Effects of hormonal contraceptives on mental rotation and verbal fluency

Sex Differences and the Influence of Sex Hormones on Cognition through Adulthood and the Aging Process

Hormones of the hypothalamic-pituitary-gonadal (HPG) axis that regulate reproductive function have multiple effects on the development, maintenance and function of the brain. Sex differences in cognitive functioning have been reported in both health and disease, which may be partly attributed to sex hormones. The aim of the current paper was to provide a theoretical review of how sex hormones influence cognitive functioning across the lifespan as well as provide an overview of the literature on sex differences and the role of sex hormones in cognitive decline, specifically in relation to Alzheimer’s disease (AD). A summary of current hormone and sex-based interventions for enhancing cognitive functioning and/or reducing the risk of Alzheimer’s disease is also provided.

Progesterone and human cognition

Progesterone is a neurosteroid and a neuroactive steroid, produced primarily by the corpus luteum and the placenta. In some animal models, progesterone affects cognitive performance, and its potential role in human cognition is especially germane to women. This role can be investigated through associations between peripheral concentrations of progesterone in blood or saliva and neuropsychological test results, through differences in cognitive profiles between women using menopausal hormone therapy with and without a progestogen, and through clinical trials. In naturally cycling reproductive-age women and pregnant women, there is no consistent relation between progesterone levels and cognition. In postmenopausal women within 6 years of menopause and not using hormone therapy, progesterone levels are positively associated with verbal memory and global cognition, but reported associations in older postmenopausal women are null. Some observational studies of postmenopausal women using hormone therapy raise concern of a small deleterious cognitive effect of progestogen (medroxyprogesterone acetate was most often reported in these studies), but this association may due to confounding factors. Small, short-term clinical trials of progesterone show no meaningful effect on cognition. The quality of evidence is low, but overall findings do not reveal consistent, clinically important effects of progesterone on cognitive function in women.

Sex Hormones and Processing of Facial Expressions of Emotion: A Systematic Literature Review

Background: We systematically reviewed the literature to determine the influence of sex hormones on facial emotion processing (FEP) in healthy women at different phases of life. Methods: Searches were performed in PubMed, Web of Science, PsycINFO, LILACS, and SciELO. Twenty-seven articles were included in the review and allocated into five different categories according to their objectives and sample characteristics (menstrual cycle, oral contraceptives, pregnancy/postpartum, testosterone, and progesterone). Results: Despite the limited number of studies in some categories and the existence of inconsistencies in the results of interest, the findings of the review suggest that FEP may be enhanced during the follicular phase. Studies with women taking oral contraceptives showed reduced recognition accuracy and decreased responsiveness of different brain structures during FEP tasks. Studies with pregnant women and women in the postpartum showed that hormonal changes are associated with alterations in FEP and in brain functioning that could indicate the existence of a hypervigilant state in new and future mothers. Exogenous administration of testosterone enhanced the recognition of threatening facial expressions and the activation of brain structures involved in the processing of emotional stimuli. Conclusions: We conclude that sex hormones affect FEP in women, which may have an impact in adaptive processes of the species and in the onset of mood symptoms associated with the premenstrual syndrome.

Does the use of hormonal contraceptives affect the mental rotation performance?

Oral contraceptive pill (OC) is one of the most popular form of contraception. Despite both behavioral and neuroimaging evidence of its significant impact on female brain and cognitive functions, much remains to be discovered regarding OCs targets in the brain and mechanisms of action. In the present study mental rotation performance was compared between women using anti-androgenic oral contraceptives (n = 35), naturally cycling (NC) women (n = 33) and men (n = 29). On average, OC users were less accurate than NC women and men. Men performed the task more accurately than NC women, but the difference reached significance only in the highest angular disparity condition (150 deg). The response time was positively related with progesterone level while accuracy was negatively related with 17ß-estradiol level, in NC, but not OC women. The comparison of slope and intercept values (parameters relating response time to angular disparity) revealed the main result of present study: OC users exhibited significantly lower slope compared to men and NC women, but there were no differences in intercept between groups. These results suggest that OC users instead of using rotation in mind strategy implemented some alternative method(s). We conclude that lower performance accuracy of OC users could be related to a less efficient performance strategy.

Cognitive function in patients on androgen suppression: A prospective, multicentric study

OBJECTIVE

To assess the effect of androgen deprivation therapy (ADT) on cognitive performance (CP) in patients with prostate cancer (PCa) after 6 months of treatment with luteinizing hormone-releasing hormone (LHRH) analogues.

MATERIAL AND METHODS

Prospective, observational, multicentre, open-label study of patients diagnosed with nonmetastatic or asymptomatic metastatic PCa scheduled to receive LHRH analogues for≥6 months. We assessed four CP domains at baseline and after 6 months of ADT: 1) Working memory: Wechsler Adult Intelligence Scale III (WAIS III) Digit Span Subtest (WAIS III-Digit); 2) Visual memory: ad hoc visual memory test; 3) Visuospatial ability: Judgement of Line Orientation (JLO) and Mental Rotation of Three-Dimensional Objects (3D-Rotation); and 4) Nonverbal analytical reasoning: WAIS III Matrix Reasoning Test (WAIS III-MRT). Changes outside the baseline 95% confidence intervals were considered significant.

RESULTS

A total of 308 patients completed the study. Of these, 245 (79.6%) experienced no statistically significant changes on any test and 63 patients (20.4%) experienced significant changes in ≥1 test. Of these, most presented a change in only one test, distributed evenly between improvements (58 patients; 18.8%) and worsening (56 patients; 18.2%). For individual tests, most patients (87.8% to 91.8%) had no change from baseline; however, the significant changes (improvement vs. deterioration, respectively) were as follows: WAIS III-Digit (6.3% vs. 5.9%); visual memory (5.3% vs. 5.7%); JLO (5.3% vs. 4.5%); 3D-Rotation (4.1% vs. 4.1%); and WAIS III-MRT (4.8% vs. 5.8%).

CONCLUSIONS

CP in patients with PCa does not appear to be adversely affected by 6 months of LHRH analogue administration.

Conducting neuropsychological assessment with transgender individuals

OBJECTIVE

The purpose of this paper is to provide an overview of helpful clinical practices when working with transgender adult individuals.

METHOD

While the number of openly transgender individuals appears to be growing with society's increased acceptance and awareness, many neuropsychologists have had few opportunities to gain experience with this patient population. In this article, we review the existing literature as it relates to clinical neuropsychological practice.

RESULTS

We describe important terminology, ideals for creating an environment of respect, and how existing clinical guidelines for transgender individuals may apply to neuropsychology. In addition, we review the primary steps in the assessment process and provide a set of principles and recommendations for conducting neuropsychological assessments with transgender patients.

CONCLUSIONS

There is a paucity of guidance in the field for working with transgender individuals. This article represents a step forward in the dialog and we look forward to future research that develops appropriate normative information, increases understanding of psychosocial factors, and better appreciates the range of hormonal influences for transgender individuals.

Considering sex differences in the cognitive controls of feeding

Women are disproportionately affected by obesity, and obesity increases women's risk of developing dementia more so than men. Remarkably little is known about how females make decisions about when and how much to eat. Research in animal models with males supports a framework in which previous experiences with external food cues and internal physiological energy states, and the ability to retrieve memories of the consequences of eating, determines subsequent food intake. Additional evidence indicates that consumption of a high-fat, high-sugar diet interferes with hippocampal-dependent mnemonic processes that operate to suppress eating, such as in situations of satiety. Recent findings also indicate that weakening this form of hippocampal-dependent inhibitory control may also extend to other forms of learning and memory, perpetuating a vicious cycle of increased Western diet intake, hippocampal dysfunction, and further impairments in the suppression of appetitive behavior that may ultimately disrupt other types of memorial interference resolution. How these basic learning and memory processes operate in females to guide food intake has received little attention. Ovarian hormones appear to protect females from obesity and metabolic impairments, as well as modulate learning and memory processes, but little is known about how these hormones modulate learned appetitive behavior. Even less is known about how a sex-specific environmental factor - widespread hormonal contraceptive use - affects associative learning and the regulation of food intake. Extending learned models of food intake to females will require considerably investigation at many levels (e.g., reproductive status, hormonal compound, parity). This work could yield critical insights into the etiology of obesity, and its concomitant cognitive impairment, for both sexes.

Sex, age, and sex hormones affect recall of words in a directed forgetting paradigm

During the course of serious discussion, an unexpected interruption may induce forgetting of the original topic of a conversation. Sex, age, and sex hormone levels may affect frequency and extension of forgetting. In a list-method directed forgetting paradigm, subjects have to learn two word lists. After learning list 1, subjects receive either a forget or a remember list 1 cue. When the participants had learned list 2 and completed a distraction task, they were asked to write down as many recalled items as possible, starting either with list 1 or list 2 items. In the present study, 96 naturally cycling women, 60 oral contraceptive users, 56 postmenopausal women, and 41 young men were assigned to one of these different experimental conditions. Forget-cued young subjects recall fewer list 1 items (list 1 forgetting) but more list 2 items (list 2 enhancement) compared with remember-cued subjects. However, forget-cued postmenopausal women showed reduced list 1 forgetting but enhanced list 2 retention. Remember-cued naturally cycling women recalled more list 1 items than oral contraceptive users, young men, and postmenopausal women. In forget-cued follicular women, salivary progesterone correlated positively with recalled list 2 items. Salivary 17β-estradiol did not correlate with recalled list 1 or list 2 items in either remember- or forget-cued young women. However, salivary 17β-estradiol correlated with item recall in remember-cued postmenopausal women. Our findings suggest that sex hormones do not globally modulate verbal memory or forgetting, but selectively affect cue-specific processing. © 2016 Wiley Periodicals, Inc.

Sex differences in social cognition: The case of face processing

Several studies have demonstrated that women show a greater interest for social information and empathic attitude than men. This article reviews studies on sex differences in the brain, with particular reference to how males and females process faces and facial expressions, social interactions, pain of others, infant faces, faces in things (pareidolia phenomenon), opposite-sex faces, humans vs. landscapes, incongruent behavior, motor actions, biological motion, erotic pictures, and emotional information. Sex differences in oxytocin-based attachment response and emotional memory are also mentioned. In addition, we investigated how 400 different human faces were evaluated for arousal and valence dimensions by a group of healthy male and female University students. Stimuli were carefully balanced for sensory and perceptual characteristics, age, facial expression, and sex. As a whole, women judged all human faces as more positive and more arousing than men. Furthermore, they showed a preference for the faces of children and the elderly in the arousal evaluation. Regardless of face aesthetics, age, or facial expression, women rated human faces higher than men. The preference for opposite- vs. same-sex faces strongly interacted with facial age. Overall, both women and men exhibited differences in facial processing that could be interpreted in the light of evolutionary psychobiology. © 2016 Wiley Periodicals, Inc.

Sex effects on spatial learning but not on spatial memory retrieval in healthy young adults

OBJECTIVES

Sex differences have been found in spatial learning and spatial memory, with several studies indicating that males outperform females. We tested in the virtual Morris Water Maze (vMWM) task, whether sex differences in spatial cognitive processes are attributable to differences in spatial learning or spatial memory retrieval in a large student sample.

METHODS

We tested 90 healthy students (45 women and 45 men) with a mean age of 23.5 years (SD=3.5). Spatial learning and spatial memory retrieval were measured by using the vMWM task, during which participants had to search a virtual pool for a hidden platform, facilitated by visual cues surrounding the pool. Several learning trials assessed spatial learning, while a separate probe trial assessed spatial memory retrieval.

RESULTS

We found a significant sex effect during spatial learning, with males showing shorter latency and shorter path length, as compared to females (all p<0.001). Yet, there was no significant sex effect in spatial memory retrieval (p=0.615). Furthermore, post-hoc analyses revealed significant sex differences in spatial search strategies (p<0.05), but no difference in the number of platform crossings (p=0.375).

CONCLUSION

Our results indicate that in healthy young adults, males show faster spatial learning in a virtual environment, as compared to females. Interestingly, we found no significant sex differences during spatial memory retrieval. Our study raises the question, whether men and women use different learning strategies, which nevertheless result in equal performances of spatial memory retrieval.

Lack of Associations between Female Hormone Levels and Visuospatial Working Memory, Divided Attention and Cognitive Bias across Two Consecutive Menstrual Cycles

Background: Interpretation of observational studies on associations between prefrontal cognitive functioning and hormone levels across the female menstrual cycle is complicated due to small sample sizes and poor replicability.

Methods: This observational multisite study comprised data of n = 88 menstruating women from Hannover, Germany, and Zurich, Switzerland, assessed during a first cycle and n = 68 re-assessed during a second cycle to rule out practice effects and false-positive chance findings. We assessed visuospatial working memory, attention, cognitive bias and hormone levels at four consecutive time-points across both cycles. In addition to inter-individual differences we examined intra-individual change over time (i.e., within-subject effects).

Results: Estrogen, progesterone and testosterone did not relate to inter-individual differences in cognitive functioning. There was a significant negative association between intra-individual change in progesterone and change in working memory from pre-ovulatory to mid-luteal phase during the first cycle, but that association did not replicate in the second cycle. Intra-individual change in testosterone related negatively to change in cognitive bias from menstrual to pre-ovulatory as well as from pre-ovulatory to mid-luteal phase in the first cycle, but these associations did not replicate in the second cycle.

Conclusions: There is no consistent association between women's hormone levels, in particular estrogen and progesterone, and attention, working memory and cognitive bias. That is, anecdotal findings observed during the first cycle did not replicate in the second cycle, suggesting that these are false-positives attributable to random variation and systematic biases such as practice effects. Due to methodological limitations, positive findings in the published literature must be interpreted with reservation.

Estrogenic Endocrine Disrupting Chemicals Influencing NRF1 Regulated Gene Networks in the Development of Complex Human Brain Diseases

During the development of an individual from a single cell to prenatal stages to adolescence to adulthood and through the complete life span, humans are exposed to countless environmental and stochastic factors, including estrogenic endocrine disrupting chemicals. Brain cells and neural circuits are likely to be influenced by estrogenic endocrine disruptors (EEDs) because they strongly dependent on estrogens. In this review, we discuss both environmental, epidemiological, and experimental evidence on brain health with exposure to oral contraceptives, hormonal therapy, and EEDs such as bisphenol-A (BPA), polychlorinated biphenyls (PCBs), phthalates, and metalloestrogens, such as, arsenic, cadmium, and manganese. Also we discuss the brain health effects associated from exposure to EEDs including the promotion of neurodegeneration, protection against neurodegeneration, and involvement in various neurological deficits; changes in rearing behavior, locomotion, anxiety, learning difficulties, memory issues, and neuronal abnormalities. The effects of EEDs on the brain are varied during the entire life span and far-reaching with many different mechanisms. To understand endocrine disrupting chemicals mechanisms, we use bioinformatics, molecular, and epidemiologic approaches. Through those approaches, we learn how the effects of EEDs on the brain go beyond known mechanism to disrupt the circulatory and neural estrogen function and estrogen-mediated signaling. Effects on EEDs-modified estrogen and nuclear respiratory factor 1 (NRF1) signaling genes with exposure to natural estrogen, pharmacological estrogen-ethinyl estradiol, PCBs, phthalates, BPA, and metalloestrogens are presented here. Bioinformatics analysis of gene-EEDs interactions and brain disease associations identified hundreds of genes that were altered by exposure to estrogen, phthalate, PCBs, BPA or metalloestrogens. Many genes modified by EEDs are common targets of both 17 β-estradiol (E2) and NRF1. Some of these genes are involved with brain diseases, such as Alzheimer's Disease (AD), Parkinson's Disease, Huntington's Disease, Amyotrophic Lateral Sclerosis, Autism Spectrum Disorder, and Brain Neoplasms. For example, the search of enriched pathways showed that top ten E2 interacting genes in AD-APOE, APP, ATP5A1, CALM1, CASP3, GSK3B, IL1B, MAPT, PSEN2 and TNF-underlie the enrichment of the Kyoto Encyclopedia of Genes and Genomes (KEGG) AD pathway. With AD, the six E2-responsive genes are NRF1 target genes: APBB2, DPYSL2, EIF2S1, ENO1, MAPT, and PAXIP1. These genes are also responsive to the following EEDs: ethinyl estradiol (APBB2, DPYSL2, EIF2S1, ENO1, MAPT, and PAXIP1), BPA (APBB2, EIF2S1, ENO1, MAPT, and PAXIP1), dibutyl phthalate (DPYSL2, EIF2S1, and ENO1), diethylhexyl phthalate (DPYSL2 and MAPT). To validate findings from Comparative Toxicogenomics Database (CTD) curated data, we used Bayesian network (BN) analysis on microarray data of AD patients. We observed that both gender and NRF1 were associated with AD. The female NRF1 gene network is completely different from male human AD patients. AD-associated NRF1 target genes-APLP1, APP, GRIN1, GRIN2B, MAPT, PSEN2, PEN2, and IDE-are also regulated by E2. NRF1 regulates targets genes with diverse functions, including cell growth, apoptosis/autophagy, mitochondrial biogenesis, genomic instability, neurogenesis, neuroplasticity, synaptogenesis, and senescence. By activating or repressing the genes involved in cell proliferation, growth suppression, DNA damage/repair, apoptosis/autophagy, angiogenesis, estrogen signaling, neurogenesis, synaptogenesis, and senescence, and inducing a wide range of DNA damage, genomic instability and DNA methylation and transcriptional repression, NRF1 may act as a major regulator of EEDs-induced brain health deficits. In summary, estrogenic endocrine disrupting chemicals-modified genes in brain health deficits are part of both estrogen and NRF1 signaling pathways. Our findings suggest that in addition to estrogen signaling, EEDs influencing NRF1 regulated communities of genes across genomic and epigenomic multiple networks may contribute in the development of complex chronic human brain health disorders.

Subcortical gray matter changes in transgender subjects after long-term cross-sex hormone administration

Sex-steroid hormones are primarily involved in sexual differentiation and development and are thought to underlie processes related to cognition and emotion. However, divergent results have been reported concerning the effects of hormone administration on brain structure including side effects like brain atrophy and dementia. Cross-sex hormone therapy in transgender subjects offers a unique model for studying the effects of sex hormones on the living human brain. In this study, 25 Female-to-Male (FtM) and 14 Male-to-Female (MtF) subjects underwent MRI examinations at baseline and after a period of at least 4-months of continuous cross-sex hormone administration. While MtFs received estradiol and anti-androgens, FtM subjects underwent high-dose testosterone treatment. The longitudinal processing stream of the FreeSurfer software suite was used for the automated assessment and delineation of brain volumes to assess the structural changes over the treatment period of cross-sex hormone administration. Most prominent results were found for MtFs receiving estradiol and anti-androgens in the form of significant decreases in the hippocampal region. Further analysis revealed that these decreases were reflected by increases in the ventricles. Additionally, changes in progesterone levels correlated with changes in gray matter structures in MtF subjects. In line with prior studies, our results indicate hormonal influences on subcortical structures related to memory and emotional processing. Additionally, this study adds valuable knowledge that progesterone may play an important role in this process.

The other side of progestins: effects in the brain

Progestins are a broad class of progestational agents widely differing in their chemical structures and pharmacological properties. Despite emerging data suggest that progestins, besides their action as endometrial protection, can also have multiple nonreproductive functions, much remains to be discovered regarding the actions exerted by these molecules in the nervous system. Here, we report the role exerted by different progestins, currently used for contraception or in postmenopausal hormone replacement therapies, in regulating cognitive functions as well as social behavior and mood. We provide evidence that the effects and mechanisms underlying their actions are still confusing due to the use of different estrogens and progestins as well as different doses, duration of exposure, route of administration, baseline hormonal status and age of treated women. We also discuss the emerging issue concerning the relevant increase of these substances in the environment, able to deeply affect aquatic wildlife as well as to exert a possible influence in humans, which may be exposed to these compounds via contaminated drinking water and seafood. Finally, we report literature data showing the neurobiological action of progestins and in particular their importance during neurodegenerative events. This is extremely interesting, since some of the progestins currently used in clinical practice exert neuroprotective and anti-inflammatory effects in the nervous system, opening new promising opportunities for the use of these molecules as therapeutic agents for trauma and neurodegenerative disorders.

Ethinyl estradiol and levonorgestrel alter cognition and anxiety in rats concurrent with a decrease in tyrosine hydroxylase expression in the locus coeruleus and brain-derived neurotrophic factor expression in the hippocampus

In the United States, more than ten million women use contraceptive hormones. Ethinyl estradiol and levonorgestrel have been mainstay contraceptive hormones for the last four decades. Surprisingly, there is scant information regarding their action on the central nervous system and behavior. Intact female rats received three weeks of subcutaneous ethinyl estradiol (10 or 30μg/rat/day), levonorgestrel (20 or 60μg/rat/day), a combination of both (10/20μg/rat/day and 30/60μg/rat/day), or vehicle. Subsequently, the rats were tested in three versions of the novel object recognition test to assess learning and memory, and a battery of tests for anxiety-like behavior. Serum estradiol and ovarian weights were measured. All treatment groups exhibited low endogenous 17β-estradiol levels at the time of testing. Dose-dependent effects of drug treatment manifested in both cognitive and anxiety tests. All low dose drugs decreased anxiety-like behavior and impaired performance on novel object recognition. In contrast, the high dose ethinyl estradiol increased anxiety-like behavior and improved performance in cognitive testing. In the cell molecular analyses, low doses of all drugs induced a decrease in tyrosine hydroxylase mRNA and protein in the locus coeruleus. At the same time, low doses of ethinyl estradiol and ethinyl estradiol/levonorgestrel increased galanin protein in this structure. Consistent with the findings above, the low dose treatments of ethinyl estradiol and combination ethinyl estradiol/levonorgestrel reduced brain-derived neurotrophic factor mRNA in the hippocampus. These effects of ethinyl estradiol 10μg alone and in combination with levonorgestrel 20μg suggest a diminution of norepinephrine input into the hippocampus resulting in a decline in learning and memory.

Oral contraceptives and cognition: A role for ethinyl estradiol

This article is part of a Special Issue "Estradiol and cognition". Estrogens have been seen to play a role in human cognitive abilities, but questions remain about the cognitive impact of ethinyl estradiol, which is contained in many oral contraceptives (OCs). Inconsistencies in past studies likely reflect small samples and heterogeneous groups of OC users. The aims of the present work were to examine OC effects on sex-typed spatial and verbal abilities by (a) comparing mental rotations and expressional fluency in normally-cycling (NC) women and men to OC users considered as a heterogeneous group and then to homogeneous groups of OC users created by classifying pills according to their active constituents, and (b) determining the relation between synthetic hormone doses in OCs and mental rotations and expressional fluency. Participants were 136 men, 93 NC women, and 148 OC users, including homogeneous monophasic (n = 55) and triphasic (n = 43) OC groups, aged 18 to 30 years. Significant effects of OC use were seen in homogeneous group comparisons but not when OC users were considered as a heterogeneous group. On mental rotations, men outperformed women, and monophasic OC users outperformed NC women. The latter difference may be attributable to estradiol, as ethinyl estradiol was inversely related to spatial ability among OC users and was lower in monophasic than in triphasic users. On expressional fluency, NC women and monophasic OC users outperformed men, and monophasic users outperformed triphasic users. Thus, results show the importance of ethinyl estradiol and of considering pill constituents when studying the cognitive effects of OCs.

Amygdala reactivity to negative stimuli is influenced by oral contraceptive use

The amygdala is a highly interconnected region of the brain that is critically important to emotional processing and affective networks. Previous studies have shown that the response of the amygdala to emotionally arousing stimuli can be modulated by sex hormones. Because oral contraceptive pills dramatically lower circulating sex hormone levels with potent analogs of those hormones, we performed a functional magnetic resonance imaging experiment to measure amygdala reactivity in response to emotional stimuli in women using oral contraceptives, and compared their amygdala reactivity with that of naturally cycling women. Here, we show that women who use oral contraceptive pills have significantly decreased bilateral amygdala reactivity in response to negatively valenced, emotionally arousing stimuli compared with naturally cycling women. We suggest that by modulating amygdala reactivity, oral contraceptive pills may influence behaviors that have previously been shown to be amygdala dependent-in particular, emotional memory.

Emotional and cognitive functional imaging of estrogen and progesterone effects in the female human brain: a systematic review

Ovarian hormones are pivotal for the physiological maintenance of the brain function as well as its response to environmental stimuli. There is mounting evidence attesting the relevance of endogenous ovarian hormones as well as exogenous estradiol and progesterone for emotional and cognitive processing. The present review systematically summarized current knowledge on sex steroid hormonal modulation of neural substrates of emotion and cognition revealed by functional magnetic resonance imaging (fMRI). Twenty-four studies of healthy naturally cycling and combined oral contraceptives (COC) user women, or women undergoing experimental manipulations, during their reproductive age, were included. Furthermore, six studies of premenstrual dysphoric disorder (PMDD), a hormonally based mood disorder, and three of gender dysphoria (GD), which provides an intriguing opportunity to examine the effect of high-dose cross-sex hormone therapy (CSHT) on brain functioning, were included. Globally, low (early follicular and the entire follicular phase for estrogen and progesterone, respectively) and high (COC, CSHT, late follicular and luteal phase for estrogen; COC, mid- and late-luteal phase for progesterone) hormonal milieu diversely affected the response of several brain regions including the amygdala, anterior cingulate cortex, and inferior frontal gyrus, but their functional recruitment across groups and domains was scattered. The constellation of findings provides initial evidence of the influence of sex steroid hormones on cortical and subcortical regions implicated in emotional and cognitive processing. Further well-powered and multimodal neuroimaging studies will be needed to identify the neural mechanism of functional brain alterations induced by sex steroid hormones.

Menstrual cycle influence on cognitive function and emotion processing-from a reproductive perspective

The menstrual cycle has attracted research interest ever since the 1930s. For many researchers the menstrual cycle is an excellent model of ovarian steroid influence on emotion, behavior, and cognition. Over the past years methodological improvements in menstrual cycle studies have been noted, and this review summarizes the findings of methodologically sound menstrual cycle studies in healthy women. Whereas the predominant hypotheses of the cognitive field state that sexually dimorphic cognitive skills that favor men are improved during menstrual cycle phases with low estrogen and that cognitive skills that favor women are improved during cycle phases with increased estrogen and/or progesterone, this review has not found sufficient evidence to support any of these hypotheses. Mental rotation has gained specific interest in this aspect, but a meta-analysis yielded a standardized mean difference in error rate of 1.61 (95% CI -0.35 to 3.57), suggesting, at present, no favor of an early follicular phase improvement in mental rotation performance. Besides the sexually dimorphic cognitive skills, studies exploring menstrual cycle effects on tasks that probe prefrontal cortex function, for instance verbal or spatial working memory, have also been reviewed. While studies thus far are few, results at hand suggest improved performance at times of high estradiol levels. Menstrual cycle studies on emotional processing, on the other hand, tap into the emotional disorders of the luteal phase, and may be of relevance for women with premenstrual disorders. Although evidence at present is limited, it is suggested that emotion recognition, consolidation of emotional memories, and fear extinction is modulated by the menstrual cycle in women. With the use of functional magnetic resonance imaging, several studies report changes in brain reactivity across the menstrual cycle, most notably increased amygdala reactivity in the luteal phase. Thus, to the extent that behavioral changes have been demonstrated over the course of the menstrual cycle, the best evidence suggests that differences in sexually dimorphic tasks are small and difficult to replicate. However, emotion-related changes are more consistently found, and are better associated with progesterone than with estradiol such that high progesterone levels are associated with increased amygdala reactivity and increased emotional memory.

Mechanisms of estradiol in fear circuitry: implications for sex differences in psychopathology

Over the past two decades, substantial knowledge has been attained about the mechanisms underlying the acquisition and subsequent extinction of conditioned fear. Knowledge gained on the biological basis of Pavlovian conditioning has led to the general acceptance that fear extinction may be a useful model in understanding the underlying mechanisms in the pathophysiology of anxiety disorders and may also be a good model for current therapies treating these disorders. Lacking in the current knowledge is how men and women may or may not differ in the biology of fear and its extinction. It is also unclear how the neural correlates of fear extinction may mediate sex differences in the etiology, maintenance, and prevalence of psychiatric disorders. In this review, we begin by highlighting the epidemiological differences in incidence rate. We then discuss how estradiol (E2), a primary gonadal hormone, may modulate the mechanisms of fear extinction and mediate some of the sex differences observed in psychiatric disorders.

Sex differences in cognitive impairment and Alzheimer's disease

Studies have shown differences in specific cognitive ability domains and risk of Alzheimer's disease between the men and women at later age. However it is important to know that sex differences in cognitive function during adulthood may have their basis in both organizational effects, i.e., occurring as early as during the neuronal development period, as well as in activational effects, where the influence of the sex steroids influence brain function in adulthood. Further, the rate of cognitive decline with aging is also different between the sexes. Understanding the biology of sex differences in cognitive function will not only provide insight into Alzheimer's disease prevention, but also is integral to the development of personalized, gender-specific medicine. This review draws on epidemiological, translational, clinical, and basic science studies to assess the impact of sex differences in cognitive function from young to old, and examines the effects of sex hormone treatments on Alzheimer's disease in men and women.

A systematic review of the impact of oral contraceptives on cognition

Combined oral contraceptives (OCs) are the most commonly prescribed medication in women of reproductive age, but despite widespread use, their effect on cognitive performance remains controversial. Given strong evidence for the neurological impact of reproductive hormones, a clear rationale for investigation exists. This systematic review sought to identify, collate and critically appraise studies assessing the impact of OCs on cognition in healthy premenopausal women. Ovid MEDLINE, PsychINFO and EMBASE were comprehensively searched using relevant keywords for original peer-reviewed observational studies or randomised trials published after 1960. Of 1289 references screened, 22 studies were eligible for inclusion. Assembled evidence supports a cognitive impact of OCs restricted to specific domains; however, the quality of evidence is poor. The most consistent finding is improved verbal memory with OC use. Evidence is also emerging that differing progestin androgenicity may lead diverse OC formulations to differentially impact certain cognitive domains, such as visuospatial ability. At present, evidence is inconclusive, contradictory and limited by methodological inconsistencies. There is scope for further research in this area to definitively determine the cognitive impact of OCs.

Progesterone and mental rotation task: is there any effect?

Mental rotation task (MRT) incorporates elements of spatial abilities, important in many professions, with people of both genders involved. Importantly, these are the areas where spatial tasks might be performed for long time periods; thus adverse effects of mental fatigue are highly unwanted. Substantial variation of MRT performance in relation to estrogen levels has been observed in many studies, whereas the role of progesterone remains elusive. Here we aimed to elucidate the effect of progesterone level on the long-duration (1.5 hours) performance of MRT. We included three groups of subjects: a group of males as a control, a group of females in their follicular phase (low progesterone) and a group of females in their luteal phase (high progesterone), MRT accuracy and response time, subjective fatigue ratings and cardiovascular measures together with 17 β -estradiol and progesterone concentrations were analyzed. We found that subjective ratings of fatigue increased, performance accuracy increased, and mean response times decreased during the task in all groups. Females in luteal phase were significantly slower not only than men, but also than females in their follicular phase. An increase in subjective fatigue ratings was positively related to progesterone level-at higher progesterone levels, females felt more tired.

Estradiol and mental rotation: relation to dimensionality, difficulty, or angular disparity?

Several studies have reported that performance on spatial rotation tests is better at menses than at high estradiol phases of the menstrual cycle in women. These effects are debated because nearly all reports of menstrual cycle variability have relied on a single test, the Mental Rotations Test (MRT, Vandenberg and Kuse, 1978). In the present study, we investigated key features of the MRT that might be responsible for its association with estradiol levels. We hypothesized that associations could be demonstrated for other tasks that share the same characteristics. Forty-four women ages 20-38 years, matched on education and general ability, were assessed at low (n=24) or high (n=20) estradiol stages of the menstrual cycle on a set of spatial tests that varied in dimensionality, plane of rotation, angular disparity, and effortfulness. Saliva was used to quantify estradiol and progesterone. Low estradiol was found to be associated with significantly better accuracy on the MRT and also on a mental rotation task that required large angles of rotation but employed only two-dimensional object representations and rotations limited to the picture plane. In contrast, a task using identical stimuli that required only small angles of rotation did not show an estradiol effect. A group difference also was seen on a test of perceptual closure. The results confirm that the estradiol effect is not limited to the MRT, and identify the rotational element, but also aspects of figural perception, as possible processes that may be responsive to estrogens. These findings advance our understanding by showing an association between estradiol and discrete spatial processes. Implications for understanding the origins of the robust sex difference commonly observed on the MRT are discussed.

Contributions of sex, testosterone, and androgen receptor CAG repeat number to virtual Morris water maze performance

The possibility that androgens contribute to the male advantage typically found on measures of spatial cognition has been investigated using a variety of approaches. To date, evidence to support the notion that androgens affect spatial cognition in healthy young adults is somewhat equivocal. The present study sought to clarify the association between testosterone (T) and spatial performance by extending measurements of androgenicity to include both measures of circulating T as well as an androgen receptor-specific genetic marker. The aims of this study were to assess the contributions of sex, T, and androgen receptor CAG repeat number (CAGr) on virtual Morris water task (vMWT) performance in a group of healthy young men and women. The hypothesis that men would outperform women on vMWT outcomes was supported. Results indicate that CAGr may interact with T to impact navigation performance and suggest that consideration of androgen receptor sensitivity is an important consideration in evaluating hormone-behavior relationships.

Oral contraceptive pill use and menstrual cycle phase are associated with altered resting state functional connectivity

At rest, brain activity can be characterized not by an absence of organized activity but instead by spatially and temporally correlated patterns of activity. In this experiment, we investigated whether and to what extent resting state functional connectivity is modulated by sex hormones in women, both across the menstrual cycle and when altered by oral contraceptive pills. Sex hormones have been shown to have important effects on task-related activity, but few studies have investigated the extent to which they can influence the behavior of functional networks at rest. These hormones are dramatically altered by the use of hormonal contraception, which is used by approximately 100 million women worldwide. However, potential cognitive side effects of hormonal contraception have been given little attention. Here, we collected resting state data for naturally-cycling women (n=45) and women using combined oral contraceptive pills (n=46) and evaluated the differences in resting state activity between these two groups using independent component analysis. We found that in the default mode network and in a network associated with executive control, resting state dynamics were altered both by the menstrual cycle and by oral contraceptive use. Specifically, the connectivity of the left angular gyrus, the left middle frontal gyrus, and the anterior cingulate cortex were different between groups. Because the anterior cingulate cortex and left middle frontal gyrus are important for higher-order cognitive and emotional processing, including conflict monitoring, changes in the relationship of these structures to the functional networks with which they interact may have important consequences for attention, affect, and/or emotion regulation.

The influence of steroid sex hormones on the cognitive and emotional processing of visual stimuli in humans

Steroid sex hormones are responsible for some of the differences between men and women. In this article, I review evidence that steroid sex hormones impact on visual processing. Given prominent sex-differences, I focus on three topics for sex hormone effects for which there is most research available: 1. Preference and mate choice, 2. Emotion and recognition, and 3. Cerebral/perceptual asymmetries and visual-spatial abilities. For each topic, researchers have examined sex hormones and visual processing using various methods. I review indirect evidence addressing variation according to: menstrual cycle phase, pregnancy, puberty, and menopause. I further address studies of variation in testosterone and a measure of prenatal testosterone, 2D:4D, on visual processing. The most conclusive evidence, however, comes from experiments. Studies in which hormones are administrated are discussed. Overall, many studies demonstrate that sex steroids are associated with visual processing. However, findings are sometimes inconsistent, differences in methodology make strong comparisons between studies difficult, and we generally know more about activational than organizational effects.

Amyloid precursor protein mutation disrupts reproductive experience-enhanced normal cognitive development in a mouse model of Alzheimer's disease

Women experience dramatic changes in hormones, mood and cognition through different periods of their reproductive lives, particularly during pregnancy and giving birth. While limited human studies of early pregnancy and motherhood showed alteration of cognitive functions in later life, researches on rodents showed a persistent improvement of learning and memory performance in females with history of giving birth compared to virgin controls. Alzheimer's disease (AD), the most common dementia in elderly, is more prevalent in women than in men. One of the risk factors is related to the sharp reduction of estrogen in aged women. It is unknown whether the history of fertility activity plays any roles in altering risk of AD in females, such as altering cognitive function. Would reproductive experience alter the risk of AD in females? If so, what might be the mechanisms of the change? In this study, we examined the effects of reproductive experience on cognitive function in an AD transgenic mouse model (APP23) and age-matched wild-type non-transgenic control mice (WT). Our data showed an age-dependent effect of reproductive experience on learning and memory activity between breeders (had one or more litters) and non-breeders (virgins). More importantly, our data, for the first time, demonstrated a genotype-dependent effect of parity on cognitive function between APP23 and WT mice. At the age of 12 months, WT breeders outperform non-breeders in spatial working and reference memory while APP23 breeders performed worse in spatial learning and memory than age-matched APP23 non-breeders. These genotype- and age-dependent effects of reproductive activity on cognitions are significantly associated with changes of neuropathology of AD in the APP23 mice, expression of proteins related to synaptic plasticity and cognitive functions in the brain.

Cognitive effects of variations in pubertal timing: is puberty a period of brain organization for human sex-typed cognition?

There is considerable interest in the organizational effects of pubertal sex hormones on human sex-related characteristics. Recent evidence from rodents suggests that there is a decreasing window of sensitivity to sex hormones throughout adolescence. If adolescence also represents a period of brain organization in human beings, then the timing of exposure to sex-typical hormones at puberty should have long-term effects on sex-typed characteristics: individuals with early timing should be more sex-typed than individuals with late timing. We tested this hypothesis in 320 young adults by relating their pubertal timing (retrospective comparison to peers) to cognitive abilities that show sex differences. Results provide partial support for the hypothesis. For men, pubertal timing was inversely related to scores on a test of three-dimensional mental rotations. Effects do not appear to be due to duration of hormone exposure (time since puberty), but other potential influences need further study.

The effect of mental rotation on changes in plasma testosterone and cortisol levels

Testosterone level has an influence on cognitive functions, especially spatial abilities. The relationship is, however, bidirectional and brain activity also affects testosterone levels. The aim of this study was to analyze the effects of an intensive 3D mental rotation task on testosterone levels in young healthy men and women. In the mental rotation task, men reached a higher top score (P=0.027) and total score (P=0.004) compared to women. In 8 out of 9 women (P=0.008) but not in men (P=0.129) testosterone levels decreased after one hour of mental rotation testing. A significant gender difference was shown (P<0.0001). In all women, plasma cortisol levels was significantly lower after testing (P=0.004). In men cortisol levels decreased in 7 out of 9 subjects (P=0.039). A significant gender difference was not found (P=0.19). No association was found in women between baseline testosterone levels and mental rotation total score (P=0.810). In men there was a positive correlation between baseline testosterone and mental rotation total score (P=0.015). A significant difference gender difference was seen in the association between testosterone and mental rotation score (P<0.05). Mental rotation stimuli caused significant changes in hormonal levels of testosterone and cortisol. A gender-specific response was detected in testosterone fluctuation.