Maternal social environment affects offspring cognition through behavioural and immune pathways in rats

Social interaction, psychotic disorders and inflammation: A triangle of interest

Social interaction difficulties are a hallmark of psychotic disorders, which in some cases can be definitely traced back to autoimmunological causes. Interestingly, systemic and intrathecal inflammation have been shown to significantly influence social processing by increasing sensitivity to threatening social stimuli, which bears some resemblance to psychosis. In this article, we review evidence for the involvement of systemic and intrathecal inflammatory processes in psychotic disorders and how this might help to explain some of the social impairments associated with this group of disorders. Vice versa, we also discuss evidence for the immunomodulatory function of social interactions and their potential role for therapeutic interventions in psychotic disorders.

The cross-talk between dopaminergic and nitric oxide systems in the medial septal nucleus, and their distinct effects on anxiety-like behaviors in male rats

Anxiety disorders, which have a noticeable global prevalence and may be caused by many factors, include a spectrum of disorders that share features of excessive fear- and anxiety-related behavioral disturbances. Different brain areas and neurotransmitter systems have been under investigation for anxiety-related disorders. In this study, we investigated the possible interaction between the dopaminergic and nitric oxide (NO) neurotransmitter systems in the medial septal nucleus and their roles in anxiety-like behaviors using elevated plus-maze (EPM) test in male rats. Our results showed that: (i) both D1-and D2-like receptor agonists, SKF-38393 and quinpirole, augmented anxiety-like behaviors at their two highest applied doses in the EPM test; (ii) both D1-and D2-like receptor antagonists, SCH- 23390 and sulpiride, reduced anxiety-like behaviors at their two highest applied doses in the EPM test; (iii) L-Arginine, a NO precursor, increased anxiety-like behaviors, but L-NAME, a non-specific nitric oxide synthase (NOS) inhibitor, reduced them in the EPM test; (iv) L-NAME could not reverse the anxiety-like parameters produced by SKF-38393, but it significantly reduced the anxiety-like behaviors induced by quinpirole; (v) Neither SCH- 23390 nor sulpiride changed anxiety-related behaviors induced by L-Arginine. It can be concluded that both dopaminergic and nitric oxide systems in the medial septal nucleus are involved in modulating anxiety-like behaviors. While NO has an involvement in the exerted effects by the D2-like agonist, such effects were not observed at the applied range of the doses for D1-and D2-like antagonists.

The social network: Neural control of sex differences in reproductive behaviors, motivation, and response to social isolation

Social animal species present a vast repertoire of social interactions when encountering conspecifics. Reproduction-related behaviors, such as mating, parental care, and aggression, are some of the most rewarding types of social interactions and are also the most sexually dimorphic ones. This review focuses on rodent species and summarizes recent advances in neuroscience research that link sexually dimorphic reproductive behaviors to sexual dimorphism in their underlying neuronal circuits. Specifically, we present a few possible mechanisms governing sexually-dimorphic behaviors, by hypothalamic and reward-related brain regions. Sex differences in the neural response to social isolation in adulthood are also discussed, as well as future directions for comparative studies with naturally solitary species.

Pregnancy associated epigenetic markers of inflammation predict depression and anxiety symptoms in response to discrimination

Latina mothers, who have one of the highest fertility rates among ethnic groups in the United States (US), often experience discrimination. Psychosocial influences during pregnancy, such as discrimination stress, promotes inflammation. However, the role of epigenetic markers of inflammation as a mediator between, and predictor of, maternal discrimination stress and neuropsychiatric outcomes has not been extensively studied. The current study investigates the role of DNA methylation at FOXP3 Treg-cell-specific demethylated region (TSDR), as a marker of regulatory T (Treg) cells that are important negative regulators of inflammation, and the promoter of tumour necrosis factor-alpha (TNF-α) gene, an important pro-inflammatory cytokine, in relation to discrimination stress during pregnancy and depression and anxiety symptomatology.

A sample of 148 Latina women residing in the US (mean age 27.6 years) were assessed prenatally at 24–32 weeks’ gestation and 4–6 weeks postnatally for perceived discrimination exposure (Everyday Discrimination Scale, EDS), emotional distress (depression, anxiety, perinatal-specific depression), acculturation, and acculturative stress. DNA methylation levels at the FOXP3 and TNFα promoter regions from blood samples collected at the prenatal stage were assessed by bisulphite pyrosequencing.

Regression analyses showed that prenatal EDS associated with postnatal emotional distress, depression and anxiety symptoms only in those individuals with higher than mean levels of FOXP3 TSDR and TNFα promoter methylation; no such significant associations were found in those with lower than mean levels of methylation for either. We further found that these relationships were mediated by TNFα only in those with high FOXP3 TSDR methylation, implying that immunosuppression via TNFα promoter methylation buffers the impact of discrimination stress on postpartum symptomatology. These results indicate that epigenetic markers of immunosuppression and inflammation play an important role in resilience or sensitivity, respectively, to prenatal stress.