Effects of estrogen changes during the menstrual cycle on spatial performance

Reproducible stability of verbal and spatial functions along the menstrual cycle

Recent studies have reported brain changes in response to ovarian hormonal fluctuations along the menstrual cycle. However, it remains unclear, whether these brain changes are of an adaptive nature or whether they are linked to changes in behavior along the menstrual cycle, particularly with respect to cognitive performance. To address this knowledge gap, we report results from 3 well-powered behavioral studies with different task designs, leveraging the advantages of each design type. In all three studies we assessed whether verbal or spatial performance (i) differed between cycle phases, (ii) were related to estradiol and / or progesterone levels and (iii) were moderated by individual hormone sensitivity as estimated by premenstrual symptoms. Overall, results of all three studies point towards a null effect of menstrual cycle phase and - to a lesser extent - ovarian hormones on verbal and spatial performance and provided no evidence for a moderation of this effect by individual hormone sensitivity. We conclude that there is substantial consistency in verbal and spatial performance across the menstrual cycle, and that future studies of intra-individual variation are needed.

The influence of estradiol and progesterone on neurocognition during three phases of the menstrual cycle: Modulating factors

Estradiol is an ovarian steroid hormone that peaks shortly before ovulation and significantly affects various brain regions and neurotransmitter systems, with similar and differential effects with progesterone, another ovarian hormone. Studies investigating the neurocognitive processes during the menstrual cycle have focused on the early follicular phase (EFP) characterized by low estradiol and progesterone levels and the mid-luteal phase (MLP) with high estradiol and progesterone levels. However, most studies have failed to include the ovulatory phase, characterized by high estradiol and low progesterone levels. Given the various hormonal changes in the menstrual cycle, we revisited studies suggesting that the menstrual cycle did not affect verbal and spatial abilities and observed that many contain mixed results. Comparing these studies makes it possible to identify relevant modulating factors, such as sample size, participant age, accurate selection of days for testing, asymmetrical practice effects, genetic polymorphisms, and task difficulty. More robust findings are related to improved mental rotation capacity during EFP with challenging tasks and differences in brain activation among menstrual cycle phases during the execution of spatial and verbal tasks. During MLP, less robust findings were observed, possibly modulated by the complex effects of the two hormones on the brain. In conclusion, we propose that it is crucial to include all three menstrual cycle phases and consider these modulating factors to avoid confounding findings.

Effects of oral contraceptives on spatial cognition depend on pharmacological properties and phase of the contraceptive cycle

The central nervous system effects of oral contraceptives (OCs) are not well-documented. In a set of 3 studies, we investigated a specific cognitive function, mental rotation, in healthy women currently using OCs for contraceptive purposes (n = 201) and in medication-free controls not using OCs (n = 44). Mental rotation was measured using a well-standardized and extensively validated psychometric test, the Vandenberg Mental Rotations Test (MRT). In an initial study (Study 1), current OC users (n = 63) were tested during the active or inactive phases of the contraceptive cycle in a parallel-groups design. Studies 2 and 3 were based on an archival dataset (n = 201 current OC users) that consisted of data on the MRT collected in real-time over a 30-year period and compiled for purposes of the present work. The OCs were combined formulations containing ethinyl estradiol (10-35 ug/day) plus a synthetic progestin. All 4 families of synthetic progestins historically used in OCs were represented in the dataset. Cognitive performance was evaluated during either active OC use ('active phase') or during the washout week of the contraceptive cycle ('inactive phase') when OC steroids are not used. The results showed a significant phase-of-cycle (POC) effect. Accuracy on the MRT was mildly diminished during the active phase of OC use, while scores on verbal fluency and speeded motor tasks were modestly improved. The POC effect was most evident in women using OCs that contained first- or second-generation progestins (the estrane family of progestins or OCs containing levonorgestrel), but not in women using OCs containing recently developed progestins and lower doses of ethinyl estradiol. Using independently established ratings of the estrogenic, androgenic, and progestogenic intensities of the different OC formulations, each brand of OC was classified according to its distinct endocrine profile. Multiple regression revealed that the effects of OC use on the MRT could be predicted based on the estrogenic strength of the contraceptives used. Estrogenic potency, not androgenic or anti-androgenic effects of the OC pill, may underlie the effects of OC usage on spatial cognition.

A novel method for reducing motion sickness susceptibility through training visuospatial ability - A two-part study

Everyone can be susceptible to motion sickness (except those with complete loss of labyrinth function) and around one in three are known to be servery susceptible. Motion sickness can be experienced in many domains, including car travel, on a boat, using virtual reality headsets and simulator use amongst others. It is expected that due to potential designs and use cases, self-driving cars will increase motion sickness onset likelihood and severity for many car travellers. Besides medication, there are limited methods through which one can actively reduce their motion sickness susceptibility. This research develops a novel visuospatial training tool and explores the effect of visuospatial training on motion sickness. With a combined sample of 42 participants split between driving simulator trials (n = 20), and on-road trials (n = 22) baseline visuospatial skills and motion sickness were first measured. After a 14-day training period where participates completed 15-min of pen and paper tasks per day, it was found that visuospatial skills improved by 40%. This increase in visuospatial ability was shown to be directly responsible for a reduction in motion sickness by 51% in the simulator (with a 60% reduction in participant dropouts) and a 58% reduction in the on-road trial. This research has successfully identified a new method to reduce motion sickness susceptibility and the impact of these findings have wide reaching implications for motion sickness research, especially in the field of self-driving vehicles.

The cycling brain: menstrual cycle related fluctuations in hippocampal and fronto-striatal activation and connectivity during cognitive tasks

Estradiol and progesterone vary along the menstrual cycle and exert opposite effects on a variety of neurotransmitter systems. However, few studies have addressed menstrual cycle-dependent changes in the brain. In the present study we investigate menstrual cycle changes in brain activation and connectivity patterns underlying cognition. Thirty-six naturally cycling women underwent functional MRI during two cognitive tasks: spatial navigation and verbal fluency. While no significant performance differences were observed along the menstrual cycle, the changes in brain activation patterns are strikingly similar during both tasks. Irrespective of the task, estradiol boosts hippocampal activation during the pre-ovulatory cycle phase and progesterone boosts fronto-striatal activation during the luteal cycle phase. Connectivity analyses suggest that the increase in right-hemispheric frontal activation is the result of inter-hemispheric decoupling and is involved in the down-regulation of hippocampal activation.

Hormonal Contraception and the Brain: Examining Cognition and Psychiatric Disorders

Background:

The combined oral contraceptive pill (OC), containing synthetic estrogens and progestins, is used by millions of women worldwide, yet little is known about its effects on cognition or on psychiatric disorders. The progestin component of OCs determines their androgenicity, i.e. whether the OC has androgen binding components with masculinising effects or antiandrogenic components with feminising effects.

Objective:

The present review discusses the literature surrounding OC use and cognition in healthy women. Given the important role that sex hormones play in psychiatric disorders, we also consider the influence of OCs on symptoms of schizophrenia, post-traumatic stress disorder, depression, bipolar disorder, anxiety disorders and indirectly, sleep quality.

Results:

Research has shown that while there are no differences between OC users and non-users, androgenic OCs enhance visuospatial ability and anti-androgenic OCs enhance verbal fluency. Little is known about OCs effects on other cognitive domains, such as memory and executive function. There is little research examining OC use in schizophrenia, post-traumatic stress disorder, bipolar disorder and anxiety disorders. There is some evidence that OC use is associated with depression, however the exact causality of this association remains to be verified.

Conclusion:

We maintain that future studies need to address several methodological limitations, such as separating OCs based on androgenicity to avoid the masking effects that occur when various OCs are considered as one group. As this review highlights several significant effects of OC use on the brain, the implications of OC use needs to be considered in future research.

Dual-Task Paradigm Reveals Variation in Left Hemisphere Involvement in Verbal Processing Across the Menstrual Cycle in Normally Cycling Women

Cognitive performance and cerebral hemispheric function are known to vary with fluctuating levels of estradiol and progesterone across the menstrual cycle in naturally cycling females. However, the literature is mixed with regard to how each hemisphere may be affected by elevated ovarian hormones. To better understand this, the current study employed a dual-task paradigm to examine potential shifts in hemispheric involvement for a verbal problem-solving task across the menstrual cycle in 30 right-handed, normally cycling young adult females (18-21 years old). To our knowledge, no study to date has utilized dual-task procedures to directly investigate the potential shifts in hemispheric function across the menstrual cycle. Specifically, participants were tested during both menses and their estimated midluteal phase where they engaged in repetitive unilateral finger-tapping while concurrently solving anagrams silently or aloud. Analysis of finger-tapping interference during the dual-task conditions revealed that solving anagrams silently was lateralized to the left hemisphere while solving anagrams aloud yielded a pattern of more bilateral hemispheric involvement, both of which were consistent across both menses and midluteal phases. Analysis of cognitive performance, however, revealed that silent anagrams performance while tapping with the right, but not left, hand significantly increased during the midluteal phase. Consistent with a number of other studies using different methodological approaches, the current dual-task findings suggest that when ovarian hormone levels are putatively elevated, there is enhanced recruitment of left hemisphere resources while performing a lateralized verbal task.

Sex and the stimulus-movement effect: Differences in acquisition of autoshaped responding in cynomolgus monkeys

The stimulus-movement effect refers to the phenomenon in which stimulus discrimination or acquisition of a response is facilitated by moving stimuli as opposed to stationary stimuli. The effect has been found in monkeys, rats, and humans, but the experiments conducted did not provide adequate female representation to investigate potential sex differences. The current experiment analyzed acquisition of stimulus touching in a progressive series of classical conditioning procedures in cynomolgus monkeys (Macaca fascicularis) as a function of sex and stimulus movement. Classical conditioning tasks arrange two or more stimuli in relation to each other with different temporal and predictive relations. Autoshaping procedures overlay operant contingencies onto a classical-conditioning stimulus arrangement. In the present case, a neutral stimulus (a small gray square displayed on a touchscreen) functioned as the conditional stimulus and a food pellet functioned as the unconditional stimulus. Although touching is not required to produce food, with repeated stimulus pairings subjects eventually touch the stimulus. Across conditions of increasing stimulus correlation and temporal contiguity, male monkeys acquired the response faster with a moving stimulus. In contrast, females acquired the response faster with a stationary stimulus. These results demonstrate that the stimulus-movement effect may be differentially affected by sex and indicate that additional experiments with females are needed to determine how sex interacts with behavioral phenomena discovered and elaborated almost exclusively using males.

Role of Strategies and Prior Exposure in Mental Rotation

The purpose of these two studies was to examine sex differences in strategy use and the effect of prior exposure on the performance on Vandenberg and Kuse's 1978 Mental Rotation Test. A total of 152 participants completed the spatial task and self-reported their strategy use. Consistent with previous studies, men outperformed women. Strategy usage did not account for these differences, although guessing did. Previous exposure to the Mental Rotation Test, American College Test scores and frequent computer or video game play predicted performance on the test. These results suggest that prior exposure to spatial tasks may provide cues to improve participants' performance.

Are hormone levels and cognitive ability related during early adolescence?

The present study assessed the longstanding question of whether there is a relationship between sex hormones and cognitive ability in young adolescent girls and boys. Three “theories” of the relationship between hormone levels and cognition were identi” ed from a broad literature base and were used to formulate hypotheses regarding the relationship between sex hormones and cognitive ability in early adolescents. Fifty-six boys, aged 10-14, and 52 girls, aged 9-14, completed two standardised spatial ability tests and one standardised test of verbal ability. Three blood samples, at 20-minute intervals, were obtained to determine levels of estradiol and testosterone. Data were collected on three occasions for all measures at 6-month intervals. A positive linear relationship between testosterone and spatial ability was identi” ed for boys at each time of measurement for both measures of spatial ability (i.e., mental rotation and block design). For girls, a positive linear relationship was identi” ed between testosterone and mental rotation only at time 3. In addition, longitudinal relationships were identi” ed between change in testosterone levels and change in spatial ability for both girls and boys. The conclusion was that testosterone is related to cognitive functioning during pubertal development for boys and to a lesser extent for girls.

Perception of Emotional Prosody: Moving Toward a Model That Incorporates Sex-Related Differences

The overall purpose of this article is to review the literature that addresses the theoretical models, neuroanatomical mechanisms, and sex-related differences in the perception of emotional prosody. Specifically, the article focuses on the right-hemisphere model of emotion processing as it pertains to the perception of emotional prosody. This article also reviews more recent research that implicates a role for the left hemisphere and subcortical structures in the perception of emotional prosody. The last major section of this article addresses sex-related differences and the potential influence of hormones on the perception of emotional prosody. The article concludes with a section that offers directions for future research.

Diminished nap effects on memory consolidation are seen under oral contraceptive use

Many young females take exogenous hormones as oral contraceptive (OC), a condition rarely controlled for in studies on sleep and memory consolidation even though sex hormones influence consolidation. This study investigated the effects of OCs on sleep-related consolidation of a motor and declarative task, utilizing a daytime nap protocol. Fifteen healthy, young females taking OCs came to the sleep lab for three different conditions: nap with previous learning, wake with previous learning and nap without learning. They underwent each condition twice, once during the "pill-active" weeks and once during the "pill-free" week, resulting in 6 visits. In all conditions, participants showed a significant off-line consolidation effect, independent of pill week or nap/wake condition. There were no significant differences in sleep stage duration, spindle activity or spectral EEG frequency bands between naps with or without the learning condition. The present data showed a significant off-line enhancement in memory irrespective of potential beneficial effects of a nap. In comparison to previous studies, this may suggest that the use of OCs may enhance off-line memory consolidation in motor and verbal tasks per se. These results stress the importance to control for the use of OCs in studies focusing on memory performance.

Changes in spatial cognition and brain activity after a single dose of testosterone in healthy women

Studies have consistently shown that males perform better than females on several spatial tasks. Animal and human literature suggests that sex hormones have an important role in both establishing and maintaining this difference. The aim of the present study was to examine the effects of exogenous testosterone on spatial cognition and brain activity in healthy women. A cross-sectional, double-blind, randomized, placebo-controlled study was performed in 42 healthy young women who either received one dose of 0.5mg sublingual testosterone or placebo. They then learned a virtual environment and performed navigation tasks during functional magnetic resonance imaging (fMRI). Subsequently, their knowledge of the virtual environment, self-reported navigation strategy, and mental rotation abilities were measured. The testosterone group had improved representations of the directions within the environment and performed significantly better on the mental rotation task compared to the placebo group, but navigation success and navigation strategy were similar in the two groups. Nevertheless, the testosterone group had significantly increased activity within the medial temporal lobe during successful navigation compared to the placebo group, and a positive correlation between testosterone load and medial temporal lobe activity was found. Fetal testosterone levels, measured as second-to-fourth digit length ratio, interacted significantly with parahippocampal activity and tended towards giving higher mental rotation task scores. These results demonstrated that testosterone had a limited effect pertaining specifically to spatial cognition involving 3D-visualization in healthy women, while complex behaviors such as navigation, relying more on learned strategies, were not altered despite increased neuronal activity in relevant brain regions.

Oral contraceptives and cognition: A role for ethinyl estradiol

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

Hippocampal volume and functional connectivity changes during the female menstrual cycle

Hippocampal volume has been shown to be sensitive to variations in estrogen and progesterone levels across rodents' estrous cycle. However, little is known about the covariation of hormone levels and brain structure in the course of the human menstrual cycle. Here, we examine this covariation with a multi-method approach that includes several brain imaging methods and hormonal assessments. We acquired structural and functional scans from 21 naturally cycling women on four time points during their cycles (early follicular phase, late follicular phase, ovulation and luteal phase). Hormone blood concentrations and cognitive performance in different domains were assessed on each of the measurement occasions. Structural MRI images were processed by means of whole-brain voxel-based morphometry and FreeSurfer. With either method, bilateral increases in hippocampal volume were found in the late follicular phase relative to the early follicular phase. The gray matter probability in regions of hippocampal volume increase was associated with lower mean diffusivity in the same region. In addition, we observed higher functional connectivity between the hippocampi and the bilateral superior parietal lobe in the late follicular phase. We did not find any reliable cycle-related performance variations on the cognitive tasks. The present results show that hormonal fluctuations covary with hippocampal structure and function in the course of the human menstrual cycle.

Progesterone and mental rotation task: is there any effect?

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

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

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

Sex hormones and mental rotation: an intensive longitudinal investigation

The present study used an intensive longitudinal design to examine whether mental rotation performance varies according to a monthly cycle in both males and females and whether these variations are related to variations in progesterone, estradiol, and testosterone levels. We collected reaction time and accuracy data for 10 males and seven females each workday over eight weeks using 136 pairs of mental rotation stimuli/day, and measured sexual hormones concentrations in the saliva twice a week. A mixed linear model statistical analysis revealed that all females and seven males showed significant cycle effects in mental rotation performance. The female cycle showed an amplitude that was twice as large compared with the amplitude found in males. For males and females, estradiol and testosterone were significantly linearly and quadratically related to interindividual variation in performance at the beginning of the study (progesterone was linearly related to performance for females). The association between testosterone and performance differed across sexes: for males, it had an inverse U-shape, for females it was U-shaped. Towards the end of the study, none of the hormones were significantly related to performance anymore. Thus, the relationship between hormones and mental rotation performance disappeared with repeated testing. Only estradiol levels were significantly elevated at the lowest point of the cycle in mental rotation performance in females. In conclusion, in this intensive longitudinal study spanning two months, a monthly cycle in mental rotation performance was found among both males and females, with a larger cycle's amplitude for females.

Evolution and the hormonal control of sexually-dimorphic spatial abilities in humans

A number of hypotheses have been proposed for the evolution of sex differences in spatial ability. Two of these hypotheses assume a sex-based division of labor in foraging during human evolutionary history, three propose sexual selection for spatial ability, and two suggest that human life history has imposed sex-specific selection on spatial abilities. We derive predictions from each of these models and test the predictions against recent data on the effects of hormones on spatial ability across the lifespan. Sexual selection for increased range size in males might be the evolutionary origin of the enhancing effects of testosterone on spatial ability, while the benefits of reduced mobility in women at different stages of reproduction could be the origin of the inhibitory effects of oestrogen on spatial ability.

Sex Differences in Competition-Based Attentional Selection

Recent studies on attentional selection demonstrate that women are more influenced by irrelevant spatial cues or distracters than men. Two possible sources can be assumed to determine this alteration in information processing. Women might suffer from deficient top-down control, which makes attentional filters less efficient. On the other hand, higher integration of information presented in close temporal relationship might mimic a deficit in spatial cueing tasks. The latter should be restricted to conditions in which contradicting information is processed. In the present study, participants had to detect changes in luminance and to ignore orientation changes of stimuli that were presented in the fast succession of two visual frames. Women committed more errors when luminance and orientation changes were presented simultaneously at distinct spatial locations (perceptual conflict) compared to men. In no other condition a difference in performance between women and men was observed. Also sensory components of the electroencephalogram showed no sex differences at all. Only posterior components related to intentional allocation of attention in conflict trials appear to be altered in women compared to men. An enhanced N2pc was evoked in women when the perceptual conflict was high. The data provide evidence that neither very early sensory processing nor the top-down control in general is deficient in women. Enhanced distractibility rather arises from a stronger integration of information, which might be due to enhanced interhemispheric information integration in women compared to men.

Two- vs. three-dimensional presentation of mental rotation tasks: Sex differences and effects of training on performance and brain activation

The well-documented sex difference in mental rotation favoring males has been shown to emerge only for 2-dimensional presentations of 3-dimensional objects, but not with actual 3-dimensional objects or with virtual reality presentations of 3-dimensional objects. Training studies using computer games with mental rotation-related content have demonstrated training effects on mental rotation performance. Here, we studied the combined effect of a two-week mental rotation (MR) training on 2-dimensional vs. 3-dimensional presentations of a classic Shepard–Metzler task (presented in a pretest–training–posttest design) and their accompanying cortical activation patterns assessed via EEG in a sample of 38 male and 39 female adolescents of about 15 years of age. Analysis of one performance parameter (reaction times) displayed only main effects of dimensionality (with shorter RTs on the 3D vs. 2D version of the MR task) and of training (significant shortening of RTs), but no significant sex difference. Analysis of the other performance parameter (scores) in the MR task revealed a sex difference favoring males that first, appeared only in the 2D version, but not in the 3D version of the MR task and, secondly, diminished after training. Neurophysiologically we observed a complex sex × dimensionality × training × hemisphere interaction showing that the hypothesized decrease of brain activation (increase in neural efficiency) with training emerged for males in both 2D and 3D conditions, whereas for females this decrease was found only in the 3D but not with the 2D version of the MR task.

Empathy, schizotypy, and visuospatial transformations

INTRODUCTION

Adopting another person's visuospatial perspective has been associated with empathy, which involves adopting the psychological perspective of another individual. Both reduced empathy and abnormal visuospatial processing have been observed in those with schizophrenia and schizophrenia-related personality traits. In the current study, we sought to explore the relationship between empathy, schizotypy, and visuospatial transformation ability.

METHODS

32 subjects (16 women) performed a visuospatial perspective-taking task and a mental letter rotation task. Response times and accuracy were analysed in relation to dimensions of self-reported empathy, indexed using the Interpersonal Reactivity Index, and schizotypy, as measured by the Schizotypal Personality Questionnaire.

RESULTS

We found that: (1) greater cognitive and affective empathy were associated with reduced negative schizotypy, and, in men, greater cognitive empathy was associated with reduced positive schizotypy; (2) improved accuracy for imagined self-other transformations in the perspective-taking task was associated with greater self-reported cognitive empathy in women and higher positive schizotypy across genders; (3) faster mental letter rotation was associated with reduced cognitive empathy and increased negative schizotypy in women.

CONCLUSIONS

Together, the findings partially support the commonalities in visuospatial transformation ability, empathy, and schizotypy, and posit an interesting link between spatial manipulations of our internal representations and interactions with the physical world.

Sex-based differences in answering strategy and the influence of cross-sex hormones

We investigated whether sex differences in answering strategy occur in normal controls (C). Furthermore, it was tested whether these sex differences were subject to change over time, and whether they were associated with hormonal treatment at time points 2 and 3 in patients with Gender Identity Disorder (GID). Two subtests measuring arithmetic ability were used: arithmetic aptitude (AA) and arithmetic operations (AO). Both the controls (n = 29) and GID patients (n = 33) were tested at baseline (T1), three months (T2) and 12 months (T3) after the start of hormonal treatment in the GID group. A repeated measures analysis of variance showed no differences between C males and females, for T1 and T2. At T3, C males guessed more than C females. At baseline, GID males and C males left an equal number of items unanswered. However, when being retested, C males left fewer items unanswered than GID males. No difference was found between C females and GID females at any time point. Our results suggest that healthy adult males become more confident when they are retested, and seem to adjust their answering strategy accordingly. Moreover, hormonal treatment of healthy adult GID patients born male is associated with a lack of adjustment in answering strategy.

All sex differences in cognitive ability may be explained by an X-Y homologous gene determining degrees of cerebral asymmetry

Male superiority in mathematical ability (along with female superiority in verbal fluency) may reflect the operation of an X-Y homologous gene (the right-shift-factor) influencing the relative rates of development of the cerebral hemispheres. Alleles at the locus on the Y chromosome will be selected at a later mean age than alleles on the X, and only by females.

Still far too sexy a topic

Geary is highly selective in his use of the literature on gender differences. His assumption of consistent female inferiority in mathematics is not necessarily supported by the facts.

Mating, math achievement, and other multiple relationships

Although Geary's partitioning of mathematical abilities into those that are biologically primary and secondary is an advance over most sociobiological theories of cognitive sex differences, it remains untestable and ignores the spatial nature of women's traditional work. An alternative model based on underlying cognitive processes offers other advantages.

How important is spatial ability to mathematics?

This commentary focuses on one of the many issues raised in Geary's target article: the importance of gender differences in spatial ability to gender differences in mathematics. I argue that the evidence for the central role of spatial ability in mathematical ability, or in gender differences in it, is tenuous at best.

Spatial visualization and sex-related differences in mathematical problem solving

Spatial visualization as a key variable in sex-related differences in mathematical problem solving and spatial aspects of geometry is traced to the 1960s. More recent relevant data are presented. The variability debate is traced to the latter part of the nineteenth century and an explanation for it is suggested. An idea is presented for further research to clarify sex-related brain laterality differences in solving spatial problems.

Sexual selection and sex differences in mathematical abilities

The principles of sexual selection were used as an organizing framework for interpreting cross-national patterns of sex differences in mathematical abilities. Cross-national studies suggest that there are no sex differences in biologically primary mathematical abilities, that is, for those mathematical abilities that are found in all cultures as well as in nonhuman primates, and show moderate heritability estimates. Sex differences in several biologically secondary mathematical domains (i.e., those that emerge primarily in school) are found throughout the industrialized world. In particular, males consistently outperform females in the solving of mathematical word problems and geometry. Sexual selection and any associated proximate mechanisms (e.g., sex hormones) influence these sex differences in mathematical performance indirectly. First, sexual selection resulted in greater elaboration in males than in females of the neurocognitive systems that support navigation in three-dimensional space. Knowledge implicit in these systems reflects an understanding of basic Euclidean geometry, and may thus be one source of the male advantage in geometry. Males also use more readily than females these spatial systems in problem-solving situations, which provides them with an advantage in solving word problems and geometry. In addition, sex differences in social styles and interests, which also appear to be related in part to sexual selection, result in sex differences in engagement iii mathematics-related activities, thus further increasing the male advantage in certain mathematical domains. A model that integrates these biological influences with sociocultural influences on the sex differences in mathematical performance is presented in this article.

Cognitive effects of Tamoxifen in pre-menopausal women with breast cancer compared to healthy controls

INTRODUCTION

The selective estrogen receptor modulator, Tamoxifen (TAM), is one of the most frequently prescribed drugs for the treatment of breast cancer; however, its effects on the cognition of users have not been adequately studied. Although TAM is an effective anti-estrogen that blocks tumour growth in the breast, it could also influence the activity of other target estrogen sites, including the brain. The exact nature of this interaction is unknown.

METHODS

A cross-sectional design was used to compare cognitive task performance of two treatment groups: 1) women using TAM for the treatment of early breast cancer (n = 23); and 2) age-matched, healthy women not using TAM (n = 23). All participants were pre-menopausal, and recipients of chemotherapy were excluded from the study.

RESULTS

It was found that TAM users scored significantly worse than controls on tasks of immediate and delayed visual memory, verbal fluency, immediate verbal memory, visuo-spatial ability, and processing speed.

DISCUSSIONS/CONCLUSIONS

Although limited by the lack of baseline data and pre-morbid intelligence measures, the results of this exploratory study suggest that at least in pre-menopausal women, TAM may exert a widespread negative influence on cognitive abilities.

IMPLICATIONS FOR CANCER SURVIVORS

Larger, randomized, prospective trials are required to confirm these results; however, TAM use in pre-menopausal breast cancer may be associated with cognitive difficulties. Knowledge and understanding of these complications will be important for professionals in communicating both the benefits and risks of TAM use in breast cancer survivors.

Music facilitate the neurogenesis, regeneration and repair of neurons

Experience has shown that therapy using music for therapeutic purposes has certain effects on neuropsychiatric disorders (both functional and organic disorders). However, the mechanisms of action underlying music therapy remain unknown, and scientific clarification has not advanced. While that study disproved the Mozart effect, the effects of music on the human body and mind were not disproved. In fact, more scientific studies on music have been conducted in recent years, mainly in the field of neuroscience, and the level of interest among researchers is increasing. The results of past studies have clarified that music influences and affects cranial nerves in humans from fetus to adult. The effects of music at a cellular level have not been clarified, and the mechanisms of action for the effects of music on the brain have not been elucidated. We propose that listening to music facilitates the neurogenesis, the regeneration and repair of cerebral nerves by adjusting the secretion of steroid hormones, ultimately leading to cerebral plasticity. Music affects levels of such steroids as cortisol (C), testosterone (T) and estrogen (E), and we believe that music also affects the receptor genes related to these substances, and related proteins. In the prevention of Alzheimer's disease and dementia, hormone replacement therapy has been shown to be effective, but at the same time, side effects have been documented, and the clinical application of hormone replacement therapy is facing a serious challenge. Conversely, music is noninvasive, and its existence is universal and mundane. Thus, if music can be used in medical care, the application of such a safe and inexpensive therapeutic option is limitless.

Sustained attention is favored by progesterone during early luteal phase and visuo-spatial memory by estrogens during ovulatory phase in young women

Studies examining the influence of the menstrual cycle on cognitive function have been highly contradictory. The maintenance of attention is key to successful information processing, however how it co-vary with other cognitive functions and mood in function of phases of the menstrual cycle is not well know. Therefore, neuropsychological performance of nine healthy women with regular menstrual cycles was assessed during ovulation (OVU), early luteal (EL), late luteal (LL) and menstrual (MEN) phases. Neuropsychological test scores of sustained attention, executive functions, manual coordination, visuo-spatial memory, verbal fluency, spatial ability, anxiety and depression were obtained and submitted to a principal components analysis (PCA). Five eigenvectors that accounted the 68.31% of the total variance were identified. Performance of the sustained attention was grouped in an independent eigenvector (component 1), and the scores on verbal fluency and visuo-spatial memory were grouped together in an eigenvector (component 5), which explained 17.69% and 12.03% of the total variance, respectively. The component 1 (p<0.034) and the component 5 (p<0.003) showed significant variations during the menstrual cycle. Sustained attention showed an increase in the EL phase, when the progesterone is high. Visuo-spatial memory was increased, while that verbal fluency was decreased during the OVU phase, when the estrogens levels are high. These results indicate that sustained attention is favored by early luteal phase progesterone and do not covaried with any other neuropsychological variables studied. The influence of the estrogens on visuo-spatial memory was corroborated, and covaried inversely with verbal fluency.

Effects of menstrual cycle phase and oral contraceptive use on verbal memory

Surgical or pharmacological suppression of ovarian hormones leads to declines in verbal memory, and estrogen treatment reverses these deficits. In the current study, we investigated the effects of menstrual cycle phase and oral contraceptives on verbal memory, as measured by the California Verbal Learning Test, in two groups of premenopausal women - 16 naturally cycling women and 20 current users of estrogen-based oral contraceptives (OCs). Naturally cycling women were assessed twice - once during the early follicular phase (Days 2-4) and once during the midluteal phase (Days 20-22) of the menstrual cycle. OC users were tested on the same cycle days, corresponding to inactive and active pill phases, respectively. We predicted that naturally cycling women would show improved verbal memory during the midluteal phase, when estradiol levels are high, compared with the follicular phase, when estradiol levels are low. We also predicted that OC users, who show no change in endogenous estradiol across the cycle, would show no change in verbal memory. Contrary to predictions, naturally cycling women showed no changes in verbal memory across the cycle, whereas OC users showed enhanced memory during the active pill phase (p<.05). None of the secondary cognitive outcome measures varied with cycle phase or OC use including measures of visuospatial memory, verbal fluency, visuospatial abilities, and attention. Overall, these results suggest that verbal memory performance in premenopausal women varies across the cycle with OC use, but does not vary systematically with changes in endogenous estradiol.

The processing of emotional prosody and semantics in schizophrenia: relationship to gender and IQ

BACKGROUND

Female patients with schizophrenia are less impaired in social life than male patients. Because social impairment in schizophrenia has been found to be associated with deficits in emotion recognition, we examined whether the female advantage in processing emotional prosody and semantics is preserved in schizophrenia.

METHOD

Forty-eight patients (25 males, 23 females) and 46 controls (23 males, 23 females) were assessed using an emotional language task (in which healthy women generally outperform healthy men), consisting of 96 sentences in four conditions: (1) neutral-content/emotional-tone (happy, sad, angry or anxious); (2) neutral-tone/emotional-content; (3) emotional-tone/incongruous emotional-content; and (4) emotional-content/incongruous emotional-tone. Participants had to ignore the emotional-content in the third condition and the emotional-tone in the fourth condition. In addition, participants were assessed with a visuospatial task (in which healthy men typically excel). Correlation coefficients were computed for associations between emotional language data, visuospatial data, IQ measures and patient variables.

RESULTS

Overall, on the emotional language task, patients made more errors than control subjects, and women outperformed men across diagnostic groups. Controlling for IQ revealed a significant effect on task performance in all groups, especially in the incongruent tasks. On the rotation task, healthy men outperformed healthy women, but male patients, female patients and female controls obtained similar scores.

CONCLUSION

The advantage in emotional prosodic and semantic processing in healthy women is preserved in schizophrenia, whereas the male advantage in visuospatial processing is lost. These findings may explain, in part, why social functioning is less compromised in women with schizophrenia than in men.

Testosterone and gonadotropins but not estrogen associated with spatial ability in women suffering from schizophrenia: a double-blind, placebo-controlled study

The aim of this study was to investigate the association between estrogen and spatial ability tasks in women suffering from schizophrenia. For this purpose, a placebo-controlled, double-blind, three-time cross-over study using 17beta-estradiol combined with norethisterone acetate for replacement therapy and as an adjunct to a naturalistic maintenance antipsychotic treatment was carried out over a period of 8 months. Nineteen women (mean age=38.0 years, SD=9.9 years) with schizophrenia hospitalized for the first time or repeatedly were included in the study. Sex hormones - 17beta-estradiol, luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin, testosterone, and dehydroepiandrosterone sulfate - were measured and the patients completed a neuropsychological test in the last two active drug and/or placebo phases. Three different spatial ability tasks - spatial orientation, spatial visualization, and flexibility of closure - were measured by a paper-and-pencil test. No association between estrogen and spatial ability was found; however, in an additional exploratory data analysis, high levels of testosterone, LH, and FSH correlated significantly with performance in the flexibility of closure task. This is the very first study, based on estrogen intervention instead of physiological hormone changes, to examine the association between estrogen and spatial ability in women with schizophrenia.

The effects of sex, sexual orientation, and digit ratio (2D:4D) on mental rotation performance

In spite of the reduced level of experimental control, this large scale study brought some clarity into the relation between mental rotation task (MRT) performance and a number of variables where contradictory associations had previously been reported in the literature. Clear sex differences in MRT were observed for a sample of 134,317 men and 120,783 women, with men outperforming women. There were also MRT differences as a function of sexual orientation: heterosexual men performed better than homosexual men and homosexual women performed better than heterosexual women. Although bisexual men performed better than homosexual men but less well than heterosexual men, no significant differences were observed between bisexual and homosexual women. MRT performance in both men and women peaked in the 20-30 year range, and declined significantly and markedly thereafter. Both men and women showed a significant negative correlation between left and right digit finger ratio and MRT scores, such that individuals with smaller digit ratios (relatively longer ring finger than index finger) performed better than individuals with larger digit ratios.

Functional anatomy of visuo-spatial working memory during mental rotation is influenced by sex, menstrual cycle, and sex steroid hormones

Recent observations indicate that sex and level of steroid hormones may influence cortical networks associated with specific cognitive functions, in particular visuo-spatial abilities. The present study probed the influence of sex, menstrual cycle, and sex steroid hormones on 3D mental rotation and brain function using 3-T fMRI. Twelve healthy women and 12 men were investigated. Menstrual cycle and hormone levels were assessed. The early follicular and midluteal phase of the menstrual cycle were chosen to examine short-term cyclical changes. Parietal and frontal areas were activated during mental rotation in both sexes. Significant differences between men and women were revealed in both phases of menstrual cycle. In men we observed a significant correlation of activation levels with testosterone levels in the left parietal lobe (BA 40). In women, a cycle-dependent correlation pattern was observed for testosterone: brain activation correlated with this male hormone only during the early follicular phase. In both cycle phases females' brain activation was significantly correlated with estradiol in frontal and parietal areas. Our study provides evidence that fMRI-related activity during performance of cognitive tasks varies across sex and phases of the menstrual cycle. The variation might be partly explained by better task performance in men, but our results indicate that further explanations like basic neuronal or neurovascular effects modulated by steroid hormones must be considered. Both estradiol and testosterone levels may influence fMRI signals of cognitive tasks, which should affect selection of subjects for future fMRI studies.

Estradiol and tryptophan depletion interact to modulate cognition in menopausal women

Despite an abundance of data in animals, there is little research in humans regarding how estrogen and serotonin (5-HT) may interact to influence cognition. Through the use of estrogen treatment (ET) and tryptophan depletion (TRP-D) in a within-subject design involving healthy menopausal women, we have manipulated both estrogen and 5-HT in order to evaluate their individual and joint effects. Although neither manipulation influenced visuospatial learning, a significant interaction suggested that estrogen exerted a protective effect on verbal memory, such that TRP-D impaired performance to a greater extent before the administration of ET. In consonance with this finding, ET was associated with a small, but positive mood effect on the day following active TRP-D. In addition, ET significantly improved letter-cued verbal fluency with and without TRP-D. Finally, time since last menstrual period was significantly associated with verbal memory scores, such that longer length of hypogonadism resulted in decreased verbal memory performance. These data support the interaction of estrogen and 5-HT in nonreproductive behavior in humans as well as highlight the role of ovarian steroids in cognition.

Effects of the menstrual cycle on looking preferences for faces in female rhesus monkeys

Fluctuations of ovarian hormones across the menstrual cycle influence a variety of social and cognitive behaviors in primates. For example, female rhesus monkeys exhibit heightened interest for males and increased agonistic interactions with other females during periods of high estrogen levels. In the present study, we hypothesized that females' preference for males during periods of high estrogen levels is also expressed at the level of face perception. We tested four intact females on two face-tasks involving neutral portraits of male and female rhesus monkeys, chimpanzees and humans. In the visual preference task (VP), monkeys had to touch a button to view a face image. The image remained on the screen as long as the button was touched, and the duration of pressing was taken as an index of the monkey's looking time for the face stimulus. In the Face-Delayed Recognition Span Test (Face-DRST), monkeys were rewarded for touching the new face in an increasing number of serially presented faces. Monkeys were tested 5 days a week across one menstrual cycle. Blood was collected every other day for analysis of estradiol and progesterone. Two of the four females were cycling at the time of testing. We did not find an influence of the cycle on Face-DRST, likely due to a floor effect. In the VP however, the two cycling individuals looked longer at conspecific male faces than female faces during the peri-ovulatory period of the cycle. Such effects were absent for human and chimpanzee faces and for the two noncycling subjects. These data suggest that ovarian hormones may influence females' preferences for specific faces, with heightened preference for male faces during the peri-ovulatory period of the cycle. Heightened interest for stimuli of significant reproductive relevance during periods of high conception risk may help guide social and sexual behavior in the rhesus monkey.

Effects of ovarian hormones on cognitive function in nonhuman primates

Several studies have suggested that estrogen benefits verbal memory and lowers the risk of Alzheimer's disease in women, and improves cognitive function in animal models. However, the negative outcome of the Women's Health Initiative Memory Study has challenged the rationale for using estrogen as a protective agent against age-related cognitive decline. In view of the limitations of the Women's Health Initiative Memory Study, it is clear that our understanding of estrogen effects would greatly benefit from further interactions between clinical and basic science. Animal models of menopause can provide crucial information regarding the consequences of estrogen loss and replacement on several systems, including cognition. In this paper, I review the evidence that nonhuman primates, who share numerous cognitive and physiological characteristics with humans, can substantially contribute to our understanding of estrogen influences on the brain and cognition. Studies in young adult females suggest that some aspects of cognition fluctuate with the menstrual cycle, but that ovariectomy and estrogen replacement have only modest effects on cognitive function. In contrast, data in aged, naturally or surgically menopausal monkeys indicate that estrogen modulates a broad range of cognitive domains. Neurobiological data are consistent with the cognitive findings and demonstrate an array of morphological and physiological changes in brain areas important for cognition following ovariectomy and/or estrogen replacement. It is concluded that nonhuman primates, by providing a bridge between rodent and human data, constitute invaluable models to further our understanding of hormonal actions on the brain and cognition and to develop effective hormonal interventions against brain and cognitive aging.

Virtual navigation in humans: the impact of age, sex, and hormones on place learning

Certain cognitive processes, including spatial ability, decline with normal aging. Spatial ability is also a cognitive domain with robust sex differences typically favoring males. However, tests of spatial ability do not seem to measure a homogeneous class of processes. For many, mentally matching rotated three-dimensional images is the gold standard for measuring spatial cognition in humans, while the Morris water task (MWT) is a preferred method in the domain of nonhuman animal research. The MWT is sensitive to hippocampal damage, a structure critical for normal learning and memory and often implicated in age-related cognitive decline. A computerized (virtual) version of the MWT (VMWT) appears to require and engage human hippocampal circuitry, and has proven useful in studying sex differences and testing spatial learning theories. In Experiment 1, we tested participants (20-90 years of age) in the VMWT and compared their performance to that on the Vandenberg Mental Rotation Test. We report an age-related deficit in performance on both tasks. In Experiment 2, we tested young (age 20-39) and elderly (age >60) participants in the VMWT and correlated their performance to the circulating levels of testosterone and cortisol. Our findings indicate that the persistence of male spatial advantage may be related to circulating testosterone, but not cortisol levels, and independent of generalized age-related cognitive decline.

Sex Differences and Individual Differences in Cognitive Performance and Their Relationship to Endogenous Gonadal Hormones and Gonadotropins

Sexually dimorphic cognitive performance in men (n=42) and women (n=42) was related to testosterone, estradiol, progesterone, luteinizing hormone, follicle-stimulating hormone, and sex hormone binding globulin, measured in 10-ml blood samples collected between 0900 and 1030 and, among women, during the follicular phase of the menstrual cycle. Significant sex differences favored men on spatial tasks (Mental Rotation and Judgment of Line Orientation) and on an inhibition task and favored women on a verbal task (category fluency). However, there were no significant relationships between any of the hormones and cognitive performance, suggesting that there are few, if any, consistent, substantial relationships between endogenous, nonfluctuating levels of gonadal hormones or gonadotropins and these cognitive abilities in men or women.