Sex and menstrual cycle phase at encoding influence emotional memory for gist and detail

Effect of stress on spatial working memory and EEG signal dynamics in the follicular and luteal phases of the menstrual cycle in young single girls

AIM

Women undergo behavioral changes during the menstrual cycle. This study aimed to investigate the effect of estradiol (Es) on stress and effect of stress on spatial working memory (WM) and also to investigate electroencephalogram (EEG) signal's dynamics in the early and late follicular (EF and LF) and luteal (LU) phases of unmarried girls' menstrual cycle.

METHODS

Stress was induced by presentation of a short (3 min) movie clip. Simultaneous with a memory test and stress induction, EEG, serum Es levels, and galvanic skin response (GSR) were assessed.

RESULTS

Serum Es concentrations were decreased in LF, LU, and EF phases. The mean GSR score decreased after stress induction in all three phases, but it increased in the LF and LU phases versus the EF phase. Spatial WM diminished after stress induction in all three phases, but it increased in the LF phase versus the two phases before and after stress induction. Average power spectrum density in all frequency bands increased after stress induction in the frontal and prefrontal channels in the spatial WM test.

CONCLUSION

The results showed that stress led to spatial WM dysfunction; however, Es improved spatial WM performance in the LF phase versus the other two phases.

Biobehavioral mechanisms underlying testosterone and mood relationships in peripubertal female adolescents

The pubertal transition is characterized by pronounced sex hormone fluctuation, refinement of affective neural circuitry, and an increased risk of depression in female adolescents. Sex hormones, including testosterone, exert modulatory effects on frontal-limbic brain networks and are associated with emotion dysregulation and depressive symptoms. Weekly changes in hormones predict affective symptoms in peripubertal female adolescents, particularly in the context of stress; however, the biobehavioral mechanisms underlying hormone change and mood relationships during the pubertal transition have yet to be determined and was the objective of the present study. Forty-three peripubertal female adolescents (ages 11-14) collected 8-weekly salivary hormone (estrone, testosterone) samples and mood assessments to evaluate hormone-mood relationships, followed by a biobehavioral testing session with psychosocial stress and EEG. Within-person correlations between weekly hormone changes and corresponding mood were performed to determine individual differences in mood sensitivity to weekly hormone change. Increased frontal theta activity indexing emotion reactivity, reduced cortisol reactivity, and reduced vagal efficiency predicted the strength of the relationship between testosterone and mood. Further, testosterone-sensitivity strength was associated with the enhancement of negative affect following stress testing. Results identify divergent frontal theta and stress responses as potential biobehavioral mechanisms underlying mood sensitivity to peripubertal testosterone fluctuation.

Declarative Memory Impairment and Emotional Bias in Recurrent Depression with a Seasonal Pattern: The Interplay between Emotion and Cognition in Seasonal Affective Disorder

Seasonal Affective Disorder (SAD) is a subtype of Major Depressive Disorder (MDD) with a seasonal pattern. Although it is a pathological condition limited to specific seasons of the year, during the symptomatic period, patients may experience a significant impairment of well-being and daily quality of life as a result of the depressed mood, associated with other symptoms defined as atypical of MDD. While extensive evidence of memory deficits has been found in MDD, explicit memory impairments in SAD are insufficiently studied. This study aims to investigate the cognitive processing of emotional stimuli in women with SAD, in particular the interplay between emotions and declarative memory. One hundred and twenty young women, screened from an initial number of 1125 university students, were divided into two groups, an experimental one that included 60 medically untreated women affected by “winter type SAD” and a control group of 60 non-SAD women. Different subjects were randomly submitted to two types of audio−visual stories, neutral or arousal, and then their memory performances were analyzed by means of a free-recall test and a recognition memory test. In both the free-recall test (p < 0.008) and in the recognition memory test (p < 0.002), the SAD group showed impaired memory performances. Taken together, our novel key findings suggest that SAD is characterized by impairment in declarative memory and attentional bias for emotional negative stimuli.

Hormonal contraceptives, stress, and the brain: The critical need for animal models

Hormonal contraceptives are among the most important health and economic developments in the 20thCentury, providing unprecedented reproductive control and a range of health benefits including decreased premenstrual symptoms and protections against various cancers. Hormonal contraceptives modulate neural function and stress responsivity. These changes are usually innocuous or even beneficial, including their effects onmood. However, in approximately 4-10% of users, or up to 30 million people at any given time, hormonal contraceptives trigger depression or anxiety symptoms. How hormonal contraceptives contribute to these responses and who is at risk for adverse outcomes remain unknown. In this paper, we discussstudies of hormonal contraceptive use in humans and describe the ways in which laboratory animal models of contraceptive hormone exposure will be an essential tool for expanding findings to understand the precise mechanisms by which hormonal contraceptives influence the brain, stress responses, and depression risk.

Ovariectomy reduces cholinergic modulation of excitatory synaptic transmission in the rat entorhinal cortex

Estrogens are thought to contribute to cognitive function in part by promoting the function of basal forebrain cholinergic neurons that project to the hippocampus and cortical regions including the entorhinal cortex. Reductions in estrogens may alter cognition by reducing the function of cholinergic inputs to both the hippocampus and entorhinal cortex. In the present study, we assessed the effects of ovariectomy on proteins associated with cholinergic synapses in the entorhinal cortex. Ovariectomy was conducted at PD63, and tissue was obtained on PD84 to 89 to quantify changes in the degradative enzyme acetylcholinesterase, the vesicular acetylcholine transporter, and muscarinic M₁ receptor protein. Although the vesicular acetylcholine transporter was unaffected, ovariectomy reduced both acetylcholinesterase and M₁ receptor protein, and these reductions were prevented by chronic replacement of 17β-estradiol following ovariectomy. We also assessed the effects of ovariectomy on the cholinergic modulation of excitatory transmission, by comparing the effects of the acetylcholinesterase inhibitor eserine on evoked excitatory synaptic field potentials in brain slices obtained from intact rats, and from ovariectomized rats with or without 17β-estradiol replacement. Eserine is known to prolong the effects of endogenously released acetylcholine, resulting in an M₁-like mediated reduction of glutamate release at excitatory synapses. The reduction in excitatory synaptic potentials in layer II of the entorhinal cortex induced by 15-min application of 10 μM eserine was greatly reduced in slices from ovariectomized rats as compared to intact rats and ovariectomized rats with replacement of 17β-estradiol. The reduced modulatory effect of eserine is consistent with the observed changes in cholinergic proteins, and suggests that reductions in 17β-estradiol following ovariectomy lead to impaired cholinergic function within the entorhinal cortex.

Social attention, memory, and memory-guided orienting change across the menstrual cycle

Numerous studies have shown that perception of emotion and emotional memory vary across the menstrual cycle. However, most of these studies used stimuli that contained not only emotional but also social elements. Importantly, the social cognitive abilities of individuals are as crucial as emotional abilities for danger avoidance and recruitment of allies. Therefore, the issue that natural hormonal fluctuations may affect emotion processing should be revisited. To investigate whether the effects of the menstrual cycle are emotion-specific or can also be attributed to social information processing, the present study examined social attention across the menstrual cycle in three tasks-visual search, memory, and memory-guided orienting-with a combination of behavioral and eye-tracking measures. We used images of people standing upright with neutral emotion as social distractors and everyday objects with physical properties matched as non-social distractors. Thirty-six healthy women without hormone use and with stable menstrual cycles of 26 - 30 days participated in the three tasks in the late follicular phase (FP) and mid-luteal phase (LP), respectively. During visual search, participants were asked to search for targets accompanied by social or non-social distractors in complex scenes. Social attentional bias, as evidenced by longer search times and shorter gaze behaviors for targets with social distractors, was found in the FP but not in the LP. In the following memory task, memory accuracy for targets was higher in the FP than in the LP, and the memory for targets with social distractors was more precise in both phases. Finally, in the orienting task, targets in social scenes were detected more slowly than in non-social scenes in LP. Taken together, these findings point to the interplay between social attention, memory, and memory-oriented attention and reveal the distinct processing pathways for social information in the FP and LP. The underlying mechanisms from an evolutionary perspective and from behavioral and neural basis were discussed.

Translation of animal endocannabinoid models of PTSD mechanisms to humans: Where to next?

The endocannabinoid system is known to be involved in mechanisms relevant to PTSD aetiology and maintenance, though this understanding is mostly based on animal models of the disorder. Here we review how human paradigms can successfully translate animal findings to human subjects, with the view that substantially increased insight into the effect of endocannabinoid signalling on stress responding, emotional and intrusive memories, and fear extinction can be gained using modern paradigms and methods for assessing the state of the endocannabinoid system in PTSD.

Gonadal steroid hormones and emotional memory consolidation: A systematic review and meta-analysis

Anxiety and stress-related disorders are more prevalent in women and associated with negative emotional memory consolidation as well as impaired fear extinction recall. Recent research has identified a role of gonadal steroid hormones in influencing emotional memories and fear extinction, however most individual studies have small samples and employed various protocols. A systematic review and meta-analysis were conducted on studies that examined sex hormones (estrogen, progesterone, testosterone, allopregnanolone, dehydroepiandrosterone) on four aspects of memory, namely, intentional recall (k = 13), recognition memory (k = 7), intrusive memories (k = 9), and extinction recall (k = 11). The meta-analysis on natural cycling women revealed that progesterone level was positively associated with negative recall and negative intrusive memories, and this effect on intentional recall was enhanced under stress induction. Estradiol level was positively associated with extinction recall. This study reveals an important role of progesterone and estradiol in influencing emotional memory consolidation. It highlights the need to control for these hormonal effects and examine progesterone and estradiol concurrently across all menstrual phases in future emotional memory paradigms.

Facial Emotion Recognition and Emotional Memory From the Ovarian-Hormone Perspective: A Systematic Review

Background

We review original papers on ovarian-hormone status in two areas of emotional processing: facial emotion recognition and emotional memory. Ovarian-hormone status is operationalized by the levels of the steroid sex hormones 17β-estradiol (E2) and progesterone (P4), fluctuating over the natural menstrual cycle and suppressed under oral contraceptive (OCs) use. We extend previous reviews addressing single areas of emotional processing. Moreover, we systematically examine the role of stimulus features such as emotion type or stimulus valence and aim at elucidating factors that reconcile the inconsistent results.

Methods

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and included papers published until September 2020 indexed in PubMed and Web of Science databases. Search terms were MeSH terms (emotional OR emotion) AND (X) AND (estrogen OR progesterone OR menstrual cycle OR oral contraceptives) with (X) representing our separately searched areas, resulting in (processing OR recognition OR empathy), and (memory OR recall). To be included, articles had to (1) be written and published in English, (2) examine healthy, non-pregnant adult women in their reproductive age, and (3) measure or at least estimate levels of E2 and P4. In PubMed, the search was (4) limited to humans and (5) to the search term present in the title or abstract.

Results

Features of the provided stimulus material (emotion type and/or valence) constitute a relevant influence that interacts with E2- and P4-related ovarian-hormone status. For instance, recognition of basic emotions appears to be more related to P4- than E2-levels. Quite consistent, OC intake (vs. natural menstrual cycling) was accompanied by impaired recognition accuracy of basic and also complex emotions, although not in a recent large-sample study assessing complex emotions. Memory recall of negative content was mainly enhanced by P4, especially after having been stressed.

Discussion and Conclusion

We document the methodological diversity in the field, presumably contributing to the heterogeneity of results. More studies explicitly contrasting the early follicular phase, mid-cycle phase, mid-luteal, and OC intake while standardizing tasks are needed. Research would take advantage of using within-subject designs and accounting for the recognition of complex emotions.

Progesterone - Friend or foe?

Estradiol is the "prototypic" sex hormone of women. Yet, women have another sex hormone, which is often disregarded: Progesterone. The goal of this article is to provide a comprehensive review on progesterone, and its metabolite allopregnanolone, emphasizing three key areas: biological properties, main functions, and effects on mood in women. Recent years of intensive research on progesterone and allopregnanolone have paved the way for new treatment of postpartum depression. However, treatment for premenstrual syndrome and premenstrual dysphoric disorder as well as contraception that women can use without risking mental health problems are still needed. As far as progesterone is concerned, we might be dealing with a two-edged sword: while its metabolite allopregnanolone has been proven useful for treatment of PPD, it may trigger negative symptoms in women with PMS and PMDD. Overall, our current knowledge on the beneficial and harmful effects of progesterone is limited and further research is imperative.

Progesterone levels predict reductions in behavioral avoidance following cognitive restructuring in women with spider phobia

BACKGROUND

Ovarian hormones have been implicated as a potential source of variability in the effectiveness of exposure therapy for anxiety disorders in women. Additionally, preclinical studies in healthy women indicate that ovarian hormones are related to cognitive modes of emotion regulation, like cognitive restructuring. The purpose of the current study was to determine whether a relationship exists between endogenous ovarian hormones and the outcomes of cognitive restructuring in clinically anxious women.

METHODS

Ninety women with spider phobia received training in cognitive restructuring or a control task and provided a blood sample for the measurement of serum estradiol and progesterone levels. Behavioral avoidance, using a behavioral approach task with a live spider, and self-reported fear of spiders were measured at baseline and 1-week post-treatment.

RESULTS

The results indicated that heightened levels of progesterone, but not estradiol, at the time of cognitive restructuring predicted greater post-treatment reductions in behavioral avoidance, but not self-reported fear, amongst women who received cognitive restructuring but not those in the control group.

LIMITATIONS

As menstrual cycle phase was not assessed; the present study provides information regarding how the benefits of cognitive therapy are predicted by between-person individual differences in absolute hormone levels, but does not examine the relationship between within-person fluctuations in hormone levels and outcomes.

CONCLUSIONS

These results suggest the effectiveness of cognitive therapy for anxiety disorders in women may differ depending on endogenous levels of progesterone, and raise the possibility that progesterone could be a useful pharmacological adjunct to cognitive therapy.

Translational studies of estradiol and progesterone in fear and PTSD

Translational models of fear have greatly informed our understanding of PTSD and its underlying fear circuitry. One of the most replicated findings in the field is the two-fold higher PTSD incidence in females compared to males. While sociocultural factors play a role, the most robust biological influencers to date are gonadal hormones, such as estradiol and progesterone, which fluctuate across the menstrual cycle. Among studies that account for these hormones, most do so in isolation or collect both and only report one. Variation in study findings suggests that the ratio between these two hormones (the P/E ratio) may be an important and missing variable to further understand gonadal hormone influences on fear. Here we review cross-species examinations of fear and PTSD, within the contexts of estradiol and progesterone as well as P/E ratios that were calculated based on extant literature. We then provide recommendations for best practices in assay methods and reporting to improve research on the P/E ratio in fear and PTSD. Ultimately, greater understanding of this important variable will advance efforts to characterize gonadal hormone influences on fear learning processes in humans and animals.

Electrophysiological and Behavioral Indices of the Role of Estrogens on Memory Processes for Emotional Faces in Healthy Young Women

It is well known that estrogens influence cognitive activities, such as memory, and emotional states. The objective of the present study was to investigate the role of estrogens in the short-term memory processing of basic emotional face expressions, by means of event-related potentials (ERPs) and a recognition memory (RM) behavioral task. Healthy young women were divided into a periovulatory (PO) group, characterized by high levels of estrogens and low levels of progesterone, and an early follicular (EF) group, characterized by low levels of both estrogens and progesterone. During the RM task, all subjects viewed images of faces expressing six basic emotions (happiness, anger, disgust, sadness, surprise, fear) and one neutral expression while their electrophysiological activity was recorded. We considered P300 components, amplitude, and latency in response to each stimulus. Soon after the presentation of each stimulus face, a target image was presented, consisting of two faces, one of which was the same, while the other was a chimerical face, obtained by mixing the upper or lower halves of the faces of the stimulus image with a different emotion. The subjects had to choose between the two alternatives, and the reaction time (RT) and accuracy of response (RM errors) were measured. The main findings of this study showed that P300 amplitudes are significantly higher in response to the expressions of happiness, but significantly lower for sadness, in PO compared to EF. The P300 data are consistent with performance in the RM task and with the measures of RT. The interest in the emotion of happiness, unlike sadness, during the PO phase may reflect the evolutionary significance of female sex hormones linked to mating behavior.

Test-retest reliability of the emotional enhancement of memory

Emotionally arousing stimuli are usually better remembered than neutral ones. This effect can be observed immediately after encoding and becomes more robust after a period of consolidation. The magnitude of this effect in an individual has been treated in various research contexts implicitly as reliable and temporally stable. However, we recently observed in 69 participants that an individual's memory advantage for negative over neutral stimuli, whether immediate or delayed, was very weakly correlated with the advantage measured after 3.5 years, albeit with slightly different memory paradigms. In the current study, we tested whether the test-retest reliability of these emotional memory effects might be larger if the temporal lapse between tests was shorter (10 weeks) and more similar memory tests were used. We observed that the better memory for emotional stimuli is highly replicable on the group level. However, the retest reliability on the individual level was very low. We replicated these findings by re-analysing data from a previous study where female participants took emotional memory tests at two different points of their menstrual cycle. We conclude, therefore, that the individual emotional enhancement of memory is not stable or that it cannot be measured reliably with the standard emotional memory paradigm.

Neuroendocrine pathways underlying risk and resilience to PTSD in women

Women are twice as likely than men to suffer from posttraumatic stress disorder (PTSD). While women have increased exposure to traumatic events of many types and have greater prevalence of comorbid psychiatric disorders compared to men, these differences do not account for the overall sex difference in the prevalence of PTSD. The current review summarizes significant findings that implicate the role of estradiol, progesterone, and allopregnanolone in female risk for PTSD symptoms and dysregulation of fear psychophysiology that is cardinal to PTSD. We also discuss how these steroid hormones influence the stress axis and neural substrates critical for the regulation of fear responses. Understanding the role of ovarian steroid hormones in risk and resilience for trauma-related adverse mental health outcomes across the lifespan in women has important translational, clinical, and intergenerational implications for mitigating the consequences of trauma exposure.

Phase of the menstrual cycle affects engagement of attention with emotional images

Changes that occur during the menstrual cycle affect various aspects of behavior, cognition, and emotion. Here, we focused on potential differences between early follicular and midluteal phases in the way women process images of behaviorally relevant content categories: children, threat, disgust, erotic scenes, low- and high-calorie food. Using eye-tracking, we examined women's engagement of attention in the key region of each image in a free-viewing condition. Specifically, we tested how quickly attention was attracted to these regions and for how long it was held there. Participants took part in two experimental sessions, one in the early follicular and one in the midluteal phase. The results showed that in the midluteal phase attention was attracted to the key region earlier than in the early follicular phase: the first fixation more often fell within the key region and there were fewer fixations preceding it. While the effect of the phase in terms of the capture of attention did not depend on the image category, the effect regarding the hold of attention was category-specific, concerning the disgust category only. Specifically, in the midluteal phase the duration of the exploration of the key region between reaching it for the first time and first exiting it was shorter, which might be due to heightened sensitivity to disgusting stimuli in this period. Overall, our results indicate the occurrence of changes in attentional processing of emotional scenes related to the menstrual cycle, which seem to differ depending on the aspect of attention deployment: in the midluteal phase the effect of enhancing orienting was general and concerned any important visual information, whereas the effect of the shortened hold of attention appeared to be limited to specific content.

The gist and details of sex differences in cognition and the brain: How parallels in sex differences across domains are shaped by the locus coeruleus and catecholamine systems

Across three different domains, there are similar sex differences in how men and women process information. There tends to be a male advantage in attending to and remembering the gist (essential central information of a scene or situation), but a female advantage in attending to and remembering the details (non-essential peripheral information of a scene or situation). This is seen in emotional memory, where emotion enhances gist memory more for males than for females, but enhances detail memory more for females than for males. It also occurs in spatial memory, where men tend to notice and remember the gist of where they or objects are in space, allowing them to more flexibly manipulate themselves or objects within that space, whereas women tend to recall the details of the space around them, allowing them to accurately remember the locations of objects. Finally, such sex differences have also been noted in perception of stimuli such that men attend to global aspects of stimuli (such as a large letter E) more than women, whereas women attend more to the local aspects (such as the many smaller letter Ts making up the E). We review the parallel sex differences seen across these domains in this paper and how they relate to the different brain systems involved in each of these task domains. In addition, we discuss how sex differences in evolutionary pressures and in the locus coeruleus and norepinephrine system may account for why parallel sex differences occur across these different task domains.

Effects of Hormone Therapy on List and Story Recall in Post-Menopausal Women

Background/Study Context: A number of longitudinal randomized controlled trials (LRCT) have used free verbal recall tests to study the effects of post-menopausal estrogen hormone therapy (HT) on episodic memory, but none have explicitly explored contrasts between list and story recall, in spite of cognitive differences between the tasks. For example, list recall provides little support for the use of gist, while story recall emphasizes it, and there is evidence that estrogen produces gist bias. Moreover, we present a literature tabulation that also suggests a task-specific HT effect.

METHODS

In an LRCT with up to eight yearly test sessions, post-menopausal women were randomly assigned either to placebo (N = 56) or to an estrogen formulation (N = 44); subgroups received either estrogen alone (hysterectomy; E-alone; N = 16) or with progestin (intact uterus; E + P; N = 28). Participants were tested on the immediate and delayed list and story recall at each session.

RESULTS

Linear mixed effects analyses of longitudinal trajectories showed that relative to placebo, the HT group declined significantly faster on immediate list recall and slower on immediate story recall. Separate analyses produced a sharpened version of this pattern for the E-alone subgroup but found no significant effects for the E + P subgroup. No significant effects were found in delayed testing.

CONCLUSION

The dissociation we found for immediate list and story recall is similar to the pattern of results in our literature tabulation. Fuzzy-Trace Theory posits parallel verbatim and gist traces plus a meta-cognitive review which becomes more gist-biased with age. Our results suggest that: (1) estrogen increases gist bias, hastening the normal age-related decline of list recall but slowing the decline of story recall relative to placebo; (2) decay of the verbatim trace over time generally causes a shift to gist, thereby accounting for the absence of a delayed recall difference; and (3) progestin weakens the effects of estrogen, thereby accounting for why the dissociation found in E-alone was absent in the E + P subgroup.

Estrogen, Stress, and Depression: Cognitive and Biological Interactions

This article reviews the interactions of estrogen changes and psychosocial stress in contributing to vulnerability to major depressive disorder (MDD) in women. Estrogen modulates brain networks and processes related to changes in stress response, cognition, and emotional dysregulation that are core characteristics of MDD. Synergistic effects of estrogen on cognitive and emotional function, particularly during psychosocial stress, may underlie the association of ovarian hormone fluctuation and depression in women. We propose a model of estrogen effects on multiple brain systems that interface with stress-related emotional and cognitive processes implicated in MDD and discuss possible mechanisms through which reproductive events and changes in estrogen may contribute to MDD risk in women with other concurrent risk factors.

Post-encoding stress enhances mnemonic discrimination of negative stimuli

Stress influences how we remember emotional events and how these events shape future behaviors. However, the impact of stress on memory specificity for emotional events has yet to be examined. To this end, the present study utilized a mnemonic discrimination task that taxes hippocampal pattern separation, the process of distinguishing between overlapping experiences, thereby allowing us to better understand the mechanisms by which stress affects gist versus detail memory of emotional events. Participants encoded scenes composed of negative or neutral objects placed on neutral backgrounds and then underwent a psychosocial stressor or matched control task. Twenty-four hours later during testing, objects were presented separately, with some identical old objects (targets), some new objects (foils), and some similar but not identical objects (lures). Target recognition was enhanced for negative compared to neutral objects in both the stress and control groups. Interestingly, post-encoding stress selectively enhanced mnemonic discrimination of negative versus neutral objects, which was not the case in the control group. Measures of salivary cortisol revealed a quadratic inverted U relationship between negative mnemonic discrimination and cortisol increase. These findings suggest that moderate cortisol release following stress is associated with enhanced memory precision for negative information.

Preextinction Stress Prevents Context-Related Renewal of Fear

Extinction learning, which creates new safety associations, is thought to be the mechanism underlying exposure therapy, commonly used for the treatment of anxiety disorders and posttraumatic stress disorder. The relative strength and availability for retrieval of both the fear and safety memories determine the response in a given situation. While the fear memory is often context-independent and may easily generalize, extinction memory is highly context-specific. "Renewal" of the extinguished fear memory might thus occur following a shift in context. The aim of the current work was to create an enhanced and generalized extinction memory to a discrete stimulus using stress exposure before extinction learning, thereby preventing renewal. In our contextual fear conditioning paradigm, 40 healthy men acquired (Day 1), retrieved and extinguished (Day 2) the fear memories, with no differences between the stress and the control group. A significant difference between the groups emerged in the renewal test (Day 3). A renewal effect was seen in the control group (N = 20), confirming the context-dependency of the extinction memory. In contrast, the stress group (N = 20) showed no renewal effect. Fear reduction was generalized to the acquisition context as well, suggesting that stress rendered the extinction memory more context-independent. These results are in line with previous studies that showed contextualization disruption as a result of pre-learning stress, mediated by the rapid effects of glucocorticoids on the hippocampus. Our findings support research investigating the use of glucocorticoids or stress induction in exposure therapy and suggest the right timing of administration in order to optimize their effects.

Using a memory systems lens to view the effects of estrogens on cognition: Implications for human health

Understanding the organizing and activating effects of gonadal steroids on adult physiology can guide insight into sex differences in and hormonal influences on health and disease, ranging from diabetes and other metabolic disorders, emotion and stress regulation, substance abuse, pain perception, immune function and inflammation, to cognitive function and dysfunction accompanying neurological disorders. Because the brain is highly sensitive to many forms of estrogens, it is not surprising that many adult behaviors, including cognitive function, are modulated by estrogens. Estrogens are known for their facilitating effects on learning and memory, but it is becoming increasingly clear that they also can impair learning and memory of some classes of tasks and may do so through direct actions on specific neural systems. This review takes a multiple memory systems approach to understanding how estrogens can at the same time enhance hippocampus-sensitive place learning and impair striatum-sensitive response learning by exploring the role estrogen receptor signaling may play in the opposing cognitive effects of estrogens. Accumulating evidence suggests that neither receptor subtype nor the timing of treatment, i.e. rapid vs slow, explain the bidirectional effects of estrogens on different types of learning. New findings pointing to neural metabolism and the provision of energy substrates by astrocytes as a candidate mechanism for cognitive enhancement and impairment are discussed.

Gender Differences in Posttraumatic Stress Symptoms after a Terrorist Attack: A Network Approach

Background: Posttraumatic stress symptoms are more prevalent in women than in men. To improve our understanding of gender differences in PTSD, detailed knowledge about the underlying symptom networks and gender specific symptom profiles is needed. Objective: We aimed to describe the gender differences in levels of individual posttraumatic stress symptoms after a terrorist attack, as well as identify possible gender differences in associations between posttraumatic stress symptoms. Method: This study used survey data from ministerial employees directly (n = 190) and indirectly (n = 1,615) exposed to the 2011 Oslo bombing. Data was collected approximately 10 months after the event. In order to investigate gender differences in levels of symptoms, we used bootstrapped means and standard deviations. Network analyses were conducted to identify gender differences in the associations between posttraumatic stress symptoms. Results: Women reported higher levels of all symptoms, and the strongest effect sizes were found for symptoms of re-experiencing, and anxious and dysphoric arousal. Among individuals with considerable levels of posttraumatic stress symptoms, women reported higher levels of physiological cue activity and exaggerated startle response. No significant gender differences in the networks of posttraumatic stress were found. Conclusions: The present results find no indication that the gender difference in prevalence of PTSD can be explained by differences in associations between symptoms. In order to determine if this finding can be applied to other participants and circumstances, future studies should seek to replicate this study in both community and clinical samples.

Cortisol reactivity and emotional memory after psychosocial stress in oral contraceptive users

Oral contraceptive (OC) users typically show a blunted or no cortisol response to psychosocial stress. Although most OC regimens include both an inactive (dummy) and active pill phase, studies have not systematically investigated cortisol responses during these pill phases. Further, high levels of cortisol following a stressor diminish retrieval of emotional material, but the effects of stress on memory among OC users are poorly understood. We examined the effects of a psychosocial stressor, the Trier Social Stress Test, vs. a control condition on cortisol responsivity and emotional memory retrieval in women tested either during their active (n = 18) or inactive pill phase (n = 21). In secondary analyses, we quantitatively compared OC users with normally cycling women and showed a significant lack of cortisol response during both active and inactive pill phase. Emotional recall did not differ between active and inactive pill phases. Stress differentially diminished recall of negative words compared with positive or neutral words, but cortisol levels were unrelated to memory performance. These findings indicate that OC users have distinct cortisol and memory responses to stress that are similar between the active and inactive pill phases. © 2016 Wiley Periodicals, Inc.

Sex- and Estrus-Dependent Differences in Rat Basolateral Amygdala

Depression and anxiety are diagnosed almost twice as often in women, and the symptomology differs in men and women and is sensitive to sex hormones. The basolateral amygdala (BLA) contributes to emotion-related behaviors that differ between males and females and across the reproductive cycle. This hints at sex- or estrus-dependent features of BLA function, about which very little is known. The purpose of this study was to test whether there are sex differences or estrous cyclicity in rat BLA physiology and to determine their mechanistic correlates. We found substantial sex differences in the activity of neurons in lateral nuclei (LAT) and basal nuclei (BA) of the BLA that were associated with greater excitatory synaptic input in females. We also found strong differences in the activity of LAT and BA neurons across the estrous cycle. These differences were associated with a shift in the inhibition-excitation balance such that LAT had relatively greater inhibition during proestrus which paralleled more rapid cued fear extinction. In contrast, BA had relatively greater inhibition during diestrus that paralleled more rapid contextual fear extinction. These results are the first to demonstrate sex differences in BLA neuronal activity and the impact of estrous cyclicity on these measures. The shift between LAT and BA predominance across the estrous cycle provides a simple construct for understanding the effects of the estrous cycle on BLA-dependent behaviors. These results provide a novel framework to understand the cyclicity of emotional memory and highlight the importance of considering ovarian cycle when studying the BLA of females.SIGNIFICANCE STATEMENT There are differences in emotional responses and many psychiatric symptoms between males and females. This may point to sex differences in limbic brain regions. Here we demonstrate sex differences in neuronal activity in one key limbic region, the basolateral amygdala (BLA), whose activity fluctuates across the estrous cycle due to a shift in the balance of inhibition and excitation across two BLA regions, the lateral and basal nuclei. By uncovering this push-pull shift between lateral and basal nuclei, these results help to explain disparate findings about the effects of biological sex and estrous cyclicity on emotion and provide a framework for understanding fluctuations in emotional memory and psychiatric symptoms.

Arousal amplifies biased competition between high and low priority memories more in women than in men: The role of elevated noradrenergic activity

Recent findings indicate that emotional arousal can enhance memory consolidation of goal-relevant stimuli while impairing it for irrelevant stimuli. According to one recent model, these goal-dependent memory tradeoffs are driven by arousal-induced release of norepinephrine (NE), which amplifies neural gain in target sensory and memory processing brain regions. Past work also shows that ovarian hormones modulate activity in the same regions thought to support NE's effects on memory, such as the amygdala, suggesting that men and women may be differentially susceptible to arousal's dual effects on episodic memory. Here, we aimed to determine the neurohormonal mechanisms that mediate arousal-biased competition processes in memory. In a competitive visuo-attention task, participants viewed images of a transparent object overlaid on a background scene and explicitly memorized one of these stimuli while ignoring the other. Participants then heard emotional or neutral audio-clips and provided a subjective arousal rating. Hierarchical generalized linear modeling (HGLM) analyses revealed that greater pre-to-post task increases in salivary alpha-amylase (sAA), a biomarker of noradrenergic activity, was associated with significantly greater arousal-enhanced memory tradeoffs in women than in men. These sex-dependent effects appeared to result from phasic and background noradrenergic activity interacting to suppress task-irrelevant representations in women but enhancing them in men. Additionally, in naturally cycling women, low ovarian hormone levels interacted with increased noradrenergic activity to amplify memory selectivity independently of emotion-induced arousal. Together these findings suggest that increased noradrenergic transmission enhances preferential consolidation of goal-relevant memory traces according to phasic arousal and ovarian hormone levels in women.

Menstrual Cycle and Hormonal Contraceptive-Dependent Changes in Intrinsic Connectivity of Resting-State Brain Networks Correspond to Behavioral Changes Due to Hormonal Status

Menstrual cycle-dependent changes have been reported for a variety of functions, including cognition, attention, emotion, inhibition, and perception. For several of these functions, an effect of hormonal contraceptives has also been discussed. Cognitive, attentional, emotional, inhibitory, and perceptual functions have been linked to distinct intrinsic connectivity networks during the resting state. However, changes in resting-state connectivity across the menstrual cycle phase and due to hormonal contraceptive use have only been investigated in two selected networks and without controlling for the type of hormonal contraceptives. In the present study, we demonstrate menstrual cycle and hormonal contraceptive-dependent changes in several intrinsic connectivity networks, including networks that have been related to emotion processing, olfaction, audition, vision, coordination, and two lateralized frontoparietal networks related to a variety of cognitive functions. These changes parallel behavioral changes in the functions associated with these networks. Changes in connectivity and changes in behavior occur during the same cycle phases. Furthermore, hormonal contraceptive-dependent effects were observed in the same networks and same target sites as menstrual cycle-related changes and were dependent on the androgenicity of the progestin component contained in the hormonal contraceptive.

Evidence of estrogen modulation on memory processes for emotional content in healthy young women

PURPOSE

It is well accepted that emotional content can affect memory, interacting with the encoding and consolidation processes. The aim of the present study was to verify the effects of estrogens in the interplay of cognition and emotion.

METHODS

Images from the International Affective Pictures System, based on valence (pleasant, unpleasant and neutral), maintaining arousal constant, were viewed passively by two groups of young women in different cycle phases: a periovulatory group (PO), characterized by high level of estrogens and low level of progesterone, and an early follicular group (EF), characterized by low levels of both estrogens and progesterone. The electrophysiological responses to images were measured, and P300 peak was considered. One week later, long-term memory was tested by means of free recall.

FINDINGS

Intra-group analysis displayed that PO woman had significantly better memory for positive images, while EF women showed significantly better memory for negative images. The comparison between groups revealed that women in the PO phase had better memory performance for positive pictures than women in the EF phase, while no significant differences were found for negative and neutral pictures. According to the free recall results, the subjects in the PO group showed greater P300 amplitude, and shorter latency, for pleasant images compared with women in the EF group.

CONCLUSION

Our results showed that the physiological hormonal fluctuation of estrogens during the menstrual cycle can influence memory, at the time of encoding, during the processing of emotional information.

Stress-induced increases in progesterone and cortisol in naturally cycling women

Studies with animals of both sexes show that the adrenal glands release progesterone in addition to cortisol in response to stress. However, little is known about the progesterone response to stress in naturally cycling women. We investigated the effect of stress on estradiol, progesterone, and cortisol levels in women during the follicular phase of the menstrual cycle. We found that physical stress (the cold pressor test) had no effect on estradiol levels, but increased progesterone and cortisol. We also found positive correlations between baseline progesterone and cortisol levels, as well as between the change in progesterone and cortisol before and after water exposure in both the stress and control sessions. Mediation analyses revealed during the stress session, the change in progesterone from baseline to 42-min post-stress onset was mediated by the magnitude of change in cortisol levels across the same time span. Overall, these findings reveal that progesterone released in response to stress as observed in animals and men extends to women during the low ovarian output follicular phase of the menstrual cycle, and that the mechanism of release may be similar to the mechanism of cortisol release.

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Progesterone rises in response to stress during the follicular phase.

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Baseline progesterone was associated with greater cortisol response to stress.

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Cortisol response to stress mediated progesterone responses to stress.

Reproducibility of hormone-driven regional grey matter volume changes in women using SPM8 and SPM12

Aim of this work was to evaluate the reproducibility of hormone driven regional grey matter volume differences in women, and their correlations with premenstrual symptoms, as determined by voxel-based morphometry (VBM). After data quality control, a total of 138 T1-weighted MR images were included in this longitudinal study, and were analyzed as three different subgroups. Women with a natural menstrual cycle were scanned at three time-points: follicular, ovulatory and luteal phase. Two groups of women, using androgenic and anti-androgenic hormonal contraceptives, respectively, were scanned twice: during the pill-free week and during pill intake. Additionally, subjects were asked to complete a "daily rating of severity of problems" questionnaire, to quantify premenstrual symptoms. All data were analyzed using SPM8 and SPM12 with identical parameter settings. In the natural menstrual cycle group, the regional grey matter volume of the insula is larger at ovulation, as compared to the luteal phase. Premenstrual symptoms correlate differently with regional grey matter volumes between women with a natural cycle and hormonal contraceptive users. Changes in hormonal environment can to various extents affect VBM findings in women. We suggest that researchers take these confounding factors into account while applying this technique, to avoid heterogeneity in data acquisition and to safeguard the sensitivity of findings. Additionally, we suggest validating the consistency of results using more than one software package.

Anorexia nervosa, emotional go/no-go, and the distinct effect of testosterone

OBJECTIVE

Behavioral disinhibition in the context of negative emotion (e.g., disgust, fear, etc.) may promote the core psychopathology of anorexia nervosa (AN). Affective models of AN position a number of clinical behaviors as functioning to reduce negative affect. Gonadal hormone dysregulation, in particular testosterone, likely plays some role in this process.

METHOD

Adolescent and young adult AN (n = 32) and healthy control (HC; n = 20) participants completed an emotional go/no-go task--a valenced measure of behavioral disinhibition--and had blood drawn to assess gonadal steroid hormone concentrations.

RESULTS

Analyses indicated that patients with AN committed significantly more commission errors, which measures the tendency to respond to nontarget stimuli. This effect was qualified by the valence of the stimulus; the higher relative level of error was true for disgust and happy stimuli, but not neutral stimuli. Hormone analyses revealed a testosterone by group interaction. Testosterone was associated with decreased commission errors for patients with AN, but had no discernible relationship with task outcome for HCs. These effects were not confounded by weight, pubertal status, or self-reported anxiety or depression.

DISCUSSION

These findings suggest patients with AN have difficulty inhibiting behavior in the context of emotional stimuli, and that this disinhibition is negatively related to levels of circulating androgens.

The estrous cycle surpasses sex differences in regulating the transcriptome in the rat medial prefrontal cortex and reveals an underlying role of early growth response 1

Background

Males and females differ in cognitive functions and emotional processing, which in part have been associated with baseline sex differences in gene expression in the medial prefrontal cortex. Nevertheless, a growing body of evidence suggests that sex differences in medial prefrontal cortex-dependent cognitive functions are attenuated by hormonal fluctuations within the menstrual cycle. Despite known genomic effects of ovarian hormones, the interaction of the estrous cycle with sex differences in gene expression in the medial prefrontal cortex remains unclear and warrants further investigations.

Results

We undertake a large-scale characterization of sex differences and their interaction with the estrous cycle in the adult medial prefrontal cortex transcriptome and report that females with high and low ovarian hormone levels exhibited a partly opposed sexually biased transcriptome. The extent of regulation within females vastly exceeds sex differences, and supports a multi-level reorganization of synaptic function across the estrous cycle. Genome-wide analysis of the transcription factor early growth response 1 binding highlights its role in controlling the synapse-related genes varying within females.

Conclusions

We uncover a critical influence of the estrous cycle on the adult rat medial prefrontal cortex transcriptome resulting in partly opposite sex differences in proestrus when compared to diestrus females, and we discovered a direct role for Early Growth Response 1 in this opposite regulation. In addition to illustrating the importance of accounting for the estrous cycle in females, our data set the ground for a better understanding of the female specificities in cognition and emotional processing.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-015-0815-x) contains supplementary material, which is available to authorized users.

Sympathetic arousal increases a negative memory bias in young women with low sex hormone levels

Emotionally arousing events are typically better attended to and remembered than neutral ones. Current theories propose that arousal-induced increases in norepinephrine during encoding bias attention and memory in favor of affectively salient stimuli. Here, we tested this hypothesis by manipulating levels of physiological arousal prior to encoding and examining how it influenced memory for emotionally salient images, particularly those that are negative rather than positive in valence. We also tested whether sex steroid hormones interact with noradrenergic activity to influence these emotional memory biases in women. Healthy naturally cycling women and women on hormonal contraception completed one of the following physiological arousal manipulations prior to viewing a series of negative, positive and neutral images: (1) immediate handgrip arousal-isometric handgrip immediately prior to encoding, (2) residual handgrip arousal-isometric handgrip 15min prior to encoding, or (3) no handgrip. Sympathetic arousal was measured throughout the session via pupil diameter changes. Levels of 17β-estradiol and progesterone were measured via salivary samples. Memory performance was assessed approximately 10min after encoding using a surprise free recall test. The results indicated that handgrip successfully increased sympathetic arousal compared to the control task. Under immediate handgrip arousal, women showed enhanced memory for negative images over positive images; this pattern was not observed in women assigned to the residual and no-handgrip arousal conditions. Additionally, under immediate handgrip arousal, both high estradiol and progesterone levels attenuated the memory bias for negative over positive images. Follow-up hierarchical linear models revealed consistent effects when accounting for trial-by-trial variability in normative International Affective Picture System valence and arousal ratings. These findings suggest that heightened sympathetic arousal interacts with estradiol and progesterone levels during encoding to increase the mnemonic advantage of negative over positive emotional material.

Post-learning stress enhances long-term memory and differentially influences memory in females depending on menstrual stage

Most work has shown that post-learning stress enhances long-term memory; however, there have been recent inconsistencies in this literature. The purpose of the present study was to examine further the effects of post-learning stress on long-term memory and to explore any sex differences that may exist. Male and female participants learned a list of 42 words that varied in emotional valence and arousal level. Following encoding, participants completed a free recall assessment and then submerged their hand into a bath of ice cold (stress) or lukewarm (no stress) water for 3 min. The next day, participants were given free recall and recognition tests. Stressed participants recalled more words than non-stressed participants 24h after learning. Stress also enhanced female participants' recall of arousing words when they were in the follicular, but not luteal, phase. These findings replicate previous work examining post-learning stress effects on memory and implicate the involvement of sex-related hormones in such effects.

Preserved emotional memory modulation in first episode psychosis

Although patients with schizophrenia have severe memory impairments and emotional deficits, studies investigating emotional memory modulation (EMM) in schizophrenia show contradictory results, possibly due to methodological differences and small group size. We investigated whether impaired EMM is already present in First Episode Psychosis (FEP) and whether impairments in EMM are task or stimulus dependent. Forty-five FEP and thirty-seven Healthy Control (HC) male participants matched for age performed visual and verbal short-term (immediate recall) and long-term (after 24h recognition) memory tasks with neutral, negative and positive stimuli. On all tasks overall memory performance for FEP was significantly below that of HC. Although EMM varied by task and type of stimulus, none of the tasks showed a difference in EMM between FEP and HC. There were no differences between FEP and HC in the way emotion modulates different memory domains. This could mean that EMM is spared in the early course of schizophrenia.

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.

Sex-specific strategy use and global-local processing: a perspective toward integrating sex differences in cognition

This article reviews the literature on sex-specific strategy use in cognitive tasks with the aim to carve out a link between sex differences in different cognitive tasks. I conclude that male strategies are commonly holistic and oriented toward global stimulus aspects, while female strategies are commonly decomposed and oriented toward local stimulus aspects. Thus, the strategies observed in different tasks, may depend on sex differences in attentional focus and hence sex differences in global-local processing. I hypothesize that strategy use may be sex hormone dependent and hence subject to change over the menstrual cycle as evidenced by findings in global-local processing and emotional memory. Furthermore, I propose sex hormonal modulation of hemispheric asymmetries as one possible neural substrate for this theory, thereby building on older theories, emphasizing the importance of sex differences in brain lateralization. The ideas described in the current article represent a perspective toward a unifying approach to the study of sex differences in cognition and their neural correlates.

Voluntary and involuntary emotional memory following an analogue traumatic stressor: the differential effects of communality in men and women

BACKGROUND

Men and women show differences in performance on emotional processing tasks. Sex also interacts with personality traits to affect information processing. Here we examine effects of sex, and two personality traits that are differentially expressed in men and women - instrumentality and communality - on voluntary and involuntary memory for distressing video-footage.

METHODS

On session one, participants (n = 39 men; 40 women) completed the Bem Sex-Role Inventory, which assesses communal and instrumental traits. After viewing film-footage of death/serious injury, participants recorded daily involuntary memories (intrusions) relating to the footage on an online diary for seven days, returning on day eight for a second session to perform a voluntary memory task relating to the film.

RESULTS

Communality interacted with sex such that men with higher levels of communality reported more frequent involuntary memories. Alternatively, a communality × sex interaction reflected a tendency for women with high levels of communality to perform more poorly on the voluntary recognition memory task.

LIMITATIONS

The study involved healthy volunteers with no history of significant psychological disorder. Future research with clinical populations will help to determine the generalizability of the current findings.

CONCLUSION

Communality has separate effects on voluntary and involuntary emotional memory. We suggest that high levels of communality in men and women may confer vulnerability to the negative effects of stressful events either through the over-encoding of sensory/perceptual-information in men or the reduced encoding of contextualised, verbally-based, voluntarily accessible representations in women.

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.

Low levels of estradiol are associated with elevated conditioned responding during fear extinction and with intrusive memories in daily life

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Intrusive memories can be seen as conditioned responses to trauma reminders.

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Novel conditioned-intrusion paradigm models both fear conditioning and intrusions.

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Low estradiol is related to higher conditioned responses during fear extinction.

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Low estradiol is related to higher intrusive memory strength in daily life.

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Conditioned responding during extinction partially explains the latter relationship.

Posttraumatic stress disorder (PTSD) can be conceptualized as a disorder of emotional memory showing strong (conditioned) responses to trauma reminders and intrusive memories among other symptoms. Women are at greater risk of developing PTSD than men. Recent studies have demonstrated an influence of ovarian steroid hormones in both fear conditioning and intrusive memory paradigms. However, although intrusive memories are considered non-extinguished emotional reactions to trauma reminders, none of the previous studies has investigated effects of ovarian hormones on fear conditioning mechanisms and intrusive memories in conjunction. This may have contributed to an overall inconsistent picture of the role of these hormones in emotional learning and memory. To remedy this, we exposed 37 healthy women with a natural menstrual cycle (during early follicular or luteal cycle phase) to a novel conditioned-intrusion paradigm designed to model real-life traumatic experiences. The paradigm included a differential fear conditioning procedure with short violent film clips as unconditioned stimuli. Intrusive memories about the film clips were assessed ambulatorily on subsequent days. Women with lower levels of estradiol displayed elevated differential conditioned skin conductance responding during fear extinction and showed stronger intrusive memories. The inverse relationship between estradiol and intrusive memories was at least partially accounted for by the conditioned responding observed during fear extinction. Progesterone levels were not associated with either fear acquisition/extinction or with intrusive memories. This suggests that lower levels of estradiol might promote stronger symptoms of PTSD through associative processes.

ADRA2B deletion variant selectively predicts stress-induced enhancement of long-term memory in females

Clarifying the mechanisms that underlie stress-induced alterations of learning and memory may lend important insight into susceptibility factors governing the development of stress-related psychological disorders, such as post-traumatic stress disorder (PTSD). Previous work has shown that carriers of the ADRA2B Glu(301)-Glu(303) deletion variant exhibit enhanced emotional memory, greater amygdala responses to emotional stimuli and greater intrusiveness of traumatic memories. We speculated that carriers of this deletion variant might also be more vulnerable to stress-induced enhancements of long-term memory, which would implicate the variant as a possible susceptibility factor for traumatic memory formation. One hundred and twenty participants (72 males, 48 females) submerged their hand in ice cold (stress) or warm (no stress) water for 3min. Immediately afterwards, they studied a list of 42 words varying in emotional valence and arousal and then completed an immediate free recall test. Twenty-four hours later, participants' memory for the word list was examined via free recall and recognition assessments. Stressed participants exhibiting greater heart rate responses to the stressor had enhanced recall on the 24-h assessment. Importantly, this enhancement was independent of the emotional nature of the learned information. In contrast to previous work, we did not observe a general enhancement of memory for emotional information in ADRA2B deletion carriers. However, stressed female ADRA2B deletion carriers, particularly those exhibiting greater heart rate responses to the stressor, did demonstrate greater recognition memory than all other groups. Collectively, these findings implicate autonomic mechanisms in the pre-learning stress-induced enhancement of long-term memory and suggest that the ADRA2B deletion variant may selectively predict stress effects on memory in females. Such findings lend important insight into the physiological mechanisms underlying stress effects on learning and their sex-dependent nature.

Decreased susceptibility to false memories from misinformation in hormonal contraception users

Sex hormones are increasingly implicated in memory formation. Recent literature has documented a relationship between hormones and emotional memory and sex differences, which are likely related to hormones, have long been demonstrated in a variety of mnemonic domains, including false memories. Hormonal contraception (HC), which alters sex hormones, has been associated with a bias towards gist memory and away from detailed memory in women who use it during an emotional memory task. Here, we investigated whether HC was associated with changes in susceptibility to false memories, which may be related to the formation of gist memories. We tested false memory susceptibility using two well-validated false memory paradigms: the Deese-Roediger-McDermott (DRM) task, and a story-based misinformation task. We found that hormonal contraceptive users were less susceptible to false memories compared to non-users in the misinformation task, and no differences were seen between groups on the DRM task. We hypothesise that the differences in false memories from the misinformation task may be related to hormonal contraceptive users' memory bias away from details, towards gist 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.

Postlearning stress differentially affects memory for emotional gist and detail in naturally cycling women and women on hormonal contraceptives

Sex differences in emotional memory have received increasing interest over the past decade. However, to date, no work has explored how a postlearning stressor might modulate the influence of sex hormone status on memory for gist and peripheral detail in an emotional versus neutral context. Here, we tested 3 predictions. First, compared with naturally cycling (NC) women in the luteal phase, women on hormonal contraception (HC) would have significantly blunted hypothalamic-pituitary-adrenal reactivity to physical stress. Second, postlearning stress would enhance detail and gist memory from an emotional story in NC women, and finally, postlearning stress would not affect emotional memory for details or gist in HC women. Healthy NC and HC women viewed a brief, narrated story containing neutral or emotionally arousing elements. Immediately after, cold pressor stress (CPS) or a control procedure was administered. One week later, participants received a surprise free recall test for story elements. NC women exhibited significantly greater cortisol increases to CPS compared with HC women. NC women who viewed the emotional story and were administered CPS recalled the most peripheral details overall and more gist from the emotional compared with the neutral story. In HC women, however, the postlearning cortisol release did not affect memory for gist or peripheral details from the emotional or neutral story in any way. Additionally, NC and HC women performed similarly on measures of attention and arousal. These findings suggest that in women, postlearning stress differentially affects memory for emotional information depending on their hormonal contraceptive status.

Asymmetric effects of emotion on mnemonic interference

Emotional experiences can strengthen memories so that they can be used to guide future behavior. Emotional arousal, mediated by the amygdala, is thought to modulate storage by the hippocampus, which may encode unique episodic memories via pattern separation--the process by which similar memories are stored using non-overlapping representations. While prior work has examined mnemonic interference due to similarity and emotional modulation of memory independently, examining the mechanisms by which emotion influences mnemonic interference has not been previously accomplished in humans. To this end, we developed an emotional memory task where emotional content and stimulus similarity were varied to examine the effect of emotion on fine mnemonic discrimination (a putative behavioral correlate of hippocampal pattern separation). When tested immediately after encoding, discrimination was reduced for similar emotional items compared to similar neutral items, consistent with a reduced bias towards pattern separation. After 24h, recognition of emotional target items was preserved compared to neutral items, whereas similar emotional item discrimination was further diminished. This suggests a potential mechanism for the emotional modulation of memory with a selective remembering of gist, as well as a selective forgetting of detail, indicating an emotion-induced reduction in pattern separation. This can potentially increase the effective signal-to-noise ratio in any given situation to promote survival. Furthermore, we found that individuals with depressive symptoms hyper-discriminate negative items, which correlated with their symptom severity. This suggests that utilizing mnemonic discrimination paradigms allows us to tease apart the nuances of disorders with aberrant emotional mnemonic processing.