Oxytocin modulation of amygdala functional connectivity to fearful faces in generalized social anxiety disorder

Potential role of oxytocin in the regulation of memories and treatment of memory disorders

Oxytocin (OXT) is an "affiliative" hormone or neurohormone or neuropeptide consists of nine amino acids, synthesized in magnocellular neurons of paraventricular (PVN) and supraoptic nuclei (SON) of hypothalamus. OXT receptors are widely distributed in various region of brain and OXT has been shown to regulate various social and nonsocial behavior. Hippocampus is the main region which regulates the learning and memory. Hippocampus particularly regulates the acquisition of new memories and retention of acquired memories. OXT has been shown to regulate the synaptic plasticity, neurogenesis, and consolidation of memories. Further, findings from both preclinical and clinical studies have suggested that the OXT treatment improves performance in memory related task. Various trials have suggested the positive impact of intranasal OXT in the dementia patients. However, these studies are limited in number. In the present study authors have highlighted the role of OXT in the formation and retrieval of memories. Further, the study demonstrated the outcome of OXT treatment in various memory and related disorders.

Oxytocin differentially modulates the early neural responses to faces and non-social stimuli

Oxytocin (OT) alters social cognition partly through effects on the processing and appraisal of faces. It is debated whether the hormone also impacts the processing of other, non-social, visual stimuli. To this end, we conducted a randomized, counter-balanced, double-blind, placebo (PL)-controlled within-subjects' electro-encephalography (EEG) study with cismale participants (to control for gender dimorphic hormonal effects; n = 37). Participants received intranasal OT (24IU) and completed a one-back task viewing emotional (fearful/ happy) and neutral faces, and threat (snakes/spiders) and non-threat (mushrooms/flowers) non-social stimuli. OT differentially impacted event-related potentials (ERP)s to faces and non-social stimuli. For faces regardless of emotion, OT evoked greater occipital N1 and anterior P1 amplitudes at ∼155 ms than after PL, and lead to sustained differences over anterior, bilateral parietal and occipital sites from 205 ms onwards. For all non-social stimuli, OT evoked greater right parietal N1 amplitudes, and later only impacted threat stimuli over right parietal and occipital sites. None of these OT-induced modulations was related to individual anxiety levels. This pattern of results indicates that OT differentially modulates the processing of faces and non-social stimuli, and that the hormone's effect on visual processing and cognition does not occur as a function of non-clinical levels of anxiety.

Therapeutic uses of oxytocin in stress-related neuropsychiatric disorders

Oxytocin (OXT), produced and secreted in the paraventricular nucleus and supraoptic nucleus of magnocellular and parvocellular neurons. The diverse presence and activity of oxytocin suggests a potential for this neuropeptide in the pathogenesis and treatment of stress-related neuropsychiatric disorders (anxiety, depression and post-traumatic stress disorder (PTSD)). For a more comprehensive understanding of the mechanism of OXT's anti-stress action, the signaling cascade of OXT binding to targeting stress were summarized. Then the advance of OXT treatment in depression, anxiety, PTSD and the major projection region of OXT neuron were discussed. Further, the efficacy of endogenous and exogenous OXT in stress responses were highlighted in this review. To augment the level of OXT in stress-related neuropsychiatric disorders, current biological strategies were summarized to shed a light on the treatment of stress-induced psychiatric disorders. We also conclude some of the major puzzles in the therapeutic uses of OXT in stress-related neuropsychiatric disorders. Although some questions remain to be resolved, OXT has an enormous potential therapeutic use as a hormone that regulates stress responses.

Arousal modulates the amygdala-insula reciprocal connectivity during naturalistic emotional movie watching

Emotional arousal is a complex state recruiting distributed cortical and subcortical structures, in which the amygdala and insula play an important role. Although previous neuroimaging studies have showed that the amygdala and insula manifest reciprocal connectivity, the effective connectivities and modulatory patterns on the amygdala-insula interactions underpinning arousal are still largely unknown. One of the reasons may be attributed to static and discrete laboratory brain imaging paradigms used in most existing studies. In this study, by integrating naturalistic-paradigm (i.e., movie watching) functional magnetic resonance imaging (fMRI) with a computational affective model that predicts dynamic arousal for the movie stimuli, we investigated the effective amygdala-insula interactions and the modulatory effect of the input arousal on the effective connections. Specifically, the predicted dynamic arousal of the movie served as regressors in general linear model (GLM) analysis and brain activations were identified accordingly. The regions of interest (i.e., the bilateral amygdala and insula) were localized according to the GLM activation map. The effective connectivity and modulatory effect were then inferred by using dynamic causal modeling (DCM). Our experimental results demonstrated that amygdala was the site of driving arousal input and arousal had a modulatory effect on the reciprocal connections between amygdala and insula. Our study provides novel evidence to the underlying neural mechanisms of arousal in a dynamical naturalistic setting.

The role of the oxytocin system in the resilience of patients with breast cancer

Breast cancer is a grave traumatic experience that can profoundly compromise patients' psychological resilience, impacting their overall quality of life. The oxytocin system represents one of the essential neurobiological bases of psychological resilience and plays a critical role in regulating resilience in response to social or traumatic events during adulthood. Oxytocin, through its direct interaction with peripheral or central oxytocin receptors, has been found to have a significant impact on regulating social behavior. However, the precise mechanism by which the activation of peripheral oxytocin receptors leads to improved social is still not completely comprehended and requires additional research. Its activation can modulate psychological resilience by influencing estrogen and its receptors, the hypothalamic-pituitary-adrenal axis, thyroid function, 5-hydroxytryptamine metabolism levels, and arginine pressure release in breast cancer patients. Various interventions, including psychotherapy and behavioral measures, have been employed to improve the psychological resilience of breast cancer patients. The potential effectiveness of such interventions may be underpinned by their ability to modulate oxytocin release levels. This review provides an overview of the oxytocin system and resilience in breast cancer patients and identifies possible future research directions and interventions.

Reduced eye gaze during facial emotion recognition in chronic depression: Effects of intranasal oxytocin

Chronic depression disorders (CDD) are characterized by impaired social cognitive functioning. Visual attention during social perception is altered in clinical depression and is known to be sensitive to intranasal treatment with oxytocin (OT). The present study thus investigated potential alterations in gaze preferences during a standardized facial emotion recognition (FER) task using remote eye tracking in patients with CDD and the effect of a single dose of intranasal OT (compared to placebo). In emotion recognition, CDD patients were not more impaired than healthy controls, and there was no OT effect. However, CDD patients (with placebo) demonstrated less attentional preference for the eye region during FER than healthy controls, which was not apparent in the CDD group after OT treatment. Our results suggest that despite largely preserved basic facial emotions recognition, attention in social perception may be altered in CDD, and that this bias may be sensitive to OT treatment. These findings highlight OTs potential as a means of augmenting psychotherapy.

Intranasal Peptide Therapeutics: A Promising Avenue for Overcoming the Challenges of Traditional CNS Drug Development

The central nervous system (CNS) has, among all organ systems in the human body, the highest failure rate of traditional small-molecule drug development, ranging from 80-100% depending on the area of disease research. This has led to widespread abandonment by the pharmaceutical industry of research and development for CNS disorders, despite increased diagnoses of neurodegenerative disorders and the continued lack of adequate treatment options for brain injuries, stroke, neurodevelopmental disorders, and neuropsychiatric illness. However, new approaches, concurrent with the development of sophisticated bioinformatic and genomic tools, are being used to explore peptide-based therapeutics to manipulate endogenous pathways and targets, including "undruggable" intracellular protein-protein interactions (PPIs). The development of peptide-based therapeutics was previously rejected due to systemic off-target effects and poor bioavailability arising from traditional oral and systemic delivery methods. However, targeted nose-to-brain, or intranasal (IN), approaches have begun to emerge that allow CNS-specific delivery of therapeutics via the trigeminal and olfactory nerve pathways, laying the foundation for improved alternatives to systemic drug delivery. Here we review a dozen promising IN peptide therapeutics in preclinical and clinical development for neurodegenerative (Alzheimer's, Parkinson's), neuropsychiatric (depression, PTSD, schizophrenia), and neurodevelopmental disorders (autism), with insulin, NAP (davunetide), IGF-1, PACAP, NPY, oxytocin, and GLP-1 agonists prominent among them.

The basolateral amygdala to posterior insular cortex tract is necessary for social interaction with stressed juvenile rats

Vocalizations, chemosignals, and behaviors are influenced by one's internal affective state and are used by others to shape social behaviors. A network of interconnected brain structures, often called the social behavior network or social decision-making network, integrates these stimuli and coordinates social behaviors, and in-network connectivity deficits underlie several psychiatric disorders such as schizophrenia and autism spectrum disorders. Here, we investigated the role of the basolateral amygdala (BLA) and its projections to the posterior insular cortex, regions independently implicated in a range of sociocognitive processes, in a social affective preference (SAP) test. Viral vectors containing the gene coding for inhibitory chemogenetic receptors (AAV5-hSyn-hM4Di-mCherry) were injected into the BLA. SAP tests, which allow for the observation of unconditioned behavioral responses to the affective states of others, were conducted after inhibition of the BLA by systemic administration of the hM4Di agonist clozapine-n-oxide (CNO), or inhibition of BLA-insula terminals by direct infusion of CNO to the insula. After vehicle infusions, rats displayed preference for interactions with stressed juvenile conspecifics. However, CNO treatment eliminated preference behavior. The current results suggest that social decision making involves the transfer of emotional information from the BLA to the insula which represents a previously unrecognized anatomical substrate for social cognition.

Association between salivary oxytocin levels and the amygdala and hippocampal volumes

Salivary oxytocin levels have been widely measured and studied in relation to social behavior because of procedural simplicity and noninvasiveness. Although the relationship between oxytocin levels in the blood and the hippocampus and amygdala is now becoming clear with reliable blood oxytocin studies, few studies have examined the relationship between salivary oxytocin and the brain function and structure. This study aimed to investigate whether the salivary oxytocin level is associated with the volume of the amygdala and hippocampus in 178 adults (92 women and 86 men) in their third to seventh decade of life. We performed volumetric analysis of the amygdala and hippocampus using FreeSurfer and measured salivary oxytocin levels using enzyme-linked immunosorbent assay. The results showed contradictory effects of the salivary oxytocin level on the amygdala volume by sex and no significant effect on the hippocampal volume. Specifically, men showed a positive correlation between the salivary oxytocin level and amygdala volume, whereas women showed a negative correlation between the salivary oxytocin level and amygdala volume. The present study's finding of sex differences in the association between salivary oxytocin and brain structure supports previous findings that there are sex differences in the oxytocin system.

Oxytocin: An Old Hormone, A Novel Psychotropic Drug And Possible Use In Treating Psychiatric Disorders

BACKGROUND

Oxytocin is a nonapeptide synthesized in the paraventricular and supraoptic nuclei of the hypothalamus. Historically, this molecule has been involved as a key factor in the formation of infant attachment, maternal behavior and pair bonding and, more generally, in linking social signals with cognition, behaviors and reward. In the last decades, the whole oxytocin system has gained a growing interest as it was proposed to be implicated in etiopathogenesis of several neurodevelopmental and neuropsychiatric disorders.

METHODS

With the main goal of an in-depth understanding of the oxytocin role in the regulation of different functions and complex behaviors as well as its intriguing implications in different neuropsychiatric disorders, we performed a critical review of the current state of art. We carried out this work through PubMed database up to June 2021 with the search terms: 1) "oxytocin and neuropsychiatric disorders"; 2) "oxytocin and neurodevelopmental disorders"; 3) "oxytocin and anorexia"; 4) "oxytocin and eating disorders"; 5) "oxytocin and obsessive-compulsive disorder"; 6) "oxytocin and schizophrenia"; 7) "oxytocin and depression"; 8) "oxytocin and bipolar disorder"; 9) "oxytocin and psychosis"; 10) "oxytocin and anxiety"; 11) "oxytocin and personality disorder"; 12) "oxytocin and PTSD".

RESULTS

Biological, genetic, and epigenetic studies highlighted quality and quantity modifications in the expression of oxytocin peptide or in oxytocin receptor isoforms. These alterations would seem to be correlated with a higher risk of presenting several neuropsychiatric disorders belonging to different psychopathological spectra. Collaterally, the exogenous oxytocin administration has shown to ameliorate many neuropsychiatric clinical conditions.

CONCLUSION

Finally, we briefly analyzed the potential pharmacological use of oxytocin in patient with severe symptomatic SARS-CoV-2 infection due to its anti-inflammatory, anti-oxidative and immunoregulatory properties.

Oxytocin Enhances Basolateral Amygdala Activation and Functional Connectivity While Processing Emotional Faces: Preliminary Findings in Autistic Versus Non-Autistic Women

Oxytocin is hypothesized to promote social interactions by enhancing the salience of social stimuli. While previous neuroimaging studies have reported that oxytocin enhances amygdala activation to face stimuli in autistic men, effects in autistic women remain unclear. In this study, the influence of intranasal oxytocin on activation and functional connectivity of the basolateral amygdala—the brain’s ‘salience detector’—while processing emotional faces vs shapes was tested in 16 autistic and 21 non-autistic women by functional magnetic resonance imaging in a placebo-controlled, within-subject, cross-over design. In the placebo condition, minimal activation differences were observed between autistic and non-autistic women. However, significant drug × group interactions were observed for both basolateral amygdala activation and functional connectivity. Oxytocin increased left basolateral amygdala activation among autistic women (35-voxel cluster, Montreal Neurological Institute (MNI) coordinates of peak voxel = −22 −10 −28; mean change = +0.079%, t = 3.159, P_Tukey = 0.0166) but not among non-autistic women (mean change = +0.003%, t = 0.153, P_Tukey = 0.999). Furthermore, oxytocin increased functional connectivity of the right basolateral amygdala with brain regions associated with socio-emotional information processing in autistic women, but not in non-autistic women, attenuating group differences in the placebo condition. Taken together, these findings extend evidence of oxytocin’s effects on the amygdala to specifically include autistic women and specify the subregion of the effect.

Low oxytocin levels are broadly associated with more pronounced psychopathology in anorexia nervosa with primarily restricting but not binge/purge eating behavior

OBJECTIVE

Anorexia nervosa (AN) is commonly associated with depression, anxiety, and deficits in socioemotional functioning. Basal levels of oxytocin, a neurohormone with antidepressant, anxiolytic, and prosocial properties, are low in women with AN. However, the relationship between oxytocin and psychopathology of AN/atypical AN has not been examined in individuals with primarily food restriction (AN/AtypAN-R) or those with restriction plus binge/purge behaviors (AN/AtypAN-BP) alone, which is important to further elucidate the neurobiology of different AN presentations. We investigated whether oxytocin levels are related to eating, affective, and socioemotional psychopathology in women with AN/AtypAN-R and separately AN/AtypAN-BP.

METHODS

In a cross-sectional study of 53 women with low-weight AN or atypical AN based on DSM-5 (AN/AtypAN-R: n=21, AN/AtypAN-BP: n=32), we obtained fasting serum oxytocin levels and self-report measures of psychopathology, including the Eating Disorder Examination-Questionnaire (EDE-Q), Beck Depression Inventory-IA (BDI), State-Trait Anxiety Inventory (STAI), and Toronto Alexithymia Scale (TAS-20).

RESULTS

In individuals with AN/AtypAN-R, oxytocin levels were negatively associated with eating psychopathology (EDE-Q Global Score: r=-0.49, p=0.024), depressive and anxiety symptoms (BDI Total Score: r=-0.55, p=0.009; STAI Trait Score: r=-0.63, p=0.002), and socioemotional symptoms (TAS-20 Difficulty Identifying Feelings Score: r=-0.49, p=0.023). In contrast, in those with AN/AtypAN-BP oxytocin levels were negatively associated with depressive symptoms only (BDI Total Score: r=-0.52, p=0.049).

CONCLUSIONS

These findings support the notion that AN/AtypAN-R and AN/AtypAN-BP might have divergent underlying neurobiology. Understanding these differences is crucial to develop targeted treatments for a population with high levels of chronicity, for which no specific pharmacological treatments are currently available.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov, identifier: NCT01121211.

Oxytocin effects on the cognition of women with postpartum depression: A randomized, placebo-controlled clinical trial

BACKGROUND

One of the most common mental disorders in the perinatal period is postpartum depression (PPD), which is associated with impaired emotional functioning due to alterations in different cognitive aspects including thought and facial emotion recognition (FER). Emotional impairments may affect the interaction and care offered to infants and their later development and therefore interventions with potential to minimize impairments associated with PPD are opportune. Oxytocin (OXT) was shown to have therapeutic properties associated with the promotion of affiliative and pro-social behaviors in different mental disorders. Few studies have assessed its therapeutic potential in PPD.

OBJECTIVES

To assess the effects of the acute administration of intranasal OXT (24 IU) on FER of baby faces and negative thoughts after delivery in mothers with and without PPD.

METHODS

We conducted a randomized double-blind, placebo-controlled trial with a crossover design involving mothers with PPD (N = 20) and without PPD (N = 35) in the puerperium. Participants completed a static task of FER of baby faces and a questionnaire of post-natal negative thoughts.

RESULTS

Mothers with PPD had increased scores of negative thoughts about motherhood/infants, but no impairments in FER, when compared to healthy mothers. OXT had no effects on the rates of correct judgments or response times in the FER task, but was associated with response biases to facial happiness and the reduction of negative thoughts in mothers with PPD.

DISCUSSION/CONCLUSION

OXT may have positive effects on maternal affiliative behavior, maternal care, and mother-infant interactions as suggested by changes found in different cognitive aspects, thus minimizing the deleterious effects of PPD on child development.

A Systematic Review of the Role of Oxytocin, Cortisol, and Testosterone in Facial Emotional Processing

A topic of interest is the way decoding and interpreting facial emotional expressions can lead to mutual understanding. Facial emotional expression is a basic source of information that guarantees the functioning of other higher cognitive processes (e.g., empathy, cooperativity, prosociality, or decision-making, among others). In this regard, hormones such as oxytocin, cortisol, and/or testosterone have been found to be important in modifying facial emotion processing. In fact, brain structures that participate in facial emotion processing have been shown to be rich in receptors for these hormones. Nonetheless, much of this research has been based on correlational designs. In recent years, a growing number of researchers have tried to carry out controlled laboratory manipulation of these hormones by administering synthetic forms of these hormones. The main objective of this study was to carry out a systematic review of studies that assess whether manipulation of these three hormones effectively promotes significant alterations in facial emotional processing. To carry out this review, PRISMA quality criteria for reviews were followed, using the following digital databases: PsycINFO, PubMed, Dialnet, Psicodoc, Web of Knowledge, and the Cochrane Library, and focusing on manuscripts with a robust research design (e.g., randomized, single- or double-blind, and/or placebo-controlled) to increase the value of this systematic review. An initial identification of 6340 abstracts and retrieval of 910 full texts led to the final inclusion of 101 papers that met all the inclusion criteria. Only about 18% of the manuscripts included reported a direct effect of hormone manipulation. In fact, emotional accuracy seemed to be enhanced after oxytocin increases, but it diminished when cortisol and/or testosterone increased. Nonetheless, when emotional valence and participants' gender were included, hormonal manipulation reached significance (in around 53% of the articles). In fact, these studies offered a heterogeneous pattern in the way these hormones altered speed processing, attention, and memory. This study reinforces the idea that these hormones are important, but not the main modulators of facial emotion processing. As our comprehension of hormonal effects on emotional processing improves, the potential to design good treatments to improve this ability will be greater.

Effects of intranasal oxytocin on threat- and reward-related functional connectivity in men and women with and without childhood abuse-related PTSD

Novel treatments that target neurobiological alterations associated with childhood trauma, particularly among those with posttraumatic stress disorder (PTSD), could mitigate negative outcomes for these at-risk individuals. PTSD is characterized by abnormalities within the brain's salience network and reward circuitry, which are modulated by intranasal oxytocin. Using a double-blind, randomized, placebo-controlled crossover design, we tested whether intranasal oxytocin (24 international units) influenced functional coupling of the amygdala with the anterior insula (AI), dorsal anterior cingulate cortex, and nucleus accumbens in response to implicitly presented fearful, angry, and happy faces among childhood trauma-exposed individuals with (n = 16, 9 women) and without PTSD (n = 18, 12 women). Psychophysiological interaction analyses revealed that oxytocin effects were limited to amygdala-AI connectivity in the fear condition, distinct for men and women, and not impacted by PTSD diagnosis. In response to fear faces, oxytocin reduced left amygdala-left AI connectivity for women but not men; reduced left amygdala-right AI connectivity among women, but increased this connectivity in men; and reduced right amygdala-right anterior insula connectivity for men, but increased it for women. Results suggest that intranasal oxytocin modulates threat salience among childhood trauma-exposed individuals and that these effects vary as a function of gender and hemisphere.

Oxytocin and Fear Memory Extinction: Possible Implications for the Therapy of Fear Disorders?

Several psychiatric conditions such as phobias, generalized anxiety, and post-traumatic stress disorder (PTSD) are characterized by pathological fear and anxiety. The main therapeutic approach used in the management of these disorders is exposure-based therapy, which is conceptually based upon fear extinction with the formation of a new safe memory association, allowing the reduction in behavioral conditioned fear responses. Nevertheless, this approach is only partially resolutive, since many patients have difficulty following the demanding and long process, and relapses are frequently observed over time. One strategy to improve the efficacy of the cognitive therapy is the combination with pharmacological agents. Therefore, the identification of compounds able to strengthen the formation and persistence of the inhibitory associations is a key goal. Recently, growing interest has been aroused by the neuropeptide oxytocin (OXT), which has been shown to have anxiolytic effects. Furthermore, OXT receptors and binding sites have been found in the critical brain structures involved in fear extinction. In this review, the recent literature addressing the complex effects of OXT on fear extinction at preclinical and clinical levels is discussed. These studies suggest that the OXT roles in fear behavior are due to its local effects in several brain regions, most notably, distinct amygdaloid regions.

HIV-1 Tat and morphine decrease murine inter-male social interactions and associated oxytocin levels in the prefrontal cortex, amygdala, and hypothalamic paraventricular nucleus

Many persons infected with HIV-1 (PWH) and opioid-dependent individuals experience deficits in sociability that interfere with daily living. Sociability is regulated by the prefrontal cortico-hippocampal-amygdalar circuit. Within this circuit HIV-1 trans-activator of transcription (HIV-1 Tat) and opioids can increase dendritic pathology and alter neuronal firing. Changes in sociability are also associated with dysregulation of hypothalamic neuropeptides such as oxytocin or corticotropin releasing factor (CRF) in the prefrontal cortico-hippocampal-amygdalar circuit. Accordingly, we hypothesized that the interaction of HIV-1 Tat and morphine would impair inter-male social interactions and disrupt oxytocin and CRF within the PFC and associated circuitry. Male mice were exposed to HIV-1 Tat for 8 weeks and administered saline or escalating doses of morphine twice daily (s.c.) during the last 2 weeks of HIV-1 Tat exposure. Tat attenuated aggressive interactions with an unknown intruder, whereas morphine decreased both non-aggressive and aggressive social interactions in the resident-intruder test. However, there was no effect of Tat or morphine on non-reciprocal interactions in the social interaction and novelty tests. Tat, but not morphine, decreased oxytocin levels in the PFC and amygdala, whereas both Tat and morphine decreased the percentage of oxytocin-immunoreactive neurons in the hypothalamic paraventricular nucleus (PVN). In Tat(+) or morphine-exposed mice, regional levels of CRF and oxytocin correlated with alterations in behavior in the social interaction and novelty tests. Overall, decreased expression of oxytocin in the prefrontal cortico-hippocampal-amygdalar circuit is associated with morphine- and HIV-Tat-induced deficits in social behavior.

Out-of-step: brain-heart desynchronization in anxiety disorders

Imaging studies in anxiety disorders (AD) show abnormal functional connectivity primarily in the salience network (SN), somatomotor network (SMN), and default mode network (DMN). However, it is not clear how precisely these network changes occur including their relation to psychopathological symptoms. Here, we show that the functional networks affected in AD overlap with cortical regions that receive visceral inputs (the so-called central/visceral autonomic network). Focusing on cardiac afferents, we suggest that network changes in AD may be due to reduced phase synchronization between ongoing neural and cardiac activity. This neuro-cardiac desynchronization occurs due to the abnormal phase resetting of neural activity at the onset of each heartbeat, as measured by a lower intertrial coherence and heartbeat-evoked potential. Biochemically, cardiac afferents reach subcortical serotonergic raphe nuclei and noradrenergic locus coeruleus (among others) which, in turn, are known to reciprocally modulate the DMN and SMN/SN on the cortical level. Consistent with the network changes in AD, decreases in serotonergic and noradrenergic activity are known to increase connectivity in both SMN and SN while, at the same time, they decrease DMN connectivity. SMN and SN increases, in turn, lead to increased emotional arousal/anxiety and bodily awareness whereas decreased DMN connectivity leads to an unstable sense-of-self in AD. Finally, we integrate our proposal with interoceptive predictive processing models suggesting neuro-cardiac desynchronization as a mechanism for "noisy" bottom-up information leading to a persistently uncertain bodily state in top-down models. In sum, integrating theories on active interference and hyperarousal, we propose a precise neuro-cardiac and biochemically -driven mechanisms for key psychopathological symptoms of AD.

Pharmacotherapy of Anxiety Disorders: Current and Emerging Treatment Options

(Appeared originally in Frontiers in Psychiatry 2020 Dec 23; 11:595584)

Outcome Value and Task Aversiveness Impact Task Procrastination through Separate Neural Pathways

The temporal decision model of procrastination has proposed that outcome value and task aversiveness are two separate aspects accounting for procrastination. If true, the human brain is likely to implicate separate neural pathways to mediate the effect of outcome value and task aversiveness on procrastination. Outcome value is plausibly constructed via a hippocampus-based pathway because of the hippocampus's unique role in episodic prospection. In contrast, task aversiveness might be represented through an amygdala-involved pathway. In the current study, participants underwent fMRI scanning when viewing both tasks and future outcomes, without any experimental instruction imposed. The results revealed that outcome value increased activations in the caudate, and suppressed procrastination through a hippocampus-caudate pathway. In contrast, task aversiveness increased activations in the anterior insula, and increased procrastination via an amygdala-insula pathway. In sum, this study demonstrates that people can incorporate both outcome value and task aversiveness into task valuation to decide whether to procrastinate or not; and it elucidates the separate neural pathways via which this occurs.

Relationship between oxytocin and serotonin and the fearfulness, dominance, and trainability of horses

Oxytocin (OXT) and serotonin (5-HT) are essential neurotransmitters associated with the behavior of animals. Recently, we found that the plasma concentration of OXT is positively correlated with horse docility and friendliness toward humans. However, the relationships between the neurotransmitters and other temperaments such as fearfulness, dominance, and trainability are unknown. This study aimed to identify whether the plasma concentration of OXT or 5-HT is correlated with fearfulness, dominance, and trainability of horses. Blood samples of 34 horses were collected at the Horse Industry Complex Center of Jeonju Kijeon College. The concentration of OXT and 5-HT was measured in the plasma samples using enzyme-linked immunosorbent assays. The fearfulness, dominance, and trainability of horses were scored by three professors who were very familiar with the horses. One-way analysis of variance with the least significant difference post-hoc analysis was used to compare the scores for fearfulness and dominance among groups. The trainability of horses was compared using the student t-test. The 5-HT was negatively correlated with dominance, but it had no relation with fearfulness. The OXT appeared to be negatively correlated with fearfulness and dominance in horses. Furthermore, OXT was positively correlated with the trainability of horses. Additionally, 5-HT appeared to enhance trainability. In conclusion, the concentration of OXT or 5-HT in horse blood plasma can be used as a biomarker to monitor the fearfulness, dominance, or trainability of horses.

Intranasal oxytocin decreases fear generalization in males, but does not modulate discrimination threshold

BACKGROUND

A previously acquired fear response often spreads to perceptually or conceptually close stimuli or contexts. This process, known as fear generalization, facilitates the avoidance of danger, and dysregulations in this process play an important role in anxiety disorders. Oxytocin (OT) has been shown to modulate fear learning, yet effects on fear generalization remain unknown.

METHODS

We employed a randomized, placebo-controlled, double-blind, between-subject design during which healthy male participants received either intranasal OT or placebo (PLC) following fear acquisition and before fear generalization with concomitant acquisition of skin conductance responses (SCRs). Twenty-four to 72 h before the fear learning and immediately after the fear generalization task, participants additionally complete a discrimination threshold task.

RESULTS

Relative to PLC, OT significantly reduced perceived risk and SCRs towards the CS+ and GS1 (the generalization stimulus that is most similar to CS+) during fear generalization, whereas the discrimination threshold was not affected.

CONCLUSIONS

Together, the results suggest that OT can attenuate fear generalization in the absence of effects on discrimination threshold. This study provides the first evidence for effects of OT on fear generalization in humans and suggests that OT may have therapeutic potential in anxiety disorders characterized by dysregulated fear generalization.

The hypothalamus in anxiety disorders

Of all mental disorders, anxiety disorders are currently the strongest contributors to the global burden of disease, with 7.3% of the general population affected worldwide. The hypothalamus is crucial hub of a network of neural structures modulating fear conditioning and extinction and, as such, highly relevant to the pathophysiology of these conditions. Three hypothalamic systems have emerged as particularly relevant in this context. First, the oxytocin system is highly likely to be involved anxiety disorders and in particular in the cognitive and behavioral deficits pertaining to social anxiety disorder. Second, peripheral markers of the hypothalamic-pituitary-adrenal axis appear altered in patients with panic disorder and generalized anxiety disorder, which may denote aberrant functioning of their central corticotropin-releasing hormone system. Furthermore, cortisol seems to augment the effects of exposure therapy in patients with specific phobia. Third, the integrity of the hypothalamic-pituitary-thyroid axis is likely compromised in panic disorder. Further, cross-disciplinary research efforts are required to shed more light on how, exactly, these hypothalamic systems interact with the neural structures involved in fear conditioning and extinction, which should ultimately open up new avenues for the prevention and treatment of anxiety disorders.

Intranasal oxytocin attenuates insula activity in response to dynamic angry faces

The effects of intranasal oxytocin on amygdala activity during emotional perception are often mixed. Given that the brain is organized into networks of interconnected areas, functional connectivity might provide an effective way to further understand the oxytocin effect. The aim of the present study was to investigate whether oxytocin administration affects amygdala activity and its functional connectivity during dynamic facial expression perception. Using a between-group, double-blind, placebo-controlled design, 55 participants were randomly assigned to groups receiving a single dose of 24 IU oxytocin or a placebo via intranasal administration. An implicit emotional task was employed to investigate the effect of oxytocin on neural responses to dynamic angry, neutral, and happy facial expressions with fMRI. Participants were instructed to respond only when the inverted dynamic faces were presented. The results indicated that oxytocin attenuated activation of insula and emotional processing-related regions (e.g., ACC, thalamus, and MFG) during the viewing of dynamic angry faces. However, functional connectivity between the regions involved in the perception of dynamic angry faces was not changed following oxytocin administration. The present findings may contribute to our understanding of the anxiolytic effects of oxytocin and eventually facilitate human clinical applications.

Molecular and neurocircuitry mechanisms of social avoidance

Humans and animals live in social relationships shaped by actions of approach and avoidance. Both are crucial for normal physical and mental development, survival, and well-being. Active withdrawal from social interaction is often induced by the perception of threat or unpleasant social experience and relies on adaptive mechanisms within neuronal networks associated with social behavior. In case of confrontation with overly strong or persistent stressors and/or dispositions of the affected individual, maladaptive processes in the neuronal circuitries and its associated transmitters and modulators lead to pathological social avoidance. This review focuses on active, fear-driven social avoidance, affected circuits within the mesocorticolimbic system and associated regions and a selection of molecular modulators that promise translational potential. A comprehensive review of human research in this field is followed by a reflection on animal studies that offer a broader and often more detailed range of analytical methodologies. Finally, we take a critical look at challenges that could be addressed in future translational research on fear-driven social avoidance.

Childhood emotional neglect and oxytocin receptor variants: Association with limbic brain volumes

Objectives: Childhood emotional neglect (EN) is a predictor for the development of affective disorders. Oxytocin (OXT) may mediate the interplay between EN and changes in stress biological systems, brain development, and mental health outcomes. We investigated, in a cross-sectional study, the associations between EN, (epi)genetic variation in the OXT receptor (OXTR) gene, and amygdalar and hippocampal volumes, two brain regions implicated in emotional processing.Methods: We recruited 63 Caucasian South African adults (35 women) with and without social anxiety disorder. Childhood EN was assessed using the Childhood Trauma Questionnaire. rs53576 and rs2254298 genotypes, as well as methylation status, was determined using DNA purified from whole blood. Bilateral amygdalar and hippocampal volumes were determined by structural magnetic resonance imaging. The relationships between these variables were investigated using linear regression.Results: The interaction of the rs2254298 A risk allele and EN was nominally associated with reduced left hippocampal volume. The rs2254298 A risk allele was independently associated with reduced bilateral amygdalar volumes. We found no association between EN, OXTR methylation and amygdalar or hippocampal volumes. The rs53576 GG risk genotype was, however, associated with decreased OXTR methylation.Conclusions: The rs2254298 A allele may increase susceptibility to the structural brain effects of EN.

Oxytocin modulates the effective connectivity between the precuneus and the dorsolateral prefrontal cortex

Our social activity is heavily influenced by the process of introspection, with emerging research suggesting a role for the Default Mode Network (DMN) in social cognition. We hypothesize that oxytocin, a neuropeptide with an important role in social behaviour, can effectively alter the connectivity of the DMN. We test this hypothesis using a randomized, double-blind, crossover, placebo-controlled trial where 15 healthy male participants received 24 IU oxytocin or placebo prior to a resting-state functional MRI scan. We used Granger Causality Analysis for the first time to probe the role of oxytocin on brain networks and found that oxytocin reverses the pattern of effective connectivity between the bilateral precuneus and the left dorsolateral prefrontal cortex (dlPFC), a key central executive network (CEN) region. Under placebo, the bilateral precuneus exerted a significant negative causal influence on the left dlPFC and the left dlPFC exerted a significant positive causal influence on the bilateral precuneus. However, under oxytocin, these patterns were reversed, i.e. positive causal influence from the bilateral precuneus to the left dlPFC and negative causal influence from the left dlPFC to the bilateral precuneus (with statistically significant effects for the right precuneus). We propose that these oxytocin-induced effects could be a mechanistic process by which it modulates social cognition. These results provide a measurable target for the physiological effects of oxytocin in the brain and offer oxytocin as a potential agent to enhance the cooperative role of the predominantly 'task-inactive' 'default mode' brain regions in both healthy and patient populations.

Oral oxytocin delivery with proton pump inhibitor pretreatment decreases food intake

Oxytocin (Oxt) is considered as a potential agent to treat multiple neuropsychiatric disorders, obesity and metabolic syndrome. Although the mechanisms underlying these effects remain unclear, nasal administration is considered to be a potential way to deliver Oxt into blood vessels. The development of an easier, more stable and efficient way is expected. A recent study demonstrated that orally administered Oxt can be transmitted into blood if it is prevented from degradation in stomach and reaches the intestinal tract. In this study, we pretreated mice with a proton pump inhibitor (PPI), omeprazole (20 mg/kg), and administered capsulized Oxt (0.25 mg), so that the Oxt can be prevented from degradation by pepsin due to the low pH in stomach and reach the intestinal tract. Functionally, these mice showed a similar decrease in food intake to those who underwent intraperitoneal administration. We also confirmed that this method dramatically increased plasma Oxt levels and the expression of neural activation marker c-Fos protein in the paraventricular and suprachiasmatic nucleus. Our study showed that by pretreating mice with PPI, Oxt in a gelatin-coated capsule can prevent Oxt from degradation by pepsin in stomach, and reach the bloodstream in an effective concentration. These results indicate that our method is a promising oral delivery of Oxt and should be investigated further for other peptide agents based on peripheral injection or nasal administration.

Acute effects of oxytocin in music performance anxiety: a crossover, randomized, placebo-controlled trial

RATIONALE

Individuals with music performance anxiety (MPA) present physical, behavioral, and cognitive manifestations of anxiety, in addition to information processing deficits, especially in facial emotion recognition (FER).

OBJECTIVES

To assess the effects of a single dose of intranasal oxytocin (24 IU) on FER in a sample of musicians with high and low MPA (primary outcome), as well as indicators of mood/anxiety and self-assessed performance (secondary outcomes).

METHODS

Crossover, randomized, double-blind, placebo-controlled trial involving 43 male musicians with different levels of MPA. Participants completed a static facial emotion recognition task and self-rated mood and performance scales. Data were analyzed using ANOVA 2 × 0 for crossover trials and the Omnibus test (measure of separability between intervention and carryover effects).

RESULTS

Only musicians with high MPA treated with oxytocin had a higher accuracy in the recognition of happiness (p < 0.03; d > 0.72). No effects of oxytocin were found on mood indicators or on self-perceived performance, regardless of MPA level.

CONCLUSIONS

The results indicate possible benefits of the acute treatment with oxytocin in MPA, which may improve the management of this common and disabling condition that affects professional musicians. The appropriate perception of positive feedback may increase confidence and feelings of social acceptance, reducing symptoms associated with the condition. The lack of effects on mood/anxiety and cognition may be explained by the context-dependent characteristic of the effects of oxytocin, since the experiment did not represent an actual situation of social threat.

TRIAL REGISTRATION

Brazilian Clinical Trials Registry (Registro Brasileiro de Ensaios Clínicos): No. RBR-9cph2q.

Positive Maternal Mental Health, Parenting, and Child Development

While maternal mental health is an important influence on child development, the existing literature focuses primarily on negative aspects of maternal mental health, particularly symptoms of depression, anxiety, or states of distress. We provide a review of the evidence on the potential importance of positive mental health for both mother and child. The evidence suggests that positive mental health is a distinct construct that is associated with improved birth outcomes and potentially with specific forms of parenting that promote both academic achievement and socioemotional function. We review studies that provide a plausible biological basis for the link between positive mental health and parenting, focusing on oxytocin-dopamine interactions. We caution that the evidence is largely preliminary and suggest directions for future research, noting the importance of identifying the operative dimensions of positive maternal mental health in relation to specific outcomes. We suggest that the inclusion of positive maternal mental health provides the potential for a more comprehensive understanding of parental influences on child development.

Early Signs of Emotional Recognition Deficits in Adolescent High-Binge Drinkers

Background: Emotional dysregulation, measured with face recognition tasks, is prevalent in alcohol use disorders (AUD), constituting a risk factor for alcohol use and relapse. It is not clear however whether emotional dysregulation is a by-product of alcohol consumption, or if it can act as a predisposing factor for AUD. Objective: Our aim was to examine early signs of emotional dysregulation in adolescent drinkers. Method: Twenty-four high-school students and 24 university students completed two tasks. On the first one, participants had to gradually increment the emotional content of different faces until they could perceive an emotional expression (emotion perception threshold task). We also examined the propensity to perceive fearful expressions in an emotion identification task. Participants were semantically primed with emotion words (i.e., "fear"), and they then had to indicate whether a neutral-fearful facial composite matched the prime. Results: Using repeated-measures ANOVAS, in the emotion perception threshold task, "happy" faces were the easiest to detect and "sad" ones the hardest. For high school students there was a differential response pattern depending on binge scores, such that High-binge drinkers found it easier to detect a sad face but harder to detect a happy one compared to Low-binge drinkers. In the facial emotion identification task, Low-binge drinkers observed more fearful expressions compared to High-binge drinkers. Conclusions: Differences in emotional processing in young adolescents depending on drinking habits point towards the relevance of emotional dysregulation as an early sign of AUD. These findings could help develop novel diagnostic and treatment tools for young populations.

The Role of the Oxytocin System in Anxiety Disorders

Oxytocin, a neuropeptide synthesized by the hypothalamus, plays a central role in human social behavior, social cognition, anxiety, mood, stress modulation, and fear learning and extinction. The relationships between oxytocin and psychiatric disorders including depression, anxiety, schizophrenia, and autism spectrum disorder have been extensively studied. In this chapter, we focus on the current knowledge about oxytocin and anxiety disorder. We discuss the anxiolytic effects of oxytocin in preclinical and clinical findings, possible related neurobehavioral mechanisms (social cognition, fear learning, and extinction), related neurotransmitter and neuroendocrine systems (hypothalamus-pituitary-adrenal axis, serotoninergic, and GABAergic systems), and studies regarding plasma levels of oxytocin, genetic and epigenetic findings, and effects of intranasal oxytocin in DSM-5 anxiety disorder (primarily social anxiety disorder and separation anxiety disorder) patients.

Pharmacotherapy of Anxiety Disorders: Current and Emerging Treatment Options

Anxiety disorders are the most prevalent psychiatric disorders and a leading cause of disability. While there continues to be expansive research in posttraumatic stress disorder (PTSD), depression and schizophrenia, there is a relative dearth of novel medications under investigation for anxiety disorders. This review's first aim is to summarize current pharmacological treatments (both approved and off-label) for panic disorder (PD), generalized anxiety disorder (GAD), social anxiety disorder (SAD), and specific phobias (SP), including selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), azapirones (e.g., buspirone), mixed antidepressants (e.g., mirtazapine), antipsychotics, antihistamines (e.g., hydroxyzine), alpha- and beta-adrenergic medications (e.g., propranolol, clonidine), and GABAergic medications (benzodiazepines, pregabalin, and gabapentin). Posttraumatic stress disorder and obsessive-compulsive disorder are excluded from this review. Second, we will review novel pharmacotherapeutic agents under investigation for the treatment of anxiety disorders in adults. The pathways and neurotransmitters reviewed include serotonergic agents, glutamate modulators, GABAergic medications, neuropeptides, neurosteroids, alpha- and beta-adrenergic agents, cannabinoids, and natural remedies. The outcome of the review reveals a lack of randomized double-blind placebo- controlled trials for anxiety disorders and few studies comparing novel treatments to existing anxiolytic agents. Although there are some recent randomized controlled trials for novel agents including neuropeptides, glutamatergic agents (such as ketamine and d-cycloserine), and cannabinoids (including cannabidiol) primarily in GAD or SAD, these trials have largely been negative, with only some promise for kava and PH94B (an inhaled neurosteroid). Overall, the progression of current and future psychopharmacology research in anxiety disorders suggests that there needs to be further expansion in research of these novel pathways and larger-scale studies of promising agents with positive results from smaller trials.

Task MRI-Based Functional Brain Network of Anxiety

Magnetic resonance imaging (MRI) is a good tool for researchers to understand the biological mechanisms and pathophysiology of the brain due to the translational characteristics of MRI methods. For the psychiatric illness, this kind of mental disorders usually have minor alterations when compared to traditional neurological disorders. Therefore the functional study, such as functional connectivity, would play a significant role for understanding the pathophysiology of mental disorders. This chapter would focus on the discussion of task MRI-based functional network studies in anxiety. For social anxiety disorder, the limbic system, such as the temporal lobe, amygdala, and hippocampus, would show alterations in the functional connectivity with frontal regions, such as anterior cingulate, prefrontal, and orbitofrontal cortices. PD has anterior cingulate cortex-amygdala alterations in fear conditioning, frontoparietal alterations in attention network task, and limbic-prefrontal alterations in emotional task. A similar amygdala-based aberrant functional connectivity in specific phobia is observed. The mesocorticolimbic and limbic-prefrontal functional alterations are found in generalized anxiety disorder. The major components of task MRI-based functional connectivity in anxiety include limbic and frontal regions which might play a vital role for the origination of anxiety under different scenarios and tasks.

Oxytocin increases eye gaze in schizophrenia

Abnormal eye gaze is common in schizophrenia and linked to functional impairment. The hypothalamic neuropeptide oxytocin modulates visual attention to social stimuli, but its effects on eye gaze in schizophrenia are unknown. We examined visual scanning of faces in men with schizophrenia and neurotypical controls to quantify oxytocin effects on eye gaze. In a randomized, double-blind, crossover study, 33 men with schizophrenia and 39 matched controls received one dose of intranasal oxytocin (40 IU) and placebo on separate testing days. Participants viewed 20 color photographs of faces while their gaze patterns were recorded. We tested for differences in fixation time on the eyes between patients and controls as well as oxytocin effects using linear mixed-effects models. We also tested whether attachment style, symptom severity, and anti-dopaminergic medication dosage moderated oxytocin effects. In the placebo condition, patients showed reduced fixation time on the eyes compared to controls. Oxytocin was associated with an increase in fixation time among patients, but a decrease among controls. Higher attachment anxiety and greater symptom severity predicted increased fixation time on the eyes on oxytocin versus placebo. Anti-dopaminergic medication dosage and attachment avoidance did not impact response to oxytocin. Consistent with findings that oxytocin optimizes processing of social stimuli, intranasal oxytocin enhanced eye gaze in men with schizophrenia. Further work is needed to determine whether changes in eye gaze impact social cognition and functional outcomes. Both attachment anxiety and symptom severity predicted oxytocin response, highlighting the importance of examining potential moderators of oxytocin effects in future studies.

The roles of early-life adversity and rumination in neural response to emotional faces amongst anxious and depressed adults

BACKGROUND

Early-life adversity (ELA) is a risk factor for internalizing psychopathology (IP). ELA is also linked to alterations in neural phenotypes of emotion processing and maladaptive emotion regulatory strategies, such as ruminative brooding, in adulthood. We therefore expected that ELA would predict cortical brain activation to emotional faces in transdiagnostic IP and in turn, mediate the extent of rumination amongst patients with IPs and ELA (IP + ELA).

METHOD

One hundred and thirty-two individuals, including 102 treatment-seeking adults with heterogeneous IPs and 30 healthy controls (HCs) performed an Emotional Face-Matching Task during functional magnetic resonance imaging. Whole-brain analyses compared HC (n = 30), IP (n = 52), and IP + ELA (n = 50) neural responses to emotional (angry, fearful, happy, and sad) faces v. shapes, controlling for depression and anxiety symptoms. Parameter estimates of activation were extracted for significant between-group differences and tested as a mediator of ruminative brooding in IP + ELA.

RESULTS

IP + ELA demonstrated increased activation in the superior frontal gyrus and anterior cingulate cortex (fear), superior parietal lobule, precuneus, posterior cingulate, and inferior temporal gyrus (fear only), and cuneus (fear and angry). These regions were preferentially correlated with ruminative brooding in IP + ELA, many of which mediated the link between IP + ELA and ruminative brooding.

CONCLUSIONS

Results provide evidence that ELA history amongst IP patients augments engagement of brain regions involved in emotion processing, above and beyond what is accounted for by current symptoms. Though longitudinal designs are needed, alterations in the neural correlates of maladaptive processing of socio-emotional information may be a common pathway by which ELA poses risk for psychopathology.

Oxytocin and Stress: Neural Mechanisms, Stress-Related Disorders, and Therapeutic Approaches

Clinical reports show that oxytocin (OT) is related to stress-related disorders such as depression, anxiety disorder, and post-traumatic stress disorder. Two key structures in the brain should be paid special attention with regard to stress regulation, namely, the hypothalamus and the hippocampus. The former is the region for central command for most, if not all, of the major endocrine systems, and the latter takes a key position in the regulation of mood and anxiety. There are extensive neural projections between the two structures, and both are functionally intertwined. The hypothalamus projects OTergic neurons to the hippocampus, and the latter possesses high levels of OT receptors. The hippocampus also regulates the secretion of glucocorticoids, a major group of stress hormones. Excessive levels of glucocorticoids in chronic stress cause atrophy of the hippocampus, whereas OT has been shown to protect hippocampal neurons from the toxic effects of glucocorticoids. In this article, we discuss how neural and endocrine mechanisms interplay in stress regulation, with an emphasis on the role of OT, as well as its therapeutic potential in the treatment of stress-related disorders.

What drives prioritized visual processing? A motivational relevance account

Emotion is fundamental to our being, and an essential aspect guiding behavior when rapid responding is required. This includes whether we approach or avoid a stimulus, and the accompanying physiological responses. A common tenet is that threat-related content drives stimulus processing and biases visual attention, so that rapid responding can be initiated. In this paper, it will be argued instead that prioritization of threatening stimuli should be encompassed within a motivational relevance framework. To more fully understand what is, or is not, prioritized for visual processing one must, however, additionally consider: (i) stimulus ambiguity and perceptual saliency; (ii) task demands, including both perceptual load and cognitive load; and (iii) endogenous/affective states of the individual. Combined with motivational relevance, this then leads to a multifactorial approach to understanding the drivers of prioritized visual processing. This accords with current recognition that the brain basis allowing for visual prioritization is also multifactorial, including transient, dynamic and overlapping networks. Taken together, the paper provides a reconceptualization of how "emotional" information prioritizes visual processing.

Real-Time Functional Connectivity-Informed Neurofeedback of Amygdala-Frontal Pathways Reduces Anxiety

BACKGROUND

Deficient emotion regulation and exaggerated anxiety represent a major transdiagnostic psychopathological marker. On the neural level these deficits have been closely linked to impaired, yet treatment-sensitive, prefrontal regulatory control over the amygdala. Gaining direct control over these pathways could therefore provide an innovative and promising intervention to regulate exaggerated anxiety. To this end the current proof-of-concept study evaluated the feasibility, functional relevance and maintenance of a novel connectivity-informed real-time fMRI neurofeedback training.

METHODS

In a randomized crossover sham-controlled design, 26 healthy subjects with high anxiety underwent real-time fMRI-guided neurofeedback training to enhance connectivity between the ventrolateral prefrontal cortex (vlPFC) and the amygdala (target pathway) during threat exposure. Maintenance of regulatory control was assessed after 3 days and in the absence of feedback. Training-induced changes in functional connectivity of the target pathway and anxiety ratings served as primary outcomes.

RESULTS

Training of the target, yet not the sham control, pathway significantly increased amygdala-vlPFC connectivity and decreased levels of anxiety. Stronger connectivity increases were significantly associated with higher anxiety reduction on the group level. At the follow-up, volitional control over the target pathway was maintained in the absence of feedback.

CONCLUSIONS

The present results demonstrate for the first time that successful self-regulation of amygdala-prefrontal top-down regulatory circuits may represent a novel intervention to control anxiety. As such, the present findings underscore both the critical contribution of amygdala-prefrontal circuits to emotion regulation and the therapeutic potential of connectivity-informed real-time neurofeedback.

The Role of Intranasal Oxytocin in Anxiety and Depressive Disorders: A Systematic Review of Randomized Controlled Trials

Several studies have demonstrated the neuromodulating function of oxytocin (OT) in response to anxiogenic stimuli as well as its potential role in the pathogenesis of depression. Consequently, intranasal OT (IN-OT) has been proposed as a potential treatment of anxiety and depressive disorders. The present systematic review aimed to summarize the randomized controlled trials (RCTs) evaluating the effect of IN-OT on anxiety and depressive symptoms. Overall, 15 studies were included, involving patients with social anxiety disorders (7 studies), arachnophobia (1), major depression (3) or post-natal depression (4), and mainly evaluating single-dose administrations of IN-OT. Results showed no significant effects on core symptomatology. Five crossover studies included functional magnetic resonance imaging investigation: one trial showed reduced amygdala hyper-reactivity after IN-OT in subjects with anxiety, while another one showed enhanced connectivity between amygdala and bilateral insula and middle cingulate gyrus after IN-OT in patients but not in healthy controls. More studies are needed to confirm these results. In conclusion, up to date, evidence regarding the potential utility of IN-OT in treating anxiety and depression is still inconclusive. Further RCTs with larger samples and long-term administration of IN-OT are needed to better elucidate its potential efficacy alone or in association with standard care.

The genetic underpinnings of callous-unemotional traits: A systematic research review

BACKGROUND

Callous-unemotional (CU) traits represent the affective features of psychopathy used to delineate youth at high risk for externalizing pathology. The genetic etiology CU traits is not currently well-understood.

METHODS

The current review surveyed the literature for studies on the genetic underpinnings of CU traits and integrated information from 39 genetic studies.

RESULTS

The results from 24 studies with quantitative data suggest that the heritability for CU traits is likely between 36-67%. A majority of the 16 molecular genetic studies focused on candidate genes in the serotonin and oxytocin systems with results that have not been well replicated. Although two genome-wide association studies have been conducted, no genome-wide significant loci have been discovered.

DISCUSSION

There is some evidence to suggest that the serotonin and oxytocin systems may play a role in CU traits; however, there is currently not enough evidence to implicate specific genetic mechanisms. The authors encourage researchers to continue to apply the most up-to-date and relevant methodology, specifically collaborations and consortiums using genome-wide and polygenic methods.

Diversity of central oxytocinergic projections

Localization and distribution of hypothalamic neurons expressing the nonapeptide oxytocin has been extensively studied. Their projections to the neurohypophyseal system release oxytocin into the systemic circulation thus controlling endocrine events associated with reproduction in males and females. Oxytocinergic neurons seem to be confined to the ventral hypothalamus in all mammals. Groups of such cells located outside the supraoptic and the paraventricular nuclei are summarized as "accessory neurons." Although evolutionary probably associated with the classical magocellular nuclei, accessory oxytocin neurons seem to consist of rather heterogenous groups: Periventricular oxytocin neurons may gain contact to the third ventricle to secrete the peptide into the cerebrospinal fluid. Perivascular neurons may be involved in control of cerebral blood flow. They may also gain access to the portal circulation of the anterior pituitary lobe. Central projections of oxytocinergic neurons extend to portions of the limbic system, to the mesencephalon and to the brain stem. Such projections have been associated with control of behaviors, central stress response as well as motor and vegetative functions. Activity of the different oxytocinergic systems seems to be malleable to functional status, strongly influenced by systemic levels of steroid hormones.

Oxytocin and Prader-Willi Syndrome

In the chapter, we explore the relationship between the peptide hormone, oxytocin (OT), and behavioral and metabolic disturbances observed in the genetic disorder Prader-Willi Syndrome (PWS). Phenotypic and genotypic characteristics of PWS are described, as are the potential implications of an abnormal OT system with respect to neural development including the possible effects of OT dysfunction on interactions with other regulatory mediators, including neurotransmitters, neuromodulators, and hormones. The major behavioral characteristics are explored in the context of OT dysfunction, including hyperphagia, impulsivity, anxiety and emotion dysregulation, sensory processing and interoception, repetitive and restrictive behaviors, and dysfunctional social cognition. Behavioral overlaps with autistic spectrum disorders are discussed. The implications of OT dysfunction on the mechanisms of reward and satiety and their possible role in informing behavioral characteristics are also discussed. Treatment implications and future directions for investigation are considered.

A Precision Medicine Approach to Oxytocin Trials

In this chapter, we introduce a new area of social pharmacology that encompasses the study of the role of neuromodulators in modulating a wide range of social behaviors and brain function, with the interplay of genetic and epigenetic factors. There are increasing evidences for the role of the neuropeptide oxytocin in modulating a wide range of social behaviors, in reducing anxiety, and in impacting the social brain network. Oxytocin also promotes social functions in patients with neuropsychiatric disorders, such as autism and reduces anxiety and fear in anxiety disorders. In this chapter, we will emphasize the importance of integrating basic research and clinical human research in determining optimal strategies for drug discoveries for social dysfunctions and anxiety disorders. We will highlight the significance of adopting a precision medicine approach to optimize targeted treatments with oxytocin in neuropsychiatry. Oxytocin effects on social behavior and brain function can vary from one individual to another based on external factors, such as heterogeneity in autism phenotype, childhood experiences, personality, attachment style, and oxytocin receptor polymorphisms. Hence, targeted therapies for subgroups of patients can help alleviating some of the core symptoms and lead to a better future for these patients and their families.

Oxytocin and brain activity in humans: A systematic review and coordinate-based meta-analysis of functional MRI studies

Oxytocin (OXT) is a neuropeptide which has a critical role in human social behaviour and cognition. Research investigating the role of OXT on functional brain changes in humans has often used task paradigms that probe socioemotional processes. Preliminary evidence suggests a central role of the amygdala in the social cognitive effects of intranasal OXT (IN-OXT), however, inconsistencies in task-design and analysis methods have led to inconclusive findings regarding a cohesive model of the neural mechanisms underlying OXT's actions. The aim of this meta-analysis was to systematically investigate these findings. A systematic search of PubMed, PsycINFO, and Scopus databases was conducted for fMRI studies which compared IN-OXT to placebo in humans. First, we systematically reviewed functional magnetic resonance imaging (fMRI) studies of IN-OXT, including studies of healthy humans, those with clinical disorders, and studies examining resting-state fMRI (rsfMRI). Second, we employed a coordinate-based meta-analysis for task-based neuroimaging literature using activation likelihood estimation (ALE), whereby, coordinates were extracted from clusters with significant differences in IN-OXT versus placebo in healthy adults. Data were included for 39 fMRI studies that reported a total of 374 distinct foci. The meta-analysis identified task-related IN-OXT increases in activity within a cluster of the left superior temporal gyrus during tasks of emotion processing. These findings are important as they implicate regions beyond the amygdala in the neural effects of IN-OXT. The outcomes from this meta-analysis can guide a priori predictions for future OXT research, and provide an avenue for targeted treatment interventions.

Intranasal oxytocin in rhesus monkeys alters brain networks that detect social salience and reward

In primates, resting state functional neuroimaging (rsfcMRI) has identified several large-scale, intrinsic brain networks, including the salience network (SN), which is involved in detecting stimulus salience. Intranasal oxytocin (IN-OT) has been shown to modulate the salience and rewarding quality of social stimuli in mammals and numerous studies have shown that it can affect the functional connectivity between brain regions. Less is known, however, about how these effects unfold over time following IN-OT administration. This study used rsfcMRI in anesthetized rhesus macaques to track temporal changes in the functional connectivity between brain regions involved in the SN, including the anterior cingulate cortex (ACC), anterior insula (AI), amygdala (amy), and ventral striatum (vstr), lasting 3 hr after IN-OT or Placebo (saline) administration. We found significant temporal changes in the functional connectivity between all regions associated with treatment condition. IN-OT increased the functional connectivity between AI_vstr, ACC_amy (right hemisphere), ACC_vstr (left hemisphere), and amy_vstr (right hemisphere), but reduced the functional connectivity between ACC_AI, and the AI_amygdala. These results suggest that IN-OT may dampen salience detection in rhesus monkeys, consistent with previous findings of reduced social vigilance, while enhancing the connectivity between the SN and regions involved in processing reward.

Neurobiological Aspects of Face Recognition: The Role of Oxytocin

Face recognition is an important index in the formation of social cognition and neurodevelopment in humans. Changes in face perception and memory are connected with altered sociability, which is a symptom of numerous brain conditions including autism spectrum disorder (ASD). Various brain regions and neuropeptides are implicated in face processing. The neuropeptide oxytocin (OT) plays an important role in various social behaviors, including face and emotion recognition. Nasal OT administration is a promising new therapy that can address social cognition deficits in individuals with ASD. New instrumental neurotechnologies enable the assessment of brain region activation during specific social tasks and therapies, and can characterize the involvement of genes and peptides in impaired neurodevelopment. The present review sought to discuss some of the mechanisms of the face distinguishing process, the ability of OT to modulate social cognition, as well as new perspectives and technologies for research and rehabilitation of face recognition.

Neuroimaging Predictors and Mechanisms of Treatment Response in Social Anxiety Disorder: an Overview of the Amygdala

PURPOSE OF REVIEW

Aberrant amygdala activity is implicated in the neurobiology of social anxiety disorder (SAD) and is, therefore, a treatment target. However, the extent to which amygdala predicts clinical improvement or is impacted by treatment has not been critically examined. This review highlights recent neuroimaging findings from clinical trials and research that test links between amygdala and mechanisms of action.

RECENT FINDINGS

Neuropredictor studies largely comprised psychotherapy where improvement was foretold by amygdala activity and regions beyond amygdala such as frontal structures (e.g., anterior cingulate cortex, medial prefrontal cortex) and areas involved in visual processes (e.g., occipital regions, superior temporal gyrus). Pre-treatment functional connectivity between amygdala and frontal areas was also shown to predict improvement signifying circuits that support emotion processing and regulation interact with treatment. Pre-to-post studies revealed decreases in amygdala response and altered functional connectivity in amygdala pathways regardless of treatment modality. In analogue studies of fear exposure, greater reduction in anxiety was predicted by less amygdala response to a speech challenge and amygdala activity decreased following exposures. Yet, studies have also failed to detect amygdala effects reporting instead treatment-related changes in regions and functional systems that support sensory, emotion, and regulation processes. An array of regions in the corticolimbic subcircuits and extrastriate cortex appear to be viable sites of action. The amygdala and amygdala pathways predict treatment outcome and are altered following treatment. However, further study is needed to establish the role of the amygdala and other candidate regions and brain circuits as sites of action.