LA LA individuals compared to S' carriers and the response to fearful faces was significantly greater in S' carriers compared to LA LA individuals. These findings provide novel evidence for emotion-specific 5-HTTLPR effects on the response of a distributed set of brain regions including areas responsive to emotionally salient stimuli and critical components of the face-processing network. These findings provide additional insight into neurobiological mechanisms through which 5-HTTLPR genotype may affect personality and related risk for neuropsychiatric illness.

The neurobiology of emotion-cognition interactions: fundamental questions and strategies for future research

Recent years have witnessed the emergence of powerful new tools for assaying the brain and a remarkable acceleration of research focused on the interplay of emotion and cognition. This work has begun to yield new insights into fundamental questions about the nature of the mind and important clues about the origins of mental illness. In particular, this research demonstrates that stress, anxiety, and other kinds of emotion can profoundly influence key elements of cognition, including selective attention, working memory, and cognitive control. Often, this influence persists beyond the duration of transient emotional challenges, partially reflecting the slower molecular dynamics of catecholamine and hormonal neurochemistry. In turn, circuits involved in attention, executive control, and working memory contribute to the regulation of emotion. The distinction between the 'emotional' and the 'cognitive' brain is fuzzy and context-dependent. Indeed, there is compelling evidence that brain territories and psychological processes commonly associated with cognition, such as the dorsolateral prefrontal cortex and working memory, play a central role in emotion. Furthermore, putatively emotional and cognitive regions influence one another via a complex web of connections in ways that jointly contribute to adaptive and maladaptive behavior. This work demonstrates that emotion and cognition are deeply interwoven in the fabric of the brain, suggesting that widely held beliefs about the key constituents of 'the emotional brain' and 'the cognitive brain' are fundamentally flawed. We conclude by outlining several strategies for enhancing future research. Developing a deeper understanding of the emotional-cognitive brain is important, not just for understanding the mind but also for elucidating the root causes of its disorders.

Hope for the best or prepare for the worst? Towards a spatial cognitive bias test for mice

Cognitive bias, the altered information processing resulting from the background emotional state of an individual, has been suggested as a promising new indicator of animal emotion. Comparable to anxious or depressed humans, animals in a putatively negative emotional state are more likely to judge an ambiguous stimulus as if it predicts a negative event, than those in positive states. The present study aimed to establish a cognitive bias test for mice based on a spatial judgment task and to apply it in a pilot study to serotonin transporter (5-HTT) knockout mice, a well-established mouse model for the study of anxiety- and depression-related behavior. In a first step, we validated that our setup can assess different expectations about the outcome of an ambiguous stimulus: mice having learned to expect something positive within a maze differed significantly in their behavior towards an unfamiliar location than animals having learned to expect something negative. In a second step, the use of spatial location as a discriminatory stimulus was confirmed by showing that mice interpret an ambiguous stimulus depending on its spatial location, with a position exactly midway between a positive and a negative reference point provoking the highest level of ambiguity. Finally, the anxiety- and depression-like phenotype of the 5-HTT knockout mouse model manifested--comparable to human conditions--in a trend for a negatively distorted interpretation of ambiguous information, albeit this effect was not statistically significant. The results suggest that the present cognitive bias test provides a useful basis to study the emotional state in mice, which may not only increase the translational value of animal models in the study of human affective disorders, but which is also a central objective of animal welfare research.

Genetic variations in COMT and DRD2 modulate attentional bias for affective facial expressions

Studies have revealed that catechol-O-methyltransferase (COMT) and dopaminegic receptor2 (DRD2) modulate human attention bias for palatable food or tobacco. However, the existing evidence about the modulations of COMT and DRD2 on attentional bias for facial expressions was still limited. In the study, 650 college students were genotyped with regard to COMT Val158Met and DRD2 TaqI A polymorphisms, and the attentional bias for facial expressions was assessed using the spatial cueing task. The results indicated that COMT Val158Met underpinned the individual difference in attentional bias for negative emotional expressions (P = 0.03) and the Met carriers showed more engagement bias for negative expressions than the Val/Val homozygote. On the contrary, DRD2 TaqIA underpinned the individual difference in attentional bias for positive expressions (P = 0.003) and individuals with TT genotype showed much more engagement bias for positive expressions than the individuals with CC genotype. Moreover, the two genes exerted significant interactions on the engagements for negative and positive expressions (P = 0.046, P = 0.005). These findings suggest that the individual differences in the attentional bias for emotional expressions are partially underpinned by the genetic polymorphisms in COMT and DRD2.