Markus Hausmann

Sex hormones affect spatial abilities during the menstrual cycle

The aim of this study was (a) to show that different measures of spatial cognition are modulated by the menstrual cycle and (b) to analyze which steroid is responsible for these cognitive alterations. The authors collected blood samples in 3-day intervals over 6 weeks from 12 young women with a regular menstrual cycle to analyze concentrations of estradiol, progesterone, testosterone, luteinizing hormone, and follicle-stimulating hormone. The performance on 3 spatial tests was measured during the menstrual and the midluteal phases. A significant cycle difference in spatial ability as tested by the Mental Rotation Test was found, with high scores during the menstrual phase and low scores during the midluteal phase. Testosterone had a strong and positive influence on mental rotation performance, whereas estradiol had a negative one. These results clearly indicate that testosterone and estradiol are able to modulate spatial cognition during the menstrual cycle.

Sex Differences and the Impact of Steroid Hormones on the Developing Human Brain

Little is known about the hormonal effects of puberty on the anatomy of the developing human brain. In a voxel-based morphometry study, sex-related differences in gray matter (GM) volume were examined in 46 subjects aged 8-15 years. Males had larger GM volumes in the left amygdala, whereas females had larger right striatal and bilateral hippocampal GM volumes than males. Sexually dimorphic areas were related to Tanner stages (TS) of pubertal development and to circulating level of steroid hormones in a subsample of 30 subjects. Regardless of sex, amygdala and hippocampal volumes varied as a function of TS and were associated with circulating testosterone (TEST) levels. By contrast, striatal GM volumes were unrelated to pubertal development and circulating steroid hormones. Whole-brain regression analyses revealed positive associations between circulating estrogen levels and parahippocampal GM volumes as well as between TEST levels and diencephalic brain structures. In addition, a negative association was found between circulating TEST and left parietal GM volumes. These data suggest that GM development in certain brain regions is associated with sexual maturation and that pubertal hormones might have organizational effects on the developing human brain.

Steroid fluctuations modify functional cerebral asymmetries: the hypothesis of progesterone-mediated interhemispheric decoupling

This study examines the modulation of functional cerebral asymmetries by gonadal hormones in three distinct groups. Young, normally cycling women performed a prototypical left (lexical decision) and two prototypical right-hemispheric tasks (figural comparison and face discrimination) during the low steroid menses and the high steroid midluteal phase. Saliva progesterone levels were measured with radioimmunoassay (RIA). Parallel to younger females, young men, and postmenopausal women were tested at matching time intervals. Results revealed significant interactions between cycle phase and visual half-field in the accuracy of all three tasks for the younger women; stronger lateralization patterns occurring during menses, while a more bilateral or at least less asymmetric cerebral organization predominated the midluteal phase, when highest levels of progesterone appear. Progesterone seemed to have a significant influence on lateralization in the figural comparison task, with high hormone levels enhancing the performance of the left hemisphere (for this task subdominant), thereby decreasing asymmetry. After menopause, when the levels of gonadal hormones are lower and more stable, the lateralization patterns for all three tasks were similar to those of men and normally cycling women during menses. These results make it likely that steroids and especially progesterone are able to reduce cerebral asymmetries. We hypothesize that progesterone attenuates the effect of glutamate on non-NMDA receptors. This could diminish cortico-cortical transmission which is mostly dependent on a glutamate-induced initial EPSP in pyramidal neurons which receive transcallosal input. The reduction in callosal transfer could then suppress the functional asymmetries.

Functional cerebral asymmetries during the menstrual cycle: a cross-sectional and longitudinal analysis

This study aims at answering two basic questions regarding the mechanisms with which hormones modulate functional cerebral asymmetries. Which steroids or gonadotropins fluctuating during the menstrual cycle affect perceptual asymmetries? Can these effects be demonstrated in a cross-sectional (follicular and midluteal cycle phases analyzed) and a longitudinal design, in which the continuous hormone and asymmetry fluctuations were measured over a time course of 6 weeks? To answer these questions, 12 spontaneously cycling right-handed women participated in an experiment in which their levels of progesterone, estradiol, testosterone, LH, and FSH were assessed every 3 days by blood-sample based radioimmunoassays (RIAs). At the same points in time their asymmetries were analyzed with visual half-field (VHF) techniques using a lexical decision, a figure recognition, and a face discrimination task. Both cross-sectional and longitudinal analyzes showed that an increase of progesterone is related to a reduction in asymmetries in a figure recognition task by increasing the performance of the left-hemisphere which is less specialized for this task. Cross-sectionally, estradiol was shown to have significant relationships to the accuracy and the response speed of both hemispheres. However, since these effects were in the same direction, asymmetry was not affected. This was not the case in the longitudinal design, where estradiol affected the asymmetry in the lexical decision and the figural comparison task. Overall, these data show that hormonal fluctuations within the menstrual cycle have important impacts on functional cerebral asymmetries. The effect of progesterone was highly reliable and could be shown in both analysis schemes. By contrast, estradiol mainly, but not exclusively, affected both hemispheres in the same direction.

Hemispheric asymmetry in spatial attention across the menstrual cycle

Functional cerebral asymmetries (FCAs) are known to fluctuate across the menstrual cycle. The mechanisms of these sex hormonal modulations are poorly understood. It has been suggested that gonadal steroid hormones might suppress or specifically activate one hemisphere. However, recent studies suggest that high levels of gonadal steroid hormones reduce FCAs by its modulating effects on cortico-cortical transmission. To investigate the activating effects of gonadal steroid hormones on the interhemispheric interaction, a visual line-bisection task was administered to normally cycling women during menses and the midluteal cycle phase as well as to similar-aged healthy men. The results replicate previous findings of a sex difference in line-bisection as a function of hand-use and show that the hand-use effect fluctuates across the menstrual cycle. High levels of estradiol during the midluteal phase were related to a decrease of the hand-use effect. It is concluded that cycle-related fluctuations in levels of gonadal steroid hormones affect hemispheric asymmetry of spatial attention, presumably by interhemispheric spreading of neuronal activation.

Estradiol Modulates Functional Brain Organization during the Menstrual Cycle: An Analysis of Interhemispheric Inhibition

According to the hypothesis of progesterone-mediated interhemispheric decoupling (Hausmann and Güntürkün, 2000), functional cerebral asymmetries (FCAs), which are stable in men and change during the menstrual cycle in women, are generated by interhemispheric inhibition of the dominant on the nondominant hemisphere. The change of lateralization during the menstrual cycle in women might indicate that sex hormones play an important role in modulating FCAs. We used functional magnetic resonance imaging to examine the role of estradiol in determining cyclic changes of interhemispheric inhibition. Women performed a word-matching task, while they were scanned twice during the cycle, once during the menstrual and once during the follicular phase. By use of a connectivity analysis we found that the inhibitory influence of left-hemispheric language areas on homotopic areas of the right hemisphere is strongest during the menses, resulting in a pronounced lateralization. During the follicular phase, due to rising estradiol levels, inhibition and thus functional cerebral asymmetries are reduced. These results reveal a powerful neuromodulatory action of estradiol on the dynamics of functional brain organization in the female brain. They may further contribute to the ongoing discussion of sex differences in brain function in that they help explain the dynamic part of functional brain organization in which the female differs from the male brain.

Migraine and cognitive function A life-course study

Objective To investigate the association between migraine and cognitive ability among members of a longitudinal birth cohort study. MethodsHeadache status was determined at age 26 (migraine, tension-type headache [TTH], headache-free control subjects) according to International Headache Society criteria, and data relating to cognitive and academic performance from ages 3 to 26 years were analyzed. ResultsStudy members diagnosed with migraine were subtly but significantly impaired, compared with those with TTH and headache-free control subjects, on tests of verbal ability (especially language reception) from ages 3 to 13, independent of headache history. Performance on other tasks, including reading, arithmetic, motor, and spatial ability, was normal. The association between migraine and verbal functioning also appeared to impact on later academic success. ConclusionFindings suggest that the poorer verbal performance was unlikely to have resulted from cumulative attacks and may be due to developmental factors beginning in utero.

Interactive effects of sex hormones and gender stereotypes on cognitive sex differences—A psychobiosocial approach.

Biological and social factors have been shown to affect cognitive sex differences. For example, several studies have found that sex hormones have activating effects on sex-sensitive tasks. On the other hand, it has been shown that gender stereotypes can influence the cognitive performance of (gender-) stereotyped individuals. However, few studies have investigated the combined effects of both factors. The present study investigated the interaction between sex hormones and gender stereotypes within a psychobiosocial approach. One hundred and fourteen participants (59 women) performed a battery of sex-sensitive cognitive tasks, including mental rotation, verbal fluency, and perceptual speed. Saliva samples were taken immediately after cognitive testing. Levels of testosterone (T) were analysed using chemiluminescence immunoassay (LIA). To activate gender stereotypes, a questionnaire was applied to the experimental group that referred to the cognitive tasks used. The control group received an identical questionnaire but with a gender-neutral content. As expected, significant sex differences favouring males and females appeared for mental rotation and verbal fluency tasks, respectively. The results revealed no sex difference in perceptual speed. The male superiority in the Revised Vandenberg and Kuse Mental Rotations Tests (MRT-3D) was mainly driven by the stereotype-active group. No significant sex difference in MRT-3D appeared in the control group. The MRT-3D was also the task in which a strong gender-stereotype favouring males was present for both males and females. Interestingly, T levels of the stereotype-activated group were 60% higher than that of male controls. The results suggest that sex hormones mediate the effects of gender stereotypes on specific cognitive abilities.

Developmental changes in line bisection: a result of callosal maturation?

Normal adults tend to bisect horizontal lines to the left of the objective middle, especially when using the left hand. This bias has been attributed to the dominance of the right hemisphere in spatial attention. The authors investigated the effect of hand use and line position in visual line bisection in right-handed children and adults, classified into 4 different age groups: 10-12, 13-15, 18-21, and 24-53 years (N = 98). All 4 groups showed the characteristic leftward bias when using the left hand. When using the right hand, the youngest group showed a rightward bias, whereas the other 3 groups all showed a leftward bias. This suggests a shift from contralateral to right-hemispheric control during puberty and may reflect maturation of the corpus callosum.

Transcallosal inhibition across the menstrual cycle: A TMS study

OBJECTIVE To determine if there are steroid-dependent changes in transcallosal transfer during the menstrual cycle in normal women. METHODS We tested 13 normally cycling women during the menstrual, follicular and midluteal phases. Blood levels of estradiol (E) and progesterone (P) were determined by radioimmunoassay. Ipsilateral tonic voluntary muscle activity suppression, called ipsilateral silent period (iSP), was evoked by applying transcranial magnetic stimulation (TMS) over the left motor cortex and by measuring the EMG of the ipsilateral first dorsal interosseus (FDI) muscle. Both iSP-duration and transcallosal conduction times were measured and related to cycle phase and steroid levels. RESULTS Duration of iSPs varied over the cycle with largest differences between follicular and midluteal phases. During the midluteal phase high levels of P were significantly related to short iSPs. This relation also applied to E levels and iSPs during the follicular phase. CONCLUSIONS Our study shows for the first time that the transcallosal transfer is modulated by E and P and changes over the menstrual cycle. SIGNIFICANCE It is suggested that gonadal steroid hormones affect the interhemispheric interaction and change the functional cerebral organization sex dependently via its neuromodulatory properties on GABAergic and glutamatergic neurons.