Sex differences in anxiety and emotional behavior

A predictive model for depression risk in individuals with hypertension: evidence from NHANES 2007-2020

OBJECTIVE

Hypertension increases the prevalence of depression to a certain extent and identification and diagnosis of depression frequently pose challenges for clinicians. The study aimed to construct and validate a scoring model predicting the prevalence of depression with hypertension.

METHODS

6124 individuals with hypertension were utilized from the 2007 to 2020 National Health and Nutrition Examination Survey database (NHANES), including 645 subjects that were assessed to have depressive symptoms, 390 in the development group and 255 in the validation group. Univariable and multivariable analyses were applied to analyze the impact of each parameter on depression with hypertension, resulting in establishment of a predictive model. Finally, the discriminability, calibration ability, and clinical efficacy of the model were verified for both the derivation set and validation set.

RESULTS

Ten variables comprised this model: age, gender, race, poverty to income ratio (PIR), smoke, sleep hours, exercise, diabetes, congestive heart failure, stroke. The area under the receiver operating characteristic curve for the derivation and validating sets was 0.790 and 0.723, respectively, which showed excellent discriminability. The model also fitted well with the actual prevalence of depression with hypertension in calibration and decision curve analysis (DCA) demonstrated that the depression model was practically useful.

CONCLUSION

This scoring model may provide an additional perspective for evaluating the underlying risk factors of depression for hypertensive individuals.

Central corticotropin releasing hormone receptor 2 may participate in gender differential regulation of cold-evoked eating behavior

Corticotropin-releasing factor (CRF) is an important stress hormone, and because of the different distributions and functions of its receptors, CRF has various effects on the stress response of animals. CRF receptor 2 (CRFR2) is functional receptor of CRF that may be related to appetite regulation and sex differences. In this study, male and female C57BL/6 mice were exposed to an ambient temperature of 4 °C, and feed intake were determined. Consequently, neuronal excitability, as well as the expression of CRFR2 and related genes in the brain were determined. As a result, 1) there were only significant changes in 2 h feed intake and rectal temperature in males; 2) neuronal excitability was elevated in the paraventricular thalamus (PVT) and paraventricular hypothalamic nucleus (PVH) brain regions of both male and female mice; 3) serum corticosterone and the expression of corticosterone receptors in the PVH were elevated in males but not in females; 4) the activation of the CRFR2 signal in the PVT and PVH brain regions differed by sex: the expression of CRFR2 was upregulated in male mice, and the phosphorylation of protein kinase B (AKT) and cAMP-response element binding protein (CREB) was significantly reduced; and 5) the cold-evoked eating behavior of male mice was abolished when CRFR2 in the PVT was knocked down. In summary, we conclude that male mice are more sensitive to cold stress than are female mice. The CRFR2/AKT/CREB signaling pathway in the PVT and PVH may mediate sex differences in the eating behavior of cold-exposed mice.

5-HT2C Receptors in the BNST Modulate Contextual Fear Conditioning Without Affecting Acute Early Life Stress-Enhanced Fear Learning in Adult Rats

BACKGROUND/OBJECTIVES

Rodents provide a useful translational model of fear- and anxiety-related behaviors. Previously stressed animals exhibit physiological and behavioral stress responses that parallel those observed in anxious humans. Patients diagnosed with post-traumatic stress disorder (PTSD) present with a spectrum of debilitating anxiety symptoms that result from exposure to one or more traumatic events, with individuals exposed to early adverse experiences and women having increased vulnerability for diagnoses; however, the mechanisms of this increased vulnerability remain unknown. PTSD involves a complex network of highly interconnected brain regions, including the bed nucleus of the stria terminalis (BNST). Serotonin (5-HT) release into the BNST yields an increased expression of both fear and anxiety, specifically through 5-HT2C receptor signaling. The present experiment addressed whether 5-HT2C receptor signaling in the BNST is necessary for the acquisition of early-life stress (ELS)-induced enhancements in adult contextual fear learning.

METHODS

Rats received 0 or 15 footshocks on postnatal day 17, an established model of acute ELS (aELS) that yields enhanced adult fear learning. In adulthood, rats received bilateral infusions of a vehicle, a 5-HT2C receptor antagonist (RS-102221), or a 5-HT2C receptor agonist (MK-212) into the BNST 15 min prior to one-footshock contextual fear conditioning in a novel context. The next day, rats were returned to the fear-conditioning context to assess their fear memory (freezing).

RESULTS

Females demonstrated aELS-induced enhancement in contextual fear learning, while males did not. BNST infusions of RS-102221 reduced contextual fear conditioning, independent of aELS condition and sex. Infusions of MK-212 had no effect.

CONCLUSIONS

Taken together, these data suggest that serotonergic signaling through 5-HT2C receptors in the BNST contributes to contextual fear conditioning, but not aELS-induced stress-enhanced fear learning (SEFL).

Berberine alleviates chronic pain-induced anxiety-like behaviors by inhibiting the activation of VLT-projecting cACC (Cg2) neurons

Chronic pain is often accompanied by anxiety, and gradually increasing anxiety makes the pain itself more protracted. Berberine has been found to be able to cross the blood-brain barrier to treat psychiatric disorders, but its neurocirculatory mechanisms remain unclear. Here, we found that neurons in cingulate area 2 (Cg2) of the caudal anterior cingulate cortex (cACC), but not in Cg1 of the cACC, projected to the ventral lateral thalamus (VLT). Next, we induced chronic inflammatory pain by plantar injection of complete Freund's adjuvant (CFA) and observed stable anxiety-like behaviors until two weeks postinjection. We specifically activated VLT-projecting cACC (Cg2) neurons in one-week-old CFA-induced mice without anxiety-like behaviors and in normal control mice to induce anxiety-like behaviors. We inhibited the activation of VLT-projecting cACC (Cg2) neurons in two-week-old CFA-treated mice with anxiety-like behaviors and observed that their anxiety-like behaviors were alleviated. On this basis, we further screened the effective dose of berberine for anxiolysis in two-week-old CFA-treated mice. We observed that the effective dose of berberine obtained above decreased the activity of VLT-projecting cACC (Cg2) neurons. The activation of VLT-projecting cACC (Cg2) neurons abrogated the anxiolytic effect of berberine in two-week-old CFA-treated mice.

Reliability and validity of the Persian version of the Children's Chronotype Questionnaire in school and preschool-aged children (CCTQIR)

Chronotype refers to individual differences in the circadian phase that affect a person's biological and psychological functioning. One of the most useful tools for measuring chronotype in children aged 4 - 11 years is the Children's Chronotype Questionnaire (CCTQ). Therefore, due to the importance of measuring chronotype in children and also the lack of a standard scale in Iran, this study aimed to examine the reliability and validity of the Persian version of this questionnaire for children. The participants of this cross-sectional study were 272 Iranian children aged five to eleven years with their parents, selected by convenience sampling method. To collect data, all participants completed the CCTQ and the Children's Sleep Habits Questionnaire (CSHQ), which were examined by the researchers for their construct and concurrent validity. Over a period of three weeks, 50 mothers participated in a test of the test-retest reliability of the CCTQ. During this time, their sleep patterns were monitored using a sleep diary to test for reliability. The Cronbach's alpha of the CCTQ-M/E was 0.71. Test-retest reliability using the Spearman correlation coefficient between two observations with an interval of three weeks was 0.83. The MSFsc index was significantly correlated with M/E, CT, and most of the parent-reported sleep/wake parameters. In addition, the three indicators of the CCTQ were significantly associated with most of the sleep/wake parameters of the sleep diary and the components of the CSHQ. The Persian version of the CCTQ has desirable psychometric properties for the assessment of chronotype in five- to eleven-year-old children.

Anxiety-Like Behaviors in Mice Unmasked: Revealing Sex Differences in Anxiety Using a Novel Light-Heat Conflict Test

Anxiety and chronic pain afflict hundreds of millions worldwide. Anxiety and pain are more prevalent in females compared to males. Unfortunately, robust sex differences in human anxiety are not recapitulated in rodent tests, and results from rodent pain studies frequently fail to translate clinically. Therefore, there is a need to develop tests that reflect the differential salience of anxiety or pain-related stimuli between the sexes. Accordingly, here we introduce the Thermal Increments Dark-Light (TIDAL) conflict test. The TIDAL test places an anxiety-relevant stimulus (dark vs. illuminated chamber) in conflict with a heat-related stimulus (incrementally heated vs. isothermic chamber); mice freely explore both apparatus chambers. Here, we aim to determine whether the TIDAL conflict test reveals in mice underappreciated sex differences in anxiety and/or heat sensitivity. We establish in four distinct experiments that females on the TIDAL conflict test persist substantially longer on the dark-heated plate, suggesting that female mice exhibit elevated anxiety-like behavior. Mice more strongly prefer the heated-dark plate on the TIDAL conflict test compared to control thermal place preference with both chambers illuminated. We also reveal that an anxiety-relieving drug, paroxetine, reduces mouse preference for the heating dark plate, supporting the validity of the TIDAL test. Therefore, our new TIDAL conflict test reliably unmasks the relative salience of anxiety (vs. heat sensitivity): mice that are female exhibit robust anxiety-like behaviors not consistently observed in classical tests. Future studies should incorporate TIDAL and other conflict tests to better understand rodent behavior and to identify mechanisms underlying anxiety and pain.

Tobacco Smoke Exposure in Children and Adolescents: Prevalence, Risk Factors and Co-Morbid Neuropsychiatric Conditions in a US Nationwide Study

BACKGROUND

Tobacco smoke exposure (TSE) is a major public health concern, impacting not only smokers but also those around them, particularly children and adolescents. TSE is linked to various neuropsychiatric conditions and significantly impacts quality of life. This study examines the prevalence, socio-demographic factors, and the impact of TSE on the severity of neurological and psychiatric co-morbidities.

METHODS

Data from the National Survey of Children's Health (NSCH) in the US from 2020 to 2021 were used in this study. We included 91,404 children and adolescents aged between 0 to 17 years for the TSE prevalence and socio-demographic analysis, and 79,182 children and adolescents aged between 3 and 17 years for the neuropsychiatric co-morbidities analysis. The mean age of these individuals was 8.7 (standard deviation: 5.3), and 11,751 (12.9%) had confirmed TSE.

RESULTS

Our analysis showed that TSE is more common in males (53%) than females (47%). Additionally, the odds of TSE were higher in families with a lower income level and with American Indian/Native Alaska racial descent. We found that 36.4% of youths with TSE developed at least one co-morbid condition. The most common neuropsychiatric co-morbidities were anxiety problems (15.7%), Attention-Deficit Hyperactivity Disorder (ADHD) (15.5%), behavioral and conduct problems (13.7%), and learning disability (12%). Females had lower odds of co-morbid anxiety (OR: 0.3, p = 0.02) and Autism Spectrum Disorder (ASD) (OR: 0.9, p = 0.04) than males. Asians showed lower odds of co-morbid ADHD (OR: 0.3, p-value: 0.001), anxiety problems (OR: 0.4, p-value: 0.003), speech/other language disorder (OR: 0.4, p-value: 0.001), developmental delay (OR: 0.4, p-value: 0.001), behavioral and conduct problems (OR: 0.4, p-value: 0.003), and learning disability (OR: 0.5, p-value: 0.004). Conversely, American Indian children and adolescents had higher odds of co-morbid headaches (OR: 3, p-value: 0.005). TSE co-occurring with Tourette's Syndrome (TS) (OR: 4.4, p < 0.001), ADHD (OR: 1.3, p < 0.001), developmental delay (OR: 1.3, p < 0.001), behavioral problems (OR: 1.3, p < 0.001), headaches (OR: 1.3, p = 0.005), depression (OR: 1.2, p = 0.02), anxiety (OR: 1.2, p < 0.01), ASD (OR: 1.2, p < 0.001), and learning disability (OR: 1.2, p = 0.03) may contribute to a more severe manifestation.

CONCLUSIONS

ADHD, behavioral/conduct problems, and learning disabilities were the most prevalent co-occurring conditions with TSE. Our findings show that 36.4% of youths with TSE had at least one neuropsychiatric comorbidity. Screening for these conditions in youths exposed to TSE is crucial for early detection and interventions to increase their mental health and well-being.

Examining Brain Activity Responses during Rat Ultrasonic Vocalization Playback: Insights from a Novel fMRI Translational Paradigm

Despite decades of preclinical investigation, there remains limited understanding of the etiology and biological underpinnings of anxiety disorders. Sensitivity to potential threat is characteristic of anxiety-like behavior in humans and rodents, but traditional rodent behavioral tasks aimed to assess threat responsiveness lack translational value, especially with regard to emotionally valenced stimuli. Therefore, development of novel preclinical approaches to serve as analogues to patient assessments is needed. In humans, the fearful face task is widely used to test responsiveness to socially communicated threat signals. In rats, ultrasonic vocalizations (USVs) are analogous social cues associated with positive or negative affective states that can elicit behavioral changes in the receiver. It is therefore likely that when rats hear aversive alarm call USVs (22 kHz), they evoke translatable changes in brain activity comparable with the fearful face task. We used functional magnetic resonance imaging in male and female rats to assess changes in BOLD activity induced by exposure to aversive 22 kHz alarm calls emitted in response to threatening stimuli, prosocial (55 kHz) USVs emitted in response to appetitive stimuli, or a computer-generated 22 kHz tone. Results show patterns of regional activation that are specific to each USV stimulus. Notably, limbic regions clinically relevant to psychiatric disorders (e.g., amygdala, bed nucleus of the stria terminalis) are preferentially activated by either aversive 22 kHz or appetitive 55 kHz USVs. These results support the use of USV playback as a promising translational tool to investigate affective processing under conditions of distal threat in preclinical rat models.

Association of anxiety, age and oral health-related quality of life with periodontitis: A case-control study

OBJECTIVE

This case-control study evaluated the association of sociodemographic profile, mental health disorders and oral health-related quality of life (OHRQoL) with periodontitis.

METHODS

Patients with periodontitis (PP, n = 50) and control patients (CP, n = 50) were allocated into 2 groups after a complete periodontal examination. Data collection included age, sex, marital status, education and application of 2 questionnaires: Hospital Anxiety and Depression Scale for the diagnosis of anxiety/depression and Impact Profile on Oral Health (OHIP-14) for classification of well-being. An adjusted multiple binary logistic regression analysis was performed to assess the effect of all studied covariates on periodontitis.

RESULTS

The results show that mean clinical attachment loss and periodontal probing depth were 5.92 (SD = 0.42) and 5.46 (SD = 0.78) in PP and 0.00 (SD = 0.00) and 2.85 (SD = 0.23) in CP, respectively (p < 0.001). The regression analysis demonstrated a significant effect on periodontitis for age (OR = 1.13; p < 0.0001; 95% CI: 1.07-1.20), with the PP having more people aged 50 years or older than CP, anxiety (OR = 1.25; p = 0.020; 95% CI: 1.04-1.50) and OHIP-14 (OR = 1.17; p < 0.0001; 95% CI: 1.08-1.226).

CONCLUSIONS

The findings showed a positive association between anxiety, OHRQoL and age with periodontitis.

A matter of personality and point of view: How the interplay of reinforcement sensitivity and general attitudes towards pain impacts the responsivity to acute pain

BACKGROUND

The relatively stable individual differences reflected in Grey's revised reinforcement sensitivity theory (rRST), with foundations in neurophysiology and learning theory, appear particularly applicable to the study of pain. However, remarkably little research has been conducted in this area. In acute pain, activation of the behavioural approach system (BAS), the behavioural inhibition system (BIS) and the fight, flight, freezing system might depend on an individual's evaluation of pain. It was thus hypothesised that higher-order interactions of rRST traits and pain attitudes affect pain responsiveness.

METHODS

To investigate relationships between rRST traits and pain attitudes and to identify patterns between clusters of participants, we conducted a study in which N = 275 healthy participants filled in Reuter and Montag's rRST-Q and the General Attitudes Towards Pain Inventory (GATPI). Experimental (pressure, electrical, thermal) and self-report data of pain responsiveness were collected in a subsample (N = 113).

RESULTS

We found significant correlations between rRST-Q and GATPI subscales of up to r = 0.34. Two clusters were identified, significantly differing in rRST-Q and GATPI scores. Pain avoiders, characterized by high BIS, flight, freezing and negative pain attitudes, were found to be significantly more pain sensitive than pain approachers, characterized by high BAS, fight and positive pain attitudes. Moderate effects (d = 0.56 to d = 0.70) were demonstrated in subjective and objective measures and across pain modalities.

CONCLUSIONS

The present study expands the scientific knowledge on factors influencing pain responsiveness. Future research is needed to confirm implications for chronic pain prevention and therapy, particularly concerning pain avoiders.

SIGNIFICANCE

We have identified two clusters of participants, pain avoiders and pain approachers, that not only present differential patterns of revised reinforcement theory traits and general attitudes towards pain but also differ in their pain responsiveness. Pain avoiders appeared more pain sensitive compared to pain approachers, both in objective and subjective measurements, with implications for the improvement of chronic pain prevention and therapy.

Are technology-based health education methods able to reduce oral health inequalities between the sexes in adolescents? A cluster randomized trial

PURPOSE

Determine if different technology-based health education interventions can reduce oral health inequalities between the sexes in a sample of adolescents.

METHODS

A cluster randomized clinical trial was conducted in three phases with an initial sample of 291 male and female adolescents 14-19 years of age. Phase I (n = 288) comprised a clinical examination performed by a calibrated examiner using the simplified oral hygiene index (OHI-S) and gingival bleeding index (GBI). Phase II involved two educational interventions: video (VD; n = 147) or oral counselling (OR; n = 141) with standardized content. In phase III, an App was made available to half of the clusters (OR + App; n = 66/OR without App; n = 71/VD + App; n = 63/VD without App; n = 63), and the clinical examination was performed a second time. Data were evaluated using descriptive analysis and nonparametric tests.

RESULTS

In phase I, boys had a lower standard of oral hygiene compared with girls, with higher mean OHI-S (p = 0.039) and GBI (p = 0.015). After VD and OR interventions, no significant difference between sexes was found regarding the mean OHI-S. However, males had a higher mean GBI compared with females in the OR group (p = 0.006). When the App was added to OR and VD groups, males in the 'OR without App' group had a higher mean GBI compared with females (p = 0.007).

CONCLUSION

This clinical trial demonstrated that educational interventions involving information technologies were effective at reducing oral health inequalities between the sexes among adolescents. However, oral counselling alone was not efficient in reducing GBI in male adolescents.

The Estrous Cycle Influences the Effects of Fatty Acid Amide Hydrolase and Monoacylglycerol Lipase Inhibition in the Anxiety-Like Behavior in Rats

Background: Sex differences in the response to the anxiety-related effects of cannabinoid drugs have been reported, with females being more sensitive than males. Evidence suggests that, according to sex and estrous cycle phase (ECP), the content of the endocannabinoids (eCBs) N-arachidonoylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG) varies in brain areas involved in the anxiety-like behavior. Methods: Considering the lack of studies evaluating sex and ECP differences in the eCB system in anxiety, using URB597, a fatty acid amide hydrolase inhibitor, or MJN110, a monoacylglycerol lipase inhibitor, we explored the effects of increasing AEA or 2-AG levels, respectively, in cycling and ovariectomized (OVX) female adult Wistar rats, as well as males, subjected to the elevated plus maze. Results: The administration of URB597 (0.1 or 0.3mg/kg; intraperitoneally) either increased or reduced the percentage of open arms time (%OAT) and open arms entries (%OAE), being anxiolytic in diestrus and anxiogenic in estrus. No effects were observed in proestrus or when all ECPs were analyzed together. Both doses produced anxiolytic-like effects in males. In OVX females, the anxiolytic-like effect of URB597 0.1 was associated with low levels of estradiol, whereas the anxiogenic-like effect of URB597 0.3 was spared by estradiol pretreatment. The systemic administration of MJN110 3.0 mg/kg reduced the risk assessment behavior (RAB), suggesting an anxiolytic-like effect independent of the ECP. When considering the ECP, MJN110 3.0 increased the %OAT and reduced the RAB, being anxiolytic in estrus and diestrus. No effects were observed in proestrus. Both doses of MJN110 were anxiogenic in males. In OVX females, the anxiolytic-like effect of MJN110 was dependent on low estradiol levels. Conclusion: Together, our findings support the evidence that females react differently to the effects of cannabinoids in the anxiety-like behavior; in addition, AEA and 2-AG modulation elicits anxiety-like responses that are closely influenced by hormone levels, mainly estradiol.

Improved accuracy for estrous cycle staging using supervised object detection

The estrous cycle regulates reproductive events and hormone changes in female mammals and is analogous to the menstrual cycle in humans. Monitoring this cycle is necessary as it serves as a biomarker for overall health and is crucial for interpreting study results. The estrous cycle comprises four stages influenced by fluctuating levels of hormones, mainly estradiol and progesterone. Tracking the cycle traditionally relies on vaginal cytology, which categorizes stages based on three epithelial cell concentrations. However, this method has limitations, including time-consuming training and variable accuracy among researchers. To address these challenges, this study assessed the feasibility and reliability of two machine learning methods. An object detection-based machine learning model, Object Detection Estrous Staging (ODES), was employed to identify cell types throughout the estrous cycle in mice. A dataset of 555 vaginal cytology images with four different stains was annotated, with 335 images for training, 45 for validation, and 175 for testing. A novel, accurate set of rules for classification was derived by analyzing training images. ODES achieved an average accuracy of 87% in classifying cycle stages and took only 3.9 minutes to analyze 175 test images. The use of object detection machine learning significantly improved accuracy and efficiency compared to previously derived supervised image classification models (33-45% accuracy) and human accuracy (66% accuracy), refining research practices for female studies. These findings facilitate the integration of the estrous cycle into research, enhancing the quality of scientific results by allowing for efficient and accurate identification of the cycle stage.

High-fat diet, microbiome-gut-brain axis signaling, and anxiety-like behavior in male rats

Obesity, associated with the intake of a high-fat diet (HFD), and anxiety are common among those living in modern urban societies. Recent studies suggest a role of microbiome-gut-brain axis signaling, including a role for brain serotonergic systems in the relationship between HFD and anxiety. Evidence suggests the gut microbiome and the serotonergic brain system together may play an important role in this response. Here we conducted a nine-week HFD protocol in male rats, followed by an analysis of the gut microbiome diversity and community composition, brainstem serotonergic gene expression (tph2, htr1a, and slc6a4), and anxiety-related defensive behavioral responses. We show that HFD intake decreased alpha diversity and altered the community composition of the gut microbiome in association with obesity, increased brainstem tph2, htr1a and slc6a4 mRNA expression, including in the caudal part of the dorsomedial dorsal raphe nucleus (cDRD), a subregion previously associated with stress- and anxiety-related behavioral responses, and, finally, increased anxiety-related defensive behavioral responses. The HFD increased the Firmicutes/Bacteroidetes ratio relative to control diet, as well as higher relative abundances of Blautia, and decreases in Prevotella. We found that tph2, htr1a and slc6a4 mRNA expression were increased in subregions of the dorsal raphe nucleus in the HFD, relative to control diet. Specific bacterial taxa were associated with increased serotonergic gene expression in the cDRD. Thus, we propose that HFD-induced obesity is associated with altered microbiome-gut-serotonergic brain axis signaling, leading to increased anxiety-related defensive behavioral responses in rats.

Age and sex effects on paired-pulse suppression and prepulse inhibition of auditory evoked potentials

Responses to a sensory stimulus are inhibited by a preceding stimulus; if the two stimuli are identical, paired-pulse suppression (PPS) occurs; if the preceding stimulus is too weak to reliably elicit the target response, prepulse inhibition (PPI) occurs. PPS and PPI represent excitability changes in neural circuits induced by the first stimulus, but involve different mechanisms and are impaired in different diseases, e.g., impaired PPS in schizophrenia and Alzheimer's disease and impaired PPI in schizophrenia and movement disorders. Therefore, these measures provide information on several inhibitory mechanisms that may have roles in clinical conditions. In the present study, PPS and PPI of the auditory change-related cortical response were examined to establish normative data on healthy subjects (35 females and 32 males, aged 19-70 years). We also investigated the effects of age and sex on PPS and PPI to clarify whether these variables need to be considered as biases. The test response was elicited by an abrupt increase in sound pressure in a continuous sound and was recorded by electroencephalography. In the PPS experiment, the two change stimuli to elicit the cortical response were a 15-dB increase from the background of 65 dB separated by 600 ms. In the PPI experiment, the prepulse and test stimuli were 2- and 10-dB increases, respectively, with an interval of 50 ms. The results obtained showed that sex exerted similar effects on the two measures, with females having stronger test responses and weaker inhibition. On the other hand, age exerted different effects: aging correlated with stronger test responses and weaker inhibition in the PPS experiment, but had no effects in the PPI experiment. The present results suggest age and sex biases in addition to normative data on PPS and PPI of auditory change-related potentials. PPS and PPI, as well as other similar paradigms, such as P50 gating, may have different and common mechanisms. Collectively, they may provide insights into the pathophysiologies of diseases with impaired inhibitory function.

Generalized fear after acute stress is caused by change in neuronal cotransmitter identity

Overgeneralization of fear to harmless situations is a core feature of anxiety disorders resulting from acute stress, yet the mechanisms by which fear becomes generalized are poorly understood. In this study, we show that generalized fear in mice results from a transmitter switch from glutamate to γ-aminobutyric acid (GABA) in serotonergic neurons of the lateral wings of the dorsal raphe. Similar change in transmitter identity was found in the postmortem brains of individuals with posttraumatic stress disorder (PTSD). Overriding the transmitter switch in mice prevented the acquisition of generalized fear. Corticosterone release and activation of glucocorticoid receptors mediated the switch, and prompt antidepressant treatment blocked the cotransmitter switch and generalized fear. Our results provide important insight into the mechanisms involved in fear generalization.

Physiological Responses to Organizational Stressors Among Police Managers

Police officers demonstrate increased risk of physical and mental health conditions due to repeated and prolonged exposure to stressful occupational conditions. Occupational stress is broken into two types: operational stress, related to the content of field duties (e.g., physical demands); and organizational stress, related to cultural and structural contexts (e.g., interpersonal relationships). Applied police research focuses on physiological activation in operational tasks as a mechanism explaining health risk and non-optimal performance outcomes. However, recent survey-based studies indicate numerous organizational stressors associated with self-reported mental health symptoms. The question of whether organizational stressors elicit significant physiological activity remains unknown. The current proof-of-concept field study tests the hypothesis that police managers will display significant physiological reactivity before, during, and after engaging in reality-based scenarios representative of stressful police management tasks developed from evidence-based pedagogical approaches. A sample of 25 training police managers (7 female, M = 16 +/- 5.3 years of experience) completed 5 reality-based scenarios, including resolving a heated conflict between colleagues, delivering negative feedback to a subordinate, and critical incident command. Significant increases in heart rate relative to rest were observed during all tasks, and in anticipation of several tasks. Greater increases in reactive heart rate were associated with longer recovery times. Sex differences and relationships between objective biological and subjective psychological measures of stress are discussed. The current findings demonstrate significant physiological responses to organizational stressors similar to levels observed during operational tasks, despite the absence of physical or aerobic exertion. Implications for police health and training are discussed.

Sex- and gender-specific differences in symptoms and health-related quality of life among patients with gastroesophageal reflux disease

Gastroesophageal Reflux Disease (GERD) is a common chronic gastrointestinal disorder affecting both men and women. Nonerosive reflux disease generally affects more women, whereas GERD complications such as Barrett's esophagus (BE) or esophageal cancer affect more men. The aim of this study was to evaluate sex- and gender-specific symptoms and health-related quality of life (HRQoL) among men and women with GERD. Patients with clinical signs of reflux and completion of 24-hour pH-Impedance testing at the University Hospital Cologne were included into the study. Evaluation of symptoms and HRQoL included the following validated questionnaires: GERD-Health-Related Quality of Life (GERD HRQL), Gastrointestinal Quality of Life Index (GIQLI), and Hospital Anxiety and Depression Scale (HADS). In all, 509 women and 355 men with GERD were included. Men had a significantly higher DeMeester score (60.2 ± 62.6 vs. 43 ± 49.3, P < 0.001) and a higher incidence of BE (18.6 vs. 11.2%, P = 0.006). Women demonstrated significantly higher levels of anxiety (30.9 vs. 14.5%, P = 0.001), more severely impacting symptoms (45.3 ± 11.3 vs. 49.9 ± 12.3, P < 0.001), as well as physical (14.2 ± 5.7 vs. 16.7 ± 5.6, P < 0.001) and social dysfunction (13.3 ± 4.8 vs. 14.8 ± 4.3, P = 0.002). Women further reported a lower HRQoL (85.3 ± 22.7 vs. 92.9 ± 20.8, P < 0.001). Men and women differ on biological, psychological, and sociocultural levels.

Perinatal exposure to bisphenol A or S: Effects on anxiety-related behaviors and serotonergic system

Bisphenols, synthetic organic compounds used in the production of plastics, are an extremely abundant class of Endocrine Disrupting Chemicals, i.e., exogenous chemicals or mixtures of chemicals that can interfere with any aspect of hormone action. Exposure to BPs can lead to a wide range of effects, and it is especially dangerous if it occurs during specific critical periods of life. Focusing on the perinatal exposure to BPA or its largely used substitute BPS, we investigated the effects on anxiety-related behaviors and the serotonergic system, which is highly involved in controlling these behaviors, in adult mice. We treated C57BL/6J dams orally with a dose of 4 μg/kg body weight/day (i.e., EFSA TDI) of BPA or BPS dissolved in corn oil or with vehicle alone, at the onset of mating and continued treatment until the offspring were weaned. Adult offspring of both sexes performed the elevated plus maze and the open field tests. Then, we analyzed the serotonergic system in dorsal (DR) and median (MnR) raphe nuclei by immunohistochemical techniques. Behavioral tests highlighted alterations in BPA- and BPS-treated mice, suggesting different effects of the bisphenols exposure on anxiety-related behavior in males (anxiolytic) and females (anxiogenic). The analysis of the serotonergic system highlighted a sex dimorphism in the DR only, with control females showing higher values of serotonin immunoreactivity (5-HT-ir) than control males. BPA-treated males displayed a significant increase of 5-HT-ir in all analyzed nuclei, whereas BPS-treated males showed an increase in ventral DR only. In females, both bisphenols-treated groups showed a significant increase of 5-HT-ir in dorsal DR compared to the controls, and BPA-treated females also showed a significant increase in MnR.These results provide evidence that exposure during the early phases of life to BPA or BPS alters anxiety and the raphe serotonergic neurons in a sex-dependent manner.

Decomposing the rural-urban differences in depression among multimorbid older patients in India: evidence from a cross-sectional study

BACKGROUND

In India, the prevalence of depression among older adults dealing with multiple health conditions varies between rural and urban areas due to disparities in healthcare access and cultural factors. The distinct patterns observed underscore the necessity for tailored research and interventions to address mental health inequalities among multimorbid older patients in diverse geographic contexts.

METHODS

This study used data from the Longitudinal Ageing Study in India (LASI) wave 1 (2017-18). A total of 7,608 adults aged ≥ 60 years who were diagnosed with two or more chronic conditions (such as hypertension, diabetes, cancer, chronic lung disease, chronic heart diseases, stroke, bone/joint disease, any neurological or psychiatric diseases, and high cholesterol) were included in this study. Descriptive statistics, bivariate analysis, logistic regression estimates, and Fairlie decomposition method were used to accomplish the study's objectives.

RESULTS

The prevalence of depression among older adults with multimorbidity was 9.48% higher in rural areas (38.33%) than in urban areas (28.85%).. Older adults with multimorbidity belonging to the scheduled caste group were 40% more likely to experience depression. Moreover, those with multimorbidity and any form of disability in activities of daily living (ADL) were 93% more likely to experience depression than those without disability, whereas those with multimorbidity and perceived good general health were 65% less likely to suffer from depression than those with poor self-perceived health. Additionally, decomposition analysis revealed that education (35.99%), caste status (10.30%), IADL disability (19.30%), and perceived discrimination (24.25%) were the primary factors contributing to the differences in depression prevalence among older adults with multimorbidity between rural and urban areas.

CONCLUSIONS

We found significant rural-urban differences in depression among older Indians with multimorbidity. The findings underscore the need for targeted interventions that address the unique challenges faced by older patients in rural areas, including lack of social capital, discrimination, and limited resources that enable access to healthcare services. Policymakers and healthcare professionals must collaboratively design and implement effective strategies to improve the mental health and overall well-being of rural older adults, particularly those with multiple comorbidities.

Meat consumption & positive mental health: A scoping review

The objective of this scoping review was to examine the breadth of the existing literature on the relation between meat consumption or meat abstention and positive psychological functioning. In April 2022, we conducted a systematic search of online databases (PubMed, PsycINFO, CINAHL Plus, Medline, Cochrane Library, and Web of Science) for primary research examining positive psychological functioning in meat consumers and those who abstain from meat. Thirteen studies met the inclusion/exclusion criteria, representing 89,138 participants (54,413 females and 33,863 males) with 78,562 meat consumers and 10,148 meat abstainers (13-102 years) from multiple geographic regions. The primary outcomes were life satisfaction, "positive mental health", self-esteem, and vigor. The secondary outcomes were "meaning in life", optimism, positive emotions, and psychological well-being. Eight of the 13 studies demonstrated no differences between the groups on positive psychological functioning, three studies showed mixed results, and two studies showed that compared to meat abstainers, meat consumers had greater self-esteem, "positive mental health", and "meaning in life". Studies varied substantially in methods and outcomes. Although a small minority of studies showed that meat consumers had more positive psychological functioning, no studies suggested that meat abstainers did. There was mixed evidence for temporal relations, but study designs precluded causal inferences. Our review demonstrates the need for future research given the equivocal nature of the extant literature on the relation between meat consumption and meat abstention and positive psychological functioning.

Prevalence and predictors of social anxiety disorders among Malaysian secondary school students during the COVID-19 pandemic: Exploring the influence of internet gaming disorder and impulsivity

This study aimed to investigate the prevalence of social anxiety disorder (SAD) among Malaysian secondary school students during the COVID-19 pandemic and to explore its correlations with demographic variables, impulsivity behavior, and internet gaming disorder (IGD). A total of 1574 participants from 12 government secondary schools across five Malaysian states, comprising 569 males and 1005 females, completed an online questionnaire containing validated Malay versions of the Social Interaction Anxiety Scale, Barratt Impulsiveness Scale, and Internet Gaming Disorder Scale - Short Form. The findings revealed a notable SAD prevalence rate of 40.53% among Malaysian adolescents. Logistic regression analysis unveiled significant associations between SAD and factors such as attention impulsiveness (OR = 2.58, p < .001), motor impulsiveness (OR = 1.47, p = .03), female gender (OR = 2, p < .001), Malay ethnicity, and IGD (OR = 1.08, p < .001). In conclusion, this study provides valuable insights into the extent of social anxiety experienced by Malaysian secondary school students during the pandemic, shedding light on the demographic and psychosocial factors linked to its emergence. Furthermore, the research underscores a robust link between IGD and SAD, emphasizing the need for comprehensive interventions addressing both issues concurrently. By recognizing the multifaceted nature of these associations, future interventions can be tailored to provide holistic support for adolescents' mental well-being.

Practical solutions for including sex as a biological variable (SABV) in preclinical neuropsychopharmacological research

Recently, many funding agencies have released guidelines on the importance of considering sex as a biological variable (SABV) as an experimental factor, aiming to address sex differences and avoid possible sex biases to enhance the reproducibility and translational relevance of preclinical research. In neuroscience and pharmacology, the female sex is often omitted from experimental designs, with researchers generalizing male-driven outcomes to both sexes, risking a biased or limited understanding of disease mechanisms and thus potentially ineffective therapeutics. Herein, we describe key methodological aspects that should be considered when sex is factored into in vitro and in vivo experiments and provide practical knowledge for researchers to incorporate SABV into preclinical research. Both age and sex significantly influence biological and behavioral processes due to critical changes at different timepoints of development for males and females and due to hormonal fluctuations across the rodent lifespan. We show that including both sexes does not require larger sample sizes, and even if sex is included as an independent variable in the study design, a moderate increase in sample size is sufficient. Moreover, the importance of tracking hormone levels in both sexes and the differentiation between sex differences and sex-related strategy in behaviors are explained. Finally, the lack of robust data on how biological sex influences the pharmacokinetic (PK), pharmacodynamic (PD), or toxicological effects of various preclinically administered drugs to animals due to the exclusion of female animals is discussed, and methodological strategies to enhance the rigor and translational relevance of preclinical research are proposed.

Anxiety and Alzheimer's disease pathogenesis: focus on 5-HT and CRF systems in 3xTg-AD and TgF344-AD animal models

Dementia remains one of the leading causes of morbidity and mortality in older adults. Alzheimer's disease (AD) is the most common type of dementia, affecting over 55 million people worldwide. AD is characterized by distinct neurobiological changes, including amyloid-beta protein deposits and tau neurofibrillary tangles, which cause cognitive decline and subsequent behavioral changes, such as distress, insomnia, depression, and anxiety. Recent literature suggests a strong connection between stress systems and AD progression. This presents a promising direction for future AD research. In this review, two systems involved in regulating stress and AD pathogenesis will be highlighted: serotonin (5-HT) and corticotropin releasing factor (CRF). Throughout the review, we summarize critical findings in the field while discussing common limitations with two animal models (3xTg-AD and TgF344-AD), novel pharmacotherapies, and potential early-intervention treatment options. We conclude by highlighting promising future pharmacotherapies and translational animal models of AD and anxiety.

Diazepam effects on anxiety-related defensive behavior of male and female high and low open-field activity inbred mouse strains

Open-field activity is a commonly used measure of anxiety-related behavior in rodents. The inbred High and Low Activity strains of mice, selected for extreme differences in open-field activity, have been used as a genetic model of anxiety-related behaviors. These selected strains have been thoroughly studied through extensive behavioral testing, quantitative trait locus (QTL) mapping, whole-genome sequencing, and RNA sequencing, to uncover phenotypic and genotypic differences related to anxiety-related behavior. However, the effects of anxiolytic drugs on anxiety-related behavior in these strains have not been studied previously. This study allowed us to expand on previous findings to further characterize the anxiety-related behavior of these unique strains, using an anxiolytic drug. The goal of this study was to determine whether the treatment of adult male and female High Activity (low anxiety) and Low Activity (high anxiety) mice with diazepam, an agonist at the benzodiazepine allosteric site on the GABAA receptor and a drug commonly prescribed to treat anxiety disorders in humans, led to decreases in anxiety-like defensive behavioral responses as assessed in the open-field test (OFT) and elevated plus-maze (EPM). We tested the effects of three doses of diazepam (0, 0.5, 1.0, 3.0 mg/kg, i.p.), given 30 min before behavioral testing to one High Activity strain (H2) and two Low Activity strains (L1 and L2). There was an anxiolytic effect of diazepam observed in the High Activity strain, with more entries into the open arms of the elevated plus-maze, an effect similar to that seen in common mouse strains. However, the only anxiolytic effect of diazepam seen in the Low Activity strains was a reduction in stretch attend posture (SAP). Low Activity strains also displayed freezing behavior in both the OFT and EPM. The combination of the observed freezing behavior, that was not reduced by diazepam, and the reduction in SAP seen with diazepam, suggests a more complex phenotype that includes a component of innate fear in addition to anxiety-related risk assessment behaviors. Since fear and anxiety are distinguishable traits, and both contribute to human anxiety disorders, these results provide novel insight about interpretation of previous genetic and phenotypic differences observed between the High and Low Activity strains.

Dental Anxiety and Its Association with Dietary Intake and Food Groups: A Cross-Sectional Study

Although there is an established connection between diet and mental health, the relationship between diet and dental anxiety has not been examined yet. The purpose of this study was to fill this gap by assessing the association between diet quality, mental distress, and dental anxiety. The data was collected through an anonymous Google Forms survey. The survey consisted of a modified version of the validated Food-Mood Questionnaire and the Modified Dental Anxiety Scale with questions about demographics, dental health, and dental health anxieties. Data collection was performed over seven months, from April to October 2021. Data were analyzed using Pearson's correlation coefficient in SPSS version 25.0 and STATA 17 for sample size calculation, data processing and regression analyses. A total of 506 responses were collected. Our data verified that diet quality modulates dental anxiety. Women exhibited a stronger link with dental anxiety than men (p < 0.01). Consumption of sugary foods was associated with different attributes of dental anxiety (p < 0.01). Low-quality energy-dense foods and dairy were associated with dental anxiety, whereas caffeine, meat, nuts, and green leafy vegetables produced a negative correlation. This cross-sectional study provides proof of concept that dietary patterns are potentially associated with dental anxiety.

Exploration of a Psychological Defensive Syndrome Against Depressive Symptomatology in a Community Sample of Indian Women

The prevalence of depressive symptomatology in Indian women and the associated treatment gap are alarming and require interventions at a community level. Such interventions may succeed if the specific risk and protective factors are appropriately identified and addressed. Identifying such factors may suggest a Psychological Defensive Syndrome (PDS) against depressive symptomatology, and inculcating this PDS through specific interventions may help individuals manage depressive symptomatology. For evaluating the feasibility of such an idea, a two-phase research project was initiated, and the current paper presents findings of its first phase. The primary aim of the first phase was to explore the predictive relationship between depressive symptomatology and rumination, reappraisal, resilience, self-efficacy, neuroticism, and extraversion. A total of 671 women (Mage = 23.71) responded to standardized questionnaires in a semi-structured interview setting. The obtained data were subjected to correlational, regression, and path analysis. The findings support all the hypotheses; women, who reported less engagement in rumination and more in reappraisal, who scored low on neuroticism and high on extraversion, resilience and self-efficacy, showed less severe depressive symptoms than their counterparts. This pattern can be thought of as a PDS against depressive symptoms in Indian women. These results highlight the importance of addressing these factors in preventing and assuaging depressive symptomatology in Indian women.

Factors associated with COVID-19 vaccination hesitancy in South Korea: A cross-sectional study

Vaccination against COVID-19 has been promoted as a way to protect oneself and others from infection. To ensure the comprehensive acceptance of COVID-19 vaccines, the factors that affect COVID-19 vaccination hesitancy should be examined. This study aimed to identify the factors that affect COVID-19 vaccination hesitancy among Korean adults, focusing on COVID-19 knowledge and attitudes toward vaccination. This was a cross-sectional study conducted with 2286 Korean adults aged 20-64 years. Demographic characteristics, knowledge regarding COVID-19, and attitudes toward vaccination were assessed. A generalized linear model with Poisson regression was used to identify factors associated with COVID-19 vaccination hesitancy. Approximately 67% of the COVID-19 knowledge-related questions were correctly answered. A neutral attitude toward vaccination and relatively low vaccination hesitancy were found. COVID-19 vaccination hesitancy was affected by individuals' attitudes toward vaccination, as well as their gender and age, but not by their knowledge. Interventions or policies considering gender and age could be helpful in reducing COVID-19 vaccination hesitancy. Strategies to disseminate more accurate and novel information related to the COVID-19 vaccines should be implemented.

Estrous cycle dependent expression of oxycodone conditioned reward in rats

Oxycodone is one of the most widely prescribed and misused opioid painkillers in the United States. Evidence suggests that biological sex and hormonal status can impact drug reward in humans and rodents, but the extent to which these factors can influence the rewarding effects of oxycodone is unclear. The purpose of this study was to utilize place conditioning to determine the effects of sex and female hormonal status on the expression of oxycodone conditioned reward in rats. Gonadally intact adult Sprague-Dawley male and female rats were used to test: (1) whether both sexes express conditioned reward to oxycodone at similar doses, (2) the impact of conditioning session length on oxycodone conditioned reward expression in both sexes, and (3) the influence of female estrous cycle stage on oxycodone conditioned reward expression. Both sexes expressed conditioned reward at the same doses of oxycodone. Increasing the length of conditioning sessions did not reveal an effect of sex and resulted in lower magnitude conditioned reward expression. Importantly however, female stage of estrous cycle significantly influenced oxycodone conditioned reward expression. These results suggest that female hormonal status can impact the rewarding effects of opioids and thus have important implications for prescription opioid treatment practices.

The Role of Serotonin in Fear Learning and Memory: A Systematic Review of Human Studies

Fear is characterized by distinct behavioral and physiological responses that are essential for the survival of the human species. Fear conditioning (FC) serves as a valuable model for studying the acquisition, extinction, and expression of fear. The serotonin (5-hydroxytryptamine, 5-HT) system is known to play a significant role in emotional and motivational aspects of human behavior, including fear learning and expression. Accumulating evidence from both animal and human studies suggests that brain regions involved in FC, such as the amygdala, hippocampus, and prefrontal cortex, possess a high density of 5-HT receptors, implicating the crucial involvement of serotonin in aversive learning. Additionally, studies exploring serotonin gene polymorphisms have indicated their potential influence on FC. Therefore, the objective of this work was to review the existing evidence linking 5-HT with fear learning and memory in humans. Through a comprehensive screening of the PubMed and Web of Science databases, 29 relevant studies were included in the final review. These studies investigated the relationship between serotonin and fear learning using drug manipulations or by studying 5-HT-related gene polymorphisms. The results suggest that elevated levels of 5-HT enhance aversive learning, indicating that the modulation of serotonin 5-HT2A receptors regulates the expression of fear responses in humans. Understanding the role of this neurochemical messenger in associative aversive learning can provide insights into psychiatric disorders such as anxiety and post-traumatic stress disorder (PTSD), among others.

Prevalence, risk factors and prognostic value of anxiety and depression in recurrent glioma patients

Anxiety and depression are frequently noticed in glioma patients, while few studies report this issue in recurrent glioma patients. Hence, this study aimed to evaluate the prevalence of anxiety and depression, as well as their risk factors and prognostic value in recurrent glioma patients. Eighty recurrent glioma patients, 40 newly-diagnosed glioma patients, and 40 healthy controls were enrolled in this study. Then, the Hospital Anxiety and Depression Scale for anxiety (HADS-A) and for depression (HADS-D) were used to assess the anxiety and depression status of all subjects. The HADS-A score (8.6 ± 3.3 vs. 7.0 ± 2.9 vs. 4.3 ± 2.5), anxiety rate (58.8% vs. 32.5% vs. 10.0%), HADS-D score (7.9 ± 3.0 vs. 6.9 ± 3.1 vs. 4.0 ± 2.6), and depression rate (45.0% vs. 30.0% vs. 7.5%) were all highest in recurrent glioma patients, followed by newly-diagnosed glioma patients, and were lowest in healthy controls (all P < 0.001). Furthermore, female sex (vs. male sex) was independently correlated with anxiety (odds ratio (OR): 3.042, P = 0.029); meanwhile, higher World Health Organization (WHO) pathological grade was independently correlated with depression (OR: 2.573, P = 0.019) in recurrent glioma patients. Additionally, anxiety was correlated with shortened progression-free survival (PFS) (P = 0.028) and overall survival (OS) (P = 0.047), while depression only had a correlation trend with shortened PFS (without statistical significance) (P = 0.069) and was associated with shortened OS (P = 0.035) in recurrent glioma patients. The prevalence of anxiety and depression is high in recurrent glioma patients, which relates to gender, WHO pathological grade, and estimates worsen survival.

Spinal cord injury in mice amplifies anxiety: A novel light-heat conflict test exposes increased salience of anxiety over heat

Spinal cord injury (SCI) predisposes individuals to anxiety and chronic pain. Anxiety- and pain-like behavior after SCI can be tested in rodents, yet commonly used tests assess one variable and may not replicate effects of SCI or sex differences seen in humans. Thus, novel preclinical tests should be optimized to better evaluate behaviors relating to anxiety and pain. Here, we use our newly developed conflict test - the Thermal Increments Dark-Light (TIDAL) test - to explore how SCI affects anxiety- vs. pain-like behavior, and whether sex affects post-SCI behavior. The TIDAL conflict test consists of two plates connected by a walkway; one plate remains illuminated and at an isothermic temperature, whereas the other plate is dark but is heated incrementally to aversive temperatures. A control mice thermal place preference test was also performed in which both plates are illuminated. Female and male mice received moderate T9 contusion SCI or remained uninjured. At 7 days post-operative (dpo), mice with SCI increased dark plate preference throughout the TIDAL conflict test compared to uninjured mice. SCI increased dark plate preference for both sexes, although female (vs. male) mice remained on the heated-dark plate to higher temperatures. Mice with SCI that repeated TIDAL at 7 and 21 dpo showed reduced preference for the dark-heated plate at 21 dpo. Overall, in female and male mice, SCI enhances the salience of anxiety (vs. heat sensitivity). The TIDAL conflict test meets a need for preclinical anxiety- and pain-related tests that recapitulate the human condition; thus, future rodent behavioral studies should incorporate TIDAL or other conflict tests to help understand and treat neurologic disorders.

Estrogens, age, and, neonatal stress: panic disorders and novel views on the contribution of non-medullary structures to respiratory control and CO2 responses

CO₂ is a fundamental component of living matter. This chemical signal requires close monitoring to ensure proper match between metabolic production and elimination by lung ventilation. Besides ventilatory adjustments, CO₂ can also trigger innate behavioral and physiological responses associated with fear and escape but the changes in brain CO₂/pH required to induce ventilatory adjustments are generally lower than those evoking fear and escape. However, for patients suffering from panic disorder (PD), the thresholds for CO₂-evoked hyperventilation, fear and escape are reduced and the magnitude of those reactions are excessive. To explain these clinical observations, Klein proposed the false suffocation alarm hypothesis which states that many spontaneous panics occur when the brain's suffocation monitor erroneously signals a lack of useful air, thereby maladaptively triggering an evolved suffocation alarm system. After 30 years of basic and clinical research, it is now well established that anomalies in respiratory control (including the CO₂ sensing system) are key to PD. Here, we explore how a stress-related affective disorder such as PD can disrupt respiratory control. We discuss rodent models of PD as the concepts emerging from this research has influenced our comprehension of the CO₂ chemosensitivity network, especially structure that are not located in the medulla, and how factors such as stress and biological sex modulate its functionality. Thus, elucidating why hormonal fluctuations can lead to excessive responsiveness to CO₂ offers a unique opportunity to gain insights into the neuroendocrine mechanisms regulating this key aspect of respiratory control and the pathophysiology of respiratory manifestations of PD.

Histamine signaling in the bed nucleus of the stria terminalis modulates stress-induced anxiety

BACKGROUND

Anxiety disorder is one of the most prevalent psychiatric disorders. Intriguingly, dysfunction of the central histaminergic system, which is recognized as a general regulator for whole-brain activity, may result in anxiety, suggesting an involvement of the central histaminergic signaling in the modulation of anxiety. However, the neural mechanisms involved have not been fully identified.

METHODS

Here, we examined the effect of histaminergic signaling in the bed nucleus of the stria terminalis (BNST) on anxiety-like behaviors both in normal and acute restraint stressed male rats by using anterograde tracing, immunofluorescence, qPCR, neuropharmacology, molecular manipulation and behavioral tests.

RESULTS

We found that histaminergic neurons in the hypothalamus send direct projections to the BNST, which forms a part of the circuitry involved in stress and anxiety. Infusion of histamine into the BNST produced anxiogenic effect. Moreover, histamine H1 and H2 receptors are expressed and distributed in the BNST neurons. Blockade of histamine H1 or H2 receptors in the BNST did not affect anxiety-like behaviors in normal rats, but ameliorated anxiogenic effect induced by acute restraint stress. Furthermore, knockdown of H1 or H2 receptors in the BNST induced anxiolytic effect in acute restraint stressed rats, which confirmed the pharmacological results.

LIMITATIONS

A single dose of histamine receptor antagonist was used.

CONCLUSIONS

Together, these findings demonstrate a novel mechanism for the central histaminergic system in the regulation of anxiety, and suggest that inhibition of histamine receptors may be a useful strategy for treating anxiety disorder.

Generalized fear following acute stress is caused by change in co-transmitter identity of serotonergic neurons

Overgeneralization of fear to harmless situations is a core feature of anxiety disorders resulting from acute stress, yet the mechanisms by which fear becomes generalized are poorly understood. Here we show that generalized fear in mice in response to footshock results from a transmitter switch from glutamate to GABA in serotonergic neurons of the lateral wings of the dorsal raphe. We observe a similar change in transmitter identity in the postmortem brains of PTSD patients. Overriding the transmitter switch in mice using viral tools prevents the acquisition of generalized fear. Corticosterone release and activation of glucocorticoid receptors trigger the switch, and prompt antidepressant treatment blocks the co-transmitter switch and generalized fear. Our results provide new understanding of the plasticity involved in fear generalization.

ENVIRONMENTAL STRESSORS DIFFERENTIALLY MODULATE ANXIETY-LIKE BEHAVIOUR IN MALE AND FEMALE ZEBRAFISH

How differently male and female responds in a stressful situation is a matter of curiosity. Apart from curiosity, this opens a new arena to the synthesis of personalized/individualized medications. Here, we used zebrafish, a suitable experimental animal model to study stress and anxiety. We evaluated the differential responses in adult male and female zebrafish on the acute exposure of three different stressors: Caffeine (100mg/L), Conspecific alarm substance (3.5ml/L), and sight of sympatric predators (Leaf fish and Snakehead) with the help of two different behavioural paradigms (Novel tank test & Predator exposure). Behavioural responses were captured over 6minutes and quantified using Smart 3.0. Male zebrafish were found to be more responsive to caffeine treatment. Conspecific alarm substance-challenged males and females showed robust alarm reactions whereas females were found to be more prone to it. Female zebrafish showed statistically significant aversion to the visual representation of sympatric predators. Taken together, each stressor induced differential responses in male and female zebrafish.

Individual differences in social homeostasis

The concept of “social homeostasis”, introduced by Matthews and Tye in 2019, has provided a framework with which to consider our changing individual needs for social interaction, and the neurobiology underlying this system. This model was conceived as including detector systems, a control center with a setpoint, and effectors which allow us to seek out or avoid additional social contact. In this article, we review and theorize about the many different factors that might contribute to the setpoint of a person or animal, including individual, social, cultural, and other environmental factors. We conclude with a consideration of the empirical challenges of this exciting new model.

Amygdala AVPR1A mediates susceptibility to chronic social isolation in females

Females are more sensitive to social exclusion, which could contribute to their heightened susceptibility to anxiety disorders. Chronic social isolation stress (CSIS) for at least 7 weeks after puberty induces anxiety-related behavioral adaptations in female mice. Here, we show that Arginine vasopressin receptor 1a ( Avpr1a )-expressing neurons in the central nucleus of the amygdala (CeA) mediate these sex-specific effects, in part, via projections to the caudate putamen. Loss of function studies demonstrate that AVPR1A signaling in the CeA is required for effects of CSIS on anxiety-related behaviors in females but has no effect in males or group housed females. This sex-specificity is mediated by AVP produced by a subpopulation of neurons in the posterodorsal medial nucleus of the amygdala that project to the CeA. Estrogen receptor alpha signaling in these neurons also contributes to preferential sensitivity of females to CSIS. These data support new therapeutic applications for AVPR1A antagonists in women.

Effects of resourcefulness on internet game addiction among college students: The mediating role of anxiety and the moderating role of gender

Introduction

The mechanism of internet game addiction is unclear. Whether anxiety mediates between resourcefulness and internet game addiction and whether gender affect its mediation role have not been studied previously.

Methods

A total of 4,889 college students from a college in southwest China were included in this study to complete the investigation, in which three questionnaires were used for evaluation.

Results

Pearson's correlation analysis indicated a remarkable negative correlation between resourcefulness with internet game addiction and anxiety, as well as a significant positive correlation between anxiety and this addiction. The structural equation model confirmed the mediation role of anxiety. The multi-group analysis confirmed the moderating role of gender in the mediation model.

Discussion

These findings have advanced the results of existing studies, indicating the buffering effect of resourcefulness on internet game addiction and revealing the potential mechanism of this relationship.

Limosilactobacillus reuteri administration alters the gut-brain-behavior axis in a sex-dependent manner in socially monogamous prairie voles

Research on the role of gut microbiota in behavior has grown dramatically. The probiotic L. reuteri can alter social and stress-related behaviors - yet, the underlying mechanisms remain largely unknown. Although traditional laboratory rodents provide a foundation for examining the role of L. reuteri on the gut-brain axis, they do not naturally display a wide variety of social behaviors. Using the highly-social, monogamous prairie vole (Microtus ochrogaster), we examined the effects of L. reuteri administration on behaviors, neurochemical marker expression, and gut-microbiome composition. Females, but not males, treated with live L. reuteri displayed lower levels of social affiliation compared to those treated with heat-killed L. reuteri. Overall, females displayed a lower level of anxiety-like behaviors than males. Live L. reuteri-treated females had lower expression of corticotrophin releasing factor (CRF) and CRF type-2-receptor in the nucleus accumbens, and lower vasopressin 1a-receptor in the paraventricular nucleus of the hypothalamus (PVN), but increased CRF in the PVN. There were both baseline sex differences and sex-by-treatment differences in gut microbiome composition. Live L. reuteri increased the abundance of several taxa, including Enterobacteriaceae, Lachnospiraceae NK4A136, and Treponema. Interestingly, heat-killed L. reuteri increased abundance of the beneficial taxa Bifidobacteriaceae and Blautia. There were significant correlations between changes in microbiota, brain neurochemical markers, and behaviors. Our data indicate that L. reuteri impacts gut microbiota, gut-brain axis and behaviors in a sex-specific manner in socially-monogamous prairie voles. This demonstrates the utility of the prairie vole model for further examining causal impacts of microbiome on brain and behavior.

Anxiety onset in adolescents: a machine-learning prediction

Recent longitudinal studies in youth have reported MRI correlates of prospective anxiety symptoms during adolescence, a vulnerable period for the onset of anxiety disorders. However, their predictive value has not been established. Individual prediction through machine-learning algorithms might help bridge the gap to clinical relevance. A voting classifier with Random Forest, Support Vector Machine and Logistic Regression algorithms was used to evaluate the predictive pertinence of gray matter volumes of interest and psychometric scores in the detection of prospective clinical anxiety. Participants with clinical anxiety at age 18-23 (N = 156) were investigated at age 14 along with healthy controls (N = 424). Shapley values were extracted for in-depth interpretation of feature importance. Prospective prediction of pooled anxiety disorders relied mostly on psychometric features and achieved moderate performance (area under the receiver operating curve = 0.68), while generalized anxiety disorder (GAD) prediction achieved similar performance. MRI regional volumes did not improve the prediction performance of prospective pooled anxiety disorders with respect to psychometric features alone, but they improved the prediction performance of GAD, with the caudate and pallidum volumes being among the most contributing features. To conclude, in non-anxious 14 year old adolescents, future clinical anxiety onset 4-8 years later could be individually predicted. Psychometric features such as neuroticism, hopelessness and emotional symptoms were the main contributors to pooled anxiety disorders prediction. Neuroanatomical data, such as caudate and pallidum volume, proved valuable for GAD and should be included in prospective clinical anxiety prediction in adolescents.

Sexually dimorphic effects of estrogen receptor 2 deletion in the dorsal raphe nucleus on emotional behaviors

Sex differences in emotional behaviors and affective disorders have been widely noted, of which sexually dimorphic secretion of gonadal steroid hormones such as estrogen is suspected to play a role. However, the underlying neural mechanisms remain poorly understood. We noted that the expression of estrogen receptor 2 (Esr2, or ERβ), a key mediator of estrogen signaling in the brain, was enriched in the dorsal raphe nucleus (DRN), a region involved in emotion regulation. To investigate whether DRN Esr2 expression confers sex-specific susceptibility or vulnerability in emotional behaviors, we generated a conditional allele of Esr2 that allowed for site-specific deletion of Esr2 in the DRN via local injection of Cre-expressing viruses. DRN-specific Esr2 deletion mildly increased anxiety behaviors in females, as shown by decreased time spent in the center zone of an open field in knockout females. By contrast, DRN Esr2 deletion had no effects on anxiety levels in males, as demonstrated by knockout males spending comparable time in the center zone of an open field and open arms of an elevated-plus maze. Furthermore, in the tail suspension test, DRN Esr2 deletion reduced immobility, a depression-like behavior, in a male-biased manner. Together, these results reveal sex-specific functions of DRN Esr2 in regulating emotional behaviors and suggest targeted manipulation of DRN Esr2 signaling as a potential therapeutic strategy to treat sex-biased affective disorders.

Effects of NADPH Oxidase Isoform-2 (NOX2) Inhibition on Behavioral Responses and Neuroinflammation in a Mouse Model of Neuropathic Pain

NADPH oxidase isoform-2 (NOX2) has been implicated in the pathophysiology of neuropathic pain (NP), mostly through the modulation of neuroinflammation. Since it is also accepted that some neuroimmune mechanisms underlying NP are sex-dependent, we aimed to evaluate the effects of early systemic treatment with the NOX2-selective inhibitor (NOX2i) GSK2795039 on behavioral responses and spinal neuroinflammation in spared nerve injury (SNI)-induced NP in male and female mice. Mechanical sensitivity was evaluated with the von Frey test, while general well-being and anxiety-like behavior were assessed with burrowing and light/dark box tests. Spinal microglial activation and cytokines IL-1β, IL-6, and IL-10, as well as macrophage colony-stimulating factor (M-CSF) were evaluated by immunofluorescence and multiplex immunoassay, respectively. NOX2i treatment reduced SNI-induced mechanical hypersensitivity and early SNI-induced microglial activation in both sexes. SNI-females, but not males, showed a transient reduction in burrowing activity. NOX2i treatment did not improve their burrowing activity, but tendentially reduced their anxiety-like behavior. NOX2i marginally decreased IL-6 in females, and increased M-CSF in males. Our findings suggest that NOX2-selective inhibition may be a potential therapeutic strategy for NP in both male and female individuals, with particular interest in females due to its apparent favorable impact in anxiety-like behavior.

Klotho Regulated by Estrogen Plays a Key Role in Sex Differences in Stress Resilience in Rats

Klotho (KL) is a glycosyl hydrolase and aging-suppressor gene. Stress is a risk factor for depression and anxiety, which are highly comorbid with each other. The aim of this study is to determine whether KL is regulated by estrogen and plays an important role in sex differences in stress resilience. Our results showed that KL is regulated by estrogen in rat hippocampal neurons in vivo and in vitro and is essential for the estrogen-mediated increase in the number of presynaptic vesicular glutamate transporter 1 (Vglut1)-positive clusters on the dendrites of hippocampal neurons. The role of KL in sex differences in stress response was examined in rats using 3-week chronic unpredictable mild stress (CUMS). CUMS produced a deficit in spatial learning and memory, anhedonic-like behaviors, and anxiety-like behaviors in male but not female rats, which was accompanied by a reduction in KL protein levels in the hippocampus of male but not female rats. This demonstrated the resilience of female rats to CUMS. Interestingly, the knockdown of KL protein levels in the rat hippocampus of both sexes caused a decrease in stress resilience in both sexes, especially in female rats. These results suggest that the regulation of KL by estrogen plays an important role in estrogen-mediated synapse formation and that KL plays a critical role in the sex differences in cognitive deficit, anhedonic-like behaviors, and anxiety-like behaviors induced by chronic stress in rats, highlighting an important role of KL in sex differences in stress resilience.

Effects of the COVID-19 pandemic on nurses’ psychological well being in an emergency room

ABSTRACT Objectives: to assess the level of anxiety of nurses in an emergency room in view of the new Coronavirus and describe the relationship between the degrees of anxiety and their sociodemographic variables. Methods: quantitative descriptive-correlational study with a sample of 60 nurses. A questionnaire was used as a data collection instrument based on the Hamilton Anxiety Assessment Scale. Results: the nurses’ average anxiety is mild. A statistically significant relationship was found between anxiety and the variables “sex” and “children”, with women having higher levels of anxiety than men, and nurses who do not have children showing mild, moderate, or severe anxiety. Conclusions: COVID-19 triggers anxiety in nurses, sometimes at pathological levels. Being female and not having children increase the anxiety experienced. Sex can be considered the determining factor for the level of anxiety experienced.

Pre-clinical Investigations of Therapeutic Markers Associated with Acute and Chronic Restraint Stress: A Nuclear Magnetic Resonance Based Contrast Metabolic Approach

Stress can be defined by two parameters, first the psychological sensing of pressure and second is the body's response. However, the exposure time to stress depicts the biological response produced against it. The effect of acute and chronic restraint stress on anxiety and the production of systemic metabolites were investigated in male Sprague-Dawley (SD) rats. Behavioural test was performed on elevated plus maze (EPM) in conjunction with the statistical analysis that exhibited the habituation during long term exposure to stress when compared with the short-term stress. These behaviour-based changes resulted in interpolated concentration of some serum metabolites like carbohydrates, amino acids and lipids as analysed by NMR. Metabolic analysis along with the multivariate analysis demonstrated that the expression of concentration of metabolites including glutamate, proline, succinate, citrate, and tyrosine is higher in the acute stress than the chronic stress, while glucose and lipids i.e., LDL and VLDL changed in the opposite trends. Thus, the aforesaid study provides an analytical strategy for the characterization of perturbed metabolites induced due to the behavioural modifications in an organism. It may further aid in developing potential therapeutic markers at the metabolic levels which may broaden the treatment options for stress and anxiety related disorders.

Sex Differences in Depression and Anxiety

Depression and anxiety disorders carry a tremendous worldwide burden and emerge as a significant cause of disability among western societies. Both disorders are known to disproportionally affect women, as they are twice more likely to be diagnosed and moreover, they are also prone to suffer from female-specific mood disorders. Importantly, the prevalence of these affective disorders has notably risen after the COVID pandemic, especially in women. In this chapter, we describe factors that are possibly contributing to the expression of such sex differences in depression and anxiety. For this, we overview the effect of transcriptomic and genetic factors, the immune system, neuroendocrine aspects, and cognition. Furthermore, we also provide evidence of sex differences in antidepressant response and their causes. Finally, we emphasize the importance to consider sex as a biological variable in preclinical and clinical research, which may facilitate the discovery and development of new and more efficacious antidepressant and anxiolytic pharmacotherapies for both women and men.

Sex, defense, and risk assessment: Who could ask for anything more?

Over the 30 years since IBNS was founded, a central theme of "Translation" has emerged. This reflects increasing realization that mental disorders such as anxiety and depression are extremely widespread, expensive and painful to societies and individuals across the world. The Blanchard lab has been particularly involved in attempts to understand the evolutionary and functional mechanisms underlying defensive behaviors as a focal component of these disorders. This involved analysis of the relationships between threatening situations/stimuli, and the behaviors (flight, freezing, fight, and risk assessment) that respond to them, for rodents; and also attempts to link these relationships to human responsivity to similar threatening events: Linkages that are complicated by factors such as domestication and sex. In particular it is important to describe and characterize the organization of defensive patterns in people as well as nonhuman animals, and to understand how these patterns can become nonfunctional and pathological.

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.