Current perspectives of the roles of the central norepinephrine system in anxiety and depression

Systematic review and meta-analysis: Impact of unipolar depression on P300 amplitude and latency

Depression is characterized by impairments of cognitive systems such as significant deficits in attention, memory, and cognitive control. The P300 (or P3) event-related potential (ERP) component has been extensively investigated over the past four decades to elucidate the underpinnings of these cognitive dysfunctions. Many studies have observed reduced P300 amplitude and prolonged P300 latency in individuals experiencing depression. The current study provides a comprehensive systematic quantitative review (i.e., meta-analysis) of the depression and P300 literature from 1981 to 2023 employing PubMed and ProQuest databases. Included articles quantitatively measured depression and P300 amplitude or latency. In total, 127 studies (total N = 12,722) comprised the current analyses (i.e., 116 examining P300 amplitude and 51 examining P300 latency), resulting in 601 effect sizes (i.e., 464 depression and P300 amplitude; 137 depression and P300 latency). Robust variance meta-regression results revealed a small significant negative effect size (r = -.15) between P300 amplitude and depression even after correcting for publication bias. There was a similar small significant positive effect size (r = .15) between P300 latency and depression. Findings from moderator analyses indicated that stimulus modality, medication use, and age impacted the P300 amplitude and depression effect size; no moderators of the P300 latency and depression relationship were observed. Regarding limitations, we did not exhaustively test all possible factors that may impact P300 and depression association. The current quantitative review confirms significant differences in P300 (both amplitude and latency) attributed to cognitive dysfunctions common in depression as well as guides future study designs and methodological approaches.

Traumatic brain injury-induced anxiety: Injury and plasticity of the central noradrenergic system

Long-term anxiety is a hallmark symptom following traumatic brain injury (TBI). Although the central noradrenergic system (CNAS) is known to play a critical role in anxiety by regulating the excitability of several intricately interconnected brain structures via its projections to them, critical questions remain regarding the nature and extent of TBI-induced neuroplastic alterations in the CNAS and how these alterations relate to anxiety disorders. Knowledge relative to these questions is pivotal to development and refinement of therapies for TBI-associated anxiety disorders, including post-traumatic stress disorder. To this end, this study was designed to determine the impacts of chronic TBI on neuroplasticity of the CNAS and their significance in anxiety disorders in a clinically relevant rodent model. A standardized weight-drop model was used to produce controlled impacts of mild-to-moderate TBI in rats. Following the elevated plus maze tests to longitudinally assess anxiety-like behavior at 2 and 18 weeks post-injury of TBI animals, brain tissues of naïve and TBI rats were coronally sectioned and immunostained for a noradrenergic (NA) marker (dopamine β-hydroxylase) and neuronal nuclei in the central NA production sites and critical anxiety-regulating brain structures. We discovered that TBI caused robust losses of NA cells in the locus coeruleus and NA innervation of the central nucleus of the amygdala, an emotional processing center. Conversely, TBI caused intense gains of NA cells in the A2/A1 cell groups and NA innervation of other major anxiety-regulating regions. These changes coincided with progressively elevated anxiety-like behavior. Possibly, NA properties of A2/A1 cells were upregulated to compensate for the TBI-induced severe cell losses in the locus coeruleus. We conclude that these bi-directional vast alterations in the CNAS following chronic TBI contribute to dysregulated anxiety and, in part, the pathophysiology of human post-traumatic stress disorder.

Sequential decreases in basolateral amygdala response to threat predict failure to recover from PTSD

Amygdala hyperreactivity early-post trauma has been a demonstrable neurobiological correlate of future posttraumautic stress disorder (PTSD). The basolateral amygdala (BLA) particularly is vital for fear memory and threat processing, but BLA functional dynamics following a traumatic event are unexplored. BLA reactivity to threat may be a trait that can predict PTSD and persist over time. Alternatively, BLA responsivity to threat cues may change over time and be related to PTSD severity. As part of a larger, multisite study, AURORA, participants 18-75 years old were enrolled in an emergency department (ED) within 72 h of a traumatic event (N = 304, 199 female). At 2-weeks and 6-months post-trauma, PTSD symptoms, BLA responses to threat (fearful>neutral faces), and functional connectivity (FC) during fMRI were assessed. Generalizability of findings was assessed in an external replication sample of ED patients (n = 33). Two weeks post-trauma right BLA reactivity positively predicted later PTSD severity. However, left BLA reactivity to threat at 6 months post-trauma was negatively associated with PTSD severity at that timepoint (ΔPseudo-R2 = 0.04, IRR = 0.38, p < 0.001). In addition, a decrease in BLA reactivity from 2-weeks to 6-months predicted greater PTSD severity at 6 months (ΔPseudo-R2 = 0.03, IRR = 0.58, p < 0.001). This replicated in the external sample. A reduction in left BLA FC with the dorsal attention network predicted increased PTSD severity over time. These findings support a shift in BLA function within the first 6 months post-trauma that predicts PTSD pathology and stand in contrast to prior conceptualizations of amygdala hyperreactivity as a trait-like PTSD risk factor.

Divergent effects of noradrenergic activation and orexin receptor 1 blockade on hippocampal structure, anxiety-like behavior, and social interaction following chronic stress

Chronic stress (Ch.S) has detrimental effects on the brain's structure and function, particularly in the hippocampus. The noradrenergic and orexinergic systems play crucial roles in the stress response and regulation of stress-related behaviors. This study aimed to investigate the interaction between noradrenergic activation and orexin receptor 1 inhibition on chronic stress-induced hippocampal alterations. The study conducted experiments on male Wistar rats, subjected to Ch.S, OXr1 blocking, noradrenergic activation, or a combination of these treatments. Plasma corticosterone level was measured using a fluorometric method. Behavioral assessment of social maze, elevated plus maze (EPM) and novel object recognition (NOR) test were performed. Then, the expression of prepro-orexin, OXr1, and glucocorticoid receptor (GR) was analyzed using semiquantitative RT-PCR. Neuronal populations were quantified through Nissl staining. The data revealed that all stress and yohimbine groups had elevated plasma corticosterone levels. Ch.S significantly altered behavior, impairing social interaction, disrupting object recognition memory and increasing anxiety-like responses in the EPM. OXr1 blocking reversed these stress-induced behavioral deficits, while yohimbine did not improve these behavioral outcomes. Chronic stress led to a significant increase in prepro-orexin, OXr1, and GR expression. While blocking OXr1 helped counteract these stress-induced changes, yohimbine failed to restore the expression levels. Ch.S reduced hippocampal neuronal populations, while OXr1 blocking partially reversed this effect, and yohimbine further recovered the reversal. These findings indicate that blocking hippocampal OXr1 can mitigate the adverse effects of chronic stress on both hippocampal structure and anxiety-like behaviors, while noradrenergic signaling appears to have differential effects on behavioral and cellular measures.

The Infraslow Fluctuation of Sigma Power During Sleep in Young Individuals with Schizophrenia

A reduction in sleep spindles, a major electrophysiological characteristic of Non-Rapid Eye Movement sleep, has been suggested as a potential biomarker of schizophrenia. While research has primarily focused on the spindle quantity, recent studies have begun to explore their temporal dynamics throughout the night. In healthy individuals, sleep spindles fluctuate on an infraslow ∼50-second timescale, alternating between phases of high and low spindle activity. This fluctuation is referred to as the infraslow fluctuation of sigma power (ISFS), which is modulated by noradrenergic activity from the locus coeruleus and linked to the organization of arousal and memory reactivation processes during sleep. Given the known deficit in sleep spindles, dysregulation of noradrenergic activity, and impairments in sleep maintenance and memory in schizophrenia, this study investigates the ISFS in sleep electroencephalography data from individuals with either Childhood-Onset Schizophrenia (COS; N = 17) or Early-Onset Schizophrenia (EOS; N = 11), aged 9 to 21 years, alongside age- and sex-matched healthy controls (N = 56). The presence and strength of the ISFS were reduced in both COS and EOS groups compared to controls, particularly in central-parietal electrodes. No significant differences in these features of the ISFS were found between the two clinical groups, despite group differences in sleep spindle density and clinical characteristics. These findings suggest that the ISFS is observable but reduced in young patients with schizophrenia and support the notion that the timing of sleep spindles may inform pathomechanistic models of the disorder, as well as future diagnostic approaches and interventions.

Age-related abnormalities in brain functional and molecular neuroimaging signatures in first-episode depression

Abnormalities in resting-state brain activity have been demonstrated in depression patients with different ages, yet the age-related changes in dynamics of brain activity in depression are still limited. Here, we investigated the impacts of age on dynamics of brain activity and the molecular architecture. Resting-state functional magnetic resonance images were obtained from 138 first-episode depression patients and 120 healthy volunteers. All the participants were classified into two age cohorts, including adolescents and adults. Two-way analysis of variance was performed to examine the effect of age on dynamic amplitude of low-frequency fluctuations (ALFF) in depression. Then, cross-modal correlation analyses between dynamic ALFF and neurotransmitter maps were established. Significant diagnosis-by-age interaction of dynamic ALFF was located in medial frontal gyrus, supplementary motor area, postcentral gyrus, paracentral lobule and rolandic operculum. Dynamic ALFF alterations in the diagnosis-by-age interaction effect were associated with serotonergic, dopaminergic, noradrenergic, and GABAergic systems. These findings highlight the interaction between depression and age in brain functional and molecular neuroimaging signatures, which may be useful for future treatment strategies of different ages of depression.

Early-Life Stress Influences the Transcriptional Activation of Alpha-2A Adrenergic Receptor and Associated Protein Kinase A Signaling Molecules in the Frontal Cortex of Rats

Early life is a highly sensitive period associated with profound changes in brain structure and function. Adverse experiences of early-life stress (ELS) are prominent risk factors for the precipitation of major depressive disorder (MDD). In recent years, dysfunction of the central noradrenergic (NA) system and subsequent deficits in norepinephrine (NE) signaling have gained increasing attention in the pathophysiology of MDD. However, the role of the α-2A adrenergic receptor and its downstream second messenger signaling system has not been investigated in connection to early-life stress-induced depression, limiting valuable insights into neurobiological mechanisms underlying this disorder. In this study, we used maternal separation (MS) as a rodent model of ELS to investigate whether ELS-induced depressive behavior is related to the α-2A adrenergic receptor and its associated second messenger signaling cascade. To do so, we studied expression levels of the α-2A adrenergic receptor (Adra2a), G alpha proteins (stimulatory subunit-Gαs [Gnas] and inhibitory subunit-Gαi [Gnai1 and Gnai2]), and downstream protein kinase A (PKA) catalytic [Prkarcα and Prkarcβ] and regulatory subunits [Prkar1α, Prkar1β, Prkar2α, and Prkar2β]) in the frontal cortex (FC) of MS rats. We found reduced sucrose preference in MS animals, along with reduced transcript levels of Adra2a, Gnai2, Prkar1β, and Prkarcβ. These findings suggest that ELS exposure may contribute to depression symptomatology via alterations in the expression of key genes involved in the NA system, highlighting potential mechanisms underlying ELS-induced depressive behavior.

Effects of prenatal cannabinoid use on the monoamine system in the fetoplacental unit: A systematic review of animal and human studies

BACKGROUND

The rapid increase in cannabis use during pregnancy-up by 170 % between 2009 and 2016-raises pressing concerns about its effects on fetal health, particularly on the delicate monoamine system within the fetoplacental unit, which is crucial for placental function and neurodevelopment.

OBJECTIVE

This systematic review explores the impact of prenatal cannabinoid exposure on the monoamine system within the fetoplacental unit, with a focus on its implications for fetal development through the lens of the Developmental Origins of Health and Disease (DOHaD) framework.

METHODS

A comprehensive search across multiple databases initially retrieved 18,252 papers. After rigorous screening, only 16 animal studies and 4 human studies met the inclusion criteria. Findings were synthesized to evaluate the effects of prenatal cannabis exposure on neurotransmitter regulation, receptor function, and gene expression.

RESULTS

Although no studies directly addressed the monoamine system in the placenta, animal models revealed significant disruptions in neurotransmitter regulation and neurodevelopmental changes following prenatal cannabis exposure. Human studies suggested potential cognitive and behavioral risks for offspring exposed in utero.

CONCLUSION

This review exposes a critical gap in the literature on cannabis' effects on the placental monoamine system. While evidence points to notable neurodevelopmental risks, the scarcity of focused research underscores the need for further investigation to fully understand the implications of prenatal cannabis exposure.

Agitation: Neurobiology and current management guidelines

There have been important updates in the guidelines for the management of agitation in emergency room settings, including psychiatric emergency services. This manuscript provides a synthesis of current recommendations, combined with a detailed breakdown of the neurobiology of agitation, linking these neuroscientific dimensions with the pharmacological profiles of the drugs recommended by practice guidelines (as well as the profiles of other important agents). Since Project BETA (Best Practices in Evaluation and Treatment of Agitation) guidelines were published in 2012 (by the American Association for Emergency Psychiatry), there have been several developments in the standard of care, including an increase in use of ketamine and droperidol. Recommended treatment strategies for clinicians will be presented, including consideration of how to address specific causes of agitation.

The Role of Chronic Stress in the Pathogenesis of Ischemic Heart Disease in Women

Psychological stress has emerged as a critical risk factor for cardiovascular disease, especially in women. While female participation in clinical research has improved, sex-specific data analysis and reporting often remain inadequate, limiting our ability to draw definitive conclusions for women. Conversely, preclinical studies consistently demonstrate adverse effects of stress on female health, yet the molecular mechanisms underlying this association remain elusive. Evidence suggests that female IHD pathogenesis is more complex than in males, involving multiple factors, including inflammation, contractile dysfunction, bioenergetic impairment, and remodeling. However, many of these mechanisms are primarily derived from male studies, and molecular investigations in female models are limited, hindering our understanding of the underlying biological pathways. This is particularly concerning given the increasing prevalence of ischemic heart disease in postmenopausal women. In order to fully elucidate the impact of stress on female cardiac health and develop targeted interventions, further preclinical research on female models is essential.

Taurine protection attenuates bisphenol-A-induced behavioral, neurochemical, and histopathological alterations in male rats

Due to the continuous exposure to bisphenol-A (BPA), the current study was conducted to evaluate taurine's neuroprotective action against BPA's adverse effect on the brain. Rats were grouped into control, BPA-treated rats, and taurine + BPA-treated rats. At the end of the 35-day treatment period, the memory of the rats was evaluated using the novel object test and the Y-maze test. An open-field test was used to measure motor activity. The changes in monoamines, monoamine oxidase (MAO), acetylcholinesterase (AChE), Na+,K+,ATPase, oxidative stress, caspase-3, and histopathology were evaluated in the cortical and hippocampal tissues of all groups. Data analysis by ANOVA revealed that BPA treatment induced motor hyperactivity and short- and long-term memory impairment. In the cortex, BPA decreased serotonin (5-HT), norepinephrine (NE), MAO, Na+,K+,ATPase, and nitric oxide (NO) and increased dopamine (DA), AChE, lipid peroxidation (MDA), glutathione (GSH), and caspase-3. In the hippocampus, BPA increased 5-HT, DA, NE, MAO, AChE, MDA, NO, GSH, and caspase-3 and decreased Na+,K+,ATPase. These neurochemical changes were accompanied by significant histopathological alterations. Taurine treatment prevented memory impairment and motor hyperactivity induced by BPA. Taurine attenuated the neurochemical changes, oxidative stress, and caspase-3 level. Taurine improved the histopathological change induced by BPA. In conclusion, taurine significantly prevented BPA-induced cognitive deficits, motor coordination impairments, neurotransmitter imbalances, histopathological alterations, oxidative stress, and apoptosis.

The influence of anxiety on exploration: A review of computational modeling studies

Exploratory behaviors can serve an adaptive role within novel or changing environments. Namely, they facilitate information gain, allowing an organism to maintain accurate beliefs about the environment and select actions that better maximize reward. However, finding the optimal balance between exploration and reward-seeking behavior - the so-called explore-exploit dilemma - can be challenging, as it requires sensitivity to one's own uncertainty and to the predictability of one's surroundings. Given the close relationship between uncertainty and anxiety, a body of work has now also emerged identifying associated effects on exploration. In particular, the field of computational psychiatry has begun to use cognitive computational models to characterize how anxiety may modulate underlying information processing mechanisms, such as estimation of uncertainty and the value of information, and how this might contribute to psychopathology. Here, we review computational modeling studies investigating how exploration is influenced by anxiety. While some apparent inconsistencies remain to be resolved, studies using reinforcement learning tasks suggest that directed (but not random) forms of exploration may be elevated by trait and/or cognitive anxiety, but reduced by state and/or somatic anxiety. Anxiety is also consistently associated with less exploration in foraging tasks. Some differences in exploration may further stem from how anxiety modulates changes in uncertainty over time (learning rates). Jointly, these results highlight important directions for future work in refining choice of tasks and anxiety measures and maintaining consistent methodology across studies.

Evidence of Differential Prediction of Anxiety and Depression by Diurnal Alpha-Amylase and Cortisol in Development

Research and theory suggest an important role of neuroendocrine function in emotional development, particularly under conditions of elevated stress. We provide empirical data to clarify associations between alpha-amylase (AA) and cortisol as well as test the differential linkages among AA, cortisol, and symptoms of anxiety, depression, and posttraumatic stress in children. Children recruited from a low-income elevated violence community (n = 100; mean age = 10, SD = 0.64; 79% Latino; 67% received free or reduced lunch) were assessed on diurnal levels of AA and cortisol along with assessments of anxiety, depression, and posttraumatic stress symptoms (PTSS). Elevated anxiety symptoms were associated with steeper linear slopes of AA with higher levels of AA in the morning but lower levels of AA in the evening. Depression was associated with differential cubic trajectories of AA when PTSSs were included in the model. Anxiety also predicted differential cubic diurnal trends in cortisol, such that greater anxiety symptoms were associated with relatively higher levels of cortisol in the evening. Again, depression symptoms when PTSS were included predicted diurnal cubic trends with elevated depression associated with lower awakening and midday cortisol that reversed to higher evening cortisol compared to youth with fewer self-reported depression symptoms.

An overview of the pathophysiology of agitation in Alzheimer's dementia with a focus on neurotransmitters and circuits

Alzheimer's dementia (AD) is a progressive, neurodegenerative disease often accompanied by neuropsychiatric symptoms that profoundly impact both patients and caregivers. Agitation is among the most prevalent and distressing of these symptoms and often requires treatment. Appropriate therapeutic interventions depend on understanding the biological basis of agitation and how it may be affected by treatment. This narrative review discusses a proposed pathophysiology of agitation in Alzheimer's dementia based on convergent evidence across research approaches. Available data indicate that agitation in Alzheimer's dementia is associated with an imbalance of activity between key prefrontal and subcortical brain regions. The monoamine neurotransmitter systems serve as key modulators of activity within these brain regions and circuits and are rendered abnormal in AD. Patients with AD who exhibited agitation symptoms during life have alterations in neurotransmitter nuclei and related systems when the brain is examined at autopsy. The authors present a model of agitation in Alzheimer's dementia in which noradrenergic hyperactivity along with serotonergic deficits and dysregulated striatal dopamine release contribute to agitated and aggressive behaviors.

Abnormalities in static and dynamic intrinsic neural activity and neurotransmitters in first-episode OCD

BACKGROUND

Obsessive-compulsive disorder (OCD) is a disabling disorder in which the temporal variability of regional brain connectivity is not well understood. The aim of this study was to investigate alterations in static and dynamic intrinsic neural activity (INA) in first-episode OCD and whether these changes have the potential to reflect neurotransmitters.

METHODS

A total of 95 first-episode OCD patients and 106 matched healthy controls (HCs) were included in this study. Based on resting-state functional magnetic resonance imaging (rs-fMRI), the static and dynamic local connectivity coherence (calculated by static and dynamic regional homogeneity, sReHo and dReHo) were compared between the two groups. Furthermore, correlations between abnormal INA and PET- and SPECT-derived maps were performed to examine specific neurotransmitter system changes underlying INA abnormalities in OCD.

RESULTS

Compared with HCs, OCD showed decreased sReHo and dReHo values in left superior, middle temporal gyrus (STG/MTG), left Heschl gyrus (HES), left putamen, left insula, bilateral paracentral lobular (PCL), right postcentral gyrus (PoCG), right precentral gyrus (PreCG), left precuneus and right supplementary motor area (SMA). Decreased dReHo values were also found in left PoCG, left PreCG, left SMA and left middle cingulate cortex (MCC). Meanwhile, alterations in INA present in brain regions were correlated with dopamine system (D2, FDOPA), norepinephrine transporter (NAT) and the vesicular acetylcholine transporter (VAChT) maps.

CONCLUSION

Static and dynamic INA abnormalities exist in first-episode OCD, having the potential to reveal the molecular characteristics. The results help to further understand the pathophysiological mechanism and provide alternative therapeutic targets of OCD.

Flibanserin conquers murine depressive pseudodementia by amending HPA axis, maladaptive inflammation and AKT/GSK/STAT/BDNF trajectory: Center-staging of the serotonergic/adrenergic circuitry

Depressive pseudodementia (DPD) is a debilitating cognitive dysfunction that accompanies major and/or frequent depressive attacks. DPD has gained significant research attention owing to its negative effects on the patients' quality of life and productivity. This study tested the procognitive potential of Flibanserin (FBN), the serotonin (5HT) receptor modulator, against propranolol (PRP), as β/5HT1A receptors blocker. Serving this purpose, female Wistar Albino rats were subjected to chronic unpredictable stress (CUS) and subsequently treated with FBN only (3 mg/kg/day, p.o), PRP only (10 mg/kg/day, p.o), or PRP followed by FBN, using the same doses. FBN ameliorated the behavioral/cognitive alterations and calmed the hypothalamic-pituitary-adrenal (HPA) axis storm by reducing the levels of stress-related hormones, viz, corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), corticosterone (CORT) parallel to epinephrine (EPI) hyperstimulation. The maladaptive inflammatory response, comprising of interleukin (IL)-1β/6, and tumor necrosis factor (TNF)-α, was consequently blunted. This was contemporaneous to the partial restoration of the protein kinase-B (AKT)/glycogen synthase kinase (GSK)3β/signal transducer and activator of transcription (STAT)-3 survival trajectory and the reinstatement of the levels of brain derived neurotrophic factor (BDNF). Microscopically, FBN repaired the hippocampal architecture and lessened CD68/GFAP immunoreactivity. Pre-administration of PRP partially abolished FBN effect along the estimated parameters, except for 5HT2A receptor expression and epinephrine level, to prove 5HT1A receptor as a fulcrum initiator of the investigated pathway, while its sole administration worsened the underlying condition. Ultimately, these findings highlight the immense procognitive potential of FBN, offering a new paradigm for halting DPD advancement via synchronizing adrenergic/serotonergic circuitry.

Genetically encoded sensors for in vivo detection of neurochemicals relevant to depression

Depressive disorders are a common and debilitating form of mental illness with significant impacts on individuals and society. Despite the high prevalence, the underlying causes and mechanisms of depressive disorders are still poorly understood. Neurochemical systems, including serotonin, norepinephrine, and dopamine, have been implicated in the development and perpetuation of depressive symptoms. Current treatments for depression target these neuromodulator systems, but there is a need for a better understanding of their role in order to develop more effective treatments. Monitoring neurochemical dynamics during depressive symptoms is crucial for gaining a better a understanding of their involvement in depressive disorders. Genetically encoded sensors have emerged recently that offer high spatial-temporal resolution and the ability to monitor neurochemical dynamics in real time. This review explores the neurochemical systems involved in depression and discusses the applications and limitations of current monitoring tools for neurochemical dynamics. It also highlights the potential of genetically encoded sensors for better characterizing neurochemical dynamics in depression-related behaviors. Furthermore, potential improvements to current sensors are discussed in order to meet the requirements of depression research.

Uncovering the correlation between neurotransmitter-specific functional connectivity and multidimensional anxiety in a non-clinical cohort

Research on anxiety faces challenges due to the wide range of symptoms, making it difficult to determine if different aspects of anxiety are linked to distinct neurobiological processes. Both alterations in functional brain connectivity (FC) and monoaminergic neurotransmitter systems are implicated as potential neural bases of anxiety. We aimed to investigate whole-brain FC involving monoaminergic nuclei and its association with anxiety dimensions in 178 non-clinical participants. Nine anxiety-related scales were used, encompassing trait and state anxiety scores, along with measures of cost-probability, hypervigilance, reward-punishment sensitivity, uncertainty, and trait worry. Resting-state functional magnetic resonance imaging data were acquired, focusing on seven brainstem regions representing serotonergic, dopaminergic, and noradrenergic nuclei, with their FC patterns voxel-wise correlated with the scales. All models underwent family-wise-error correction for multiple comparisons. We observed intriguing relationships: trait and state anxiety scores exhibited opposing correlations in FC between the dorsal raphe nucleus and the paracingulate gyrus. Additionally, we identified shared neural correlates, such as a negative correlation between the locus coeruleus and the frontal pole. This connection was significantly associated with scores on measures of probability, hypervigilance, reward sensitivity, and trait worry. These findings underscore the intricate interplay between anxiety dimensions and subcortico-cortical FC patterns, shedding light on the underlying neural mechanisms governing anxiety.

Effects of acute inhibition of dopamine β-hydroxylase on neural responses to pups in adult virgin male California mice (Peromyscus californicus)

The neural mechanisms underlying paternal care in biparental mammals are not well understood. The California mouse (Peromyscus californicus) is a biparental rodent in which virtually all fathers are attracted to pups, while virgin males vary widely in their behavior toward unrelated infants, ranging from attacking to avoiding to huddling and grooming pups. We previously showed that pharmacologically inhibiting the synthesis of the neurotransmitter norepinephrine (NE) with the dopamine β-hydroxylase inhibitor nepicastat reduced the propensity of virgin male and female California mice to interact with pups. The current study tested the hypothesis that nepicastat would reduce pup-induced c-Fos immunoreactivity, a cellular marker of neural activity, in the medial preoptic area (MPOA), medial amygdala (MeA), basolateral amygdala (BLA), and bed nucleus of the stria terminalis (BNST), brain regions implicated in the control of parental behavior and/or anxiety. Virgin males were injected with nepicastat (75 mg/kg, i.p.) or vehicle 2 hours prior to exposure to either an unrelated pup or novel object for 60 minutes (n = 4-6 mice per group). Immediately following the 60-minute stimulus exposure, mice were euthanized and their brains were collected for c-Fos immunohistochemistry. Nepicastat reduced c-Fos expression in the MeA and MPOA of pup-exposed virgin males compared to vehicle-injected controls. In contrast, nepicastat did not alter c-Fos expression in any of the above brain regions following exposure to a novel object. Overall, these results suggest that the noradrenergic system might influence MeA and MPOA function to promote behavioral interactions with pups in virgin males.

Stress integration by an ascending adrenergic-melanocortin circuit

Stress is thought to be an important contributing factor for eating disorders; however, neural substrates underlying the complex relationship between stress and appetite are not fully understood. Using in vivo recordings from awake behaving mice, we show that various acute stressors activate catecholaminergic nucleus tractus solitarius (NTSTH) projections in the paraventricular hypothalamus (PVH). Remarkably, the resulting adrenergic tone inhibits MC4R-expressing neurons (PVHMC4R), which are known for their role in feeding suppression. We found that PVHMC4R silencing encodes negative valence in sated mice and is required for avoidance induced by visceral malaise. Collectively, these findings establish PVHMC4R neurons as an effector of stress-activated brainstem adrenergic input in addition to the well-established hypothalamic-pituitary-adrenal axis. Convergent modulation of stress and feeding by PVHMC4R neurons implicates NTSTH → PVHMC4R input in stress-associated appetite disorders.

Pathogenesis of depression and the potential for traditional Chinese medicine treatment

Depression is a prevalent mental disorder that significantly diminishes quality of life and longevity, ranking as one of the primary causes of disability globally. Contemporary research has explored the potential pathogenesis of depression from various angles, encompassing genetics, neurotransmitter systems, neurotrophic factors, the hypothalamic-pituitary-adrenal axis, inflammation, and intestinal flora, among other contributing factors. In addition, conventional chemical medications are plagued by delayed onset of action, persistent adverse effects, and restricted therapeutic efficacy. In light of these limitations, the therapeutic approach of traditional Chinese medicine (TCM) has gained increasing recognition for its superior effectiveness. Numerous pharmacological and clinical studies have substantiated TCM's capacity to mitigate depressive symptoms through diverse mechanisms. This article attempts to summarize the mechanisms involved in the pathogenesis of depression and to describe the characteristics of herbal medicines (including compounded formulas and active ingredients) for the treatment of depression. It further evaluates their effectiveness by correlating with the multifaceted pathogenesis of depression, thereby furnishing a reference for future research endeavors.

Investigating the Relationship between Smoking and Panic Disorder: A Cross-Sectional Study among US Adults

Background

Previous research on panic risk factors within the US population has been limited. This cross-sectional study is aimed at exploring the association between smoking and panic among adults in the United States.

Methods

We conducted an analysis of data from the National Health and Nutrition Examination Survey.

Results

The study included 2,222 participants. Those diagnosed with panic disorder were more likely to be female, unmarried, have lower income, engage in higher rates of smoking, and exhibit greater alcohol consumption. Participants who smoke cigarettes occasionally indicated a significant increase in panic disorder (unadjusted OR 95% CI: 4.396 [2.032-9.513]; P < 0.001). The significance of our results remained even after performing the multivariate analysis (full-adjusted OR 95% CI: 2.89 [1.30-6.42]). Furthermore, participants who never smoked cigarettes demonstrated strong and significantly low odds for panic disorder, regardless of adjustment (unadjusted OR 95% CI: 0.180 [0.055-0.591]). There was no association between pipe and cigar smoking and panic disorder in both unadjusted and full-adjusted models.

Conclusion

This study highlights that smoking remains a significant risk factor for panic disorder, even after accounting for potential confounding variables. Further prospective longitudinal research should be done to investigate the causality between smoking and panic disorder.

Accurate detection depression cell model with a dual-locked fluorescence probe in response to noradrenaline and HClO

Due to the serious harm of depression to human health and quality of life, an accurate diagnosis of depression is warranted. For the complex etiology of depression, a single biomarker diagnostic method often leads to misdiagnosis. As noradrenaline and HClO are closely related to depression, a "dual-locked" fluorescence probe R-NE-HClO for diagnosing of depression through the simultaneous detection of noradrenaline and HClO was designed and synthesized. Fluorescence of R-NE-HClO can only be restored in the presence of both noradrenaline and HClO. The probe demonstrates excellent selectivity for noradrenaline and HClO and low cytotoxicity in cell imaging experiments. It is to be observed that we successfully applied the probe to accurately detect depressed cells which provides a possible tool for diagnosing depression.

Brainwide Mendelian Randomization Study of Anxiety Disorders and Symptoms

BACKGROUND

To gain insights into the role of brain structure and function on anxiety (ANX), we conducted a genetically informed investigation leveraging information from ANX genome-wide association studies available from the UK Biobank (n = 380,379), the FinnGen Program (n = 290,361), and the Million Veteran Program (n = 175,163) together with UK Biobank genome-wide data (n = 33,224) related to 3935 brain imaging-derived phenotypes (IDPs).

METHODS

A genetic correlation analysis between ANX and brain IDPs was performed using linkage disequilibrium score regression. To investigate ANX-brain associations, a 2-sample Mendelian randomization was performed considering multiple methods and sensitivity analyses. A subsequent multivariable Mendelian randomization was conducted to distinguish between direct and indirect effects. Finally, a generalized linear model was used to explore the associations of brain IDPs with ANX symptoms.

RESULTS

After false discovery rate correction (q < .05), we identified 41 brain IDPs genetically correlated with ANX without heterogeneity among the datasets investigated (i.e., UK Biobank, FinnGen, and Million Veteran Program). Six of these IDPs showed genetically inferred causal effects on ANX. In the subsequent multivariable Mendelian randomization analysis, reduced area of the right posterior middle cingulate gyrus (β = -0.09, p = 8.01 × 10-4) and reduced gray matter volume of the right anterior superior temporal gyrus (β = -0.09, p = 1.55 × 10-3) had direct effects on ANX. In the ANX symptom-level analysis, the right posterior middle cingulate gyrus was negatively associated with "tense, sore, or aching muscles during the worst period of anxiety" (β = -0.13, p = 8.26 × 10-6).

CONCLUSIONS

This study identified genetically inferred effects that are generalizable across large cohorts, thereby contributing to our understanding of how changes in brain structure and function can lead to ANX.

Neuromelanin-sensitive magnetic resonance imaging in the study of mental disorder: A systematic review

Dopamine and norepinephrine are implicated in the pathophysiology of mental disorders, but non-invasive study of their neuronal function remains challenging. Recent research suggests that neuromelanin-sensitive magnetic resonance imaging (NM-MRI) techniques may overcome this limitation by enabling the non-invasive imaging of the substantia nigra (SN)/ ventral tegmental area (VTA) dopaminergic and locus coeruleus (LC) noradrenergic systems. A review of 19 studies that met the criteria for NM-MRI application in mental disorders found that despite the use of heterogeneous sequence parameters and metrics, nearly all studies reported differences in contrast ratio (CNR) of LC or SN/VTA between patients with mental disorders and healthy controls. These findings suggest that NM-MRI is a valuable tool in psychiatry, but the differences in sequence parameters across studies hinder comparability, and a standardized analysis pipeline is needed to improve the reliability of results. Further research using standardized methods is needed to better understand the role of dopamine and norepinephrine in mental disorders.

Exploring stress response's role in executive function impairments among adults with early adverse childhood experiences

Adverse childhood experiences (ACEs) are recognised as precursors to numerous physical and mental health challenges. However, research on their impact on inhibitory control and working memory, particularly among healthy young adults, remains limited. The role played by the stress response as a moderator in these effects is likewise underexplored. Our study addresses this gap by examining cognitive impairments in non-clinical adults with early childhood trauma, specifically trauma before the age of 13 years, and by assessing the influence of the stress response on these effects. A total of 15 participants with early ACEs were compared with a control group (n = 18) using the Corsi Block Tapping Test (CBTT) and Stroop Word Colour Test (SCWT). Results showed that participants with early ACEs exhibited lower scores on the SCWT but not the CBTT. The stress response emerged as a potential factor in the relationship between early ACEs and cognitive performance. The implications of these findings are then discussed in relation to the existing literature.

Therapeutic Potential of Myricetin in the Treatment of Neurological, Neuropsychiatric, and Neurodegenerative Disorders

Myricetin (MC), 3,5,7,3',4',5'-hexahydroxyflavone, chemically belongs to a flavonoid category known to confer antioxidant, antimicrobial, antidiabetic, and neuroprotective effects. MC is known to suppress the generation of Reactive Oxygen Species (ROS), lipid peroxidation (MDA), and inflammatory markers. It has been reported to improve insulin function in the human brain and periphery. Besides this, it modulates several neurochemicals including glutamate, GABA, serotonin, etc. MC has been shown to reduce the expression of the enzyme Mono Amine Oxidase (MAO), which is responsible for the metabolism of monoamines. MC treatment reduces levels of plasma corticosterone and restores hippocampal BDNF (full form) protein in stressed animals. Further, MC has shown its protective effect against amyloid-beta, MPTP, rotenone, 6-OHDA, etc. suggesting its potential role against neurodegenerative disorders. The aim of the present review is to highlight the therapeutic potential of MC in the treatment of several neurological, neuropsychiatric, and neurodegenerative disorders.

Exposure of embryos to fenbuconazole causes persistent neurotoxicity in adult zebrafish

In this study, the persistent effects of embryonic exposure to fenbuconazole (FBZ), a triazole fungicide, on neurobehaviour in zebrafish were investigated. After exposure of fertilized eggs to FBZ for 72 h (h), the larvae were cultured to adulthood in clean water. In adult zebrafish embryonically exposed to 50 and 500 ng L-1 FBZ, the ratio of brain weight/body weight was significantly decreased, and the number of apoptotic cells in the brain was significantly increased, accompanied by upregulated protein levels of P53 and downregulated levels of BCL2. The novel tank test showed a significant reduction in the moved distance and speed, and a longer period of adaptation to new environments in the 500 ng L-1 group. The social preference experiment showed impaired social interaction behaviour and reduced time of aggregation in the 500 ng L-1 group. Increased dopamine and norepinephrine levels in the brain might be responsible for this anxiety-like behaviour. In addition to upregulated protein levels of tyrosine hydroxylase and β2-adrenoceptor, the transcription of genes related to dopamine and norepinephrine synthesis in the brain such as th1, th2, ddc, drd1b, dat, and dbh, was increased. The methylation levels of related genes were reduced, which were matched with their increased transcriptional levels. These results demonstrate that embryonic FBZ exposure might cause persistent neurotoxicity in adulthood, which suggests the rational cautious use of FBZ.

Health phenome of Parkinson's patients reveals prominent mood-sleep cluster

Background

Associations between phenotypic traits, environmental exposures, and Parkinson's disease have largely been evaluated one-by-one, piecemeal, and pre-selections. A comprehensive picture of comorbidities, phenotypes, exposures, and polypharmacy characterizing the complexity and heterogeneity of real-world patients presenting to academic movement disorders clinics in the US is missing.

Objectives

To portrait the complexity of features associated with patients with Parkinson's disease in a study of 933 cases and 291 controls enrolled in the Harvard Biomarkers Study.

Methods

The primary analysis evaluated 64 health features for associations with Parkinson's using logistic regression adjusting for age and sex. We adjusted for multiple testing using the false discovery rate (FDR) with £ 0.05 indicating statistical significance. Exploratory analyses examined feature correlation clusters and feature combinations.

Results

Depression (OR = 3.11, 95% CI 2.1 to 4.71), anxiety (OR = 3.31, 95% CI 2.01-5.75), sleep apnea (OR 2.58, 95% CI 1.47-4.92), and restless leg syndrome (RLS; OR 4.12, 95% CI 1.81-12.1) were significantly more common in patients with Parkinson's than in controls adjusting for age and sex with FDR £ 0.05. The prevalence of depression, anxiety, sleep apnea, and RLS were correlated, and these diseases formed part of a larger cluster of mood traits and sleep traits linked to PD. Exposures to pesticides (OR 1.87, 95% CI 1.37-2.6), head trauma (OR 2.33, 95% CI 1.51-3.73), and smoking (OR 0.57, 95% CI 0.43-0.75) were significantly associated with the disease consistent with previous studies. Vitamin supplementation with cholecalciferol (OR 2.18, 95% CI 1.4-3.45) and coenzyme Q10 (OR 2.98, 95% CI 1.89-4.92) was more commonly used by patients than controls. Cumulatively, 43% (398 of 933) of Parkinson's patients had at least one psychiatric or sleep disorder, compared to 21% (60 of 291) of healthy controls.

Conclusions

43% of Parkinson's patients seen at Harvard-affiliated teaching hospitals have depression, anxiety, and disordered sleep. This syndromic cluster of mood and sleep traits may be pathophysiologically linked and clinically important.

Ventromedial hypothalamus relays chronic stress inputs and exerts bidirectional regulation on anxiety state and related sympathetic activity

Chronic stress can induce negative emotion states, including anxiety and depression, leading to sympathetic overactivation and disturbed physiological homeostasis in peripheral tissues. While anxiety-related neural circuitry integrates chronic stress information and modulates sympathetic nervous system (SNS) activity, the critical nodes linking anxiety and sympathetic activity still need to be clarified. In our previous study, we demonstrated that the ventromedial hypothalamus (VMH) is involved in integrating chronic stress inputs and exerting influence on sympathetic activity. However, the underlying synaptic and electrophysiological mechanisms remain elusive. In this study, we combined in vitro electrophysiological recordings, behavioral tests, optogenetic manipulations, and SNS activity analyses to explore the role of VMH in linking anxiety emotion and peripheral SNS activity. Results showed that the VMH played an important role in bidirectionally regulating anxiety-like behavior and peripheral sympathetic excitation. Chronic stress enhanced excitatory inputs into VMH neurons by strengthening the connection with the paraventricular hypothalamus (PVN), hence promoting anxiety and sympathetic tone outflow, an important factor contributing to the development of metabolic imbalance in peripheral tissues and cardiovascular diseases.

The effect of tennis batting sound on anxiety: a randomized controlled trial and basic acoustic analysis

Purpose

To investigate the potential role of the unique sound of tennis in alleviating anxiety. Previous research has consistently shown that exercise can mitigate anxiety, primarily attributed to the impact of increased physical activity on hormonal and neurostructural changes. However, in daily life we find that one of the reasons people are drawn to tennis is its distinctive sound. In this study, we specifically examined the influence of this sound on anxiety.

Methods and results

In a randomized controlled experiment involving 96 participants reporting chronic anxiety (n1 = n2 = 48), we found that the control group exhibited an average reduction of 0.00156 in anxiety scores 4 weeks before and after the study. On the other hand, the experimental group, exposed to tennis stroke sound stimuli, showed an average reduction of 0.02896 in anxiety scores after 4 weeks, with some individuals even experiencing a decrease from anxiety to mild anxiety. Furthermore, the analysis of sound data revealed that the sound of tennis exhibited a pleasing timbre, with the primary sound frequencies ranging from 100 to 2,800 Hz. The rhythm of the sound had an average interval of approximately 1.758″ (± 0.41), corresponding to speed of approximately 93.6 km/h. The sound exhibited a steady rhythm, orderly variations in pitch, and a soothing timbre.

Conclusion

This study confirms that the sound of tennis alone contributes to anxiety relief, attributed to its suitable loudness, steady rhythm, and orderly variations in pitch, all of which align with human auditory characteristics. This indicates that a considerable portion of the anxiety-alleviating effects of tennis attributed to its comforting sound.

Heterogeneity of Response to Methylphenidate in Apathetic Patients in the ADMET 2 Trial

OBJECTIVE

The Apathy in Dementia Methylphenidate Trial 2 (ADMET 2) found that methylphenidate was effective in treating apathy with a small-to-medium effect size but showed heterogeneity in response. We assessed clinical predictors of response to help determine individual likelihood of treatment benefit from methylphenidate.

DESIGN

Univariate and multivariate analyses of 22 clinical predictors of response chosen a priori.

SETTING

Data from the ADMET 2 randomized, placebo controlled multi-center clinical trial.

PARTICIPANTS

Alzheimer's disease patients with clinically significant apathy.

MEASUREMENTS

Apathy assessed with the Neuropsychiatric Inventory apathy domain (NPI-A).

RESULTS

In total, 177 participants (67% male, mean [SD] age 76.4 [7.9], mini-mental state examination 19.3 [4.8]) had 6-months follow up data. Six potential predictors met criteria for inclusion in multivariate modeling. Methylphenidate was more efficacious in participants without NPI anxiety (change in NPI-A -2.21, standard error [SE]:0.60) or agitation (-2.63, SE:0.68), prescribed cholinesterase inhibitors (ChEI) (-2.44, SE:0.62), between 52 and 72 years of age (-2.93, SE:1.05), had 73-80 mm Hg diastolic blood pressure (-2.43, SE: 1.03), and more functional impairment (-2.56, SE:1.16) as measured by the Alzheimer's Disease Cooperative Study Activities of Daily Living scale.

CONCLUSION

Individuals who were not anxious or agitated, younger, prescribed a ChEI, with optimal (73-80 mm Hg) diastolic blood pressure, or having more impaired function were more likely to benefit from methylphenidate compared to placebo. Clinicians may preferentially consider methylphenidate for apathetic AD participants already prescribed a ChEI and without baseline anxiety or agitation.

The impact of a guided paced breathing audiovisual intervention on anxiety symptoms in Palestinian children: a pilot randomized controlled trial

BACKGROUND

Children in Palestine may be at high risk for anxiety symptoms. However, access to mental health services is limited. Therefore, the objective of this study was to conduct a pilot randomized controlled trial to examine whether a guided audiovisual paced breathing intervention was feasible, acceptable, and improved anxiety symptoms in Palestinian children.

METHODS

Students (6-10 years old) in an after-school program in Palestine were randomly assigned to the intervention or control condition. All participants completed a pre- and post-intervention measure of anxiety using the Revised Children's Manifest Anxiety Scale. Participants in the intervention completed 24 sessions over 8 weeks and rated breathing ease as well as pre- and post-session relaxation on a 5-point Likert scale. To examine condition differences in post-intervention anxiety, four analyses of covariance were conducted, adjusting for age, sex, and pre-intervention anxiety.

RESULTS

A total of 144 participants (65.3% girls; Mage  = 7.5 ± 1.2; 50% per condition) enrolled in the study. There were no differences in demographics or baseline anxiety between the two conditions (ps > .05). Participants reported that it was easy to breathe during the sessions (Ms = 4.1-4.7, SDs = 0.5-1.1). For all but the first session, participants reported being more relaxed after the breathing session than before (ps < .003). Post-intervention, participants in the intervention reported fewer anxiety symptoms compared to participants in the control condition (ps < .01).

CONCLUSION

A guided paced breathing audiovisual intervention was feasible and had a significant positive impact on anxiety symptoms in Palestinian children compared to a control condition. Future research should examine whether the audiovisual guided breathing intervention significantly improves long-term outcomes.

The relationship of lifetime history of depression on the ovarian tumor immune microenvironment

BACKGROUND

Depression is associated with a higher ovarian cancer risk. Prior work suggests that depression can lead to systemic immune suppression, which could potentially alter the anti-tumor immune response.

METHODS

We evaluated the association of pre-diagnosis depression with features of the anti-tumor immune response, including T and B cells and immunoglobulins, among women with ovarian tumor tissue collected in three studies, the Nurses' Health Study (NHS; n = 237), NHSII (n = 137) and New England Case-Control Study (NECC; n = 215). Women reporting depressive symptoms above a clinically relevant cut-point, antidepressant use, or physician diagnosis of depression at any time prior to diagnosis of ovarian cancer were considered to have pre-diagnosis depression. Multiplex immunofluorescence was performed on tumor tissue microarrays to measure immune cell infiltration. In pooled analyses, we estimated odds ratios (OR) and 95% confidence intervals (CI) for the positivity of tumor immune cells using a beta-binomial model comparing those with and without depression. We used Bonferroni corrections to adjust for multiple comparisons.

RESULTS

We observed no statistically significant association between depression status and any immune markers at the Bonferroni corrected p-value of 0.0045; however, several immune markers were significant at a nominal p-value of 0.05. Specifically, there were increased odds of having recently activated cytotoxic (CD3+CD8+CD69+) and exhausted-like T cells (CD3+Lag3+) in tumors of women with vs. without depression (OR = 1.36, 95 %CI = 1.09-1.69 and OR = 1.24, 95 %CI = 1.01-1.53, respectively). Associations were comparable when considering high grade serous tumors only (comparable ORs = 1.33, 95 %CI = 1.05-1.69 and OR = 1.25, 95 %CI = 0.99-1.58, respectively). There were decreased odds of having tumor infiltrating plasma cells (CD138+) in women with vs. without depression (OR = 0.54, 95 %CI = 0.33-0.90), which was similar among high grade serous carcinomas, although not statistically significant. Depression was also related to decreased odds of having naïve and memory B cells (CD20+: OR = 0.54, 95 %CI = 0.30-0.98) and increased odds of IgG (OR = 1.22, 95 %CI = 0.97-1.53) in high grade serous carcinomas.

CONCLUSION

Our results provide suggestive evidence that depression may influence ovarian cancer outcomes through changes in the tumor immune microenvironment, including increasing T cell activation and exhaustion and reducing antibody-producing B cells. Further studies with clinical measures of depression and larger samples are needed to confirm these results.

Dissecting the Relationship Between Neuropsychiatric and Neurodegenerative Disorders

Neurodegenerative diseases (NDDs) and neuropsychiatric disorders (NPDs) are two common causes of death in elderly people, which includes progressive neuronal cell death and behavioral changes. NDDs include Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, multiple sclerosis, and motor neuron disease, characterized by cognitive defects and memory impairment, whereas NPDs include depression, seizures, migraine headaches, eating disorders, addictions, palsies, major depressive disorders, anxiety, and schizophrenia, characterized by behavioral changes. Mounting evidence demonstrated that NDDs and NPDs share an overlapping mechanism, which includes post-translational modifications, the microbiota-gut-brain axis, and signaling events. Mounting evidence demonstrated that various drug molecules, namely, natural compounds, repurposed drugs, multitarget directed ligands, and RNAs, have been potentially implemented as therapeutic agents against NDDs and NPDs. Herein, we highlighted the overlapping mechanism, the role of anxiety/stress-releasing factors, cytosol-to-nucleus signaling, and the microbiota-gut-brain axis in the pathophysiology of NDDs and NPDs. We summarize the therapeutic application of natural compounds, repurposed drugs, and multitarget-directed ligands as therapeutic agents. Lastly, we briefly described the application of RNA interferences as therapeutic agents in the pathogenesis of NDDs and NPDs. Neurodegenerative diseases and neuropsychiatric diseases both share a common signaling molecule and molecular phenomenon, namely, pro-inflammatory cytokines, γCaMKII and MAPK/ERK, chemokine receptors, BBB permeability, and the gut-microbiota-brain axis. Studies have demonstrated that any alterations in the signaling mentioned above molecules and molecular phenomena lead to the pathophysiology of neurodegenerative diseases, namely, Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, and neuropsychiatric disorders, such as bipolar disorder, schizophrenia, depression, anxiety, autism spectrum disorder, and post-traumatic stress disorder.

Brain-Wide Mendelian Randomization Study of Anxiety Disorders and Symptoms

Background

To gain insights into the role of brain structure and function on anxiety (ANX), we conducted a genetically informed investigation leveraging information from ANX genome-wide association studies available from UK Biobank (UKB; N=380,379), FinnGen Program (N=290,361), and Million Veteran Program (MVP; N=199,611) together with UKB genome-wide data (N=33,224) related to 3,935 brain imaging-derived phenotypes (IDP).

Methods

A genetic correlation analysis between ANX and brain IDPs was performed using linkage disequilibrium score regression. To investigate ANX-brain associations, a two-sample Mendelian randomization (MR) was performed considering multiple methods and sensitivity analyses. A subsequent multivariable MR (MVMR) was executed to distinguish between direct and indirect effects. Finally, a generalized linear model was used to explore the associations of brain IDPs with ANX symptoms.

Results

After false discovery rate correction (FDR q<0.05), we identified 41 brain IDPs genetically correlated with ANX without heterogeneity among the datasets investigated (i.e., UKB, FinnGen, and MVP). Six of these IDPs showed genetically inferred causal effects on ANX. In the subsequent MVMR analysis, reduced area of the right posterior middle-cingulate gyrus (rpMCG; beta=-0.09, P= 8.01×10 -4 ) and reduced gray-matter volume of the right anterior superior temporal gyrus (raSTG; beta=-0.09, P=1.55×10 -3 ) had direct effects on ANX. In the ANX symptom-level analysis, rpMCG was negatively associated with "tense sore oraching muscles during the worst period of anxiety" (beta=-0.13, P=8.26×10 -6 ).

Conclusions

This study identified genetically inferred effects generalizable across large cohorts, contributing to understand how changes in brain structure and function can lead to ANX.

Life-threatening, high-intensity trauma- and context-dependent anxiety in zebrafish and its modulation by epinephrine

Trauma-related psychopathology transpires in some individuals after exposure to a life-threatening event. While aberrant adrenergic processes may contribute to this, a clear understanding of how said processes influence trauma-related conditions, remain inadequate. Here, we aimed to develop and describe a novel zebrafish (Danio rerio) model of life-threatening trauma-induced anxiety that may be representative of trauma related anxiety, and to evaluate the impact of stress-paired epinephrine (EPI) exposure in the model system. Four groups of zebrafish were each exposed to different and unique stress-related paradigms, i.e., i) a sham (trauma free), ii) high-intensity trauma (triple hit; THIT), iii) high-intensity trauma in the presence of EPI exposure (EHIT), and iv) EPI exposure on its own, all applied in the presence of a color context. Novel tank anxiety was subsequently assessed at 1, 4, 7 and 14 days after the traumatic event. The present results demonstrate that 1) through day 14, THIT or EPI exposure alone induced persistent anxiety-like behavior, 2) EHIT blunted the delayed anxiety-like sequalae associated with severe trauma, 3) exposure to a trauma-paired color context prior to anxiety testing bolstered the subsequent anxiety-like behavior of THIT, but not EHIT -exposed fish, and 4) despite this, THIT- and EPI-exposed fish showed a lesser degree of contextual avoidance behavior compared to sham- or EHIT-exposed fish. These results indicate that the stressors induced long-lasting anxiety-like behavior reminiscent of post trauma anxiety, while EPI displays complex interactions with the stressor, including a buffering effect to subsequent exposure of a trauma-paired cue.

Anxiety and depression: A top-down, bottom-up model of circuit function

A functional interplay of bottom-up and top-down processing allows an individual to appropriately respond to the dynamic environment around them. These processing modalities can be represented as attractor states using a dynamical systems model of the brain. The transition probability to move from one attractor state to another is dependent on the stability, depth, neuromodulatory tone, and tonic changes in plasticity. However, how does the relationship between these states change in disease states, such as anxiety or depression? We describe bottom-up and top-down processing from Marr's computational-algorithmic-implementation perspective to understand depressive and anxious disease states. We illustrate examples of bottom-up processing as basolateral amygdala signaling and projections and top-down processing as medial prefrontal cortex internal signaling and projections. Understanding these internal processing dynamics can help us better model the multifaceted elements of anxiety and depression.

Naringenin mitigates reserpine-induced anxiety-like behavior, neurodegeneration, and oxidative stress in male rats

Reserpine (Res) induces anxiety-like behaviors, orofacial dyskinesia, and neurodegeneration in animals, the pathophysiology of which has been related to oxidative stress. The purpose of this study was to investigate whether naringenin (NG) could prevent reserpine-induced anxiety-like behaviors, orofacial dyskinesia, and neurodegeneration in male rats. Twenty-eight male rats were distributed into different groups as follows: Control rats; vehicle rats, which received the vehicles (normal saline, orally; acetic acid, intraperitoneally); Res rats (1 mg/kg/day) every other day for 3 days; and Res + NG rats, which received NG (50 mg/kg, orally, pre-treatment for 7 days), followed by Res. Administration of Res significantly increased chewing frequency compared with the control group (P < 0.01) and NG reversed the effect of Res on this factor (P < 0.05). Res induced an anxiety-like behavior in rats in the plus maze, and pre-treatment with NG improved this behavior. In addition, Res significantly increased the level of oxidative stress markers and degenerated neurons in the striatum; NG was able to ameliorate these damages. The results of this study demonstrated that Res caused behavioral disorders and increased the levels of oxidative stress in male rats; the use of NG was effective in treating these disorders. Therefore, NG should be considered as a preventive agent for reserpine-induced brain damage in male rats.

Effects of Changing Veterinary Handling Techniques on Canine Behaviour and Physiology Part 1: Physiological Measurements

Signs of distress in dogs are often normalized during routine veterinary care, creating an animal welfare concern. We sought to test whether targeted interventions during veterinary visits affect physiological indicators of stress in dogs. Some 28 dogs were examined within four visits across 8 weeks. All dogs received the same care during the first visit and were then randomized into control and intervention groups for visits 2-4. In the intervention group, 14 dogs underwent procedures designed to reduce stress and to enlist their collaboration during examination. The 14 dogs in the control group received routine care. At each visit, heart rate (HR), serum cortisol (CORT), neutrophil lymphocyte ratio (NLR), and creatine kinase (CK) were measured. A composite stress index based on the summed standardized scores for these markers was constructed. No differences in HR, NLR, and CK parameters between groups were found, and both groups had a decrease in CORT by visit four. However, the intervention group showed a greater overall decrease in CORT between the first and fourth visit than the control group (p < 0.04). The composite stress index differed between the first and fourth visits for the intervention group, but not for the control group (Intervention p = 0.03; Control p= 0.288). There was a tendency for the composite stress index to worsen at visit four vs. visit one for the control group. The findings suggest that dogs that participated in adaptive, collaborative exams and procedures designed to minimize fear had a greater reduction in stress over time compared to those receiving standard care.

Altered neurotransmission in stress-induced depressive disorders: The underlying role of the amygdala in depression

Depression is the second leading cause of disability in the world population, for which currently available pharmacological therapies either have poor efficacy or have some adverse effects. Accumulating evidence from clinical and preclinical studies demonstrates that the amygdala is critically implicated in depressive disorders, though the underlying pathogenesis mechanism needs further investigation. In this literature review, we overviewed depression and the key role of Gamma-aminobutyric acid (GABA) and Glutamate neurotransmission in depression. Notably, we discussed a new cholecystokinin-dependent plastic changes mechanism under stress and a possible antidepressant response of cholecystokinin B receptor (CCKBR) antagonist. Moreover, we discussed the fundamental role of the amygdala in depression, to discuss and understand the pathophysiology of depression and the inclusive role of the amygdala in this devastating disorder.

Inhibition of norepinephrine signaling during a sensitive period disrupts locus coeruleus circuitry and emotional behaviors in adulthood

Deficits in arousal and stress responsiveness are a feature of numerous psychiatric disorders including depression and anxiety. Arousal is supported by norepinephrine (NE) released from specialized brainstem nuclei, including the locus coeruleus (LC) neurons into cortical and limbic areas. During development, the NE system matures in concert with increased exploration of the animal's environment. While several psychiatric medications target the NE system, the possibility that its modulation during discreet developmental periods can have long-lasting consequences has not yet been explored. We used a chemogenetic strategy in mice to reversibly inhibit NE signaling during brief developmental periods and then evaluated any long-lasting impact of our intervention on adult NE circuit function and on emotional behavior. We also tested whether developmental exposure to the α2 receptor agonist guanfacine, which is commonly used in the pediatric population and is not contraindicated during pregnancy and nursing, recapitulates the effect seen with the chemogenetic strategy. Our results reveal that postnatal days 10-21 constitute a sensitive period during which alterations in NE signaling lead to changes in baseline anxiety, increased anhedonia, and passive coping behaviors in adulthood. Disruption of NE signaling during this sensitive period also caused altered LC autoreceptor function, along with circuit specific changes in LC-NE target regions at baseline, and in response to stress. Our findings indicate an early critical role for NE in sculpting brain circuits that support adult emotional function. Interfering with this role by guanfacine and similar clinically used drugs can have lasting implications for mental health.

High-performance fluorescence probe for fast and specific visualization of norepinephrine in vivo and depression-like mice

Norepinephrine (NE), as an important neurotransmitter, is closely associated with the pathogenesis of anxiety and depressive disorders. Effective monitoring of NE fluctuation aids in the diagnosis of depression and the therapeutic assessment of the antidepressant intervention. The construction of novel fluorescent probes with high specificity towards NE for imaging in depression models is still in demand urgently. In this work, a novel resorufin-based red-emitting fluorescent probe for real-time tracking NE was developed. NE can significantly increase the fluorescence of probe LNE by triggering deprotection of carbonothioate ligand via nucleophilic substitution. The probe LNE demonstrated significant NE selectivity and sensitivity over other analytes in vitro. In addition, probe LNE showed a fast response time (<10 min), and the change in fluorescence signal was positively linked with NE concentration, which could be utilized to track the dysregulation of NE in vivo. More importantly, this powerful probe was successfully employed for real-time visual and imaging of NE in living cells and depression-like behavior animals.

Prefrontal modulation of anxiety through a lens of noradrenergic signaling

Anxiety disorders are the most common class of mental illness in the U.S., affecting 40 million individuals annually. Anxiety is an adaptive response to a stressful or unpredictable life event. Though evolutionarily thought to aid in survival, excess intensity or duration of anxiogenic response can lead to a plethora of adverse symptoms and cognitive dysfunction. A wealth of data has implicated the medial prefrontal cortex (mPFC) in the regulation of anxiety. Norepinephrine (NE) is a crucial neuromodulator of arousal and vigilance believed to be responsible for many of the symptoms of anxiety disorders. NE is synthesized in the locus coeruleus (LC), which sends major noradrenergic inputs to the mPFC. Given the unique properties of LC-mPFC connections and the heterogeneous subpopulation of prefrontal neurons known to be involved in regulating anxiety-like behaviors, NE likely modulates PFC function in a cell-type and circuit-specific manner. In working memory and stress response, NE follows an inverted-U model, where an overly high or low release of NE is associated with sub-optimal neural functioning. In contrast, based on current literature review of the individual contributions of NE and the PFC in anxiety disorders, we propose a model of NE level- and adrenergic receptor-dependent, circuit-specific NE-PFC modulation of anxiety disorders. Further, the advent of new techniques to measure NE in the PFC with unprecedented spatial and temporal resolution will significantly help us understand how NE modulates PFC function in anxiety disorders.

Ketogenic Diet and Inflammation: Implications for Mood and Anxiety Disorders

The ketogenic diet, known as a low-carbohydrate, high-protein, and high-fat diet, drastically restrains the major source of energy for the body, forcing it to burn all excess fat through a process called ketosis-the breaking down of fat into ketone bodies. First suggested as a medical treatment for children suffering from epilepsy, this diet has gained increased popularity as a rapid weight loss strategy. Over the past few years, there have been numerous studies suggesting that the ketogenic diet may provide therapeutic effects for several psychiatric conditions such as mood- and anxiety-related disorders. However, despite significant progress in research, the mechanisms underlying its therapeutic effects remain largely unexplored and are yet to be fully elucidated. This chapter provides an in-depth overview of preclinical and clinical evidence supporting the use of a ketogenic diet in the management of mood and anxiety disorders and discusses its relationship with inflammatory processes and potential mechanisms of actions for its therapeutic effects.

The effect of 2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) on locomotor behaviour and muscle physiology of the sea cucumber Apostichopus japonicus

The 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) is the predominant congener of polybrominated diphenyl ethers, and it is also a persistent organic pollutant that with a higher detection rate in samples from environment and animals. To date, there have been few studies of the effects of BDE-47 on locomotion in sea cucumbers. In this study, we investigated the influence of different concentrations of BDE-47 (low: 0.1 μg/L; moderate: 1.0 μg/L; high: 10.0 μg/L) on locomotion of Apostichopus japonicus and evaluated changes in their muscle physiology using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry. The behavioural studies showed that the average and maximum velocity of movement decreased significantly in both the moderate and high BDE-47 groups after 1 day of exposure. In addition, levels of 55 metabolites were identified and characterized in the longitudinal muscle of A. japonicus exposed to BDE-47. The alteration of taurine and norepinephrine levels indicated that BDE-47 had drastic physiological effects on the longitudinal muscle of A. japonicus.

Hypertension, Anxiety and Obstructive Sleep Apnea in Cardiovascular Disease and COVID-19: Mediation by Dietary Salt

This perspective paper used a grounded theory method to synthesize evidence proposing that sodium toxicity from excessive dietary salt intake is a potential common pathophysiological mechanism that mediates the association of hypertension, obstructive sleep apnea, and anxiety with cardiovascular disease and COVID-19. Increased anxiety in these conditions may be linked to a high-salt diet through stimulation of the sympathetic nervous system, which increases blood pressure while releasing catecholamines, causing a "fight or flight" response. A rostral shift of fluid overload from the lower to the upper body occurs in obstructive sleep apnea associated with COVID-19 and cardiovascular disease, and may be related to sodium and fluid retention triggered by hypertonic dehydration. Chronic activation of the renin-angiotensin-aldosterone system responds to salt-induced dehydration by increasing reabsorption of sodium and fluid, potentially exacerbating fluid overload. Anxiety may also be related to angiotensin II that stimulates the sympathetic nervous system to release catecholamines. More research is needed to investigate these proposed interrelated mechanisms mediated by dietary salt. Furthermore, dietary interventions should use a whole-food plant-based diet that eliminates foods processed with salt to test the effect of very low sodium intake levels on hypertension, anxiety, and obstructive sleep apnea in cardiovascular disease and COVID-19.

Disruptions of circadian rhythms, sleep, and stress responses in zebrafish: New infrared-based activity monitoring assays for toxicity assessment

Behavioural disruptions are sensitive indicators of alterations to normal animal physiology and can be used for toxicity assessment. The small vertebrate zebrafish is a leading model organism for toxicological studies. The ability to continuously monitor the toxicity of drugs, pollutants, or environmental changes over several days in zebrafish can have high practical application. Although video-recordings can be used to monitor short-term zebrafish behaviour, it is challenging to videorecord prolonged experiments (e.g. circadian behaviour over several days) because of the darkness periods (nights) and the heavy data storage and image processing requirements. Alternatively, infrared-based activity monitors, widely used in invertebrate models such as drosophila, generate simple and low-storage data and could optimize large-scale prolonged behavioural experiments in zebrafish, thus favouring the implementation of high-throughput testing strategies. Here, we validate the use of a Locomotor Activity Monitor (LAM) to study the behaviour of zebrafish larvae, and we characterize the behavioural phenotypes induced by abnormal light conditions and by the Parkinsonian toxin MPP⁺. When zebrafish were deprived from daily light-cycle synchronization, the LAM detected various circadian disruptions, such as increased activity period, phase shifts, and decreased inter-daily stability. Zebrafish exposed to MPP⁺ (10, 100, 500 μM) showed a concentration-dependent decrease in activity, sleep disruptions, impaired habituation to repetitive startles (visual-motor responses), and a slower recovery to normal activity after the startle-associated stress. These phenotypes evidence the feasibility of using infrared-based LAM to assess multi-parameter behavioural disruptions in zebrafish. The procedures in this study have wide applicability and may yield standard methods for toxicity testing.

Sex-specific Effects of Endocrine-disrupting Chemicals on Brain Monoamines and Cognitive Behavior

The period of brain sexual differentiation is characterized by the development of hormone-sensitive neural circuits that govern the subsequent presentation of sexually dimorphic behavior in adulthood. Perturbations of hormones by endocrine-disrupting chemicals (EDCs) during this developmental period interfere with an organism's endocrine function and can disrupt the normative organization of male- or female-typical neural circuitry. This is well characterized for reproductive and social behaviors and their underlying circuitry in the hypothalamus and other limbic regions of the brain; however, cognitive behaviors are also sexually dimorphic, with their underlying neural circuitry potentially vulnerable to EDC exposure during critical periods of brain development. This review provides recent evidence for sex-specific changes to the brain's monoaminergic systems (dopamine, serotonin, norepinephrine) after developmental EDC exposure and relates these outcomes to sex differences in cognition such as affective, attentional, and learning/memory behaviors.