Ovarian cycle effects on immediate reward selection bias in humans: a role for estradiol

Ovarian hormones predict cooperative strategies updating during multiple rounds of the prisoner's dilemma

Increasing research has focused on how ovarian hormones influence individual prosocial motivation and cooperation. However, most results remain ambiguous and contradictory. Here, we collected progesterone (PROG) and oestradiol from 62 healthy women with regular menstrual cycles to explore whether variations in ovarian hormones could flexibly change their cooperative preference according to their opponents' strategies in multiple rounds of a prisoner's dilemma (PD) game. Participants in different menstrual phases (32 in the follicular phase [FP] and 30 in the luteal phase [LP]) were asked to complete 20 rounds of PD games with each of three computer opponents holding different cooperative strategies. The results revealed that in PD games that did not require cooperation for increased outcomes, women in the LP (high PROG) reduced their cooperation rate more significantly than women in the FP (low PROG). In contrast, when the game design required reciprocity, simultaneously elevated levels of PROG and oestradiol predicted greater instances of participants choosing to cooperate. Furthermore, we found that elevated PROG levels accounted for women's elevated prosocial choices, regardless of the need to increase outcomes through cooperation. These results implied higher levels of PROG and oestradiol influence women's cooperative strategies resulting in increased social interactions.

Giftedness and atypical sexual differentiation: enhanced perceptual functioning through estrogen deficiency instead of androgen excess

Syndromic autism spectrum conditions (ASC), such as Klinefelter syndrome, also manifest hypogonadism. Compared to the popular Extreme Male Brain theory, the Enhanced Perceptual Functioning model explains the connection between ASC, savant traits, and giftedness more seamlessly, and their co-emergence with atypical sexual differentiation. Overexcitability of primary sensory inputs generates a relative enhancement of local to global processing of stimuli, hindering the abstraction of communication signals, in contrast to the extraordinary local information processing skills in some individuals. Weaker inhibitory function through gamma-aminobutyric acid type A (GABAA) receptors and the atypicality of synapse formation lead to this difference, and the formation of unique neural circuits that process external information. Additionally, deficiency in monitoring inner sensory information leads to alexithymia (inability to distinguish one's own emotions), which can be caused by hypoactivity of estrogen and oxytocin in the interoceptive neural circuits, comprising the anterior insular and cingulate gyri. These areas are also part of the Salience Network, which switches between the Central Executive Network for external tasks and the Default Mode Network for self-referential mind wandering. Exploring the possibility that estrogen deficiency since early development interrupts GABA shift, causing sensory processing atypicality, it helps to evaluate the co-occurrence of ASC with attention deficit hyperactivity disorder, dyslexia, and schizophrenia based on phenotypic and physiological bases. It also provides clues for understanding the common underpinnings of these neurodevelopmental disorders and gifted populations.

Estradiol and the Catechol-o-methyltransferase Gene Interact to Predict Working Memory Performance: A Replication and Extension

Decades of evidence across taxa have established the importance of dopamine (DA) signaling in the pFC for successful working memory performance. Genetic and hormonal factors can shape individual differences in prefrontal DA tone. The catechol-o-methyltransferase (COMT) gene regulates basal prefrontal DA, and the sex hormone 17β-estradiol potentiates DA release. E. Jacobs and M. D'Esposito [Estrogen shapes dopamine-dependent cognitive processes: Implications for women's health. Journal of Neuroscience, 31, 5286-5293, 2011] investigated the moderating role of estradiol on cognition using the COMT gene and COMT enzymatic activity as a proxy for pFC DA tone. They found that increases in 17β-estradiol within women at two time points during the menstrual cycle influenced working memory performance in a COMT-dependent manner. Here, we aimed to replicate and extend the behavioral findings of Jacobs and D'Esposito by employing an intensive repeated-measures design across a full menstrual cycle. Our results replicated the original investigation. Within-person increases in estradiol were associated with improved performance on 2-back lure trials for participants with low basal levels of DA (Val/Val carriers). The association was in the opposite direction for participants with higher basal levels of DA (Met/Met carriers). Our findings support the role of estrogen in DA-related cognitive functions and further highlight the need to consider gonadal hormones in cognitive science research.

Striatal dopamine synthesis and cognitive flexibility differ between hormonal contraceptive users and nonusers

In rodents and nonhuman primates, sex hormones are powerful modulators of dopamine (DA) neurotransmission. Yet less is known about hormonal regulation of the DA system in the human brain. Using positron emission tomography (PET), we address this gap by comparing hormonal contraceptive users and nonusers across multiple aspects of DA function: DA synthesis capacity via the PET radioligand 6-[18F]fluoro-m-tyrosine ([18F]FMT), baseline D2/3 receptor binding potential using [11C]raclopride, and DA release using methylphenidate-paired [11C]raclopride. Participants consisted of 36 healthy women (n = 15 hormonal contraceptive users; n = 21 naturally cycling/non users of hormonal contraception), and men (n = 20) as a comparison group. A behavioral index of cognitive flexibility was assessed prior to PET imaging. Hormonal contraceptive users exhibited greater DA synthesis capacity than NC participants, particularly in dorsal caudate, and greater cognitive flexibility. Furthermore, across individuals, the magnitude of striatal DA synthesis capacity was associated with cognitive flexibility. No group differences were observed in D2/3 receptor binding or DA release. Analyses by sex alone may obscure underlying differences in DA synthesis tied to women's hormone status. Hormonal contraception (in the form of pill, shot, implant, ring, or intrauterine device) is used by ~400 million women worldwide, yet few studies have examined whether chronic hormonal manipulations impact basic properties of the DA system. Findings from this study begin to address this critical gap in women's health.

Sex moderates family history of alcohol use disorder and childhood maltreatment effects on an fMRI stop-signal task

Childhood maltreatment (CM) and a family history (FH) of alcohol use disorder (AUD) are each associated with increased impulsivity. However, their unique or shared brain targets remain unknown. Furthermore, both CM and FH demonstrate sex-dependent effects on brain and behavior. We hypothesized that CM and FH interact in brain regions involved in impulsivity with sex-dependent effects. 144 first-year college students (18-19 years old) with varying experiences of CM and/or FH but without current AUD performed an fMRI stop-signal task. We tested interactions between FH, CM, and sex on task performance and blood oxygen level-dependent (BOLD) signal during successful inhibitions. We examined correlations between BOLD response and psychiatric symptoms. Significant three-way interactions of FH, CM, and sex were detected for brain and behavioral data, largely driven by male subjects. In males, CM was associated with poorer response inhibition but only for those with less FH; males with higher levels of both CM and FH demonstrated better response inhibition. Three-way interaction effects on voxel-wise BOLD response during response inhibition were found in bilateral middle frontal gyrus, left inferior frontal gyrus, dorsomedial prefrontal cortex, and posterior cingulate cortex. Network-level analyses implicated the left frontoparietal network, executive control network, and default-mode network. Greater BOLD response in these networks correlated with lower depressive, impulsive, and attentional symptoms, reduced alcohol misuse, greater resilience scores, and heightened trait anxiety. The results highlight sex-divergent effects of heritable and environmental risk factors that may account for sex-dependent expression of psychopathology in response to risk factors.

Effect of transcranial direct current stimulation on homeostatic and hedonic appetite control and mood states in women presenting premenstrual syndrome across menstrual cycle phases

PURPOSE

This study investigated the acute effect of anodal transcranial direct current stimulation (a-tDCS) over the left dorsolateral prefrontal cortex (DLPFC) on appetite, energy intake, food preferences, and mood states in the luteal and follicular phases of the menstrual cycle in women presenting premenstrual syndrome.

METHODS

Sixteen women (26.5 ± 5.2 years; 1.63 ± 0.1 m; 64.2 ± 12.8 kg; body mass index 24.0 ± 5.0 kg/m²; body fat 27.6 ± 7.5%) with the eumenorrheic menstrual cycle were submitted to a-tDCS and sham-tDCS conditions over their follicular and luteal phases. At pre - and post-tDCS, hunger and desire to eat something tasty, (analogic visual scale), the profile of mood states (POMS), and the psychological components of food preferences (Leeds Food Preference Questionnaire-BR) were assessed. Participants recorded their food intake for the rest of the day using a diary log.

RESULTS

There was a trend towards main effect of condition for decreased implicit wanting for low-fat savory food after a-tDCS but not sham-tDCS regardless of menstrual cycle phase (p = 0.062). There was no effect for self-reported hunger, desire to eat, energy and macronutrient intake, and on other components of food preferences (explicit liking and wanting for low- and high-fat savory and sweet foods, implicit wanting for low- and high-fat sweet and high-fat savory food); as well as for mood states.

CONCLUSIONS

Although no significant effects of a-tDCS were found, the present investigation provides relevant perspectives for future studies.

Effects of the estrous cycle on impulsive choice and interval timing in female rats

Research in humans and animals shows differences in impulsive choice, which is a failure to wait for larger, delayed rewards, when comparing males and females. It is possible that fluctuations in sex hormones (estradiol and progesterone) across the reproductive cycle contribute to sex differences in impulsive choice. The current study delivered an impulsive choice task with peak interval trials to female rats while estrous cycles, the rodent reproductive cycle, were tracked over the course of the task. Female rats were more sensitive to changes in delay in the proestrus phase of the estrous cycle and made more larger-later choices when in estrus, particularly when the delay to the smaller reward was short. Estradiol increases dramatically during proestrus while progesterone peaks during estrus, suggesting that estradiol and progesterone may affect impulsive choice through mechanisms such as delay discounting, delay aversion, and/or timing processes. Analyses of timing of the choice task delays showed inconsistent effects of the estrous cycle across delays, suggesting that reward-timing interactions may have complicated how hormone fluctuations affected interval timing. Further research is needed to determine the mechanism underlying increased larger-later choices during the estrus phase, increased delay sensitivity during the proestrus phase, and variability in interval timing across delays and estrous cycle stages.

Stress-altering anterior insular cortex activity affects risk decision-making behavior in mice of different sexes

Stress can affect people's judgment and make them take risky decisions. Abnormal decision-making behavior is a core symptom of psychiatric disorders, such as anxiety, depression, and substance abuse. However, the neuronal mechanisms underlying such impairments are largely unknown. The anterior insular cortex (AIC) is a crucial structure to integrate sensory information with emotional and motivational states. These properties suggest that AIC can influence a subjective prediction in decision-making. In this study, we demonstrated that stressed mice prefer to take more risky choices than control mice using a gambling test. Manipulating the neural activity of AIC or selectively inhibiting the AIC-BLA pathway with chemogenetic intervention resulted in alterations in risk decision-making in mice. Different sexes may have different decision-making strategies in risky situations. Endogenous estrogen levels affect emotional cognition by modulating the stress system function in women. We observed decision-making behavior in mice of different sexes with or without stress experience. The result showed that female mice did not change their choice strategy with increasing risk/reward probability and performed a lower risk preference than male mice after stress. Using the pharmacological method, we bilaterally injected an estrogen receptor (ER) antagonist that resulted in more risky behavior and decreased synaptic plasticity in the AIC of female mice. Our study suggested that the AIC is a crucial region involved in stress-induced alteration of decision-making, and estrogen in the AIC may regulate decision-making behavior by regulating synaptic plasticity.

Post-partum depression: From clinical understanding to preclinical assessments

Post-partum depression (PPD) with varying clinical manifestations affecting new parents remains underdiagnosed and poorly treated. This minireview revisits the pharmacotherapy, and relevant etiological basis, capable of advancing preclinical research frameworks. Maternal tasks accompanied by numerous behavioral readouts demand modeling different paradigms that reflect the complex and heterogenous nature of PPD. Hence, effective PPD-like characterization in animals towards the discovery of pharmacological intervention demands research that deepens our understanding of the roles of hormonal and non-hormonal components and mediators of this psychiatric disorder.

Discounting for Money, Food, and Sex, over the Menstrual Cycle

Sexual desire, physical activity, economic choices and other behaviours fluctuate over the menstrual cycle. However, we have an incomplete understanding of how preferences for smaller sooner or larger later rewards (known as delay discounting) change over the menstrual cycle. In this pre-registered, cross-sectional study, Bayesian linear and quadratic binomial regression analyses provide compelling evidence that delay discounting does change over the menstrual cycle. Data from 203 naturally cycling women show increased discounting (preference for more immediate rewards) mid-cycle, which is at least partially driven by changes in fertility. This study provides evidence for a robust and broad-spectrum increase in delay discounting (Cohen’s h ranging from 0.1 to 0.4) around the fertile point in the menstrual cycle across multiple commodities (money, food, and sex). We also show, for the first time, that discounting changes over the menstrual cycle in a pseudo-control group of 99 women on hormonal contraception. Interestingly, such women increase their discounting of sex toward the end of the menstrual phase — possibly reflecting a prioritisation of bonding-related sexual activity before menstrual onset.

Variations in progesterone and estradiol across the menstrual cycle predict generosity toward socially close others

The human tendency to share goods with others at personal costs declines across the perceived social distance to them, an observation termed social discounting. Cumulating evidence suggests that social preferences are influenced by the agent's neurohormonal state. Here we tested whether endogenous fluctuations in steroid hormone compositions across the menstrual cycle were associated with differences in generosity in a social discounting task. Adult healthy, normally-cycling, women made incentivized decisions between high selfish rewards for themselves and lower generous rewards for themselves but also for other individuals at variable social distances from their social environment. We determined participants' current levels of menstrual-cycle-dependent steroid hormones via salivary sampling. Results revealed that the increase in progesterone levels as well as the decrease in estradiol levels, but not changes in testosterone or cortisol, across the menstrual cycle, accounted for increased generosity specifically toward socially close others, but not toward remote strangers.

Association between resting-state EEG oscillation and psychometric properties in perimenopausal women

Background

The perimenopausal period is associated with a higher risk of various mood disorders. Similarly, although resting-state electroencephalogram (rsEEG) brain oscillatory activity has been associated with various neuropsychological disorders and behaviours, these issues have not been assessed in perimenopausal women. This study aimed to evaluate quantitative relationships between psychometric properties and rsEEG rhythms (delta, theta, alpha, beta and gamma powers) in perimenopausal women.

Methods

A cross-sectional correlational descriptive study was conducted to quantitatively analyze the correlations between rsEEG low-to-high band activities (delta, theta, alpha, beta, and gamma powers) and psychometric properties in 14 perimenopausal women. Participants completed a psychological inventory comprising the State Anxiety Inventory (SAI), Depression Inventory (DI), Behavioural Inhibition Scale (BIS) and short-form UPPS Impulsive Behaviour Scale (IS) before EEG recording.

Results

Results showed that impulsivity was positively related to the beta power, symmetrical at most channels (frontal, temporal, central, parietal and occipital regions; p < .05); but did not related to the delta, theta, alpha and gamma powers. The brainwave low-to-high bands, delta, theta, alpha, beta and gamma power were not associated with DI, SAI or BIS scores.

Conclusions

This study’s findings propose that significantly enhanced resting-state beta activity is a trait of impulsivity in perimenopausal women. Therefore, results have potential implications for the preclinical or clinical evaluation of these issues in perimenopausal women.

No Differences in Value-Based Decision-Making Due to Use of Oral Contraceptives

Fluctuating ovarian hormones have been shown to affect decision-making processes in women. While emerging evidence suggests effects of endogenous ovarian hormones such as estradiol and progesterone on value-based decision-making in women, the impact of exogenous synthetic hormones, as in most oral contraceptives, is not clear. In a between-subjects design, we assessed measures of value-based decision-making in three groups of women aged 18 to 29 years, during (1) active oral contraceptive intake (N = 22), (2) the early follicular phase of the natural menstrual cycle (N = 20), and (3) the periovulatory phase of the natural menstrual cycle (N = 20). Estradiol, progesterone, testosterone, and sex-hormone binding globulin levels were assessed in all groups via blood samples. We used a test battery which measured different facets of value-based decision-making: delay discounting, risk-aversion, risk-seeking, and loss aversion. While hormonal levels did show the expected patterns for the three groups, there were no differences in value-based decision-making parameters. Consequently, Bayes factors showed conclusive evidence in support of the null hypothesis. We conclude that women on oral contraceptives show no differences in value-based decision-making compared to the early follicular and periovulatory natural menstrual cycle phases.

Sex differences in economic decision-making: Exogenous estradiol has opposing effects on fairness framing in women and men

Burgeoning evidence indicates that women are more sensitive to the context of an offer and show a stronger propensity to adjust their behavior with changing fairness frames. We evaluated whether the sex hormone estradiol and associated stereotypical beliefs contribute to fairness framings by administering topical estradiol (2 mg) to 108 healthy women and 104 heathy men in a randomized, double-blind, placebo-controlled between-subject study design. Participants played the role of the responder in a modified version of the Ultimatum Game (UG), in which identical offers for the division of a given amount of money were framed as either fair or unfair. Furthermore, participants completed an unframed UG and a delayed discounting task to probe possible effects of estradiol on altruistic preferences and delay gratification. Our results show that women were more sensitive to fairness frames than men. Intriguingly, however, estradiol had sex-specific effects on fairness sensitivity by increasing the acceptance rate of proposals with a fair frame in men and reducing it in women. Furthermore, the mere belief of receiving estradiol treatment significantly increased the acceptance of unfair-framed offers in both sexes, but estradiol did not significantly alter the response to unframed offers and impulsive decision-making. Collectively, our findings indicate that estradiol has opposing effects on the sensitivity to the perceived fairness of economic offers in women and men. The profound effects of estradiol treatment and stereotypical beliefs provide support for the notion that sex differences in fairness framing are rooted in both biological and environmental factors.

Acute depletion of dopamine precursors in the human brain: effects on functional connectivity and alcohol attentional bias

Individuals who abuse alcohol often show exaggerated attentional bias (AB) towards alcohol-related cues, which is thought to reflect reward conditioning processes. Rodent studies indicate that dopaminergic pathways play a key role in conditioned responses to reward- and alcohol-associated cues. However, investigation of the dopaminergic circuitry mediating this process in humans remains limited. We hypothesized that depletion of central dopamine levels in adult alcohol drinkers would attenuate AB and that these effects would be mediated by altered function in frontolimbic circuitry. Thirty-four male participants (22-38 years, including both social and heavy drinkers) underwent a two-session, placebo-controlled, double-blind dopamine precursor depletion procedure. At each visit, participants consumed either a balanced amino acid (control) beverage or an amino acid beverage lacking dopamine precursors (order counterbalanced), underwent resting-state fMRI, and completed behavioral testing on three AB tasks: an alcohol dot-probe task, an alcohol attentional blink task, and a task measuring AB to a reward-conditioned cue. Dopamine depletion significantly diminished AB in each behavioral task, with larger effects among subjects reporting higher levels of binge drinking. The depletion procedure significantly decreased resting-state functional connectivity among ventral tegmental area, striatum, amygdala, and prefrontal regions. Beverage-related AB decreases were mediated by decreases in functional connectivity between the fronto-insular cortex and striatum and, for alcohol AB only, between anterior cingulate cortex and amygdala. The results support a substantial role for dopamine in AB, and suggest specific dopamine-modulated functional connections between frontal, limbic, striatal, and brainstem regions mediate general reward AB versus alcohol AB.

Neuroendocrine Modulation of Cognitive Performance in the Patients with Fibromyalgia

BACKGROUND

Fibromyalgia (FM) is a chronic widespread pain disorder associated with fatigue, tender points, sleep disturbances, and mood disorders. Symptoms associated with FM also include decreased cognitive function in which the neural basis is poorly understood. Neuroendocrine hormones may be correlated with cognitive performance under some ill conditions. However, we are unaware of current evidence on neuroendocrine hormones as factors influencing cognitive function in adults with FM.

OBJECTIVES

The aim of the study was to assess whether neuroendocrine hormones could affect cognition in the patients with FM.

STUDY DESIGN

This study used a case-control trial design.

SETTING

Study patients were recruited from the neurological outpatient clinics in the Second Affiliated Hospital and Affiliated Chaohu Hospital of Anhui Medical University and met the American College of Rheumatology criteria for FM.

METHODS

Forty-six patients with FM were compared with twenty-nine healthy controls (HCs). Several measures of cognitive performance and serum levels of neuroendocrine hormones were used to make these comparisons, and the patients were also asked to complete questionnaires on depression and sleep quality. Partial correlation analysis was performed to control the confounders and linear regression analysis was used to examine the effects of neuroendocrine hormones on cognitive measures.

RESULTS

The FM patients had worse performance in attention, short-term memory, orientation, object working memory and spatial reference memory, higher depression scores, and worse sleep quality than HCs. The raised level of cortisol and gonadotropin-releasing hormone (GnRH) can protect general cognition, whereas the raised level of cortisol and thyroid-stimulating hormone (TSH) will damage spatial memory.

LIMITATIONS

We did not study the sex hormones comprehensively.

CONCLUSIONS

The FM patients showed significant cognitive impairment in several domains. The altered levels of cortisol, thyrotrophin-releasing hormone (TRH), and GnRH may mediate cognitive changes in FM.

Influence of the natural hormonal milieu on brain and behavior in women who smoke cigarettes: Rationale and methodology

Women experience more severe health consequences from smoking, have greater difficulty quitting, and respond less favorably to nicotine replacement therapy than men. The influence of fluctuating ovarian hormones, specifically estradiol (E) and progesterone (P), on brain and behavioral responses during exposure to smoking reminders (i.e., cues) may be a contributing factor. Results from our laboratory suggest that women in the late follicular phase of their menstrual cycle (MC) have enhanced smoking cue (SC) vulnerabilities and reduced functional connectivity in neurocircuitry underlying cognitive control, potentially placing them at greater risk for continued smoking and relapse. The primary aim of this study is to examine and link hormonal status with brain and behavioral responses to SCs over the course of three monthly MCs in naturally cycling women who are chronic cigarette smokers. This longitudinal, counterbalanced study collects brain and behavioral responses to SCs at three time points during a woman's MC. Participants complete psychological and physical examinations, biochemical hormonal verification visits, and at least three laboratory/neuroimaging scan visits. The scan visits include a 10-min SC task during blood oxygen level-dependent (BOLD) data acquisition and are timed to occur during the early follicular phase (low E and P), late follicular phase (high E, unopposed by P), and mid-luteal phase (high P, high E). The primary outcomes include brain responses to SCs (compared to non-SCs), subjective craving, E and P hormone levels, and behavioral responses to SCs. This study addresses a critical gap in our knowledge: namely, the impact of the natural hormonal milieu on brain and behavioral responses to SCs, a powerful relapse trigger. Additionally, this study will provide a roadmap for human sex differences researchers who are obliged to consider the often confounding cyclic hormonal fluctuations of women.

Influence of ovarian hormones on value-based decision-making systems: Contribution to sexual dimorphisms in mental disorders

Women and men exhibit differences in behavior when making value-based decisions. Various hypotheses have been proposed to explain these findings, stressing differences in functional lateralization of the brain, functional activation, neurotransmitter involvement and more recently, sex hormones. While a significant interaction of neurotransmitter systems and sex hormones has been shown for both sexes, decision-making in women might be particularly affected by variations of ovarian hormones. In this review we have gathered information from animal and human studies on how ovarian hormones affect decision-making processes in females by interacting with neurotransmitter systems at functionally relevant brain locations and thus modify the computation of decision aspects. We also review previous findings on impaired decision-making in animals and clinical populations with substance use disorder and depression, emphasizing how little we know about the role of ovarian hormones in aberrant decision-making.

Neural Basis of Increased Cognitive Control of Impulsivity During the Mid-Luteal Phase Relative to the Late Follicular Phase of the Menstrual Cycle

Hormonal changes across the menstrual cycle have been shown to influence reward-related motivation and impulsive behaviors. Here, with the aim of examining the neural mechanisms underlying cognitive control of impulsivity, we compared event-related monetary delay discounting task behavior and concurrent functional magnetic resonance imaging (fMRI) revealed brain activity as well as resting state (rs)-fMRI activity, between women in the mid-luteal phase (LP) and women in the late follicular phase (FP). The behavioral data were analyzed and related to neural activation data. In the delay discounting task, women in the late FP were more responsive to short-term rewards (i.e., showed a greater discount rate) than women in the mid-LP, while also showing greater activity in the dorsal striatum (DS). Discount rate (transformed k) correlated with functional connectivity between the DS and dorsal lateral prefrontal cortex (dlPFC), consistent with previous findings indicating that DS-dlPFC circuitry may regulate impulsivity. Our rs-fMRI data further showed that the right dlPFC was significantly more active in the mid-LP than in late FP, and this effect was sensitive to absolute and relative estradiol levels during the mid-LP. DS-dlPFC functional connectivity magnitude correlated negatively with psychometric impulsivity scores during the late FP, consistent with our behavioral data and further indicating that relative estradiol levels may play an important role in augmenting cognitive control. These findings provide new insight into the treatment of conditions characterized by hyper-impulsivity, such as obsessive compulsive disorder, Parkinson disease, and attention deficit hyperactivity disorder. In conclusion, our results suggest that cyclical gonadal hormones affect cognitive control of impulsive behavior in a periodic manner, possibility via DS-dlPFC circuitry.

Reconsidering the role of sex hormones in psychopathy development: Estrogen and psychopathy among male justice-involved youth

Prominent theory suggests that factor one psychopathic traits may develop from increased input from hormones in the hypothalamic pituitary gonadal axis (HPG; i.e., testosterone) and decreased input from the hypothalamic pituitary adrenal axis (HPA; i.e., cortisol). Although there are extensive findings connecting low cortisol to psychopathy, less support has emerged for high levels of testosterone. This study examined whether incorporating the HPG hormone, estradiol, into this model would reveal relationships in line with theory: high levels of estradiol and testosterone in combination with low levels of cortisol would inform psychopathic traits. Baseline and reactive hormone levels were measured and compared to Psychopathy Checklist-Youth Version (PCL-YV) interviews among 66 male justice-involved youth (M age = 15.73) in a Southeastern juvenile detention center. The primary findings of this study were relationships between interacting HPA and HPG axis hormones with facet one and facet two psychopathic traits. Specifically, psychopathy total scores, interpersonal traits, and affective traits related to estradiol and testosterone reactivity, in that psychopathy scores were more likely with decreases in hormone reactivity (i.e., change in hormone level) following a stressor. Moreover, affective traits related to reactivity in all three hormones. These findings support inclusion of estradiol in neurobiological models of psychopathy and consideration of the individual components of psychopathy. This study adds to the growing body of research supporting interactions between variations in functioning of the HPA and HPG axes in relation to psychopathy.

Estradiol and Women's Health: Considering the Role of Estradiol as a Marker in Behavioral Medicine

The sex hormone estradiol, as measured through saliva, represents a non-invasive and cost-effective approach to understanding the influence of hormonal factors on physical and psychological well-being among women. Estradiol levels dramatically change at hormonal transitions, such as puberty, menopause, and postpartum. It is at these transitions where women are at increased risk for psychological and somatic distress. Salivary estradiol also has implications for decision-making and has been broadly associated with engagement in health-compromising behaviors which can influence women's ability to cope with and manage chronic health conditions. This review summarizes the evidence for salivary estradiol as a marker of physical and psychological health, and discusses practical information regarding saliva collection and assay. The overall intent is to expand and clarify knowledge of the relation between changes in salivary estradiol and women's health as well as to provide a means of integrating salivary estradiol into future behavioral medicine research.

Testicular hormones mediate robust sex differences in impulsive choice in rats

Impairments in choosing optimally between immediate and delayed rewards are associated with numerous psychiatric disorders. Such ‘intertemporal’ choice is influenced by genetic and experiential factors; however, the contributions of biological sex are understudied and data to date are largely inconclusive. Rats were used to determine how sex and gonadal hormones influence choices between small, immediate and large, delayed rewards. Females showed markedly greater preference than males for small, immediate over large, delayed rewards (greater impulsive choice). This difference was neither due to differences in food motivation or reward magnitude perception, nor was it affected by estrous cycle. Ovariectomies did not affect choice in females, whereas orchiectomies increased impulsive choice in males. These data show that male rats exhibit less impulsive choice than females and that this difference is at least partly maintained by testicular hormones. These differences in impulsive choice could be linked to gender differences across multiple neuropsychiatric conditions.

How ovarian hormones influence the behavioral activation and inhibition system through the dopamine pathway

The behavioral activation system (BAS) and the behavioral inhibition system (BIS) have been proposed to relate to stable traits that predict inter-individual differences in motivation. Prior reports point dopamine (DA) pathways, mainly including ventral tegmental area (VTA) and substantia nigra (SN), implicate in subserving reward-related functions associated with BAS and inhibitory functions related with BIS. However, as an important factor that affects DA releasing, it remains an open question whether the ovarian hormones may also be related to BIS/BAS. Here, to investigate effects of the estradiol (E2) and progesterone (PROG) on BIS/BAS and related DA pathways, we employed a BIS/BAS scale and the resting-state functional magnetic resonance imaging (fMRI) during the late follicular phase (FP) and the mid-luteal phase (LP). On the behavioral level, when women had high PROG levels, their E2 levels were found positively correlated with BIS scores, but those women whose PROG levels were low, their E2 levels were negative correlation with BIS scores. On the neural level, we demonstrated BAS was related with the VTA pathway, included brain reward regions of nucleus accumbens (NAc) and orbitofrontal cortex (OFC). Meanwhile, the BIS was correlated with the SN-dorsolateral prefrontal cortex (dlPFC) pathway. ROI-based resting-state functional connectivity (RSFC) analyses further revealed that, RSFC between the SN and dlPFC was modulated by ovarian hormones. With higher PROG levels, increased E2 levels among women were accompanied by stronger RSFC of the SN-dlPFC, but when PROG levels were low, E2 levels were negatively correlated with the SN-dlPFC RSFC. These findings revealed a combined enhancement effect of E2 and PROG on BIS, and the SN-dlPFC pathway was mainly involved in this process.

Evolution, the Menstrual Cycle, and Theoretical Overreach

A considerable amount of recent psychological research has attributed a variety of menstrual-cycle-related changes in social behavior to evolutionarily adaptive functions. Although these studies often draw interesting and unusual conclusions about female emotion and behavior within evolutionary theory, their significant limitations have not yet been addressed. In this article, we outline several methodological and conceptual issues related to the menstrual cycle that constitute threats to the internal validity and theoretical integrity of these studies. We recommend specific guidelines to address these issues and emphasize the need to apply more comprehensive and sophisticated theoretical structures when considering menstrual-cycle-related changes in emotion and behavior.

Auditory learning in an operant task with social reinforcement is dependent on neuroestrogen synthesis in the male songbird auditory cortex

Animals continually assess their environment for cues associated with threats, competitors, allies, mates or prey, and experience is crucial for those associations. The auditory cortex is important for these computations to enable valence assignment and associative learning. The caudomedial nidopallium (NCM) is part of the songbird auditory association cortex and it is implicated in juvenile song learning, song memorization, and song perception. Like human auditory cortex, NCM is a site of action of estradiol (E2) and is enriched with the enzyme aromatase (E2-synthase). However, it is unclear how E2 modulates auditory learning and perception in the vertebrate auditory cortex. In this study we employ a novel, auditory-dependent operant task governed by social reinforcement to test the hypothesis that neuro-E2 synthesis supports auditory learning in adult male zebra finches. We show that local suppression of aromatase activity in NCM disrupts auditory association learning. By contrast, post-learning performance is unaffected by either NCM aromatase blockade or NCM pharmacological inactivation, suggesting that NCM E2 production and even NCM itself are not required for post-learning auditory discrimination or memory retrieval. Therefore, neuroestrogen synthesis in auditory cortex supports the association between sounds and behaviorally relevant consequences.

Sex and the dopaminergic system: Insights from addiction studies

Sex differences are present in psychiatric disorders associated with disrupted dopamine function, and thus, sex differences in dopamine neurobiology may underlie these clinical disparities. In this chapter, we review sex differences in the dopaminergic system with a focus on substance use disorders, especially tobacco smoking, as our exemplar disorder. This chapter is organized into five sections describing sex differences in the dopaminergic system: (1) neurobiology, (2) role of sex hormones, (3) genetic underpinnings, (4) cognitive function, and (5) influence on addiction. In each section, we provide an overview of the topic area, summarize sex differences identified to date, highlight addiction research, especially clinical neuroimaging studies, and suggest avenues for future research.

Effects of Hormonal Contraceptives on Mood: A Focus on Emotion Recognition and Reactivity, Reward Processing, and Stress Response

PURPOSE OF REVIEW

We review recent research investigating the relationship of hormonal contraceptives and mood with a focus on relevant underlying mechanisms, such as emotion recognition and reactivity, reward processing, and stress response.

RECENT FINDINGS

Adverse effects of hormonal contraceptives (HCs) on mood seem most consistent in women with a history of depressive symptoms and/or previous negative experience with HC-intake. Current evidence supports a negativity bias in emotion recognition and reactivity in HC-users, although inconsistent to some extent. Some data, however, do indicate a trend towards a blunted reward response and a potential dysregulation of the stress response in some HC-users. HC-effects on psychological and neurophysiological mechanisms underlying mood are likely context-dependent. We provide suggestions on how to address some of the contributing factors to this variability in future studies, such as HC-dose, timing, administration-mode, and individual risk. A better understanding of how and when HCs affect mood is critical to provide adequate contraceptive choices to women worldwide.

Hunger increases delay discounting of food and non-food rewards

How do our valuation systems change to homeostatically correct undesirable psychological or physiological states, such as those caused by hunger? There is evidence that hunger increases discounting for food rewards, biasing choices towards smaller but sooner food reward over larger but later reward. However, it is not understood how hunger modulates delay discounting for non-food items. We outline and quantitatively evaluate six possible models of how our valuation systems modulate discounting of various commodities in the face of the undesirable state of being hungry. With a repeated-measures design, an experimental hunger manipulation, and quantitative modeling, we find strong evidence that hunger causes large increases in delay discounting for food, with an approximately 25% spillover effect to non-food commodities. The results provide evidence that in the face of hunger, our valuation systems increase discounting for commodities, which cannot achieve a desired state change as well as for those commodities that can. Given that strong delay discounting can cause negative outcomes in many non-food (consumer, investment, medical, or inter-personal) domains, the present findings suggest caution may be necessary when making decisions involving non-food outcomes while hungry.

Development of a Spatial Discount Task to Measure Impulsive Choices in Dogs

Simple Summary

Impulsivity is believed to play a role in problematic behaviors in dogs. In this study, we developed a test to assess dogs’ tendency to make impulsive choices, that is their preference for smaller immediate reward instead of larger, but harder to obtain ones. Dogs were first trained that a bowl presented on a certain side always contained a large food amount, whereas the one presented on the opposite side (although at the same distance from the dog) contained less food. Then, the bowl with less food was progressively placed closer to the dog. As expected, dogs’ choices to feed from the bowl with less food increased as the distance of the latter decreased. Choices did not depend on factors that could interfere, such as dogs’ level of motivation for food, training experience, or learning ability. This indicates that the test is likely to be actually assessing impulsivity, not other traits. Also, female dogs were more likely to make impulsive choices than males, in accordance with what is known in humans and rodents, supporting the validity of the test. The test was completed in less than 1 h, making it a valid option to assess impulsivity in dogs in various contexts.

Abstract

Impulsive choices reflect an individual’s tendency to prefer a smaller immediate reward over a larger delayed one. Here, we have developed a behavioural test which can be easily applied to assess impulsive choices in dogs. Dogs were trained to associate one of two equidistant locations with a larger food amount when a smaller amount was presented in the other location, then the smaller amount was placed systematically closer to the dog. Choices of the smaller amount, as a function of distance, were considered a measure of the dog’s tendency to make impulsive choices. All dogs (N = 48) passed the learning phase and completed the entire assessment in under 1 h. Choice of the smaller food amount increased as this was placed closer to the dog. Choices were independent from food motivation, past training, and speed of learning the training phase; supporting the specificity of the procedure. Females showed a higher probability of making impulsive choices, in agreement with analogue sex differences found in human and rodent studies, and supporting the external validity of our assessment. Overall, the findings support the practical applicability and represent a first indication of the validity of this method, making it suitable for investigations into impulsivity in dogs.

Neural systems underlying reward cue processing in early adolescence: The role of puberty and pubertal hormones

Affective neuroscience research suggests that maturational changes in reward circuitry during adolescence present opportunities for new learning, but likely also contribute to increases in vulnerability for psychiatric disorders such as depression and substance abuse. Basic research in animal models and human neuroimaging has made progress in understanding the normal development of reward circuitry in adolescence, yet, few functional neuroimaging studies have examined puberty-related influences on the functioning of this circuitry. The goal of this study was to address this gap by examining the extent to which striatal activation and cortico-striatal functional connectivity to cues predicting upcoming rewards would be positively associated with pubertal status and levels of pubertal hormones (dehydroepiandrosterone, testosterone, estradiol). Participants included 79 adolescents (10-13 year olds; 47 girls) varying in pubertal status who performed a novel reward cue processing task during fMRI. Pubertal maturation was assessed using sex-specific standardized composite measures based on Tanner staging (self-report and clinical assessment) and scores from the Pubertal Development Scale. These composite measures were computed to index overall pubertal maturation as well as maturation of the adrenal and gonadal axes separately for boys and girls. Basal levels of circulating pubertal hormones were measured using immunoassays from three samples collected weekly upon awakening across a three-week period. Results indicated greater striatal activation and functional connectivity between nucleus accumbens (NAcc) and medial prefrontal cortex (mPFC) to reward cue (vs. no reward cue) on this task. Also, girls with higher levels of estradiol showed reduced activation in left and right caudate and greater NAcc-putamen connectivity. Girls with higher levels of testosterone showed greater NAcc connectivity with the anterior cingulate cortex and the insula. There were no significant associations in boys. Findings suggest that patterns of activation and connectivity in cortico-striatal regions are associated with reward cue processing, particularly in girls. Longitudinal follow-up neuroimaging studies are needed to fully characterize puberty-specific effects on the development of these neural regions and how such changes may contribute to pathways of risk or resilience in adolescence.

Both Val158Met Polymorphism of Catechol-O-Methyltransferase Gene and Menstrual Cycle Affect Prepulse Inhibition but Not Attentional Modulation of Prepulse Inhibition in Younger-Adult Females

Prepulse inhibition (PPI) can be modulated by both the Val158Met (rs4680) polymorphism of the Catechol-O-Methyltransferase (COMT) gene and the menstrual-cycle-related hormone fluctuations, each of which affects the subcortical/cortical dopamine metabolism. PPI can also be modulated by attention. The attentional modulation of PPI (AMPPI) is sensitive to psychoses. Whether the Val158Met polymorphism affects the AMPPI in female adults at different menstrual-cycle phases is unknown. This study examined whether AMPPI and/or PPI are affected by the Val158Met polymorphism in 177 younger-adult females whose menstrual cycles were mutually different across the menstruation, proliferative, or secretory phases. The AMPPI was evaluated by comparing PPI under the condition of the auditory precedence-effect-induced perceptual spatial separation between the prepulse stimulus and a masking noise (PPI_PSS) against that under the condition of the precedence-effect-induced perceptual spatial co-location (PPI_PSC). The results showed that both the menstrual cycle and the COMT Val158Met polymorphism affected both PPI_PSC and PPI_PSS, but not the AMPPI (difference between PPI_PSS and PPI_PSC). Moreover, throughout the menstrual cycle, both PPI_PSC and PPI_PSS decreased monotonously in Val/Val-carrier participants. However, the decreasing pattern was not overserved in either Met/Met-carrier or Met/Val-carrier participants. Thus, in healthy younger-adult females, PPI_PSC and PPI_PSS, but not the AMPPI, is vulnerable to changes of ovarian hormones, and the COMT Val158Met polymorphism also has a modulating effect on this menstrual-cycle-dependent PPI variation. In contrast, the AMPPI seems to be more steadily trait-based, less vulnerable to ovarian hormone fluctuations, and may be useful in assisting the diagnosis of schizophrenia in female adults.

Trait determinants of impulsive behavior: a comprehensive analysis of 188 rats

Impulsivity is a naturally occurring behavior that, when accentuated, can be found in a variety of neuropsychiatric disorders. The expression of trait impulsivity has been shown to change with a variety of factors, such as age and sex, but the existing literature does not reflect widespread consensus regarding the influence of modulating effects. We designed the present study to investigate, in a cohort of significant size (188 rats), the impact of four specific parameters, namely sex, age, strain and phase of estrous cycle, using the variable delay-to-signal (VDS) task. This cohort included (i) control animals from previous experiments; (ii) animals specifically raised for this study; and (iii) animals previously used for breeding purposes. Aging was associated with a general decrease in action impulsivity and an increase in delay tolerance. Females generally performed more impulsive actions than males but no differences were observed regarding delay intolerance. In terms of estrous cycle, no differences in impulsive behavior were observed and regarding strain, Wistar Han animals were, in general, more impulsive than Sprague-Dawley. In addition to further confirming, in a substantial study cohort, the decrease in impulsivity with age, we have demonstrated that both the strain and sex influences modulate different aspects of impulsive behavior manifestations.

Estrogens, Aging, and Working Memory

PURPOSE OF REVIEW

Working memory (WM) is a key process that is integral to many complex cognitive tasks, and it declines significantly with advancing age. This review will survey recent evidence supporting the idea that the functioning of the WM system in women is modulated by circulating estrogens.

RECENT FINDINGS

In postmenopausal women, increased estrogen concentrations may be associated with improved WM function, which is evident on WM tasks that have a high cognitive load or significant manipulation demands. Experimental studies in rhesus monkeys and human neuroimaging studies support a prefrontal locus for these effects. Defining the basic neurochemical or cellular mechanisms that underlie the ability of estrogens to regulate WM is a topic of current research in both human and animal investigations. An emerging body of work suggests that frontal executive elements of the WM system are influenced by the circulating estrogen concentrations currently available to the CNS and that the effects are region-specific within the frontal cortex. These findings have implications for women's brain health and cognitive aging.

Suicide Risk and the Menstrual Cycle: a Review of Candidate RDoC Mechanisms

PURPOSE OF REVIEW

Risk for suicidal behavior may fluctuate across the menstrual cycle. Here, we use the RDoC framework to review potential mechanisms by which the cycle may increase acute suicide risk.

RECENT FINDINGS

The menstrual cycle impacts the majority of RDoC constructs linked to suicide risk, particularly among hormone-sensitive women, such as those with premenstrual dysphoric disorder or premenstrual exacerbation of a psychiatric disorder. Despite this, there are no published studies examining suicidal ideation, planning, or behavior longitudinally across the cycle. More work is needed to understand how hormone sensitivity may relate to both trait and state suicide risk. Intensive multilevel investigations of cyclical hormone effects on suicide risk through specific RDoC mechanisms are suggested. This is a fertile research area and may provide key insights regarding the mechanisms of acute suicide risk.

Addiction and Dopamine: Sex Differences and Insights from Studies of Smoking

Mesolimbic dopaminergic function influences addiction through effects on reinforcement learning, decision-making, and impulsivity. This review covers sex differences in dopaminergic neurochemistry, their hormonal and genetic determinants, and how differences in dopaminergic tone interact with sex and/or ovarian hormone status to affect cognitive functions. Findings from research on cigarette smoking reveal sex differences in striatal and midbrain dopamine D2-type receptor availability and striatal dopamine release that suggest mechanisms of nicotine dependence, and stronger subjective responses to nicotine and efficacy of nicotine replacement therapies in male smokers than in their female counterparts. Opportunities exist to extend such efforts in studies of how sex and hormone status influence other addictions.

Steroid Hormones and Their Action in Women's Brains: The Importance of Hormonal Balance

Sex hormones significantly impact women's lives. Throughout the different stages of life, from menarche to menopause and all stages in between, women experience dramatic fluctuations in the levels of progesterone and estradiol, among other hormones. These fluctuations affect the body as a whole, including the central nervous system (CNS). In the CNS, sex hormones act via steroid receptors. They also have an effect on different neurotransmitters such as GABA, serotonin, dopamine, and glutamate. Additionally, studies show that sex hormones and their metabolites influence brain areas that regulate mood, behavior, and cognitive abilities. This review emphasizes the benefits a proper hormonal balance during the different stages of life has in the CNS. To achieve this goal, it is essential that hormone levels are evaluated considering a woman's age and ovulatory status, so that a correct diagnosis and treatment can be made. Knowledge of steroid hormone activity in the brain will give women and health providers an important tool for improving their health and well-being.

DAT1-Genotype and Menstrual Cycle, but Not Hormonal Contraception, Modulate Reinforcement Learning: Preliminary Evidence

Hormone by genotype interactions have been widely ignored by cognitive neuroscience. Yet, the dependence of cognitive performance on both baseline dopamine (DA) and current 17ß-estradiol (E2) level argues for their combined effect also in the context of reinforcement learning. Here, we assessed how the interaction between the natural rise of E2 in the late follicular phase (FP) and the 40 base-pair variable number tandem repeat polymorphism of the dopamine transporter (DAT1) affects reinforcement learning capacity. 30 women with a regular menstrual cycle performed a probabilistic feedback learning task twice during the early and late FP. In addition, 39 women, who took hormonal contraceptives (HC) to suppress natural ovulation, were tested during the "pill break" and the intake phase of HC. The present data show that DAT1-genotype may interact with transient hormonal state, but only in women with a natural menstrual cycle. We found that carriers of the 9-repeat allele (9RP) experienced a significant decrease in the ability to avoid punishment from early to late FP. Neither homozygote subjects of the 10RP allele, nor subjects from the HC group showed a change in behavior between phases. These data are consistent with neurobiological studies that found that rising E2 may reverse DA transporter function and could enhance DA efflux, which would in turn reduce punishment sensitivity particularly in subjects with a higher transporter density to begin with. Taken together, the present results, although based on a small sample, add to the growing understanding of the complex interplay between different physiological modulators of dopaminergic transmission. They may not only point out the necessity to control for hormonal state in behavioral genetic research, but may offer new starting points for studies in clinical settings.

COMT Val158Met Polymorphism Exerts Sex-Dependent Effects on fMRI Measures of Brain Function

Evidence suggests that dopamine levels in the prefrontal cortex (PFC) modulate executive functions. A key regulator of PFC dopamine is catechol-O-methyltransferase (COMT). The activity level of the COMT enzyme are influenced by sex and the Val¹⁵⁸Met polymorphism (rs4680) of the COMT gene, with male sex and Val alleles both being associated with higher bulk enzyme activity, and presumably lower PFC dopamine. COMT genotype has not only been associated with individual differences in frontal dopamine-mediated behaviors, but also with variations in neuroimaging measures of brain activity and functional connectivity. In this study, we investigated whether COMT genotype predicts individual differences in neural activity and connectivity, and whether such effects are sex-dependent. We tested 93 healthy adults (48 females), genotyped for the Val¹⁵⁸Met polymorphism, in a delay discounting task and at rest during fMRI. Delay discounting behavior was predicted by an interaction of COMT genotype and sex, consistent with a U-shaped relationship with enzyme activity. COMT genotype and sex similarly exhibited U-shaped relationships with individual differences in neural activation, particularly among networks that were most engaged by the task, including the default-mode network. Effects of COMT genotype and sex on functional connectivity during rest were also U-shaped. In contrast, flexible reorganization of network connections across task conditions varied linearly with COMT among both sexes. These data provide insight into the potential influences of COMT-regulated variations in catecholamine levels on brain function, which may represent endophenotypes for disorders of impulsivity.

Developmental differences in reward sensitivity and sensation seeking in adolescence: Testing sex-specific associations with gonadal hormones and pubertal development

Sensation seeking has been found to increase, on average, from childhood to adolescence. Developmental scientists have hypothesized that this change could be driven by the rise of gonadal hormones at puberty, which affect reward-related processing in the brain. In a large, age-heterogeneous, population-based sample of adolescents and young adults (N = 810; ages 13-20 years), we tested for sex-specific associations between age, self-reported pubertal development, gonadal hormones (estradiol and testosterone) as measured in saliva, reward sensitivity as measured by a multivariate battery of in-laboratory tasks (including the Iowa gambling task, balloon analogue risk task, and stoplight task), and self-reported sensation seeking. Reward sensitivity was more strongly associated with sensation seeking in males than females. For both males and females, reward sensitivity was unrelated to age but was higher among those who reported more advanced pubertal development. There were significant sex differences in the effects of self-reported pubertal development on sensation seeking, with a positive association evident in males but a negative association in females. Moreover, gonadal hormones also showed diverging associations with sensation seeking-positive with testosterone but negative with estradiol. Overall, the results indicate that sensation seeking among adolescents and young adults depends on a complex constellation of developmental influences that operate via sex-specific mechanisms. (PsycINFO Database Record

Ovarian hormones, sleep and cognition across the adult female lifespan: An integrated perspective

Loss of ovarian function in women is associated with sleep disturbances and cognitive decline, which suggest a key role for estrogens and/or progestins in modulating these symptoms. The effects of ovarian hormones on sleep and cognitive processes have been studied in separate research fields that seldom intersect. However, sleep has a considerable impact on cognitive function. Given the tight connections between sleep and cognition, ovarian hormones may influence selective aspects of cognition indirectly, via the modulation of sleep. In support of this hypothesis, a growing body of evidence indicates that the development of sleep disorders following menopause contributes to accelerated cognitive decline and dementia in older women. This paper draws from both the animal and human literature to present an integrated view of the effects of ovarian hormones on sleep and cognition across the adult female lifespan.

Interactive Effects of Dopamine Baseline Levels and Cycle Phase on Executive Functions: The Role of Progesterone

Estradiol and progesterone levels vary along the menstrual cycle and have multiple neuroactive effects, including on the dopaminergic system. Dopamine relates to executive functions in an “inverted U-shaped” manner and its levels are increased by estradiol. Accordingly, dopamine dependent changes in executive functions along the menstrual cycle have been previously studied in the pre-ovulatory phase, when estradiol levels peak. Specifically it has been demonstrated that working memory is enhanced during the pre-ovulatory phase in women with low dopamine baseline levels, but impaired in women with high dopamine baseline levels. However, the role of progesterone, which peaks in the luteal cycle phase, has not been taken into account previously. Therefore, the main goals of the present study were to extend these findings (i) to the luteal cycle phase and (ii) to other executive functions. Furthermore, the usefulness of the eye blink rate (EBR) as an indicator of dopamine baseline levels in menstrual cycle research was explored. 36 naturally cycling women were tested during three cycle phases (menses–low sex hormones; pre-ovulatory–high estradiol; luteal–high progesterone and estradiol). During each session, women performed a verbal N-back task, as measure of working memory, and a single trial version of the Stroop task, as measure of response inhibition and cognitive flexibility. Hormone levels were assessed from saliva samples and spontaneous eye blink rate was recorded during menses. In the N-back task, women were faster during the luteal phase the higher their progesterone levels, irrespective of their dopamine baseline levels. In the Stroop task, we found a dopamine-cycle interaction, which was also driven by the luteal phase and progesterone levels. For women with higher EBR performance decreased during the luteal phase, whereas for women with lower EBR performance improved during the luteal phase. These findings suggest an important role of progesterone in modulating dopamine-cycle interactions. Additionally, we identified the eye blink rate as a non-invasive indicator of baseline dopamine function in menstrual cycle research.

Model approach for stress induced steroidal hormone cascade changes in severe mental diseases

INTRODUCTION

Stress was described by Cushing and Selye as an adaptation to a foreign stressor by the anterior pituitary increasing ACTH, which stimulates the release of glucocorticoid and mineralocorticoid hormones. The question is raised whether stress can induce additional steroidal hormone cascade changes in severe mental diseases (SMD), since stress is the common denominator.

METHODS

A systematic literature review was conducted in PubMed, where the steroidal hormone cascade of patients with SMD was compared to the impact of increasing stress on the steroidal hormone cascade (a) in healthy amateur marathon runners with no overtraining; (b) in healthy well-trained elite soldiers of a ranger training unit in North Norway, who were under extreme physical and mental stress, sleep deprivation, and insufficient calories for 1 week; and, (c) in soldiers suffering from post traumatic stress disorder (PTSD), schizophrenia (SI), and bipolar disorders (BD).

RESULTS

(a) When physical stress is exposed moderately to healthy men and women for 3-5 days, as in the case of amateur marathon runners, only few steroidal hormones are altered. A mild reduction in testosterone, cholesterol and triglycerides is detected in blood and in saliva, but there was no decrease in estradiol. Conversely, there is an increase of the glucocorticoids, aldosterone and cortisol. Cellular immunity, but not specific immunity, is reduced for a short time in these subjects. (b) These changes are also seen in healthy elite soldiers exposed to extreme physical and mental stress but to a somewhat greater extent. For instance, the aldosterone is increased by a factor of three. (c) In SMD, an irreversible effect on the entire steroidal hormone cascade is detected. Hormones at the top of the cascade, such as cholesterol, dehydroepiandrosterone (DHEA), aldosterone and other glucocorticoids, are increased. However, testosterone and estradiol and their metabolites, and other hormones at the lower end of the cascade, seem to be reduced. 1) The rate and extent of reduction of the androgen metabolites may cause a decrease of cellular and specific immunity which can lead to viral and bacterial infections; joint and stomach inflammation; general pain; and allergic reactions. 2) The decrease in testosterone, and estradiol in SMD may have detrimental effects in cell repair as the estradiol metabolite, 2-methoxy-estradiol (2ME2), helps to transforms stem cells into functional cells. As dopamine and 2ME2 are inversely metabolized via various forms of catechol-O-methyl transferase (COMT), well-being and hypertension may be related. 2ME2 is related to vascular endothelial growth factor (VEGF), which regulates blood capillary growth and O2 supply. As reduced O2 is a key marker of stress, the increase of glucocorticoids in all forms of mental and physical stress cannot counterbalance the reduced 2ME2 in cellular and mental stress. The increased cholesterol and triglycerides are related to stroke and infarction, contributing to a reduced life expectancy in SMD between 14 and 20 years. The increase of aldosterone leads to increases in anxiety, edema, and lung infections.

DISCUSSION

Increasing mental and physical stress is related to systematic deviations in the steroidal hormone cascade in the non-psychotic state, which then may cause life threatening co-morbidities in PTSD, SI, and BD.

Serotonergic modulation of orbitofrontal activity and its relevance for decision making and impulsivity

BACKGROUND

The orbitofrontal cortex seems to play a crucial role in reward-guided learning and decision making, especially for impulsive choice procedures including delayed reward discounting. The central serotonergic system is closely involved in the regulation of impulsivity, but how the serotonergic firing rate and release, best investigated by the loudness dependence of auditory evoked potentials (LDAEP), interact with orbitofrontal activity is still unknown.

METHODS

Twenty healthy volunteers (11 males, 9 females, 31.3 ± 10.6 years old) were studied in a 3T MRI scanner (Philips, Hamburg, Germany) during a delay discounting task, after their LDAEP was recorded using a 32 electrodes EEG machine (Brain Products, Munich, Germany).

RESULTS

Significant positive correlations were only found between the LDAEP and the medial orbitofrontal part of the superior frontal gyrus (SFG/MO) [Δ immediate reward - delayed reward] for the right (r = 0.519; P = 0.019) and left side (r = 0.478; P = 0.033). This relationship was stronger for females compared with males. Orbitofrontal activity was also related to the Barratt Impulsivity Scale.

CONCLUSIONS

This study revealed that low serotonergic activity as measured by a strong LDAEP was related to a high fMRI signal intensity of SFG/MO during immediate reward behavior which is related to impulsivity. Since this relationship was only found for the infralimbic medial and not for the middle or lateral part of the orbitofrontal cortex, an exclusive projection tract of the serotonergic system to this cortical region can be assumed to regulate impulsive reward-orientated decision making. Hum Brain Mapp 38:1507-1517, 2017. © 2016 Wiley Periodicals, Inc.

Adolescent neural response to reward is related to participant sex and task motivation

Risky decision making is prominent during adolescence, perhaps contributed to by heightened sensation seeking and ongoing maturation of reward and dopamine systems in the brain, which are, in part, modulated by sex hormones. In this study, we examined sex differences in the neural substrates of reward sensitivity during a risky decision-making task and hypothesized that compared with girls, boys would show heightened brain activation in reward-relevant regions, particularly the nucleus accumbens, during reward receipt. Further, we hypothesized that testosterone and estradiol levels would mediate this sex difference. Moreover, we predicted boys would make more risky choices on the task. While boys showed increased nucleus accumbens blood oxygen level-dependent (BOLD) response relative to girls, sex hormones did not mediate this effect. As predicted, boys made a higher percentage of risky decisions during the task. Interestingly, boys also self-reported more motivation to perform well and earn money on the task, while girls self-reported higher state anxiety prior to the scan session. Motivation to earn money partially mediated the effect of sex on nucleus accumbens activity during reward. Previous research shows that increased motivation and salience of reinforcers is linked with more robust striatal BOLD response, therefore psychosocial factors, in addition to sex, may play an important role in reward sensitivity. Elucidating neurobiological mechanisms that support adolescent sex differences in risky decision making has important implications for understanding individual differences that lead to advantageous and adverse behaviors that affect health outcomes.

Neural Systems Underlying Individual Differences in Intertemporal Decision-making

Excessively choosing immediate over larger future rewards, or delay discounting (DD), associates with multiple clinical conditions. Individual differences in DD likely depend on variations in the activation of and functional interactions between networks, representing possible endophenotypes for associated disorders, including alcohol use disorders (AUDs). Numerous fMRI studies have probed the neural bases of DD, but investigations of large-scale networks remain scant. We addressed this gap by testing whether activation within large-scale networks during Now/Later decision-making predicts individual differences in DD. To do so, we scanned 95 social drinkers (18-40 years old; 50 women) using fMRI during hypothetical choices between small monetary amounts available "today" or larger amounts available later. We identified neural networks engaged during Now/Later choice using independent component analysis and tested the relationship between component activation and degree of DD. The activity of two components during Now/Later choice correlated with individual DD rates: A temporal lobe network positively correlated with DD, whereas a frontoparietal-striatal network negatively correlated with DD. Activation differences between these networks predicted individual differences in DD, and their negative correlation during Now/Later choice suggests functional competition. A generalized psychophysiological interactions analysis confirmed a decrease in their functional connectivity during decision-making. The functional connectivity of these two networks negatively correlates with alcohol-related harm, potentially implicating these networks in AUDs. These findings provide novel insight into the neural underpinnings of individual differences in impulsive decision-making with potential implications for addiction and related disorders in which impulsivity is a defining feature.

Reproductive Steroid Regulation of Mood and Behavior

In this article, we examine evidence supporting the role of reproductive steroids in the regulation of mood and behavior in women and the nature of that role. In the first half of the article, we review evidence for the following: (i) the reproductive system is designed to regulate behavior; (ii) from the subcellular to cellular to circuit to behavior, reproductive steroids are powerful neuroregulators; (iii) affective disorders are disorders of behavioral state; and (iv) reproductive steroids affect virtually every system implicated in the pathophysiology of depression. In the second half of the article, we discuss the diagnosis of the three reproductive endocrine-related mood disorders (premenstrual dysphoric disorder, postpartum depression, and perimenopausal depression) and present evidence supporting the relevance of reproductive steroids to these conditions. Existing evidence suggests that changes in reproductive steroid levels during specific reproductive states (i.e., the premenstrual phase of the menstrual cycle, pregnancy, parturition, and the menopause transition) trigger affective dysregulation in susceptible women, thus suggesting the etiopathogenic relevance of these hormonal changes in reproductive mood disorders. Understanding the source of individual susceptibility is critical to both preventing the onset of illness and developing novel, individualized treatments for reproductive-related affective dysregulation. © 2016 American Physiological Society. Compr Physiol 6:1135-1160, 2016e.