Sexual Behavior in the Human Male

The chronic mild stress (CMS) model of depression: History, evaluation and usage

https://www.cell.com/trends/neurosciences/pdf/S0166-2236(15)00176-9.pdf

Depression as a Microglial Disease

The limited success in understanding the pathophysiology of major depression may result from excessive focus on the dysfunctioning of neurons, as compared with other types of brain cells. Therefore, we examined the role of dynamic alterations in microglia activation status in the development of chronic unpredictable stress (CUS)-induced depressive-like condition in rodents. We report that following an initial period (2-3 days) of stress-induced microglial proliferation and activation, some microglia underwent apoptosis, leading to reductions in their numbers within the hippocampus, but not in other brain regions, following 5 weeks of CUS exposure. At that time, microglia displayed reduced expression of activation markers as well as dystrophic morphology. Blockade of the initial stress-induced microglial activation by minocycline or by transgenic interleukin-1 receptor antagonist overexpression rescued the subsequent microglial apoptosis and decline, as well as the CUS-induced depressive-like behavior and suppressed neurogenesis. Similarly, the antidepressant drug imipramine blocked the initial stress-induced microglial activation as well as the CUS-induced microglial decline and depressive-like behavior. Treatment of CUS-exposed mice with either endotoxin, macrophage colony-stimulating factor or granulocyte-macrophage colony-stimulating factor, all of which stimulated hippocampal microglial proliferation, partially or completely reversed the depressive-like behavior and dramatically increased hippocampal neurogenesis, whereas treatment with imipramine or minocycline had minimal or no anti-depressive effects, respectively, in these mice. These findings provide direct causal evidence that disturbances in microglial functioning has an etiological role in chronic stress-induced depression, suggesting that microglia stimulators could serve as fast-acting anti-depressants in some forms of depressive and stress-related conditions.

http://basicmed.med.ncku.edu.tw/public/project/1526-1443055689-1.pdf

Dynamic microglial alterations underlie stress-induced depressive-like behavior and suppressed neurogenesis

The role of inflammation and microglial activation in the pathophysiology of psychiatric disorders

Psychological stress contributes to the development of clinical depression. This has prompted many preclinical studies to investigate the neurobiology of this relationship, however, the effects of stress on glia remain unclear. In this study, we wished to determine, first, how exposure to chronic psychological stress affects microglial activity within the prefrontal cortex (PFC) and, second, whether the observed changes were meaningfully related to corresponding changes in local neuronal activity and PFC-regulated behavior. Therefore, we examined markers of microglial activation, antigen presentation, apoptosis, and persistent neuronal activation within the PFC after exposure to repeated restraint stress. We also examined the effect of stress on spatial working memory, a PFC-dependent function. Finally, we tested the ability of a microglial activation inhibitor (minocycline) to alter the impact of chronic stress on all of these endpoints. Stressor exposure produced positively correlated increases in microglial and long-term neuronal activation in the PFC but not antigen presentation or apoptosis. As expected, it also impaired spatial working memory. Importantly, minocycline reduced the impact of stress on neuronal activation and working memory, as well as microglial activation. These results suggest a role for microglia in mediating the effects of stress on PFC neuronal function and PFC-regulated behavior.

/pdf/evidence-that-microglia-mediate-the-neurobiological-effects-4b87bw268b.pdf

Evidence that Microglia Mediate the Neurobiological Effects of Chronic Psychological Stress on the Medial Prefrontal Cortex

Some nonheterosexual individuals are eschewing lesbian/gay and bisexual identities for queer and pansexual identities. The present study aimed to examine the sexual and demographic characteristics of nonheterosexual individuals who adopt these labels. A convenience sample of 2,220 nonheterosexual (1,459 lesbian/gay, 413 bisexual, 168 queer, 146 pansexual, and 34 other "write-in") individuals were recruited for a cross-sectional online survey. In support of our hypotheses, those adopting pansexual identities were younger than those adopting lesbian, gay, and bisexual identities, and those adopting queer and pansexual identities were more likely to be noncisgender than cisgender, and more likely to be cisgender women than men. The majority of pansexual individuals demonstrated sexual orientation indices within the bisexual range, and showed equivalent patterns of sexual attraction, romantic attraction, sexual behavior, and partner gender as bisexual-identified men and women. In contrast, three-quarters of queer men, and more than half of queer women, reported sexual attraction in the homosexual range. This study found that rather than a general movement toward nontraditional sexual identities, queer and pansexual identities appear most appealing to nonheterosexual women and noncisgender individuals. These findings contribute important information regarding who adopts queer and pansexual identities in contemporary sexual minority populations.

Who Adopts Queer and Pansexual Sexual Identities

The present study examined essentialist beliefs about sexual orientation and their implications for sexual identity uncertainty, internalized homonegativity and psychological wellbeing in a sample of gay men. A combination of targeted sampling and snowball strategies were used to recruit 639 gay identifying men for a cross-sectional online survey. Participants completed a questionnaire assessing sexual orientation beliefs, sexual identity uncertainty, internalized homonegativity, and psychological wellbeing outcomes. Structural equation modeling was used to test whether essentialist beliefs were associated with psychological wellbeing indirectly via their effect on sexual identity uncertainty and internalized homonegativity. A unique pattern of direct and indirect effects was observed in which facets of essentialism predicted sexual identity uncertainty, internalized homonegativity and psychological wellbeing. Of note, viewing sexual orientation as immutable/biologically based and as existing in discrete categories, were associated with less sexual identity uncertainty. On the other hand, these beliefs had divergent relationships with internalized homonegativity, with immutability/biological beliefs associated with lower, and discreteness beliefs associated with greater internalized homonegativity. Of interest, although sexual identity uncertainty was associated with poorer psychological wellbeing via its contribution to internalized homophobia, there was no direct relationship between identity uncertainty and psychological wellbeing. Findings indicate that essentializing sexual orientation has mixed implications for sexual identity uncertainty and internalized homonegativity and wellbeing in gay men. Those undertaking educational and clinical interventions with gay men should be aware of the benefits and of caveats of essentialist theories of homosexuality for this population.

Essentialist beliefs, sexual identity uncertainty, internalized homonegativity and psychological wellbeing in gay men.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/1753-6405.12364

Minority stress and community connectedness among gay, lesbian and bisexual Australians: a comparison of rural and metropolitan localities

In this study, we examined how beliefs about the nature and origin of sexual orientation were associated with sexual identity outcomes, namely internalized sexual stigma and sexual orientation uncertainty, and in turn, psychological well-being in sexual minority women. A community sample of 393 lesbian and 205 bisexual women were recruited for a cross-sectional online survey. Using multigroup structural equation modeling, we examined whether believing sexual orientation to be inborn/immutable (i.e., natural) and/or as existing in discrete categories (i.e., discrete) was indirectly associated with psychological well-being via internalized stigma and sexual orientation uncertainty and whether some of these relationships were moderated by nonprototypical attractions (nonexclusive same-sex attractions in lesbian women and straight- or lesbian-leaning attractions in bisexual women) and age. Overall, similar patterns of direct effects were observed in lesbian and bisexual women. In both groups, naturalness beliefs were associated with lower internalized-stigma, whereas discreteness beliefs were associated with greater internalized stigma. In bisexual women, nonprototypical sexual attraction patterns moderated the relationship between discreteness beliefs and sexual orientation uncertainty. Younger age was associated with increased sexual orientation uncertainty in both lesbian and bisexual women. Specific to lesbian women, nonprototypical attraction predicted less endorsement of immutability and binary/discrete beliefs about sexual orientation, and unexpectedly, greater internalized stigma. The present study identifies potential implications of common lay theories of sexual orientation for lesbian versus bisexual women. (PsycINFO Database Record

James S. Morandini

Papers

Evidence that Microglia Mediate the Neurobiological Effects of Chronic Psychological Stress on the Medial Prefrontal Cortex

Who Adopts Queer and Pansexual Sexual Identities

Essentialist beliefs, sexual identity uncertainty, internalized homonegativity and psychological wellbeing in gay men.

Minority stress and community connectedness among gay, lesbian and bisexual Australians: a comparison of rural and metropolitan localities

Born this way: Sexual orientation beliefs and their correlates in lesbian and bisexual women.