Estrogen and the prefrontal cortex: towards a new understanding of estrogen's effects on executive functions in the menopause transition

Dopaminergic contributions to working memory-related brain activation in postmenopausal women

OBJECTIVE

The current study examined the effects of pharmacologic dopaminergic manipulations on working memory-related brain activation in postmenopausal women to further understand the neurochemistry underlying cognition after menopause.

METHODS

Eighteen healthy postmenopausal women, mean age 55.21 years, completed three study days with dopaminergic drug challenges during which they performed a functional magnetic resonance imaging visual verbal N-back test of working memory. Acute stimulation with 1.25 mg oral D2 agonist bromocriptine, acute blockade with 1.5 mg oral haloperidol, and matching placebo were administered randomly and blindly on three study days.

RESULTS

We found that dopaminergic stimulation increased activation primarily in the posterior regions of the working memory network compared with dopaminergic blockade using a whole brain cluster-level corrected analysis. The dopaminergic medications did not affect working memory performance.

CONCLUSIONS

Patterns of increased blood-oxygen-level dependent signal activation after dopaminergic stimulation were found in this study in posterior brain regions with no effect on working memory performance. Further studies should examine specific dopaminergic contributions to brain functioning in healthy postmenopausal women to determine the effects of the increased brain activation on cognition and behavior.

Understanding women's experience of memory over the menopausal transition: subjective and objective memory in pre-, peri-, and postmenopausal women

OBJECTIVE

Many women complain of forgetfulness during the menopausal transition. This study aimed to examine women's subjective perception of memory and their objective memory performance across the menopausal transition.

METHODS

One hundred thirty women, aged 40 to 60 years were recruited from outpatient Menopause and Gynaecological clinics at the Royal Women's Hospital, Melbourne. Women were divided into menopausal stage groups according to the Stages of Reproductive Aging Workshop criteria based on menstrual patterns. All women completed self-report measures of depressive, anxiety, vasomotor, and sleep symptoms; attitude to menopause; and various aspects of memory, including memory contentment, frequency of forgetting, sense of control over memory, and use of memory strategies. Women also completed a comprehensive neuropsychological evaluation assessing memory and executive function.

RESULTS

Comprehensive neuropsychological assessment showed no difference between premenopausal (n = 36), perimenopausal (n = 54), and postmenopausal (n = 40) groups in performance on memory and executive tasks. Perimenopausal women, however, reported significantly more frequent forgetting (η = 0.09, P < 0.01) and less contentment with their memory (η = 0.08, P < 0.01) than pre- and postmenopausal women.

CONCLUSIONS

Although no impairment was observed in neuropsychological performance, when compared with pre- and postmenopausal women, perimenopausal women were more likely to be dissatisfied with their memory. During the menopausal transition women with a more negative attitude to menopause and more intense depressive, anxiety, vasomotor, and sleep symptoms are more vulnerable to feeling less content with their memory.

Effects of Immediate or Delayed Estradiol on Behavior in Old Menopausal Macaques on Obesogenic Diet

Macaques have served as effective models of human disease, including pathological processes associated with obesity and the metabolic syndrome. This study approached several questions: (1) does a western-style diet (WSD) contribute to sedentary behavior or is sedentary behavior a consequence of obesity and (2) does estradiol (E) hormone therapy offset WSD or ameliorate sedentary behavior? We further questioned whether the timing of E administration (immediately following hysterectomy, ImE; or after a 2-year delay, DE) would impact behavior. Focal observations were taken on the animals in social housing over a period of 2.5 years before and after initiation of the WSD and hysterectomy. In addition, anxiety was assessed through the Human Intruder and Novel Object Tests. All animals gained weight, but ImE delayed the time to maximum weight achieved at 18 months. Over the course of the study, ImE-treated monkeys spent more time "alone" and less time in "close social" contact than placebo-controls. The DE-treated monkeys were not different from placebo-controls in these 2 outcomes. The placebo-control group exhibited more "self-groom" behavior, an indicator of anxiety, than did the ImE-treated group, and DE-treated animals approached levels observed in the ImE-treated animals. All animals exhibited an increase in "consume" behavior over time with no statistical difference between the groups. By the end of the protocol, the placebo-control group exhibited less activity compared to ImE + DE-treated animals combined. Animals also showed increased anxiety after starting on the WSD in the Human Intruder Test and the Novel Object Test. In summary, the data indicated that WSD per se promoted increased consummatory behavior, sedentary behavior, and anxiety-type behaviors, whereas ImE promoted activity. Thus, WSD may precipitate the behaviors observed in humans who then become obese, sedentary, anxious, and socially isolated. ImE replacement ameliorates some of these behaviors, but not all.

Stress Induced Hormone and Neuromodulator Changes in Menopausal Depressive Rats

Objective: Previously, we showed that neuromodulators are important factors involved in depression, here we aim to further investigate the interactions between neuromodulators and sex hormone involved in menopause related depression in rats. Methods: Menopausal depression was made with bilateral ovariectomies in female SD rats followed by chronic mild unpredictable stress treatment for 21 days. Thirty six rats were randomly divided into four groups: sham surgery group, sham/stress group, surgery group, surgery/stress group. Then open-field locomotor scores and sucrose intake were employed to observe behavior changes. The levels of norepinephrine (NE), dopamine (DA), serotonin (5-HT) in the cerebral spinal fluid and serum adrenocorticotropic hormone (ACTH), cortisone were determined with High-performance liquid chromatography (HPLC). Serum estradiol (E2), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were measured with radioimmunoassay. Results: The open-field locomotor scores and sucrose intake were significantly decreased after the surgery and stress treatment (p < 0.01). The Serum E₂ level decreased significantly after the surgery (p < 0.01), but serum LH, FSH levels increased significantly in the surgery group than the sham surgery group (p < 0.01). The cortisone levels increased significantly in sham/stress group than that in the sham surgery group during the first 2 weeks at stressful treatment, but decrease afterwards. The monoamine levels in the surgery/stress group were much lower than those in the sham surgery group (p < 0.01). The correlation analysis found that LH and FSH are related more to the neurotransmitter release than E₂. Conclusion: Ovary removal rats showed depression-like behaviors, with LH and FSH increase and monoamine decrease, and the levels of these monoamines in the stress treated groups changed only after the stressful treatment. The LH, FSH hormone increasing might be the reason for the lower monoamine release, which in turn might be the reason for depressed syndromes in the menopause. The cortisone and ACTH in the serum in the surgery/stress group were much higher than that in the sham surgery group.

Impact of Tryptophan Depletion on Executive System Function during Menopause is Moderated by Childhood Adversity

Many healthy women with no history of cognitive dysfunction experience subjective executive difficulties during menopause. Preclinical literature suggests latent effects of early life adversity on serotonin function may play a role in this phenomenon. However, evidence in human participants regarding the mechanisms by which loss of estradiol contributes to this vulnerability is lacking. Here we examined the impact of tryptophan depletion (TD) and adverse childhood experiences (ACE) on brain activation during a working memory task in menopausal women. We hypothesized that an interactive effect between ACE and TD would be observed when women were hypogonadal, and that treatment with estradiol would attenuate this effect. Thirty-three women underwent functional imaging at four time points (123 total scans) in this double-blind, placebo controlled, cross-over study. The effects of TD, ACE, and TD × ACE were evaluated using a voxel-wise, mixed-effects, 2 × 2 ANOVA. In the absence of exogenous estradiol, a TD by ACE interaction was observed on BOLD signal in the right DLPFC such that TD increased activation in high ACE subjects but decreased activation in low ACE subjects. While a similar interaction was observed with placebo treatment, treatment with estradiol attenuated the effects of ACE and TD such that no between or within group differences were observed. Together, these results suggest that early life adversity may have a lasting impact on serotonergic circuits underlying executive function that are unmasked by loss of estradiol during menopause.

Impact of early life adversity and tryptophan depletion on functional connectivity in menopausal women: A double-blind, placebo-controlled crossover study

During the menopause transition, women are at increased risk of subjective symptoms of executive dysfunction. Evidence from animal and human participant studies suggests adverse childhood experiences (ACE) may be a risk factor for executive complaints during this hormonal transition. Preclinical literature indicates early life adversity effects on serotonin function may play a role in this increased susceptibility. However, the mechanisms underlying this increase in vulnerability in human participants remain relatively unknown. Here we examined the impact of ACE and tryptophan depletion (TD), a paradigm used to lower central serotonin levels, on functional network connectivity in discovery and replication datasets. We hypothesized that ACE would be associated with decreased within-network connectivity. We predicted that TD would further lower connectivity in women with high levels of early adversity, but have no effect in women with low levels of early adversity. Forty women underwent two functional imaging sequences at two time points (141 total scans) in a double-blind, placebo controlled, crossover study. The effects of ACE and TD were evaluated using generalized estimating equations (GEE). As predicted, ACE was associated with lower within-network connectivity. While TD had no effect on connectivity in the low ACE group, TD increased connectivity in the high ACE group. The robust effect of ACE remained significant in the replication dataset, though the ACE×TD interaction did not. Together, these results suggest that early life adversity has lasting impacts on large-scale functional networks underlying executive function. Alterations in functional network connectivity may be one mechanism by which early life adversity increases the risk of cognitive disorders during menopause.

Considering sex and gender in Alzheimer disease and other dementias

Suffering related to dementia is multifaceted because cognitive and physical functioning slowly deteriorates. Advanced age and sex, two of the most prominent risk factors for dementia, are not modifiable. Lifestyle factors such as smoking, excessive alcohol use, and poor diet modulate susceptibility to dementia in both males and females. The degree to which the resulting health conditions (eg, obesity, type 2 diabetes, and cardiovascular disease) impact dementia risk varies by sex. Depending on the subtype of dementia, the ratio of male to female prevalence differs. For example, females are at greater risk of developing Alzheimer disease dementia, whereas males are at greater risk of developing vascular dementia. This review examines sex and gender differences in the development of dementia with the goal of highlighting factors that require further investigation. Considering sex as a biological variable in dementia research promises to advance our understanding of the pathophysiology and treatment of these conditions.

Effects of obesogenic diet and estradiol on dorsal raphe gene expression in old female macaques

The beneficial effects of bioidentical ovarian steroid hormone therapy (HT) during the perimenopause are gaining recognition. However, the positive effects of estrogen (E) plus or minus progesterone (P) administration to ovariectomized (Ovx) lab animals were recognized in multiple systems for years before clinical trials could adequately duplicate the results. Moreover, very large numbers of women are often needed to find statistically significant results in clinical trials of HT; and there are still opposing results being published, especially in neural and cardiovascular systems. One of the obvious differences between human and animal studies is diet. Laboratory animals are fed a diet that is low in fat and refined sugar, but high in micronutrients. In the US, a large portion of the population eats what is known as a "western style diet" or WSD that provides calories from 36% fat, 44% carbohydrates (includes 18.5% sugars) and 18% protein. Unfortunately, obesity and diabetes have reached epidemic proportions and the percentage of obese women in clinical trials may be overlooked. We questioned whether WSD and obesity could decrease the positive neural effects of estradiol (E) in the serotonin system of old macaques that were surgically menopausal. Old ovo-hysterectomized female monkeys were fed WSD for 2.5 years, and treated with placebo, Immediate E (ImE) or Delayed E (DE). Compared to old Ovx macaques on primate chow and treated with placebo or E, the WSD-fed monkeys exhibited greater individual variance and blunted responses to E-treatment in the expression of genes related to serotonin neurotransmission, CRH components in the midbrain, synapse assembly, DNA repair, protein folding, ubiquitylation, transport and neurodegeneration. For many of the genes examined, transcript abundance was lower in WSD-fed than chow-fed monkeys. In summary, an obesogenic diet for 2.5 years in old surgically menopausal macaques blunted or increased variability in E-induced gene expression in the dorsal raphe. These results suggest that with regard to function and viability in the dorsal raphe, HT may not be as beneficial for obese women as normal weight women.

Aluminum-induced molecular neurodegeneration: The protective role of genistein and chickpea extract

Neurotoxicity of Al is well established and linked to oxidative damage and neurodegeneration. This study investigated the protective role of genistein (Gen) and chickpea extract (CPE) against AlCl₃-induced neurodegeneration. HPLC analysis revealed that biochanin A-7-O-β-D-glucoside and biochanin A are the major components of the CPE. Gene expression of TNF-α, APP, BACE1, PSEN-2 and ER-β were assessed in brain extract using RT-PCR. Also, NF-кB subunit P65 and COX-2 expression were evaluated by western blotting. The cholinergic function, histological examination and oxidative status were also estimated. The AlCl₃ significantly up regulated the expression of the NF-кB subunit P65, COX-2, TNF- α, BACE1and APP while it significantly down regulated PSEN-2 and ER-β expression. The activity of acetyl cholinesterase (AChE) and the oxidative stress parameters as well as the histological examination confirmed the deleterious effect of AlCl₃. The administration of either CPE or Gen attenuated the expression of inflammatory cytokines, inhibited the amyloidogenesis and restored both the AChE activity and ER-β expression. Gen and CPE also inhibited the oxidative stress and ameliorated the histological alterations. Accordingly, the present study provides an insight on the molecular role of Gen and CPE as protective agents against neuronal injury.

Estrogen Replacement Improves Verbal Memory and Executive Control in Oligomenorrheic/Amenorrheic Athletes in a Randomized Controlled Trial

OBJECTIVE

Both estrogen and exercise may have cognition enhancing benefits; however, young oligomenorrheic/amenorrheic athletes (OA) with estrogen deficiency have not been evaluated for cognitive deficits. Our objective was to determine whether 6 months of estrogen replacement will impact cognitive domains in OA. We hypothesized that estrogen replacement would improve verbal memory and executive control in OA.

METHODS

We performed cognitive assessments at baseline and after 6 months in 48 OA (14-25 years) randomized to estrogen (EST+) (oral 30 µg ethinyl estradiol [n = 16] or transdermal 100 µg 17-β-estradiol patch [n = 13]) or no estrogen (EST-) (n = 19) in an ongoing clinical trial. Neurocognitive testing included California Verbal Learning Test-Second Edition (CVLT-II) (for verbal memory) and Delis-Kaplan Executive Function System Color-Word Interference Test (D-KEFS-CWIT) (executive control).

RESULTS

On average, subjects (mean ± SEM age: 19.9 ± 3.1 years, body mass index: 20.6 ± 2.3 kg/m²) participated in 10.3 ± 5.9 hours per week of weight-bearing activities of their lower limbs. The EST+ group performed better for CVLT-II verbal memory scores for immediate recall over 6 months of therapy compared to EST- (P < .05) even after controlling for baseline scores and age. Changes in D-KEFS-CWIT scores over 6 months did not differ between the groups. However, the EST+ group had greater improvements in inhibition-switching completion time over 6 months compared with the EST- group after controlling for baseline scores and age (P = .01).

CONCLUSIONS

OA show improvements in verbal memory and executive control following 6 months of estrogen replacement. These findings in athletes, who are in their prime of neurocognitive development, underscore the need for future studies exploring cognition in OA.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00946192.

Adverse Childhood Experiences and Risk for First-Episode Major Depression During the Menopause Transition

OBJECTIVE

Stress exposures may have a differential impact on risk and resilience for depression depending on their timing across development. We sought to determine whether adverse childhood experiences (ACEs) and their onset with respect to puberty contribute to the increased risk observed in first-episode major depressive disorder (MDD) during the menopause transition.

METHODS

Participants were from the Penn Ovarian Aging Study cohort, which is composed of women from Philadelphia County, Pennsylvania, who underwent behavioral, cognitive, and endocrine evaluations approximately yearly from 1996 to 2012 and completed the Adverse Childhood Experiences Questionnaire at study end point (n = 243). ACEs that first occurred 2 or more years before menarche were considered prepubertal. Incident menopause MDD was defined as first observed onset of the disorder in the perimenopause to postmenopause transition using the Structured Clinical Interview for DSM-III-R and the Primary Care Evaluation of Mental Disorders.

RESULTS

Incident menopause MDD occurred in 48% of the 100 women who reported lifetime MDD. Women reporting ≥ 2 total ACEs were at significantly greater risk for lifetime MDD (adjusted odds ratio [aOR] = 2.05, P = .034) and incident menopause MDD (aOR = 2.58, P = .03) compared to those reporting 0 ACEs; women with ≥ 2 postpubertal ACEs were 2.3 times more likely to experience incidence menopause MDD (P = .024) after controlling for race, smoking, body mass index, and employment. Experiencing only 1 ACE in the prepubertal window, regardless of additional ACEs in postpuberty, was associated with reduced risk for lifetime and incident menopause MDD.

CONCLUSIONS

Timing and number of adverse experiences with respect to puberty differentially impacted risk and resilience for MDD across the female life span and during the menopause transition in this community cohort.

Lisdexamfetamine Effects on Executive Activation and Neurochemistry in Menopausal Women with Executive Function Difficulties

Many women with no history of executive dysfunction report difficulties in this domain during the menopause transition. Lisdexamfetamine (LDX) has been suggested to be a safe and effective treatment option for these women. However, the mechanism by which LDX improves executive functioning in these women is not known. Here we investigated the effects of LDX on brain activation and neurochemistry, hypothesizing that LDX would be associated with increased activation and decreased glutamate in executive regions. Fourteen women underwent multimodal neuroimaging at 7T at three time points in this baseline-corrected, double-blind, placebo-controlled, crossover study. Effects of LDX on symptom severity, blood-oxygen-level-dependent (BOLD) signal, and dorsolateral prefrontal cortex (DLPFC) glutamate+glutamine (Glx) were measured using a clinician-administered questionnaire, fMRI during performance of a fractal n-back task, and ¹H-MRS, respectively. The effect of treatment (LDX minus baseline vs placebo minus baseline) on these behavioral and neural markers of executive function was examined using repeated measures mixed effects models. LDX treatment was associated with decreased symptom severity, increased activation in the insula and DLPFC, and decreased DLPFC Glx. In addition, the magnitude of LDX-induced improvement in symptom severity predicted both direction and magnitude of LDX-induced change in insular and DLPFC activation. Moreover, symptom severity was positively correlated with Glx concentration in the left DLPFC at baseline. These findings provide novel evidence that the neural mechanisms by which LDX acts to improve self-reported executive functioning in healthy menopausal women with midlife onset of executive difficulties include modulation of insular and DLPFC recruitment as well as decrease in DLPFC Glx concentration.

Sex as a Biological Variable: Who, What, When, Why, and How

The inclusion of sex as a biological variable in research is absolutely essential for improving our understanding of disease mechanisms contributing to risk and resilience. Studies focusing on examining sex differences have demonstrated across many levels of analyses and stages of brain development and maturation that males and females can differ significantly. This review will discuss examples of animal models and clinical studies to provide guidance and reference for the inclusion of sex as an important biological variable relevant to a Neuropsychopharmacology audience.

Effect of Reproductive History and Exogenous Hormone Use on Cognitive Function in Mid- and Late Life

OBJECTIVES

To investigate the association between reproductive history indicators of hormonal exposure, including reproductive period, pregnancy, and use of hormonal contraceptives, and mid- and late-life cognition in postmenopausal women.

DESIGN

Analysis of baseline data from two randomized clinical trials: the Women's Isoflavone Soy Health and the Early vs Late Intervention Trial of Estradiol.

SETTING

University academic research center.

PARTICIPANTS

Naturally menopausal women (N = 830).

MEASUREMENTS

Participants were uniformly evaluated using a cognitive battery and a structured reproductive history questionnaire. Outcomes were composite scores for verbal episodic memory, executive function, and global cognition. Reproductive variables included ages at pregnancies, menarche, and menopause; reproductive period; number of pregnancies; and use of hormones for contraception and menopausal symptoms. Multivariable linear regression was used to evaluate associations between cognitive scores (dependent variable) and reproductive factors (independent variables), adjusting for age, race and ethnicity, income, and education.

RESULTS

On multivariable modeling, age at menarche of 13 and older was inversely associated with global cognition (P = .05). Last pregnancy after age 35 was positively associated with verbal memory (P = .03). Use of hormonal contraceptives was positively associated with global cognition (P trend = .04), and verbal memory (P trend = .007). The association between hormonal contraceptive use and verbal memory and executive function was strongest for more than 10 years of use. Reproductive period was positively associated with global cognition (P = .04) and executive function (P = .04).

CONCLUSION

In this sample of healthy postmenopausal women, reproductive life events related to sex hormones, including earlier age at menarche, later age at last pregnancy, longer reproductive period, and use of oral contraceptives are positively related to aspects of cognition in later life.

Impact of Sex and Menopausal Status on Episodic Memory Circuitry in Early Midlife

Cognitive neuroscience of aging studies traditionally target participants age 65 and older. However, epidemiological surveys show that many women report increased forgetfulness earlier in the aging process, as they transition to menopause. In this population-based fMRI study, we stepped back by over a decade to characterize the changes in memory circuitry that occur in early midlife, as a function of sex and women's reproductive stage. Participants (N = 200; age range, 45-55) performed a verbal encoding task during fMRI scanning. Reproductive histories and serologic evaluations were used to determine menopausal status. Results revealed a pronounced impact of reproductive stage on task-evoked hippocampal responses, despite minimal difference in chronological age. Next, we examined the impact of sex and reproductive stage on functional connectivity across task-related brain regions. Postmenopausal women showed enhanced bilateral hippocampal connectivity relative to premenopausal and perimenopausal women. Across women, lower 17β-estradiol concentrations were related to more pronounced alterations in hippocampal connectivity and poorer performance on a subsequent memory retrieval task, strongly implicating sex steroids in the regulation of this circuitry. Finally, subgroup analyses revealed that high-performing postmenopausal women (relative to low and middle performers) exhibited a pattern of brain activity akin to premenopausal women. Together, these findings underscore the importance of considering reproductive stage, not simply chronological age, to identify neuronal and cognitive changes that unfold in the middle decades of life. In keeping with preclinical studies, these human findings suggest that the decline in ovarian estradiol production during menopause plays a significant role in shaping memory circuitry.

SIGNIFICANCE STATEMENT

Maintaining intact memory function with age is one of the greatest public health challenges of our time, and women have an increased risk for memory disorders relative to men later in life. We studied adults early in the aging process, as women transition into menopause, to identify neuronal and cognitive changes that unfold in the middle decades of life. Results demonstrate regional and network-level differences in memory encoding-related activity as a function of women's reproductive stage, independent of chronological age. Analyzing data without regard to sex or menopausal status obscured group differences in circuit-level neural strategies associated with successful memory retrieval. These findings suggest that early changes in memory circuitry are evident decades before the age range traditionally targeted by cognitive neuroscience of aging studies.

Can Exercise Ameliorate Aromatase Inhibitor-Induced Cognitive Decline in Breast Cancer Patients?

Aromatase inhibitors (AIs) have been commonly used as an effective adjuvant therapy in treatment of breast cancer, especially for menopausal women with estrogen receptor-positive breast cancer. Due to the nature of aromatase, the key enzyme for endogenous estrogen synthesis, inhibitory of aromatase-induced side effects, such as cognitive impairment has been reported in both human and animal studies. While extensive evidence suggested that physical exercises can improve learning and memory activity and even prevent age-related cognitive decline, basic research revealed some common pathways between exercise and estrogen signaling that affected cognitive function. This review draws on clinical and basic studies to assess the potential impact of exercise in cognitive function from women treated with AIs for breast cancer and explore the potential mechanism and effects of exercise on estrogen-related cognition.

Persistence of Gender Related-Effects on Visuo-Spatial and Verbal Working Memory in Right Brain-Damaged Patients

The aim of the present study was to verify if gender differences in verbal and visuo-spatial working memory would persist following right cerebral lesions. To pursue our aim we investigated a large sample (n. 346) of right brain-damaged patients and healthy participants (n. 272) for the presence of gender effects in performing Corsi and Digit Test. We also assessed a subgroup of patients (n. 109) for the nature (active vs. passive) of working memory tasks. We tested working memory (WM) administering the Corsi Test (CBT) and the Digit Span (DS) using two different versions: forward (fCBT and fDS), subjects were required to repeat stimuli in the same order that they were presented; and backward (bCBT and bDS), subjects were required to repeat stimuli in the opposite order of presentation. In this way, passive storage and active processing of working memory were assessed. Our results showed the persistence of gender-related effects in spite of the presence of right brain lesions. We found that men outperformed women both in CBT and DS, regardless of active and passive processing of verbal and visuo-spatial stimuli. The presence of visuo-spatial disorders (i.e., hemineglect) can affect the performance on Corsi Test. In our sample, men and women were equally affected by hemineglect, therefore it did not mask the gender effect. Generally speaking, the persistence of the men's superiority in visuo-spatial tasks may be interpreted as a protective factor, at least for men, within other life factors such as level of education or kind of profession before retirement.

Cannabinoids reverse the effects of early stress on neurocognitive performance in adulthood

Early life stress (ES) significantly increases predisposition to psychopathologies. Cannabinoids may cause cognitive deficits and exacerbate the effects of ES. Nevertheless, the endocannabinoid system has been suggested as a therapeutic target for the treatment of stress- and anxiety-related disorders. Here we examined whether cannabinoids administered during "late adolescence" (extensive cannabis use in humans at the ages 18-25) could reverse the long-term adverse effects of ES on neurocognitive function in adulthood. Male and female rats were exposed to ES during post-natal days (P) 7-14, injected with the cannabinoid CB1/2 receptor agonist WIN55,212-2 (WIN; 1.2 mg/kg, i.p.) for 2 wk during late adolescence (P45-60) and tested in adulthood (P90) for working memory, anxiety, and alterations in CB1 receptors (CB1r), and glucocorticoid receptors (GRs) in the stress circuit [hippocampus, prefrontal cortex (PFC), and basolateral amygdala (BLA)]. ES males and females exhibited impaired performance in short-term memory in adulthood in the spatial location and social recognition tasks; males were also impaired in the novel object recognition task. WIN administered during late adolescence prevented these stress-induced impairments and reduced anxiety levels. WIN normalized the ES-induced up-regulation in PFC-GRs and CA1-CB1r in females. In males, WIN normalized the ES-induced up-regulation in PFC-GR and down-regulation in BLA-CB1r. There is a crucial role of the endocannabinoid system in the effects of early life stress on behavior at adulthood. Differences in recognition memory and in the expression of GRs and CB1r in the fear circuit suggest sex differences in the mechanism underlying coping with stress.

Sex differences in inhibitory control in socially-housed baboons (Papio papio)

Inhibitory control is an important component of executive function. An emerging literature in humans suggests that inhibitory control is sexually dimorphic and modulated by sex steroids, but evidence for such a link in nonhuman animals is scarce. In this study, we examined the effects of menstrual cycle and biological sex on response inhibition, as measured by a Stop-Signal task, in the baboon (Papio papio). The monkeys (n=13) were socially-housed, with voluntary access to multiple touchscreen computerized stations. The task required monkeys to inhibit prepotent responses (touching a target, "Go" trials) following the appearance of a visual stop signal on 25% of the trials ("Stop" trials). The cognitive data, consisting of computerized records of the monkeys' performance on the Stop-Signal task over a year of testing, were matched to records of female sexual swellings. Same-day menstrual and cognitive data were available for 5 females, aged 5-18 years. These data were compared to those of 8 males (5-14 years old) performing the Stop-Signal task over the same time period. Contrary to our hypothesis, performance on the task was not significantly affected by the phase (ovulatory vs. luteal) of the cycle in females. However, males were slower than females on Go trials and were less efficient in inhibiting responses on Stop trials. Slower responses in males were indicative of a speed-accuracy trade-off, as overall accuracy was also better in males than in females. Analyses of trial history indicated that males did not speed as much as females following a successful Go trial, but did not differ from females in post-error slowing or post-inhibiting responses. Overall, the data show that biological sex modulates Stop-Signal performance in the baboon, with males exhibiting slower response execution overall, less efficient inhibition, but greater accuracy than females. This pattern of sex differences may reflect motivational sex differences in which males emphasize accuracy rather than speed. Interestingly, these sex differences do not seem to vary as a function of ovarian hormones in females. Males' greater focus on accuracy is possibly due to enhanced sensitivity to reward mediated by testosterone levels.

Phytoestrogen consumption and risk for cognitive decline and dementia: With consideration of thyroid status and other possible mediators

It is predicted that around 20% of the worlds population will be age 60 or above by 2050. Prevalence of cognitive decline and dementia is high in older adults and modifiable dietary factors may be able to reduce risk for these conditions. Phytoestrogens are bioactive plant chemicals found in soy, which have a similarity in structure to natural estradiol (the most abundant circulating estrogen). This structural likeness enables phytoestrogens to interact with estrogen receptors in the brain, potentially affecting cognition. However, findings in this domain are largely inconsistent, with approximately 50% of studies showing positive effects of phytoestrogens on cognition and the other half resulting in null/negative findings. This paper provides an updated review of the relationship between consumption of phytoestrogens and risk for cognitive decline and/or dementia. In particular, possible mediators were identified to explain discrepant findings and for consideration in future research. A case can be made for a link between phytoestrogen consumption, thyroid status and cognition in older age, although current findings in this area are very limited. Evidence suggests that inter-individual variants that can affect phytoestrogen bioavailability (and thus cognitive outcome) include age and ability to breakdown ingested phytoestrogens into their bioactive metabolites. Factors of the study design that must be taken into account are type of soy product, dosage, frequency of dietary intake and type of cognitive test used. Guidelines regarding optimal phytoestrogen dosage and frequency of intake are yet to be determined.

Salivary cortisol and explicit memory in postmenopausal women using hormone replacement therapy

Circulating cortisol levels are known to influence explicit memory in humans and other primates. The present study investigated salivary cortisol and its association with explicit memory performance in 99 postmenopausal women (64 treated with conjugated equine estrogens or estradiol, and 35 matched controls not using any form of hormone therapy). Controls were compared with treated women taking estrogens alone (n=39), or taking estrogens in combination with a progestin (n=25). Mean time on hormone therapy was approximately 5 years, with initiation of treatment in close proximity to the onset of menopause. Explicit memory was assessed with the California Verbal Learning Test (CVLT). Saliva was collected before (basal or resting sample) and after (post-test sample) completing a set of cognitive tasks. Cortisol was measured using a high-sensitivity radioimmunoassay. Treated women were found to have higher resting cortisol concentrations than controls matched for time of day. Basal cortisol was a modest predictor of learning and memory on the CVLT. Higher cortisol was associated with better recall and fewer memory errors, which is consistent with experimental studies examining explicit memory under small increases in circulating cortisol load. Potential cumulative effects on the central nervous system of sustained exposure to mildly increased cortisol in conjunction with the long-term use of oral estrogens are discussed in the context of aging and dementia.

Premenstrual Dysphoric Disorder: Epidemiology and Treatment

Recently designated as a disorder in the DSM-5, premenstrual dysphoric disorder (PMDD) presents an array of avenues for further research. PMDD's profile, characterized by cognitive-affective symptoms during the premenstruum, is unique from that of other affective disorders in its symptoms and cyclicity. Neurosteroids may be a key contributor to PMDD's clinical presentation and etiology, and represent a potential avenue for drug development. This review will present recent literature on potential contributors to PMDD's pathophysiology, including neurosteroids and stress, and explore potential treatment targets.

Renewal of conditioned responding to food cues in rats: Sex differences and relevance of estradiol

Cues associated with food can stimulate food anticipation, procurement, and consumption, independently of hunger. These and other behaviors driven by learned cues are persistent and can reappear after extinction, because the original learned associations continue to exist. Renewal, or reinstatement, of extinguished conditioned behavior may explain the inability to change maladaptive eating habits driven by food cues, similar to the mechanisms of drug use relapse. Here, we investigated sex differences in context-induced renewal of responding to food cues, and the role of estradiol in females in a Pavlovian conditioning preparation. We compared adult male and female rats because there is evidence for sex differences in learning and memory and in the control of feeding. Context-induced renewal involves conditioning and extinction in different contexts and the renewal of conditioned behavior is induced by return to the conditioning context ("ABA renewal"; experimental groups). Control groups remain in the same context during conditioning, extinction, and test. In Experiment 1, male and female rats were trained to associate a tone with food pellets during acquisition, and after extinction with tone only presentations, were tested for renewal of responding to the tone. Learning was assessed through the expression of the conditioned response, which included approach and activity directed at food receptacle (food cup behavior). Males and females learned the acquisition and extinction of tone-food associations similarly, but there were sex differences during renewal of the conditioned responses to the food cue. Males showed robust renewal of responding, while renewal in intact females was inconsistent. Males in the experimental group had significantly higher food cup behavior compared to males in the control group, while females in both groups showed similar levels of food cup behavior during the tone. In Experiment 2, we examined a potential role of estradiol in renewal, by comparing intact females with ovariectomized females with, and without, estradiol replacement. Rats in all groups acquired and extinguished tone-food associations similarly. During the test for renewal, the ovariectomized rats with estradiol replacement in the experimental group showed renewal of responding, evidenced by significantly higher food cup behavior compared to the control group. Intact and ovariectomized rats in the experimental groups had similar rates of food cup behavior as their corresponding control groups. These results provide novel evidence for sex differences and relevance of estradiol in renewal of responding to food cues and more broadly in contextual processing and appetitive associative learning, potentially relevant to maladaptive eating habits and eating disorders.

Sex differences and stress across the lifespan

Sex differences in stress responses can be found at all stages of life and are related to both the organizational and activational effects of gonadal hormones and to genes on the sex chromosomes. As stress dysregulation is the most common feature across neuropsychiatric diseases, sex differences in how these pathways develop and mature may predict sex-specific periods of vulnerability to disruption and increased disease risk or resilience across the lifespan. The aging brain is also at risk to the effects of stress, where the rapid decline of gonadal hormones in women combined with cellular aging processes promote sex biases in stress dysregulation. In this Review, we discuss potential underlying mechanisms driving sex differences in stress responses and their relevance to disease. Although stress is involved in a much broader range of diseases than neuropsychiatric ones, we highlight here this area and its examples across the lifespan.

Distinct cognitive effects of estrogen and progesterone in menopausal women

The effects of postmenopausal hormone treatment on cognitive outcomes are inconsistent in the literature. Emerging evidence suggests that cognitive effects are influenced by specific hormone formulations, and that progesterone is more likely to be associated with positive outcomes than synthetic progestin. There are very few studies of unopposed progesterone in postmenopausal women, and none that use functional neuroimaging, a sensitive measure of neurobiological function. In this study of 29 recently postmenopausal women, we used functional MRI and neuropsychological measures to separately assess the effects of estrogen or progesterone treatment on visual and verbal cognitive function. Women were randomized to receive 90 days of either estradiol or progesterone counterbalanced with placebo. After each treatment arm, women were given a battery of verbal and visual cognitive function and working memory tests, and underwent functional MRI including verbal processing and visual working memory tasks. We found that both estradiol and progesterone were associated with changes in activation patterns during verbal processing. Compared to placebo, women receiving estradiol treatment had greater activation in the left prefrontal cortex, a region associated with verbal processing and encoding. Progesterone was associated with changes in regional brain activation patterns during a visual memory task, with greater activation in the left prefrontal cortex and right hippocampus compared to placebo. Both treatments were associated with a statistically non-significant increase in number of words remembered following the verbal task performed during the fMRI scanning session, while only progesterone was associated with improved neuropsychological measures of verbal working memory compared to placebo. These results point to potential cognitive benefits of both estrogen and progesterone.

Postmenopausal hormone therapy and cognition

This article is part of a Special Issue "Estradiol and cognition". Prior to the publication of findings from the Women's Health Initiative (WHI) in 2002, estrogen-containing hormone therapy (HT) was used to prevent age-related disease, especially cardiovascular disease, and to treat menopausal symptoms such as hot flushes and sleep disruptions. Some observational studies of HT in midlife and aging women suggested that HT might also benefit cognitive function, but randomized clinical trials have produced mixed findings in terms of health and cognitive outcomes. This review focuses on hormone effects on cognition and risk for dementia in naturally menopausal women as well as surgically induced menopause, and highlights findings from the large-scale WHI Memory Study (WHIMS) which, contrary to expectation, showed increased dementia risk and poorer cognitive outcomes in older postmenopausal women randomized to HT versus placebo. We consider the 'critical window hypothesis', which suggests that a window of opportunity may exist shortly after menopause during which estrogen treatments are most effective. In addition, we highlight emerging evidence that potential adverse effects of HT on cognition are most pronounced in women who have other health risks, such as lower global cognition or diabetes. Lastly, we point towards implications for future research and clinical treatments.

New onset executive function difficulties at menopause: a possible role for lisdexamfetamine

RATIONALE

Reports of cognitive decline, particularly in the domains of executive functions (EFs), are common among menopausal women.

OBJECTIVE

This study aims to determine the impact of the psychostimulant lisdexamfetamine (LDX) on subjective and objective cognitive function among menopausal women who report new-onset EF complaints.

METHODS

Thirty-two healthy perimenopausal and early postmenopausal women experiencing mid-life-onset executive function difficulties as measured using the Brown Attention Deficit Disorder Scale (BADDS) were administered LDX 40-60 mg/day for 4 weeks in this double-blind, placebo-controlled, cross-over study. Diagnosis of lifetime ADHD was exclusionary. BADDS total and subscale scores and performance on verbal memory and working memory tasks were outcomes of interest.

RESULTS

Analyses revealed a significant effect of LDX treatment over placebo for total BADDS scores (p = 0.0001) and for four out of the five BADDS subscales (all p < 0.004). LDX treatment also resulted in significant improvement in delayed paragraph recall (p = 0.018), but there was no significant effect of treatment on other cognitive measures. Systolic blood pressure (p = 0.017) and heart rate increased significantly (p = 0.006) when women were on LDX but remained, on average, within the normal range.

CONCLUSIONS

LDX 40-60 mg/day was well tolerated and improved the subjective measures of executive function as well as objective measures of delayed verbal recall in this sample of healthy menopausal women.

Peripheral and Central Mechanisms of Stress Resilience

Viable new treatments for depression and anxiety have been slow to emerge, likely owing to the complex and incompletely understood etiology of these disorders. A budding area of research with great therapeutic promise involves the study of resilience, the adaptive maintenance of normal physiology and behavior despite exposure to marked psychological stress. This phenomenon, documented in both humans and animal models, involves coordinated biological mechanisms in numerous bodily systems, both peripheral and central. In this review, we provide an overview of resilience mechanisms throughout the body, discussing current research in animal models investigating the roles of the neuroendocrine, immune, and central nervous systems in behavioral resilience to stress.

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.

A randomized, placebo-controlled, double-blind trial of sertraline for postpartum depression

RATIONALE

Postpartum depression (PMD) occurs in roughly 10 % of postpartum women and negatively impacts the mother and her offspring, but there are few placebo-controlled studies of antidepressant treatment in this population.

OBJECTIVE

The objective was this study is to compare the selective serotonin reuptake inhibitor (SSRI) sertraline to placebo for treating PMD.

METHODS

This was a single-center, 6-week, randomized double-blind placebo-controlled trial of sertraline with a 1-week placebo lead-in. The participants (n = 38) were women with depression onset within 3 months of delivery; a subset (n = 27) met strict DSM-IV criteria for PMD (onset within 4 weeks of delivery). The participants were prescribed sertraline 50 mg or placebo daily to a maximum of 200 mg/day. Primary outcome variables were the Hamilton Depression Rating Scale (HAM-D) and Clinical Global Impressions (CGI) scores, which were used to determine the rates of response and remission.

RESULTS

Sertraline produced a significantly greater response rate (59 %) than placebo (26 %) and a more than twofold increased remission rate (53 % vs. 21 %). Mixed models did not reveal significant group by time effects, although in the subset of women who met the DSM-IV criteria, there was a statistically significant group by time effect for the HAM-D, Hamilton Anxiety Rating Scale (HAM-A), and CGI.

CONCLUSIONS

Women with PMD are more likely to have a remission of their depression with sertraline treatment, a finding that is more pronounced in women who have onset of depression within 4 weeks of childbirth. These data support the continued use of 4 weeks for the DSM-5 postpartum onset specifier for major depressive disorder.

The brain on stress: vulnerability and plasticity of the prefrontal cortex over the life course

The prefrontal cortex (PFC) is involved in working memory and self-regulatory and goal-directed behaviors and displays remarkable structural and functional plasticity over the life course. Neural circuitry, molecular profiles, and neurochemistry can be changed by experiences, which influence behavior as well as neuroendocrine and autonomic function. Such effects have a particular impact during infancy and in adolescence. Behavioral stress affects both the structure and function of PFC, though such effects are not necessarily permanent, as young animals show remarkable neuronal resilience if the stress is discontinued. During aging, neurons within the PFC become less resilient to stress. There are also sex differences in the PFC response to stressors. While such stress and sex hormone-related alterations occur in regions mediating the highest levels of cognitive function and self-regulatory control, the fact that they are not necessarily permanent has implications for future behavior-based therapies that harness neural plasticity for recovery.

Menopause effects on verbal memory: findings from a longitudinal community cohort

CONTEXT

Although cognitive complaints are common among menopausal women, it is debatable whether there is an objective decline in cognition with menopause that exceeds what is expected with normal aging.

OBJECTIVE

The objective of the study was to determine whether reproductive senescence is associated with an age-independent decline in verbal memory.

DESIGN AND SETTING

The study was a 14-year, longitudinal, population-based cohort study of women who underwent yearly endocrine, behavioral, and cognitive assessments from pre- to postmenopause.

PARTICIPANTS

Caucasian and African American premenopausal women (n = 403), who were enrolled in the Penn Ovarian Aging Study, participated in the study.

MAIN OUTCOME MEASURES

Buschke Selective Reminding Test (immediate and delayed verbal recall), the digit symbol substitution task, and the symbol copy task were used to measure outcomes.

RESULTS

A total of 3958 assessments were conducted in this sample of 403 women. In models that were adjusted for age and important cofactors, immediate (P = .03) and delayed (P = .03) recall on the Buschke Selective Reminding Test declined from the pre- to postmenopausal stages. Further evaluation identified a significant decline (P < .002) in delayed recall early in the transition and immediate recall (P = .04) late in the transition. Race was a significant factor in performance on all tasks (all P < .0001) except the delayed verbal recall task (P = .06) in adjusted models. Endocrine measures were significantly associated with cognitive performance in unadjusted models.

CONCLUSIONS

Certain cognitive domains are sensitive to the physiological changes of reproductive senescence independent of age. The differences in cognitive performance between African American and Caucasian women were not explained by factors examined in this study but are of important public health concern that warrants further investigation.