Altered Prefrontal Cortex Function Marks Heightened Anxiety Risk in Children

Transformations in prefrontal ensemble activity underlying rapid threat avoidance learning

The capacity to learn cues that predict aversive outcomes, and understand how to avoid those outcomes, is critical for adaptive behavior. Naturalistic avoidance often means accessing a safe location, but whether a location is safe depends on the nature of the impending threat. These relationships must be rapidly learned if animals are to survive. The prelimbic subregion (PL) of the medial prefrontal cortex (mPFC) integrates learned associations to influence these threat avoidance strategies. Prior work has focused on the role of PL activity in avoidance behaviors that are fully established, leaving the prefrontal mechanisms that drive rapid avoidance learning poorly understood. To determine when and how these learning-related changes emerge, we recorded PL neural activity using miniscope calcium imaging as mice rapidly learned to avoid a threatening cue by accessing a safe location. Over the course of learning, we observed enhanced modulation of PL activity representing intersections of a threatening cue with safe or risky locations and movements between them. We observed rapid changes in PL population dynamics that preceded changes observable in the encoding of individual neurons. Successful avoidance could be predicted from cue-related population dynamics during early learning. Population dynamics during specific epochs of the conditioned tone period correlated with the modeled learning rates of individual animals. In contrast, changes in single-neuron encoding occurred later, once an avoidance strategy had stabilized. Together, our findings reveal the sequence of PL changes that characterize rapid threat avoidance learning.

Effects of Interleukin-19 overexpression in the medial prefrontal cortex on anxiety-related behaviors, BDNF expression and p38/JNK/ERK pathways

Anxiety is a prevalent mental illness known for its high incidence, comorbidity, and tendency to recur, posing significant societal and individual burdens. Studies have highlighted Interleukin-19 (IL-19) as having potential relevance in neuropsychiatric disorders. Our previous research revealed that IL-19 overexpression in colonies exacerbated anxiety-related behaviors induced by dextran sodium sulfate/stress. However, the precise role and molecular mechanisms of IL-19 in anxiety regulation remain uncertain. In this study, we initiated an acute restraint stress (ARS)-induced anxious mouse model and identified heightened expression of IL-19 and IL-20Rα in the medial prefrontal cortex (mPFC) of ARS mice. Notably, IL-19 and IL-20Rα were predominantly present in the excitatory pyramidal neurons of the mPFC under both basal and ARS conditions. Utilizing the adeno-associated virus (AAV) strategy, we demonstrated that IL-19 overexpression in the mPFC induced anxiety-related behaviors and elevated stress susceptibility. Additionally, we observed decreased protein levels of brain-derived neurotrophic factor (BDNF) and postsynaptic density protein 95 (PSD95) in the mPFC of IL-19 overexpression mice, accompanied by reduced phosphorylation of in the p38, JNK, and Erk signaling pathways. These findings emphasize the role of IL-19 in modulating anxiety-related behaviors within the mPFC and suggest its potential as a pathological gene and therapeutic target for anxiety.

Anatomical analyses of collateral prefrontal cortex projections to the basolateral amygdala and the nucleus accumbens core in rats

The basolateral amygdala (BLA) and the nucleus accumbens core (NAcc) share some similar behavioral functions, such as associative learning, Pavlovian to instrumental transfer, and choice behavior. However, their prefrontal anatomical inputs have not been well characterized before, especially the collateral projections. In this study, we analyzed the distribution and collateralization of projections to the BLA and the NAcc from the prefrontal cortices (PFC), including the prelimbic (PL) and the infralimbic (IL) divisions of the medial prefrontal cortex (mPFC) and the subregions of the orbitofrontal cortex (OFC), such as the medial OFC (MO), the lateral OFC (LO), and the ventral OFC (VO). Double retrograde tracing approach was used, in which Cholera toxin subunit B conjugated with the Alexa Fluor 488 (CTB-AF488) or Alexa Fluor 594 (CTB-AF594) were unilaterally injected into the BLA and the NAcc, respectively, in male Long-Evans rats (n = 6). Among the sampled neurons, prefrontal projection to the BLA or the NAcc is more robust on the ipsilateral side, and more robust from the PL, the IL, and the MO compared to from the LO and the VO. The majority of the projections from the PFC to the BLA and/or the NAcc are confined in deep layer. In addition, for each of the prefrontal areas, about 15-25% BLA-projecting neurons send collateral projections to the NAcc, and vice versa. In conclusion, our data suggested that prefrontal control over the BLA and the NAcc is not entirely independent. The functional importance of the collateral projections awaits further examination.

Dexmedetomidine alleviates anxiety-like behaviors in female mice with musculoskeletal pain through SIRT1/p53 axis

BACKGROUND

Musculoskeletal pain is the most common form of chronic pain. Anxiety increases pain intensity and appears to have a major impact on the prevalence and also disability of musculoskeletal pain in women. We examined the effect of dexmedetomidine (DEX) on anxiety-like behaviors associated with musculoskeletal pain and the underlying molecular mechanism in female mice.

METHODS

Musculoskeletal pain was induced by injection of acidified saline into the gastrocnemius muscle in adult female mice, and the von Frey filament test is used to measure mechanical sensitivity. DEX and EX527 (SIRT1 inhibitor) were administered after modelling. Behavioral tests were used for anxiety and motor activity tests. SIRT1, p53 and acetyl-p53 were quantified by Western blot.

RESULTS

Adult female mice with musculoskeletal pain exhibit increased fear-like behavior by reducing SIRT1 expression in the medial prefrontal cortex (mPFC). While administration of DEX was able to alleviate mechanical hypersensitivity and anxiety-like behaviors by blocking SIRT1 decline and acetyl-p53 upregulation in mPFC, EX527 inhibited acetyl-p53 rise and reversed the antinociceptive and anxiolytic effects of DEX.

CONCLUSION

DEX may alleviate anxiety-like behaviors in mice with musculoskeletal pain via the SIRT1/p53 axis. These results suggest that DEX may have a potential therapeutic role in musculoskeletal pain-induced anxiety.

Decoupling between hub-connected functional connectivity of the social brain network and real-world social network in individuals with social anhedonia

Altered hub regions in brain network have been consistently reported in patients with schizophrenia. However, it is unclear whether similar altered hub regions of the brain would be exhibited in individuals with subclinical features of schizophrenia such as social anhedonia (SA). In this study, we examined the hub regions of resting-state social brain network (SBN) of 35 participants with SA and 50 healthy controls (HC). We further examined the prediction effect of hub-connected FCs with SBN on the real-life social network characteristics. Our findings showed that the right amygdala, left temporal lobe and right media superior frontal gyrus were the hub regions of SBN both in SA and HC groups. In the SA group, the left temporal lobe connected functional connectivity (FC) did not predict social network characteristics, while the other FCs strengthened the association with social network characteristics. These findings were replicated in an independent sample of 33 SA and 32 HC. These findings suggested that the left temporal lobe as one of the hub regions of SBN exhibited the abnormality of their connected FCs in the association with social network characteristics in individuals with SA.

Bed nucleus of the stria terminalis and amygdala responses to unpredictable threat in children

Substantial evidence from studies in humans suggests the amygdala is pivotal for anxiety. Findings from animal models and translational studies suggests the bed nucleus of the stria terminalis (BNST) is also critical for anxiety and the anticipation of unpredictable threat in adults. However, it remains unknown whether the BNST is involved in unpredictable threat anticipation in children. Forty-two 8-10-year-olds completed resting-state functional magnetic resonance imaging (fMRI) scans and an unpredictable threat fMRI task in which they were trained to associate cues with images. Intrinsic connectivity analyses were performed to establish functional BNST and amygdala networks. BNST and amygdala activation to cues and images was tested. Significant findings were followed by task-based functional connectivity analyses. Children showed evidence for BNST and amygdala intrinsic connectivity that was similar to previous patterns observed in adults. In response to unpredictable cues relative to neutral face cues, children had a significant amygdala response but no response in the BNST. The amygdala, but not the BNST, also showed a significantly greater response to fear face images relative to neutral images. Thus, unpredictable threat activated the amygdala, but not BNST, in children. This finding is contrary to studies showing robust BNST activation to unpredictable threat in adults and may suggest that the BNST's role in threat processing emerges later in development.

Increased attentional network activity in premature ejaculation patients with anxiety revealed by resting-state functional magnetic resonance imaging

Psychological account hypothesizes that premature ejaculation (PE) is a learned pattern of rapid ejaculation maintained by anxiety about sexual failure, whereas neuropsychological accounts hypothesizes that PE is the result of dysfunction of central nervous system regulating ejaculatory. However, the central neural mechanism underlying PE patients with anxiety remains unclear. Resting-state functional magnetic resonance imaging (fMRI) data were collected in 20 PE (diagnoses based on PE Guidelines drafted by the International Society for Sexual Medicine [ISSM]) patients with anxiety and 25 matched healthy controls (HCs) from January 2019 to December 2020. The values of fractional amplitude of low-frequency fluctuation (fALFF) were compared between groups. Moreover, the correlations between fALFF and the severity of PE and anxiety of patients were examined. PE patients with anxiety had increased fALFF values in the right inferior frontal gyrus (opercular part) and middle frontal gyrus. In addition, significant positive correlations were found between the scores of PE diagnostic tool (PEDT) and fALFF values of the right inferior frontal gyrus (opercular part), as well as the right middle frontal gyrus. Moreover, fALFF values of the right inferior frontal gyrus (opercular part) and middle frontal gyrus were positively correlated with the scores of self-rating anxiety scale (SAS). Our results suggested that increased attentional network activity might play a critical role in the neural basis of PE patients with anxiety.

Threat-anticipatory psychophysiological response is enhanced in youth with anxiety disorders and correlates with prefrontal cortex neuroanatomy

Background

Threat anticipation engages neural circuitry that has evolved to promote defensive behaviours; perturbations in this circuitry could generate excessive threat-anticipation response, a key characteristic of pathological anxiety. Research into such mechanisms in youth faces ethical and practical limitations. Here, we use thermal stimulation to elicit pain-anticipatory psychophysiological response and map its correlates to brain structure among youth with anxiety and healthy youth.

Methods

Youth with anxiety (n = 25) and healthy youth (n = 25) completed an instructed threat-anticipation task in which cues predicted nonpainful or painful thermal stimulation; we indexed psychophysiological response during the anticipation and experience of pain using skin conductance response. High-resolution brain-structure imaging data collected in another visit were available for 41 participants. Analyses tested whether the 2 groups differed in their psychophysiological cue-based pain-anticipatory and pain-experience responses. Analyses then mapped psychophysiological response magnitude to brain structure.

Results

Youth with anxiety showed enhanced psychophysiological response specifically during anticipation of painful stimulation (b = 0.52, p = 0.003). Across the sample, the magnitude of psychophysiological anticipatory response correlated negatively with the thickness of the dorsolateral prefrontal cortex (pFWE < 0.05); psychophysiological response to the thermal stimulation correlated positively with the thickness of the posterior insula (pFWE < 0.05).

Limitations

Limitations included the modest sample size and the cross-sectional design.

Conclusion

These findings show that threat-anticipatory psychophysiological response differentiates youth with anxiety from healthy youth, and they link brain structure to psychophysiological response during pain anticipation and experience. A focus on threat anticipation in research on anxiety could delineate relevant neural circuitry.

Research Review: Pediatric anxiety disorders - what have we learnt in the last 10 years?

BACKGROUND

Anxiety disorders first emerge during the critical developmental periods of childhood and adolescence. This review synthesizes recent findings on the prevalence, risk factors, and course of the anxiety disorders; and their neurobiology and treatment.

METHODS

For this review, searches were conducted using PubMed, PsycINFO, and clinicaltrials.gov. Findings related to the epidemiology, neurobiology, risk factors, and treatment of pediatric anxiety disorders were then summarized.

FINDINGS

Anxiety disorders are high prevalence, and early-onset conditions associated with multiple risk factors including early inhibited temperament, environment stress, and structural and functional abnormalities in the prefrontal-amygdala circuitry as well as the default mode and salience networks. The anxiety disorders are effectively treated with cognitive behavioral therapy (CBT), selective serotonin reuptake inhibitors (SSRIs), and serotonin-norepinephrine reuptake inhibitors (SNRIs).

CONCLUSIONS

Anxiety disorders are high prevalence, early-onset conditions associated with a distinct neurobiological fingerprint, and are consistently responsive to treatment. Questions remain regarding who is at risk of developing anxiety disorders as well as the way in which neurobiology predicts treatment response.

Greater Dynamic and Lower Static Functional Brain Connectivity Prospectively Predict Placebo Response in Pediatric Generalized Anxiety Disorder

Objectives: Placebo response is one of the most significant barriers to detecting treatment effects in pediatric (and adult) clinical trials focusing on affective and anxiety disorders. We sought to identify neurofunctional predictors of placebo response in adolescents with generalized anxiety disorder (GAD) by examining dynamic and static functional brain connectivity. Methods: Before randomization to blinded placebo, adolescents, aged 12-17 years, with GAD (N = 25) underwent resting state functional magnetic resonance imaging. Whole brain voxelwise correlation analyses were used to determine the relationship between change in anxiety symptoms from baseline to week 8 and seed-based dynamic and static functional connectivity maps of regions in the salience and ventral attention networks (amygdala, dorsal anterior cingulate cortex [dACC], and ventrolateral prefrontal cortex [VLPFC]). Results: Greater dynamic functional connectivity variability in amygdala, dACC, VLPFC, and regions within salience, default mode, and frontoparietal networks was associated with greater placebo response. Lower static functional connectivity between amygdala and dorsolateral prefrontal cortex, amygdala and medial prefrontal cortex, dACC and posterior cingulate cortex and greater static functional connectivity between VLPFC and inferior parietal lobule were associated with greater placebo response. Conclusion: Placebo response is associated with a distinct dynamic and static connectivity fingerprint characterized by "variable" dynamic but "weak" static connectivity in the salience, default mode, frontoparietal, and ventral attention networks. These data provide granular evidence of how circuit-based biotypes mechanistically relate to placebo response. Finding biosignatures that predict placebo response is critically important in clinical psychopharmacology and to improve our ability to detect medication-placebo differences in clinical trials.

Medial prefrontal cortex in neurological diseases

The medial prefrontal cortex (mPFC) is a crucial cortical region that integrates information from numerous cortical and subcortical areas and converges updated information to output structures. It plays essential roles in the cognitive process, regulation of emotion, motivation, and sociability. Dysfunction of the mPFC has been found in various neurological and psychiatric disorders, such as depression, anxiety disorders, schizophrenia, autism spectrum disorders, Alzheimer's disease, Parkinson's disease, and addiction. In the present review, we summarize the preclinical and clinical studies to illustrate the role of the mPFC in these neurological diseases.

Stationary and ambulatory attention patterns are differentially associated with early temperamental risk for socioemotional problems: Preliminary evidence from a multimodal eye-tracking investigation

Behavioral Inhibition (BI) is a temperament type that predicts social withdrawal in childhood and anxiety disorders later in life. However, not all BI children develop anxiety. Attention bias (AB) may enhance the vulnerability for anxiety in BI children, and interfere with their development of effective emotion regulation. In order to fully probe attention patterns, we used traditional measures of reaction time (RT), stationary eye-tracking, and recently emerging mobile eye-tracking measures of attention in a sample of 5- to 7-year-olds characterized as BI (N = 23) or non-BI (N = 58) using parent reports. There were no BI-related differences in RT or stationary eye-tracking indices of AB in a dot-probe task. However, findings in a subsample from whom eye-tracking data were collected during a live social interaction indicated that BI children (N = 12) directed fewer gaze shifts to the stranger than non-BI children (N = 25). Moreover, the frequency of gazes toward the stranger was positively associated with stationary AB only in BI, but not in non-BI, children. Hence, BI was characterized by a consistent pattern of attention across stationary and ambulatory measures. We demonstrate the utility of mobile eye-tracking as an effective tool to extend the assessment of attention and regulation to social interactive contexts.

Consequences of Not Planning Ahead: Reduced Proactive Control Moderates Longitudinal Relations Between Behavioral Inhibition and Anxiety

OBJECTIVE

Children with the temperament of behavioral inhibition (BI) face increased risk for developing an anxiety disorder later in life. However, not all children with BI manifest anxiety symptoms, and use of a cognitive control strategy could moderate the pathway between BI and anxiety. Individuals vary widely in the strategy used to instantiate control. The present study examined whether a more planful style of cognitive control (ie, proactive control) or a more impulsive strategy of control (ie, reactive control) would moderate the association between early BI and later anxiety symptoms.

METHOD

Participants were part of a longitudinal study examining the relations between BI (measured at 2-3 years of age) and later anxiety symptoms (measured at 13 years). Use of a cognitive control strategy was assessed at 13 years using the AX variant of the continuous performance task.

RESULTS

BI in toddlerhood significantly predicted increased use of a more reactive cognitive control style in adolescence. In addition, cognitive control strategy moderated the relation between BI and anxious symptoms, such that reliance on a more reactive strategy predicted higher levels of anxiety for children high in BI.

CONCLUSION

The present study is the first to identify the specific control strategy that increases risk for anxiety. Thus, it is not cognitive control per se, but the specific control strategy children adopt that could increase risk for anxiety later in life. These findings have important implications for future evidence-based interventions because they suggest that an emphasis on decreasing reactive cognitive control and increasing proactive cognitive control might decrease anxious cognition.

Early childhood social reticence and neural response to peers in preadolescence predict social anxiety symptoms in midadolescence

BACKGROUND

Early childhood social reticence (SR) and preadolescent social anxiety (SA) symptoms increase the risk for more severe SA in later adolescence. Yet, not all at-risk youth develop more severe SA. The emergence of distinct patterns of neural response to socially evocative contexts during pivotal points in development may help explain this discontinuity. We tested the extent to which brain function during social interactions in preadolescence influenced the effects of SA and early childhood SR on predicting SA symptoms in midadolescence.

METHODS

Participants (N = 53) were assessed for SR from ages 2 to 7. At age 11, SA symptoms were assessed and brain function was measured using functional magnetic resonance imaging (fMRI) as participants anticipated social evaluation from purported peers with a reputation for being unpredictable, nice, and mean. At age 13, SA symptoms were re-assessed. Moderated-mediation models tested the extent to which early childhood SR, preadolescent SA, and preadolescent brain function predicted midadolescent SA.

RESULTS

In individuals with preadolescent SA, the presence of early childhood SR and SR-linked differences in brain activation predicted more severe SA in midadolescence. Specifically, in those who exhibited preadolescent SA, greater early childhood SR was associated with enhanced bilateral insula engagement while anticipating unpredictable-versus-nice social evaluation in preadolescence, and more severe SA in midadolescence.

CONCLUSIONS

SR-linked neural responses to socially evocative peer interactions may predict more severe SA symptoms in midadolescence among individuals with greater preadolescent SA symptoms and childhood SR. This same pattern of neural response may not be associated with more severe SA symptoms in youth with only one risk factor.

The Genetic and Environmental Relationship Between Childhood Behavioral Inhibition and Preadolescent Anxiety

This study uses novel approaches to examine genetic and environmental influences shared between childhood behavioral inhibition (BI) and symptoms of preadolescent anxiety disorders. Three hundred and fifty-two twin pairs aged 9-13 and their mothers completed questionnaires about BI and anxiety symptoms. Biometrical twin modeling, including a direction-of-causation design, investigated genetic and environmental risk factors shared between BI and social, generalized, panic and separation anxiety. Social anxiety shared the greatest proportion of genetic (20%) and environmental (16%) variance with BI with tentative evidence for causality. Etiological factors underlying BI explained little of the risk associated with the other anxiety domains. Findings further clarify etiologic pathways between BI and anxiety disorder domains in children.

The Effects of Early Postpartum Depression on Infant Temperament

Research linking postpartum depression (PPD) with negative child outcomes has predominantly examined PPD at six weeks postpartum or later, and has not controlled for depression during pregnancy. The present study examined associations between PPD at three weeks postpartum and temperament in 6-month-old infants in a sample of women who were not depressed during pregnancy. Depression was assessed at three weeks and six months postpartum using the Postpartum Depression Screening Scale (PDSS). Observed and maternal report of infant temperament was assessed when infants were 6-months-old. PPD symptoms significantly predicted observed temperament behaviour and marginally explained maternal report of infant temperament. Symptoms of PPD at three weeks postpartum were a stronger predictor than at six months. Findings suggest that early depressive symptoms may be particularly problematic, and have implications for early assessment and treatment of PPD even in women who were not depressed during pregnancy or are otherwise considered low risk.

Shyness and Trajectories of Functional Network Connectivity Over Early Adolescence

High shyness during early adolescence is associated with impaired peer relationships and risk for psychiatric disorders. Little is known, however, about the relation between shyness and trajectories of brain development over early adolescence. The current study longitudinally examined trajectories of resting-state functional connectivity (rs-fc) within four brain networks in 147 adolescents. Subjects underwent functional magnetic resonance imaging at three different time points, at average ages 10.5 (range = 7.8-13.0), 11.7 (range = 9.3-14.1), and 12.9 years (range = 10.1-15.2). Multilevel linear modeling indicated that high shyness was associated with a less steep negative slope of default mode network (DMN) rs-fc over early adolescence relative to low shyness. Less steep decreases in DMN rs-fc may relate to increased self-focus in adolescents with high shyness.

Early enriched physical environment reverses impairments of the hippocampus, but not medial prefrontal cortex, of socially-isolated mice

Early social isolation (SI) produces a variety of emotional, behavioral and cognitive abnormalities. Conversely, environmental enrichment (EE), a complicated social and physical construct, offers beneficial effects on brain plasticity and development. However, whether or not exclusive physical EE is sufficient to reverse the adverse consequences of early SI remains unclear. Here we reported that 1month-old solitary mice housed in the EE for 8weeks corrected spatial cognitive dysfunction, but did not ameliorate social interaction deficits and increased anxiety-like behavior. Pathological analyses revealed that the enriched environment decreased cellular apoptosis, synaptic protein loss, myelination defect and microglial activation in the hippocampus, but not medial prefrontal cortex (mPFC) of mice housed singly. Moreover, increased nuclear factor-kappaB and interleukin-1β levels, and downregulation of brain-derived neurotrophic factor signaling pathway were normalized in the hippocampus rather than mPFC of these animals. Our results revealed a brain region-specific effectiveness of physical EE in remediating brain impairment of adolescent SI mice, with a complete reversal of hippocampus-dependent cognitive dysfunctions, but without mitigation of mPFC associated anxiety and social interaction defects. This finding emphasizes the irreplaceable role of social life for the early brain development.

Recruitment of orbitofrontal cortex during unpredictable threat among adults at risk for affective disorders

BACKGROUND

Mood and anxiety disorders are characterized by altered prefrontal-amygdala function and increased behavioral inhibition (BI) in response to potential threat. Whether these alterations constitute a vulnerability or a symptom of illness remains unclear. The medial orbitofrontal cortex (mOFC) is thought to play a central role in estimating probability and cost of threat, in turn informing selection of subsequent behaviors. To better understand the behavioral and neural processes that may be associated with risk for psychopathology, we used a virtual reality paradigm to examine behavioral and neural responses of psychiatrically healthy adults with familial history of affective disorders during anticipation of unpredictable threat.

METHODS

Twenty psychiatrically healthy adults with high familial risk for affective disorders and 20 low-risk matched controls underwent functional magnetic resonance imaging concurrent with a paradigm in which they explored virtual contexts associated with the threat of shock or safety from shock. Subjective anxiety ratings, skin conductance, exploratory behavior, and neural responses were examined for threat versus safe conditions.

RESULTS

High-risk adults evidenced greater right mOFC activation, as well as greater BI, compared to low-risk adults. There were no significant group differences in subjective ratings or autonomic responses. Individuals exhibiting greater activity in the right mOFC showed greater BI and decreased skin conductance response.

CONCLUSIONS

These results suggest that BI and mOFC recruitment during anticipation of aversive outcomes may reflect a vulnerability for affective disorders. However, such a response may also serve as a compensatory response, protecting these high-risk individuals from negative outcomes (i.e., increased physiological arousal). These results suggest that the OFC may play a central role in driving threat-related behaviors and thus may be a target for efforts aimed at early detection or prevention.