Genetics of Affective and Anxiety Disorders

Brain function abnormalities and neuroinflammation in people living with HIV-associated anxiety disorders

Background

People living with HIV (PLWH) exhibits an increased susceptibility to anxiety disorders, concomitant with heightened vulnerability to aberrant immune activation and inflammatory responses, and endocrine dysfunction. There exists a dearth of scholarly investigations pertaining to the neurological, immune, and endocrine dimensions of HIV-associated anxiety disorders.

Method

This study aimed to compare a group of 16 individuals diagnosed with HIV-associated anxiety disorders (HIV ANXs) according to the Diagnostic and statistical manual of mental disorders (5th ed.), with a HIV individual control group (HIV control) of 49 PLWH without mental disorders. Muti-modal magnetic resonance was employed to assess the brain function and structure of both groups. Seed-based functional connectivity (FC) was used to assess the regional intrinsic brain activity and the influence of regional disturbances on FC with other brain regions. Peripheral blood cytokines and chemokines concentrations were measured using liquid chip and ELISA.

Results

Amplitude of low-frequency fluctuations in the right inferior temporal gyrus (ITG) was increased. There is a significant decreased regional homogeneity in HIV ANXs in the right superior occipital gyrus (SOG). The right ITG and the right SOG were separately set as the seed brain region of interest (ROI 1 and ROI 2) to be analyzed the FC. FC decreased in HIV ANXs between ROI1 and the right middle occipital gyrus, the right SOG, FC between ROI2 and left ITG increased in HIV ANXs. No significant structural difference was found between two groups. Pro-inflammatory chemokines showed higher levels in the HIV ANXs. Pro-inflammatory cytokines, neurotrophic factors, and endocrine factors were significantly correlated with alterations in brain function.

Conclusion

This study suggests that patients with HIV-associated anxiety disorders may exhibit abnormalities in neurologic, immune, and endocrine functioning. Consequently, it is imperative to implement additional screening and intervention measures for anxiety disorders among PLWH.

SIRT1 in the BNST modulates chronic stress-induced anxiety of male mice via FKBP5 and corticotropin-releasing factor signaling

Although clinical reports have highlighted association of the deacetylase sirtuin 1 (SIRT1) gene with anxiety, its exact role in the pathogenesis of anxiety disorders remains unclear. The present study was designed to explore whether and how SIRT1 in the mouse bed nucleus of the stria terminalis (BNST), a key limbic hub region, regulates anxiety. In a chronic stress model to induce anxiety in male mice, we used site- and cell-type-specific in vivo and in vitro manipulations, protein analysis, electrophysiological and behavioral analysis, in vivo MiniScope calcium imaging and mass spectroscopy, to characterize possible mechanism underlying a novel anxiolytic role for SIRT1 in the BNST. Specifically, decreased SIRT1 in parallel with increased corticotropin-releasing factor (CRF) expression was found in the BNST of anxiety model mice, whereas pharmacological activation or local overexpression of SIRT1 in the BNST reversed chronic stress-induced anxiety-like behaviors, downregulated CRF upregulation, and normalized CRF neuronal hyperactivity. Mechanistically, SIRT1 enhanced glucocorticoid receptor (GR)-mediated CRF transcriptional repression through directly interacting with and deacetylating the GR co-chaperone FKBP5 to induce its dissociation from the GR, ultimately downregulating CRF. Together, this study unravels an important cellular and molecular mechanism highlighting an anxiolytic role for SIRT1 in the mouse BNST, which may open up new therapeutic avenues for treating stress-related anxiety disorders.

Disturbed relationship between glucocorticoid receptor and 5-HT1AR/5-HT2AR in ADHD rats: A correlation study

Objective

This work is to investigate the alterations of the central 5-hydroxytryptamine (5-HT) system in spontaneously hypertensive rats (SHR) and the correlation with the behaviors of SHR, and to explore the effects of glucocorticoid intervention on the central 5-HT system and SHR behaviors.

Materials and methods

Three weeks old SHR were chosen as the attention-deficit hyperactivity disorder (ADHD) model and treated with glucocorticoid receptor (GR) agonist or inhibitor, whereas Wista Kyoto rats (WKY) were chosen as the normal control group. Open-field test and Làt maze test were used to evaluate the spontaneous activities and non-selective attention. The levels of 5-HT in the extracellular fluid specimens of the prefrontal cortex of rats were analyzed by high-performance liquid chromatography. The expressions of GR, 5-HT1A receptor (5-HT1AR), and 5-HT2A receptor (5-HT2AR) in the prefrontal cortex were analyzed through immunohistochemistry.

Results

Our study demonstrated that the 5-HT level was lower in the prefrontal cortex of SHR compared to that of WKY. The Open-field test and Làt maze test showed that GR agonist (dexamethasone, DEX) intervention ameliorated attention deficit and hyperactive behavior, whereas GR inhibitor (RU486) aggravated the disorders. With DEX, the expression levels of 5-HT and 5-HT2AR in the prefrontal cortex of SHR were significantly higher than those in the control group, whereas the expression level of 5-HT1AR was lower. However, the expression levels of 5-HT and 5-HT2AR were significantly decreased after the intervention with RU486, while the expression level of 5-HT1AR increased. Results showed that glucocorticoid was negatively correlated with 5-HT1AR and positively correlated with 5-HT2AR.

Conclusion

In the prefrontal cortex of ADHD rats, the down-regulation of 5-HT and 5-HT2AR expressions and the up-regulation of 5-HT1AR, compared with WYK rats, suggested a dysfunctional central 5-HT system in ADHD rats. The GR agonist can upregulate the expression of 5-HT and 5-HT2AR and downregulate the expression of 5-HT1AR in the prefrontal cortex of SHR as well as reduce the hyperactivity and attention deficit behavior in SHR, while the opposite was true for the GR inhibitor. It is suggested that the dysfunction of the 5-HT system in ADHD rats is closely related to glucocorticoid receptor activity.

Translational relevance of forward genetic screens in animal models for the study of psychiatric disease

Psychiatric disorders represent a significant burden in our societies. Despite the convincing evidence pointing at gene and gene-environment interaction contributions, the role of genetics in the etiology of psychiatric disease is still poorly understood. Forward genetic screens in animal models have helped elucidate causal links. Here we discuss the application of mutagenesis-based forward genetic approaches in common animal model species: two invertebrates, nematodes (Caenorhabditis elegans) and fruit flies (Drosophila sp.); and two vertebrates, zebrafish (Danio rerio) and mice (Mus musculus), in relation to psychiatric disease. We also discuss the use of large scale genomic studies in human populations. Despite the advances using data from human populations, animal models coupled with next-generation sequencing strategies are still needed. Although with its own limitations, zebrafish possess characteristics that make them especially well-suited to forward genetic studies exploring the etiology of psychiatric disorders.

Mechanisms of synaptic transmission dysregulation in the prefrontal cortex: pathophysiological implications

The prefrontal cortex (PFC) serves as the chief executive officer of the brain, controlling the highest level cognitive and emotional processes. Its local circuits among glutamatergic principal neurons and GABAergic interneurons, as well as its long-range connections with other brain regions, have been functionally linked to specific behaviors, ranging from working memory to reward seeking. The efficacy of synaptic signaling in the PFC network is profundedly influenced by monoaminergic inputs via the activation of dopamine, adrenergic, or serotonin receptors. Stress hormones and neuropeptides also exert complex effects on the synaptic structure and function of PFC neurons. Dysregulation of PFC synaptic transmission is strongly linked to social deficits, affective disturbance, and memory loss in brain disorders, including autism, schizophrenia, depression, and Alzheimer's disease. Critical neural circuits, biological pathways, and molecular players that go awry in these mental illnesses have been revealed by integrated electrophysiological, optogenetic, biochemical, and transcriptomic studies of PFC. Novel epigenetic mechanism-based strategies are proposed as potential avenues of therapeutic intervention for PFC-involved diseases. This review provides an overview of PFC network organization and synaptic modulation, as well as the mechanisms linking PFC dysfunction to the pathophysiology of neurodevelopmental, neuropsychiatric, and neurodegenerative diseases. Insights from the preclinical studies offer the potential for discovering new medical treatments for human patients with these brain disorders.

Environmentally relevant concentrations of sertraline disrupts behavior and the brain and liver transcriptome of juvenile yellow catfish (Tachysurus fulvidraco): Implications for the feeding and growth axis

Sertraline (SER) is one of the most prevalent antidepressants detected in aquatic environments, but its impact on fish behavior and growth remain poorly understood. As such, behavior and growth were assessed in yellow catfish (Tachysurus fulvidraco) following SER exposure. SER induced shoaling, reduced food consumption and growth, and increased cannibalism at environmentally relevant concentrations. To ascertain toxicity mechanisms, acetylcholinesterase (AChE) activity and transcripts related to growth and feeding were measured. AChE activity was increased in fish exposed to 10 and 100 μg/L SER. Transcript levels of neuropeptide Y, somatostatin, growth hormone, and insulin growth factor 1 were reduced in the brain following SER exposure. RNA-seq conducted in brain and liver revealed that gene networks associated with feeding and growth (i.e. leptin expression networks in the brain and insulin signaling pathways in the liver) were altered, proposed to be associated with the decreased food intake and growth. The brain also accumulated SER, which may relate to neurobehavioral responses. Lastly, the main metabolite of SER, norsertraline, was detected in the liver, and may also relate to toxicity. This study uncovers mechanisms and key events proposed to lead to impaired behavior and growth after exposure to some antidepressants.

The Relationship between Life Events and Personality Style to the Development of Depressive and Anxiety Disorders Among Adolescents

Background::

The separation of anxiety disorder and depressive disorder as two distinct disorders is often questioned. The aim of the current study is to examine whether there is a different profile of life events and personality characteristics for anxiety and depression disorders in adolescents.

Methods::

One hundred forty-six adolescents participated in the study; 57 boys and 89 girls, ranging in age from 11-18 years (mean=15.08+1.97). The study group included 92 adolescents with a clinical diagnosis of depression or anxiety, and the comparison group included 54 teenagers with no known psychopathology.

Results::

Multinomial logistic regression produced different predictive profiles for anxiety disorder and depressive disorders. Life event variables, especially minor life events and early traumas, were found to be predictors for depression. Furthermore, an interaction was found between early trauma and minor life events in the prediction of depression, such that the existence of trauma weakened the statistical correlation between minor life events and the onset of depression.

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In addition, contrary to the literature regarding adults, it was found that during adolescence, personality variables have a unique contribution as predictive factors for vulnerability to the onset of anxiety and depression, thus reducing the significance of life events.

Conclusion::

Our findings suggest that different profiles of life events and personality characteristics can be identified for the two disorders. In addition, it appears that early traumas are a dominant factor that overshadow more recent life events at the onset of depression among adolescents.

Depressive Symptoms among Middle-Aged Women-Understanding the Cause

Menopause is an important event in a woman’s life associated with hormonal changes that play a substantial role in the functioning of her body. A decline in the level of estrogens contributes to depressive symptoms and mood disorders during this period. The severity of depressive symptoms experienced by middle-aged women depends on many factors, including sociodemographic data (e.g., menopause, employment status, and marital status) and genetic variables (MAO-A and 5-HTT gene polymorphisms). In order to assess their influence on the development of depression in females, we analyzed 1453 healthy Polish women in different stages of menopause. Based on the results, we found that the l/l + l/s inheritance model for the 5-HTT gene polymorphism was more common in women without and with moderate depressive symptoms according to the Beck Depression Inventory (BDI), while the l/s model was more often observed in women with mild depression. Moreover, the overdominant 3/3 + 4/4 genotype of the MAO-A gene polymorphism was more often found in respondents without depressive symptoms, while women with depressive symptoms had more often the overdominant 3/4 genotype.

Neural correlates of NOS1 ex1f-VNTR allelic variation in panic disorder and agoraphobia during fear conditioning and extinction in fMRI

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NOS1 ex1f-VNTR is associated with neural correlates during fear extinction learning.

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Differential effects are prominent in amygdala and hippocampus.

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Patients with panic disorder and agoraphobia differ from healthy controls.

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Genotype associated effects were not altered after cognitive behavioral therapy.

Neuronal nitric oxide synthase (NOS-I) impacts on fear/anxiety-like behavior in animals. In humans, the short (S) allele of a functional promotor polymorphism of NOS1 (NOS1 ex1f-VNTR) has been shown to be associated with higher anxiety and altered fear conditioning in healthy subjects in the amygdala and hippocampus (AMY/HIPP). Here, we explore the role of NOS1 ex1f-VNTR as a pathophysiological correlate of panic disorder and agoraphobia (PD/AG). In a sub-sample of a multicenter cognitive behavioral therapy (CBT) randomized controlled trial in patients with PD/AG (n = 48: S/S-genotype n=15, S/L-genotype n=21, L/L-genotype n=12) and healthy control subjects, HS (n = 34: S/S-genotype n=7, S/L-genotype n=17, L/L-genotype=10), a differential fear conditioning and extinction fMRI-paradigm was used to investigate how NOS1 ex1f-VNTR genotypes are associated with differential neural activation in AMY/HIPP. Prior to CBT, L/L-allele carriers showed higher activation than S/S-allele carriers in AMY/HIPP. A genotype × diagnosis interaction revealed that the S-allele in HS was associated with a pronounced deactivation in AMY/HIPP, while patients showed contrary effects. The interaction of genotype × stimulus type (CS+, conditioned stimulus associated with an aversive stimulus vs. CS-, unassociated) showed effects on differential learning in AMY/HIPP. All effects were predominately found during extinction. Genotype associated effects in patients were not altered after CBT. Low statistical power due to small sample size in each subgroup is a major limitation. However, our findings provide first preliminary evidence for dysfunctional neural fear conditioning/extinction associated with NOS1 ex1f-VNTR genotype in the context of PD/AG, shedding new light on the complex interaction between genetic risk, current psychopathology and treatment-related effects.

Examination of associations between personality traits, and polymorphisms of MAO-A and 5-HTT with the severity of menopausal symptoms and depression levels

The aim of the present study was to investigate the association between different personality traits with monoamine oxidase A (MAO-A) and serotonin transporter (5-HTT), and to examine their effects on the severity of menopause symptoms as well as the levels of depression in menopausal women. The study was designed as an analytical cross-sectional study, performed on 132 healthy post-menopausal women in Iran. Personality was assessed using the Revised Edition of the NEO Personality Index (Neuroticism-Extroversion-Openness-Five Factor Inventory). The symptoms score sheet, used for measuring menopausal symptoms, was used to classify the participants according to their menopausal symptoms. Furthermore, Beck Depression Inventory short version was also used to assess depressive symptoms. Examination of blood samples taken from all participants was to identify DNA polymorphisms of 5-HTT using PCR. The results of the present study showed that a high level of neuroticism (P<0.0001), low levels of extroversion (P<0.002), an openness to experience (P=0.039) and conscientiousness (P=0.001) were all positively associated with the severity of menopausal symptoms. In addition, a high level of neuroticism (P<0.0001), low levels of extroversion (P<0.0001), and a low level of agreeableness (P<0.024) and conscientiousness (P<0.0001) were all positively associated with depressive symptoms. There was no statistically significant association between MAO-A and 5-HTT polymorphisms with menopause and depression scores. Based on these results, there appears to be a significant association between personality traits with both depression and menopausal symptoms. Identification of homogeneous groups of women who are predisposed to depression and severe menopausal symptoms may allow for the implementation of early prevention programs.

Trace Amine-Associated Receptor 5 Provides Olfactory Input Into Limbic Brain Areas and Modulates Emotional Behaviors and Serotonin Transmission

Trace amine-associated receptors (TAARs) are a class of G-protein-coupled receptors found in mammals. While TAAR1 is expressed in several brain regions, all the other TAARs have been described mainly in the olfactory epithelium and the glomerular layer of the olfactory bulb and are believed to serve as a new class of olfactory receptors sensing innate odors. However, there is evidence that TAAR5 could play a role also in the central nervous system. In this study, we characterized a mouse line lacking TAAR5 (TAAR5 knockout, TAAR5-KO) expressing beta-galactosidase mapping TAAR5 expression. We found that TAAR5 is expressed not only in the glomerular layer in the olfactory bulb but also in deeper layers projecting to the limbic brain olfactory circuitry with prominent expression in numerous limbic brain regions, such as the anterior olfactory nucleus, the olfactory tubercle, the orbitofrontal cortex (OFC), the amygdala, the hippocampus, the piriform cortex, the entorhinal cortex, the nucleus accumbens, and the thalamic and hypothalamic nuclei. TAAR5-KO mice did not show gross developmental abnormalities but demonstrated less anxiety- and depressive-like behavior in several behavioral tests. TAAR5-KO mice also showed significant decreases in the tissue levels of serotonin and its metabolite in several brain areas and were more sensitive to the hypothermic action of serotonin 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propilamino)tetralin (8-OH-DPAT). These observations indicate that TAAR5 is not just innate odor-sensing olfactory receptor but also serves to provide olfactory input into limbic brain areas to regulate emotional behaviors likely via modulation of the serotonin system. Thus, anxiolytic and/or antidepressant action of future TAAR5 antagonists could be predicted. In general, "olfactory" TAAR-mediated brain circuitry may represent a previously unappreciated neurotransmitter system involved in the transmission of innate odors into emotional behavioral responses.

Resilient Phenotype in Chronic Mild Stress Paradigm Is Associated with Altered Expression Levels of miR-18a-5p and Serotonin 5-HT1a Receptor in Dorsal Part of the Hippocampus

Disturbed serotonergic signaling in the hippocampus observed in many individuals vulnerable to stress has been suggested as one of the primary factors contributing to the development of depression. However, little is known about the physiology of the brain in the resilient phenotype. Resilient subjects maintain a positive mood and psychological balance despite being under the stress influence. In our study, we generated stress-vulnerable and resilient rats by using a chronic mild stress (CMS) paradigm. Using different molecular approaches, we revealed that resilient animals exhibited a significantly decreased expression level of miR-18a-5p and, in the same time, an elevated level of 5-HT1AR in dorsal, but not ventral, part of the hippocampus. Described biochemical changes were not observed in animals behaviorally vulnerable to stress. Further, in vitro analysis showed that miR-18a-5p may be a negative epigenetic regulator of 5-HT1AR since the treatment of adult hippocampal neurons with miR-18a-5p mimic significantly lowered the expression level of mRNA encoding 5-HT1AR. Moreover, bioinformatic analysis of potential target genes expressed in the hippocampus and being regulated by miR-18a-5p showed that this microRNA may regulate biological processes, such as axonogenesis, which are important in the functioning of the hippocampus in both rats and humans. All these molecular features may contribute to serotonergic homeostatic balance at the level of serotonin turnover observed in hippocampi of resilient but not stress-vulnerable rats. Delineation of further molecular and biochemical markers underlying resilience to stress may contribute to the development of new antidepressant strategies which will restore resilient phenotype in depressed patients.

SKA2 gene - A novel biomarker for latent anxiety and preterm birth prediction

BACKGROUND

There is a relationship between preterm birth (PTB) and anxiety. Spindle and Kinetochore Associated Complex Subunit 2 (SKA2) gene polymorphism (NC_000017.11: g.59110368 G > A) has also been associated with the development of anxiety. The current study was designed to evaluate the relationship between SKA2 gene SNP (NC_000017.11: g.59110368 G > A) with the occurrence of anxiety and PTB which might be considered a predictive biomarker for the prediction of preterm delivery.

METHODS

SKA2 gene (SNP rs7208505) genotyping was performed in 300 women with term birth (TB) and 293 women with PTB using PCR-RFLP method and then followed by DNA sequencing. Cortisol level was analyzed with ELISA method and the presence of anxiety was detected using Spielberg Inventory.

RESULTS

The AA genotype of SKA2 gene significantly increased the risk of PTB compared to the GG genotype by 9.6 fold ([CI] 4.5-20.2, P < 0.001) according to codominant model. Also, the frequency of A allele was significantly higher in PTB group (χ2 = 20.4, df = 1, P < 0.001) in comparison with the control group that increased the risk of PTB by 1.703 fold ([CI] 1.39-2.23, P < 0.001). Women with higher cortisol level with average 343.7 ± 3 nmol/L had AA genotype, while, the concentrations of cortisol in women with AG, and GG genotypes were 244.2 ± 3.1 nmol/L and 192.6 ± 2.5 nmol/L, respectively (P < 0.001). The score of apparent and latent anxiety in women with the AA genotype was higher compared to the AG and GG genotypes and also this score in women with the AG genotype was higher than the GG genotypes (P < 0.001). The history of preterm delivery was higher in women with the AA genotype (42.1%) in comparison with the GG (14.9%) and AG (22%) genotypes (P < 0.05).

CONCLUSION

The results of the current study suggest that prognosis of women with the AA genotype are more susceptible to be spontaneous preterm birth. Therefore, the A allele of SKA2 gene (NC_000017.11:g.59110368 G > A) could be as a predictive biomarker for the risk of PTB.

High-Fat Feeding Improves Anxiety-Type Behavior Induced by Ovariectomy in Rats

Menopause-induced changes may include increased incidence of both depression/anxiety and obesity. We hypothesized that behavioral changes that may develop after ovarian failure could be related to neurochemical and metabolic aspects affected by this condition and that high-fat intake may influence these associations. The present study investigated in rats the effects of ovariectomy, either alone or combined with high-fat diets enriched with either lard or fish-oil, on metabolic, behavioral and monoaminergic statuses, and on gene expression of neuropeptides and receptors involved in energy balance and mood regulation. Female rats had their ovaries removed and received either standard chow (OvxC) or high-fat diets enriched with either lard (OvxL) or fish-oil (OvxF) for 8 weeks. The Sham group received only chow diet. Ovariectomy increased feed efficiency and body weight gain and impaired glucose homeostasis and serotonin-induced hypophagia, effects either maintained or even accentuated by the lard diet but counteracted by the fish diet. The OvxL group developed obesity and hyperleptinemia. Regarding components of hypothalamic serotonergic system, both ovariectomy alone or combined with the fish diet increased 5-HT2C expression while the lard diet reduced 5-HT1B mRNA. Ovariectomy increased the anxiety index, as derived from the elevated plus maze test, while both high-fat groups showed normalization of this index. In the forced swimming test, ovariectomy allied to high-lard diet, but not to fish-oil diet, reduced the latency to immobility, indicating vulnerability to a depressive-like state. Linear regression analysis showed hippocampal AgRP to be negatively associated with the anxiety index and hypothalamic AgRP to be positively associated with the latency to immobility. These AgRp gene expression associations are indicative of a beneficial involvement of this neuropeptide on both depression and anxiety measures. The present findings demonstrate metabolic, neurochemical and behavioral alterations after ovaries removal and highlight a positive effect of high-fat feeding on the anxiety-like behavior shown by ovariectomized animals. Since the polyunsaturated ômega-3 intake (fish diet), unlike the saturated fat intake (lard diet), failed to induce deleterious metabolic or neurochemical consequences, further studies are needed focusing on the potential of this dietary component as an adjuvant anxiolytic agent after menopause.

A Computational Approach to Identify the Biophysical and Structural Aspects of Methylenetetrahydrofolate Reductase (MTHFR) Mutations (A222V, E429A, and R594Q) Leading to Schizophrenia

The association between depression and methylenetetrahydrofolate reductase (MTHFR) has been continually demonstrated in clinical studies, yet there are sparse resources available to build a relationship between the mutations associated with MTHFR and depression. The common mutations found to be associated with schizophrenia and MTHFR are A222V, E429A, and R594Q. Although abundant research on structural and functional effects caused by A222V mutation is available, very less amount of studies have been done on the other two mutants (E429A and R594Q). Hence in this study, a comparative analysis was carried out between the most common A222V mutation, a prevalent E429A mutation, and a less prevalent and less deleterious R594Q mutation. To predict structural rearrangements upon mutation, we proposed a computational pipeline using in silico prediction tools, molecular docking, and molecular dynamics simulation analysis. Since the association of flavin adenine dinucleotide (FAD) is important for the functioning of the protein, binding analysis between protein and the coenzyme was performed. This would enable us to understand the interference level of each mutation over FAD-binding activity. Consequently, we found that two mutations (A222V and E429A) showed lesser binding activity and structural deviations when compared to the native molecule and mutant R594Q. Comparatively, higher structural changes were observed with A222V mutant complex in comparison to other mutant complexes. Computational studies like this could render better insights into the structural changes in the protein and their relationship with the disease condition.

Impacts of the antidepressant fluoxetine on the anti-predator behaviours of wild guppies (Poecilia reticulata)

Chemical pollution from pharmaceuticals is increasingly recognised as a major threat to aquatic communities. One compound of great concern is fluoxetine, which is one of the most widely prescribed psychoactive drugs in the world and frequently detected in the environment. The aim of this study was to investigate the effects of 28-d fluoxetine exposure at two environmentally relevant levels (measured concentrations: 4ng/L and 16ng/L) on anti-predator behaviour in wild guppies (Poecilia reticulata). This was achieved by subjecting fluoxetine-exposed and unexposed guppies to a simulated bird strike and recording their subsequent behavioural responses. We found that exposure to fluoxetine affected the anti-predator behaviour of guppies, with exposed fish remaining stationary for longer (i.e. 'freezing' behaviour) after the simulated strike and also spending more time under plant cover. By contrast, control fish were significantly more active and explored the tank more, as indicated by the distance covered per minute over the period fish spent swimming. Furthermore, behavioural shifts were sex-dependent, with evidence of a non-monotonic dose-response among the fluoxetine-exposed fish. This is one of the first studies to show that exposure to environmentally relevant concentrations of fluoxetine can alter the anti-predator behaviour of adult fish. In addition to the obvious repercussions for survival, impaired anti-predator behaviour can have direct impacts on fitness and influence the overall population dynamics of species.

A Novel Interaction between Tryptophan Hydroxylase 2 (TPH2) Gene Polymorphism (rs4570625) and BDNF Val66Met Predicts a High-Risk Emotional Phenotype in Healthy Subjects

Poor inhibitory processing of negative emotional content is central to many psychiatric disorders, including depression and anxiety. Moreover, increasing evidence suggests that core aspects of emotion-inhibitory processing are largely inherited and as such may represent a key intermediate or risk-related phenotype for common affective diseases (e.g., unipolar depressive, anxiety disorders). The current study employed a candidate-gene approach in order to most effectively examine this complex behavioral phenotype. We examined the novel interaction between BDNF (Val⁶⁶Met) and TPH2 (rs4570625) polymorphisms and their influence on behavioral inhibition of negative emotion in two independent investigations of healthy adults. BDNF Met carriers consistently report greater symptoms of affective disease and display corresponding behavioral rigidity, while TPH2 T carriers display poor inhibitory processing. These genotypes are traditionally perceived as ‘risk’ genotypes when compared to their respective major Val and G homozygous genotypes, but evidence is mixed. Recent studies in humans and mutant mouse models suggest biological epistasis between BDNF and genes involved in serotonin regulation. Moreover, polymorphisms in the TPH2 gene may have greater influence on serotonergic function than other more commonly studied polymorphisms (e.g., 5-HTTLPR). We observed consistent evidence across two different emotion-inhibition paradigms, one with high internal validity (Study 1, n = 119) and one with high ecological validity (Study 2, n = 115) that the combination of Val/Val and G/G genotypes was clearly associated with impaired inhibition of negative emotional content. This was followed by individuals carrying the BDNF—Met allele (including Met/Val and Met/Met) when combined with the TPH2—T allele (including T/G and T/T combinations). The consistency of these results across tasks and studies suggests that these two groups may be particularly vulnerable to the most common psychiatric disorders and should be targets for future clinical investigation.

The Relationship between Personality Traits, the 5HTT Polymorphisms, and the Occurrence of Anxiety and Depressive Symptoms in Elite Athletes

The purpose of this study was to determine the relationship between personality, the serotonin transporter (5HTT) polymorphisms and the occurrence of anxiety and depressive symptoms in elite athletes. 133 healthy participants completed the NEO Five-Factor Inventory (NEO-FFI). The mood states were assessed using the Profile of Mood States (POMS) questionnaire. The athlete's mental skills were assessed through the Sport Performance Psychological Inventory (IPPS-48). The occurrence of psychiatric and personality disorders was assessed using the Clinical Interview for DSM-IV Disorders. A polymerase chain reaction was employed to identify genotypes at the 5HTTLPR polymorphism. The 5HTTLPR s/s genotype was associated with both neuroticism (p< 0.001) and tension/anxiety symptoms according to the POMS (p<0.02), cognitive anxiety and emotional arousal control according to the IPPS-48 (p<0.01). Significant correlations were proved between neuroticism and symptoms of anxiety and depression (p<0.05). Neuroticism mediates the association between the 5HTTLPR polymorphism and symptoms of cognitive anxiety and emotional arousal control (p<0.05). These results suggest a significant interaction between the 5HTTLPR polymorphism, neuroticism and sport related stress that predict adverse mental health outcomes in athletes. Identification of homogeneous groups of athletes having predispositions to anxiety and depressive symptoms may help to implement early prevention programs.

Converging evidence for an impact of a functional NOS gene variation on anxiety-related processes

Being a complex phenotype with substantial heritability, anxiety and related phenotypes are characterized by a complex polygenic basis. Thereby, one candidate pathway is neuronal nitric oxide (NO) signaling, and accordingly, rodent studies have identified NO synthase (NOS-I), encoded by NOS1, as a strong molecular candidate for modulating anxiety and hippocampus-dependent learning processes. Using a multi-dimensional and -methodological replication approach, we investigated the impact of a functional promoter polymorphism (NOS1-ex1f-VNTR) on human anxiety-related phenotypes in a total of 1019 healthy controls in five different studies. Homozygous carriers of the NOS1-ex1f short-allele displayed enhanced trait anxiety, worrying and depression scores. Furthermore, short-allele carriers were characterized by increased anxious apprehension during contextual fear conditioning. While autonomous measures (fear-potentiated startle) provided only suggestive evidence for a modulatory role of NOS1-ex1f-VNTR on (contextual) fear conditioning processes, neural activation at the amygdala/anterior hippocampus junction was significantly increased in short-allele carriers during context conditioning. Notably, this could not be attributed to morphological differences. In accordance with data from a plethora of rodent studies, we here provide converging evidence from behavioral, subjective, psychophysiological and neuroimaging studies in large human cohorts that NOS-I plays an important role in anxious apprehension but provide only limited evidence for a role in (contextual) fear conditioning.

Relative luminosity in the plus maze upon the exploratory behaviour of female Wistar rats

Objective This study evaluated the provision of two configuration of the Elevated Pluz-Maze (EPM) by analizing the exploratory behaviour of female Wistar rats in different phases of the estrous cycle in EPMs with different gradients of luminosity between the open and enclosed arms (O/E∆Lux).Methods Female Wistar rats were treated with Midazolam (MDZ, 1.0 mg.kg-1) and were tested for their exploratory behaviour in either the EPM 10 O/E∆Lux or EPM 96 O/E∆Lux.Results A multiple regression analysis indicated that the O/E∆Lux is negatively associated with the %Open arm entries and %Open arm time, suggesting that as O/E∆Lux increases, the open arm exploration decreases. The estrous cycle phase did not influence the open-arm exploration in either EPM. MDZ- induced anxiolysis was detected in 96 O/E∆Lux EPM in all phases of the EC.Discussion Results of this study suggest the importance of the O/E∆Lux to establish the arm preference in the EPM, and to preserve the predictive validity of the EPM.

Altered amygdalar resting-state connectivity in depression is explained by both genes and environment

Recent findings indicate that alterations of the amygdalar resting-state fMRI connectivity play an important role in the etiology of depression. While both depression and resting-state brain activity are shaped by genes and environment, the relative contribution of genetic and environmental factors mediating the relationship between amygdalar resting-state connectivity and depression remain largely unexplored. Likewise, novel neuroimaging research indicates that different mathematical representations of resting-state fMRI activity patterns are able to embed distinct information relevant to brain health and disease. The present study analyzed the influence of genes and environment on amygdalar resting-state fMRI connectivity, in relation to depression risk. High-resolution resting-state fMRI scans were analyzed to estimate functional connectivity patterns in a sample of 48 twins (24 monozygotic pairs) informative for depressive psychopathology (6 concordant, 8 discordant and 10 healthy control pairs). A graph-theoretical framework was employed to construct brain networks using two methods: (i) the conventional approach of filtered BOLD fMRI time-series and (ii) analytic components of this fMRI activity. Results using both methods indicate that depression risk is increased by environmental factors altering amygdalar connectivity. When analyzing the analytic components of the BOLD fMRI time-series, genetic factors altering the amygdala neural activity at rest show an important contribution to depression risk. Overall, these findings show that both genes and environment modify different patterns the amygdala resting-state connectivity to increase depression risk. The genetic relationship between amygdalar connectivity and depression may be better elicited by examining analytic components of the brain resting-state BOLD fMRI signals.

Reference genome of wild goat (capra aegagrus) and sequencing of goat breeds provide insight into genic basis of goat domestication

BACKGROUND

Domestic goats (Capra hircus) have been selected to play an essential role in agricultural production systems, since being domesticated from their wild progenitor, bezoar (Capra aegagrus). A detailed understanding of the genetic consequences imparted by the domestication process remains a key goal of evolutionary genomics.

RESULTS

We constructed the reference genome of bezoar and sequenced representative breeds of domestic goats to search for genomic changes that likely have accompanied goat domestication and breed formation. Thirteen copy number variation genes associated with coat color were identified in domestic goats, among which ASIP gene duplication contributes to the generation of light coat-color phenotype in domestic goats. Analysis of rapidly evolving genes identified genic changes underlying behavior-related traits, immune response and production-related traits.

CONCLUSION

Based on the comparison studies of copy number variation genes and rapidly evolving genes between wild and domestic goat, our findings and methodology shed light on the genetic mechanism of animal domestication and will facilitate future goat breeding.

Measuring Relational Care in Nursing Homes: Psychometric Evaluation of the Relational Care Scale

Background and Purpose: The Relational Care Scale (RCS) is a Canadian evaluative instrument designed to measure nursing home residents’ perceptions of care aides’ relational abilities. Care aides’ abilities to be reliable and empathetic with nursing home residents are very important determinants of quality of care, but few instruments are designed specifically for residents or focus exclusively on these determinants. Initially developed and tested in metropolitan teaching-affiliated nursing homes in Ontario, we expanded testing by reevaluating the psychometric properties of the RCS in 5 rural nursing homes in British Columbia. Method: There were 62 residents living in 5 rural nursing homes who completed 3 instruments: the RCS under investigation, the Experiences in Close Relationships-Relationship Structures (ECR-RS) questionnaire to test for convergent validity, and the Lubben Social Network Scale-6 (LSNS-6) to test for discriminant validity. Results: The reliability of the RCS was strongly supported (Cronbach’s alpha = .90, item–total correlation > .77). Consistent with previous testing, a unidimensional internal structure was extracted. A moderate to strong correlation between the RCS and the Anxiety and Avoidance subscales of the ECR-RS supported convergent validity of the instrument. Last, partial support was obtained for the discriminant validity of the RCS. Conclusions: The RCS was easy to use for both residents and researchers. Expanded testing demonstrated its recurring reliability and validity.

The Effects of Romantic Love on Mentalizing Abilities

The effects of the human pair-bonded state of "romantic love" on cognitive function remain relatively unexplored. Theories on cognitive priming suggest that a state of love may activate love-relevant schemas, such as mentalizing about the beliefs of another individual, and may thus improve mentalizing abilities. On the other hand, recent functional MRI (fMRI) research on individuals who are in love suggests that several brain regions associated with mentalizing may be "deactivated" during the presentation of a love prime, potentially affecting mentalizing cognitions and behaviors. The current study aimed to investigate experimentally the effect of a love prime on a constituent aspect of mentalizing-the attribution of emotional states to others. Ninety-one participants who stated they were "deeply in love" with their romantic partner completed a cognitive task involving the assessment of emotional content of facial stimuli (the Reading the Mind in the Eyes task) immediately after the presentation of either a love prime or a neutral prime. Individuals were significantly better at interpreting the emotional states of others after a love prime than after a neutral prime, particularly males assessing negative emotional stimuli. These results suggest that presentation of a love stimulus can prime love-relevant networks and enhance subsequent performance on conceptually related mentalizing tasks.

Abnormal anxiety- and depression-like behaviors in mice lacking both central serotonergic neurons and pancreatic islet cells

Dysfunction of central serotonin (5-HT) system has been proposed to be one of the underlying mechanisms for anxiety and depression, and the association of diabetes mellitus and psychiatric disorders has been noticed by the high prevalence of anxiety/depression in patients with diabetes mellitus. This promoted us to examine these behaviors in central 5-HT-deficient mice and those also suffering with diabetes mellitus. Mice lacking either 5-HT or central serotonergic neurons were generated by conditional deletion of Tph2 or Lmx1b respectively. Simultaneous depletion of both central serotonergic neurons and pancreatic islet cells was achieved by administration of diphtheria toxin (DT) in Pet1-Cre;Rosa26-DT receptor (DTR) mice. The central 5-HT-deficient mice showed reduced anxiety-like behaviors as they spent more time in and entered more often into the light box in the light/dark box test compared with controls; similar results were observed in the elevated plus maze test. However, they displayed no differences in the immobility time of the forced swimming and tail suspension tests suggesting normal depression-like behaviors in central 5-HT-deficient mice. As expected, DT-treated Pet1-Cre;Rosa26-DTR mice lacking both central serotonergic neurons and pancreatic islet endocrine cells exhibited several classic diabetic symptoms. Interestingly, they displayed increased anxiety-like behaviors but reduced immobility time in the forced swimming and tail suspension tests. Furthermore, the hippocampal neurogenesis was dramatically enhanced in these mice. These results suggest that the deficiency of central 5-HT may not be sufficient to induce anxiety/depression-like behaviors in mice, and the enhanced hippocampal neurogenesis may contribute to the altered depression-like behaviors in the 5-HT-deficient mice with diabetes. Our current investigation provides understanding the relationship between diabetes mellitus and psychiatric disorders.

Behavioral phenotyping of Nestin-Cre mice: implications for genetic mouse models of psychiatric disorders

Genetic mouse models based on the Cre-loxP system have been extensively used to explore the influence of specific gene deletions on different aspects of behavioral neurobiology. However, the interpretation of the effects attributed to the gene deletion might be obscured by potential side effects secondary to the Cre recombinase transgene insertion or Cre activity, usually neither controlled nor reported. Here, we performed a comprehensive behavioral analysis of endophenotypes of neuropsychiatric disorders in the extensively used Nestin(Cre) mouse line, commonly employed to restrict genetic modifications to the CNS. We observed no alterations in locomotion, general exploratory activity, learning and memory, sociability, startle response and sensorimotor gating. Although the overall response to stimuli triggering anxiety-like behaviors remained unaltered in Nestin(Cre) mice, a strong impairment in the acquisition of both contextual- and cued-conditioned fear was observed. These results underline the importance of adequately controlling the behavioral performance of the employed Cre-lines per-se in pre-clinical neurobehavioral research.

Identifying novel interventional strategies for psychiatric disorders: integrating genomics, 'enviromics' and gene-environment interactions in valid preclinical models

Psychiatric disorders affect a substantial proportion of the population worldwide. This high prevalence, combined with the chronicity of the disorders and the major social and economic impacts, creates a significant burden. As a result, an important priority is the development of novel and effective interventional strategies for reducing incidence rates and improving outcomes. This review explores the progress that has been made to date in establishing valid animal models of psychiatric disorders, while beginning to unravel the complex factors that may be contributing to the limitations of current methodological approaches. We propose some approaches for optimizing the validity of animal models and developing effective interventions. We use schizophrenia and autism spectrum disorders as examples of disorders for which development of valid preclinical models, and fully effective therapeutics, have proven particularly challenging. However, the conclusions have relevance to various other psychiatric conditions, including depression, anxiety and bipolar disorders. We address the key aspects of construct, face and predictive validity in animal models, incorporating genetic and environmental factors. Our understanding of psychiatric disorders is accelerating exponentially, revealing extraordinary levels of genetic complexity, heterogeneity and pleiotropy. The environmental factors contributing to individual, and multiple, disorders also exhibit breathtaking complexity, requiring systematic analysis to experimentally explore the environmental mediators and modulators which constitute the 'envirome' of each psychiatric disorder. Ultimately, genetic and environmental factors need to be integrated via animal models incorporating the spatiotemporal complexity of gene-environment interactions and experience-dependent plasticity, thus better recapitulating the dynamic nature of brain development, function and dysfunction.

Mechanisms underlying the antidepressant response and treatment resistance

Depression is a complex and heterogeneous disorder affecting millions of Americans. There are several different medications and other treatments that are available and effective for many patients with depression. However, a substantial percentage of patients fail to achieve remission with these currently available interventions, and relapse rates are high. Therefore, it is necessary to determine both the mechanisms underlying the antidepressant response and the differences between responders and non-responders to treatment. Delineation of these mechanisms largely relies on experiments that utilize animal models. Therefore, this review provides an overview of the various mouse models that are currently used to assess the antidepressant response, such as chronic mild stress, social defeat, and chronic corticosterone. We discuss how these mouse models can be used to advance our understanding of the differences between responders and non-responders to antidepressant treatment. We also provide an overview of experimental treatment modalities that are used for treatment-resistant depression, such as deep brain stimulation and ketamine administration. We will then review the various genetic polymorphisms and transgenic mice that display resistance to antidepressant treatment. Finally, we synthesize the published data to describe a potential neural circuit underlying the antidepressant response and treatment resistance.

Organization of multisynaptic inputs to the dorsal and ventral dentate gyrus: retrograde trans-synaptic tracing with rabies virus vector in the rat

Behavioral, anatomical, and gene expression studies have shown functional dissociations between the dorsal and ventral hippocampus with regard to their involvement in spatial cognition, emotion, and stress. In this study we examined the difference of the multisynaptic inputs to the dorsal and ventral dentate gyrus (DG) in the rat by using retrograde trans-synaptic tracing of recombinant rabies virus vectors. Three days after the vectors were injected into the dorsal or ventral DG, monosynaptic neuronal labeling was present in the entorhinal cortex, medial septum, diagonal band, and supramammillary nucleus, each of which is known to project to the DG directly. As in previous tracing studies, topographical patterns related to the dorsal and ventral DG were seen in these regions. Five days after infection, more of the neurons in these regions were labeled and labeled neurons were also seen in cortical and subcortical regions, including the piriform and medial prefrontal cortices, the endopiriform nucleus, the claustrum, the cortical amygdala, the medial raphe nucleus, the medial habenular nucleus, the interpeduncular nucleus, and the lateral septum. As in the monosynaptically labeled regions, a topographical distribution of labeled neurons was evident in most of these disynaptically labeled regions. These data indicate that the cortical and subcortical inputs to the dorsal and ventral DG are conveyed through parallel disynaptic pathways. This second-order input difference in the dorsal and ventral DG is likely to contribute to the functional differentiation of the hippocampus along the dorsoventral axis.

Antidepressant activity: contribution of brain microdialysis in knock-out mice to the understanding of BDNF/5-HT transporter/5-HT autoreceptor interactions

Why antidepressants vary in terms of efficacy is currently unclear. Despite the leadership of selective serotonin reuptake inhibitors (SSRIs) in the treatment of depression, the precise neurobiological mechanisms involved in their therapeutic action are poorly understood. A better knowledge of molecular interactions between monoaminergic system, pre- and post-synaptic partners, brain neuronal circuits and regions involved may help to overcome limitations of current treatments and identify new therapeutic targets. Intracerebral in vivo microdialysis (ICM) already provided important information about the brain mechanism of action of antidepressants first in anesthetized rats in the early 1990s, and since then in conscious wild-type or knock-out mice. The principle of ICM is based on the balance between release of neurotransmitters (e.g., monoamines) and reuptake by selective transporters [e.g., serotonin transporter for serotonin 5-hydroxytryptamine (5-HT)]. Complementary to electrophysiology, this technique reflects pre-synaptic monoamines release and intrasynaptic events corresponding to ≈80% of whole brain tissue content. The inhibitory role of serotonergic autoreceptors infers that they limit somatodendritic and nerve terminal 5-HT release. It has been proposed that activation of 5-HT_1A and 5-HT_1B receptor sub-types limits the antidepressant-like activity of SSRIs. This hypothesis is based partially on results obtained in ICM experiments performed in naïve, non-stressed rodents. The present review will first remind the principle and methodology of ICM performed in mice. The crucial need of developing animal models that display anxiety and depression-like behaviors, neurochemical and brain morphological phenotypes reminiscent of these mood disorders in humans, will be underlined. Recently developed genetic mouse models have been generated to independently manipulate 5-HT_1A auto and heteroreceptors and ICM helped to clarify the role of the pre-synaptic component, i.e., by measuring extracellular levels of neurotransmitters in serotonergic nerve terminal regions and raphe nuclei. Finally, we will summarize main advantages of using ICM in mice through recent examples obtained in knock-outs (drug infusion through the ICM probe allows the search of a correlation between changes in extracellular neurotransmitter levels and antidepressant-like activity) or alternatives (infusion of a small-interfering RNA suppressing receptor functions in the mouse brain). We will also focus this review on post-synaptic components such as brain-derived neurotrophic factor in adult hippocampus that plays a crucial role in the neurogenic and anxiolytic/antidepressant-like activity of chronic SSRI treatment. Limitations of ICM will also be considered.

Afraid to help: social anxiety partially mediates the association between 5-HTTLPR triallelic genotype and prosocial behavior

There is growing evidence that the serotonin system influences prosocial behavior. We examined whether anxiety mediated the association between variation in the serotonin transporter gene regulatory region (5-HTTLPR) and prosocial behavior. We collected self-reported tendencies to avoid certain situations and history of helping others using standard instruments and buccal cells for standard 5-HTTLPR genotyping from 398 undergraduate students. Triallelic 5-HTTLPR genotype was significantly associated with prosocial behavior and the effect was partially mediated by social anxiety, such that those carrying the S' allele reported higher levels of social avoidance and lower rates of helping others. These results are consistent with accounts of the role of serotonin on anxiety and prosocial behavior and suggest that targeted efforts to reduce social anxiety in S' allele carriers may enhance prosocial behavior.

Increased anxiety in offspring reared by circadian Clock mutant mice

The maternal care that offspring receive from their mothers early in life influences the offspring’s development of emotional behavior in adulthood. Here we found that offspring reared by circadian clock-impaired mice show elevated anxiety-related behavior. Clock mutant mice harboring a mutation in Clock, a key component of the molecular circadian clock, display altered daily patterns of nursing behavior that is fragmented during the light period, instead of long bouts of nursing behavior in wild-type mice. Adult wild-type offspring fostered by Clock mutant mice exhibit increased anxiety-related behavior. This is coupled with reduced levels of brain serotonin at postnatal day 14, whose homeostasis during the early postnatal period is critical for normal emotional behavior in adulthood. Together, disruption of the circadian clock in mothers has an adverse impact on establishing normal anxiety levels in offspring, which may increase their risk of developing anxiety disorders.

Contextual fear conditioning in virtual reality is affected by 5HTTLPR and NPSR1 polymorphisms: effects on fear-potentiated startle

The serotonin (5-HT) and neuropeptide S (NPS) systems are discussed as important genetic modulators of fear and sustained anxiety contributing to the etiology of anxiety disorders. Sustained anxiety is a crucial characteristic of most anxiety disorders which likely develops through contextual fear conditioning. This study investigated if and how genetic alterations of the 5-HT and the NPS systems as well as their interaction modulate contextual fear conditioning; specifically, function polymorphic variants in the genes coding for the 5-HT transporter (5HTT) and the NPS receptor (NPSR1) were studied. A large group of healthy volunteers was therefore stratified for 5HTTLPR (S+ vs. LL carriers) and NPSR1 rs324981 (T+ vs. AA carriers) polymorphisms resulting in four genotype groups (S+/T+, S+/AA, LL/T+, LL/AA) of 20 participants each. All participants underwent contextual fear conditioning and extinction using a virtual reality (VR) paradigm. During acquisition, one virtual office room (anxiety context, CXT+) was paired with an unpredictable electric stimulus (unconditioned stimulus, US), whereas another virtual office room was not paired with any US (safety context, CXT−). During extinction no US was administered. Anxiety responses were quantified by fear-potentiated startle and ratings. Most importantly, we found a gene × gene interaction on fear-potentiated startle. Only carriers of both risk alleles (S+/T+) exhibited higher startle responses in CXT+ compared to CXT−. In contrast, anxiety ratings were only influenced by the NPSR1 polymorphism with AA carriers showing higher anxiety ratings in CXT+ as compared to CXT−. Our results speak in favor of a two level account of fear conditioning with diverging effects on implicit vs. explicit fear responses. Enhanced contextual fear conditioning as reflected in potentiated startle responses may be an endophenotype for anxiety disorders.

Family burden, family health and personal mental health

Background

The economic and moral implications of family burden are well recognised. What is less understood is whether or how family health and family burden relate to personal mental health. This study examines family health and perceived family burden as predictors of personal mental health, taking personal and sociodemographic factors into consideration.

Methods

Data used was from the National Comorbidity Study Replication (NCS-R), namely the random 30% of participants (N = 3192) to whom the family burden interview was administered. Measures of family burden and mental health were considered for analysis.

Results

Binary logistic regressions were used as means of analyses. Perception of family burden was associated with an increased vulnerability to personal mental health problems, as was the presence of mental health difficulties within the family health profile. Which member of the family (kinship) was ill bore no relation to prediction of personal mental health. Personal and socio-demographic factors of sex, age, marital status, education and household income were all predictive of increased vulnerability to mental health problems over the last 12 months.

Conclusions

Certain elements of family health profile and its perceived burden on the individuals themselves appears related to risk of personal incidence of mental health problems within the individuals themselves. For moral and economic reasons, further research to understand the dynamics of these relationships is essential to aid developing initiatives to protect and support the mental health and wellbeing of relatives of ill individuals.

Effects of fluoxetine on the swimming and behavioural responses of the Arabian killifish

The selective serotonin reuptake inhibitor fluoxetine has frequently been detected in surface waters around the world. Fluoxetine modulates levels of serotonin, a neurotransmitter that regulates several important physiological and behavioural processes including fear and anxiety, aggression, locomotion and feeding. In this study, groups of sub-adult Arabian killifish (Aphanius dispar) were exposed to either 0, 0.03, 0.3 or 3 μg/L fluoxetine hydrochloride for 7 days and their swimming behaviour and social interactions videotaped in a circular arena. The fish were subsequently exposed to a predator alarm chemical (from dragonfly larvae fed with A. dispar) and their short-term responses recorded. The video was analysed using the open-sourced software program Ctrax which objectively quantified swimming and social behaviours. Aggression (chasing behaviour was significantly reduced at 3.0 μg/L fluoxetine. After the addition of the predator alarm chemicals fish responded quickly, increasing the percentage of time spent drifting or motionless and reducing average swimming velocity. Controls and fish exposed to 0.03 or 3 μg/L fluoxetine reduced swimming speed by 20-30 % but returned to pre-exposure velocities within 6 min. Fish exposed to 0.3 μg/L fluoxetine reduced swimming speed by 38 % after addition of the predator alarm and did not return to pre-exposure speeds during the recording period (19 min). Schooling behaviour was also affected by fluoxetine and predator alarm with fish exposed to 0.3 μg/L fluoxetine significantly reducing nearest neighbour distance and swimming speed relative to nearest neighbour the following addition of the predator alarm.

Serotonergic genotypes, neuroticism, and financial choices

Life financial outcomes carry a significant heritable component, but the mechanisms by which genes influence financial choices remain unclear. Focusing on a polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR), we found that individuals possessing the short allele of this gene invested less in equities, were less engaged in actively making investment decisions, and had fewer credit lines. Short allele carriers also showed higher levels of the personality trait neuroticism, despite not differing from others with respect to cognitive skills, education, or wealth. Mediation analysis suggested that the presence of the 5-HTTLPR short allele decreased real life measures of financial risk taking through its influence on neuroticism. These findings show that 5-HTTLPR short allele carriers avoid risky and complex financial choices due to negative emotional reactions, and have implications for understanding and managing individual differences in financial choice.

Enhancing genotyping of MAOA-LPR and 5-HTT-LPR in rhesus macaques (Macaca mulatta)

BACKGROUND

Genetic variation in monoamine oxidase A (MAOA) and serotonin transporter (5-HTT)-linked polymorphic regions (LPR) is associated with neuropsychiatric behavior.

METHODS

We genotyped 37 macaques using conventional PCR product gel fractionation and by capillary electrophoresis of multiplexed amplicons and compared the data.

RESULTS

Genotype concordance was 97% and 95% for MAOA-LPR and 5-HTT-LPR, respectively. Capillary electrophoresis was more sensitive and cost-effective.

CONCLUSIONS

Multiplexing MAOA-LPR and 5-HTT-LPR will enhance the genotyping of large sample sets.

Imaging trait anxiety in high anxiety F344 rats: Focus on the dorsomedial prefrontal cortex

Functional magnetic resonance imaging (fMRI) has become an important method in clinical psychiatry research whereas there are still only few comparable preclinical investigations. Herein, we report that fMRI in rats can provide key information regarding brain areas underlying anxiety behavior. Perfusion as surrogate for neuronal activity was measured by means of arterial spin labeling-based fMRI in various brain areas of high anxiety F344 rats and control Sprague-Dawley rats. In one of these areas, the dorsomedial prefrontal cortex (dmPFC), c-Fos labeling was compared between these two strains with immunolabeling. The effects of a neurotoxic ibotenic acid lesion of the dmPFC in F344 rats were examined in a social approach-avoidance anxiety procedure and fMRI. Regional brain activity of high anxiety F344 rats was different in selective cortical and subcortical areas as compared to that of low anxiety Sprague-Dawley rats; the largest difference (i.e. hyperactivity) was measured in the dmPFC. Independently, c-Fos labeling confirmed that F344 rats show increased dmPFC activity. The functional role was confirmed by neurotoxic lesion of the dmPFC that reversed the high anxiety-like behavior and partially normalized the brain activity pattern of F344 rats. The current findings may have translational value as increased activity is reported in an equivalent cortical area in patients with social anxiety, suggesting that pharmacological or functional inhibition of activity in this brain area should be explored to alleviate social anxiety in patients.

Modeling borderline personality disorder based on the neurobehavioral foundation of major personality traits

Borderline personality disorder (BPD) is an exceedingly complex behavioral phenomenon that is in need of conceptual clarification within a larger model of personality disorders (PDs). The association of personality traits to BPD is discussed initially as a means of introducing a dimensional personality approach to understanding BPD. While this model suggests that PDs emerge at the extremes of personality dimensions, attempts to demonstrate such an association have been empirically disappointing and conceptually unilluminating. Therefore, in this article, we attempt to extend such models by outlining the neurobehavioral systems that underlie major personality traits, and highlight the evidence that they are subject to experience-dependent modification that can be enduring through effects on genetic expression, mainly through processes known as epigenetics. It is through such processes that risk for personality disorder may be modified by experience at any point in development, but perhaps especially during early critical periods of development. We conclude by presenting a multidimensional model of PDs, in general, and BPD, in particular, that relies on the concepts developed earlier in the article. Our goal is to provide a guide for novel clinical conceptualization and assessment of PDs, as well as research on their psychobiological nature and pharmacological treatment.

Love is more than just a kiss: a neurobiological perspective on love and affection

Love, attachment, and truth of human monogamy have become important research themes in neuroscience. After the introduction of functional Magnetic Resonance Imaging (fMRI) and Positron Emission Tomography (PET), neuroscientists have demonstrated increased interest in the neurobiology and neurochemistry of emotions, including love and affection. Neurobiologists have studied pair-bonding mechanisms in animal models of mate choice to elucidate neurochemical mechanisms underlying attachment and showed possible roles for oxytocin, vasopressin, and dopamine and their receptors in pair-bonding and monogamy. Unresolved is whether these substances are also critically involved in human attachment. The limited number of available imaging studies on love and affection is hampered by selection bias on gender, duration of a love affair, and cultural differences. Brain activity patterns associated with romantic love, shown with fMRI, overlapped with regions expressing oxytocin receptors in the animal models, but definite proof for a role of oxytocin in human attachment is still lacking. There is also evidence for a role of serotonin, cortisol, nerve growth factor, and testosterone in love and attachment. Changes in brain activity related to the various stages of a love affair, gender, and cultural differences are unresolved and will probably become important research themes in this field in the near future. In this review we give a resume of the current knowledge of the neurobiology of love and attachment and we discuss in brief the truth of human monogamy.

The importance of serotonin for orbitofrontal function

The orbitofrontal cortex (OFC) receives a dense serotonin (5-hydroxytryptamine, or 5-HT) innervation from the dorsal raphe nucleus, with a smaller contribution from the median raphe nucleus. The reciprocal innervation from the OFC enables the OFC to regulate not only its own 5-HT input but the 5-HT input to the rest of the forebrain. This article reviews the evidence from studies in rodents and primates that implicate 5-HT in the OFC in the ability of animals to adapt their responding to changes in reward contingencies in the environment. A consensus is emerging that reductions in orbitofrontal 5-HT, whether the result of localized infusions of 5,7-dihydroxytryptamine (5,7-DHT), peripheral treatment with parachloroamphetamine (PCA) or para-chlorophenylalanine (PCPA), or chronic cold stress impairs this ability. Genetic variation in the 5-HT transporter can also affect this ability. An explanation regarding insensitivity to reward loss is ruled out by the finding that marmosets with 5-HT reductions in the OFC display a decline of responding as rapid as that of control animals when reward is withheld during extinction of a two-pattern discrimination task. The failure of these same animals to explore alternative stimuli during extinction, along with the recent electrophysiological evidence that dorsal raphe nucleus neurons encode future motivational outcomes, implicates orbitofrontal 5-HT in the process by which animals either exploit current resources or explore alternative resources based on current reward expectations.