Elizabeth Hampson

Variations in sex-related cognitive abilities across the menstrual cycle ☆

Sex differences in human cognitive and motor skills may in part be due to organizational or activational effects of sex hormones on the brain. In this study, an extensive battery of cognitive and motor tests was administered to normally cycling women at two phases of the menstrual cycle, in order to detect any hormone-mediated changes in performance. Results confirmed changes across the menstrual cycle on a variety of speeded manual and articulatory measures, and on some nonverbal/spatial tests. The results provide qualified support for the hypothesis that the high levels of gonadal steroids provide qualified support for the hypothesis that the high levels of gonadal steroids present at the luteal phase of the cycle may facilitate skills favoring females, but be detrimental to skills favoring males. The implications of these results for research in the area of human sex differences are discussed.

Estrogen-related variations in human spatial and articulatory-motor skills

A group of normally cycling women completed a battery of cognitive and motor tests during menses and during the late follicular phase of the menstrual cycle. Enhanced performance on tests of articulatory and fine motor skills was observed during the late follicular phase, while performance on tests of spatial ability was poorer at that time, compared with performance during menses. Variations in estradiol (E2) levels may be at least partially responsible for these effects.

Reciprocal effects of hormonal fluctuations on human motor and perceptual-spatial skills.

Normal adult women showed systematic performance fluctuations across the menstrual cycle on several motor and perceptual tests that typically yield sex differences in performance. The midluteal phase, characterized by high levels of estradiol and progesterone, was associated with improved performance on tests of speeded motor coordination and impaired performance on a perceptual-spatial test, relative to performance during menses. Variations in gonadal steroid levels may contribute substantially to the sex differences reported in human cognitive and motor skills.

A curvilinear relationship between testosterone and spatial cognition in humans: Possible influence of hand preference

The nature of the relationship, if any, between performance on visuo-spatial tests in humans and circulating testosterone (T) concentrations remains controversial. We investigated possible relationships between salivary T and cortisol (C) concentrations and performance on visuo-spatial and verbal cognitive tests in a sample of healthy young adults. Among right-handers, salivary T was found to be negatively correlated with spatial performance in males, but was positively correlated with a measure of spatial visualization in females. This pattern was not evident in left-handers. Across the entire observed range of T, the relationship between spatial cognition and T was best described by an inverted quadratic function in right-handers, but not in left-handers. A significant difference in spatial accuracy was seen among right-handers tested in early vs. late morning testing sessions, in accordance with the expected diurnal change in circulating T. No significant relationships between salivary C and visuo-spatial performance were found. These results are consistent with prior literature suggesting a curvilinear relationship between spatial performance and circulating T concentrations, with intermediate levels of T being associated with better spatial functioning, but raise the possibility that hand preference may be one factor that moderates the observed relationship.

A Beneficial Effect of Estrogen on Working Memory in Postmenopausal Women Taking Hormone Replacement Therapy

Recent neurophysiological data suggest that the prefrontal cortex (PFC) may be susceptible to modulation by estrogen. In humans, the PFC mediates a number of cognitive processes that contribute to memory function, particularly working memory. The present study examined whether memory tasks that recruit PFC-dependent information processing might exhibit estrogen sensitivity in women. Performance on several memory tasks, including measures of working memory, was evaluated in three groups of postmenopausal women: (1) women who were tested when taking estrogen only (n = 38, M(age) = 55.1 years), (2) women who were tested when taking estrogen and a progestin concurrently (n = 23, M(age) = 55.9 years), and (3) women who were not taking hormone replacement therapy (n = 35, M(age) = 56.0 years). Estrogen users exhibited significantly better performance on a verbal task and on a spatial task, each with a prominent working memory component, but did not differ from nonusers on control tasks involving simple passive recall. These findings are consistent with the hypothesis that estrogen is active within PFC and is capable of influencing functions dependent on this region. The results of this study raise the possibility that estrogen may play a role in maintaining certain frontal lobe functions in women.

Gonadal Hormone Levels and Spatial Learning Performance in the Morris Water Maze in Male and Female Meadow Voles, Microtus pennsylvanicus

The present study examined the relationships between spatial learning and circulating levels of plasma estradiol and testosterone in adult male and female meadow vole, Microtus pennsylvanicus. Meadow voles are induced ovulators and most females that are housed with females or in isolation are in constant diestrus, whereas most females that are housed with males are in constant behavioral estrus. In this study sexually mature, adult male and female meadow voles housed with either females (constant diestrus) or males (constant behavioral estrus) were required to learn the spatial position of a hidden, submerged platform in the Morris water maze. Individual voles were tested using two blocks of four trials twice a day for 3 days for a total of six blocks. Task retention was examined with a probe trial 1 day after the last acquisition trial. Females were divided into two groups based on the median level of plasma estradiol [High Estradiol (15.79 +/- 1.20 pg/ml) and Low Estradiol (6.22 +/- 2.79 pg/ml) Females]. Males were similarly divided on the basis of median plasma testosterone levels [High (2.53 +/- 0.96 ng/ml) and Low Testosterone (0.45 +/- 0.08 ng/ml) Males]. High Estradiol females exhibited significantly longer latencies to reach the hidden platform, indicating poorer acquisition, than did either males (P = 0.025) or Low Estradiol females (for Blocks, 2, 3, 4, and 6, P = 0.037). Male superiority in spatial learning performance was evident only when High Estradiol females were compared to males. There were no significant performance differences between High and Low Testosterone males. There were also no group differences in retention, with all voles displaying significant retention of the spatial task. There was, however, a significant correlation between plasma estradiol levels in females and retention, with higher estradiol levels being associated with poorer retention. These results suggest that levels of estradiol in adult female meadow voles are significantly related to spatial learning, with low levels of estradiol being associated with better spatial learning. There was no evidence that levels of testosterone were related to spatial performance in adult male meadow voles. The results suggest that estradiol may have activational effects on spatial learning in the adult meadow vole and that sex differences in spatial learning are evident only when High Estradiol females are compared to adult males.

Spatial reasoning in children with congenital adrenal hyperplasia due to 21‐hydroxylase deficiency

It has been proposed that exposure of the central nervous system to high concentrations of androgens during sensitive periods in early development may facilitate the ability to process spatial information. Most tests of this proposal have been derived from nonhuman species. To test this hypothesis in humans, we evaluated spatial reasoning in preadolescent children with congenital adrenal hyperplasia (CAH), a condition characterized by elevated androgens during gestation. The Primary Mental Abilities (PMA) Spatial Relations test was administered to 12 children with CAH (7 girls, 5 boys) and 10 unaffected sibling controls (6 girls, 4 boys), ranging in age from 8 to 12 years. Results showed a significant interaction between sex and clinical status. Girls with CAH achieved significantly higher spatial scores than control girls, whereas boys with CAH showed significantly lower spatial scores than control boys. On the PMA Perceptual Speed test, given for comparison, girls with CAH scored significantly lower tha...

Contribution of sex differences in the acute stress response to sex differences in water maze performance in the rat.

Male rats outperform females in spatial tasks, such as the water maze (WM). Female rats are known to have higher basal serum corticosterone (CORT) levels and to manifest a more rapid and stronger CORT response to novel stressors. Sex differences in stress responses to the handling and forced swimming in the WM task might contribute to the sex difference in WM performance. In Experiment 1, naive females were found to be impaired relative to naive males in swimming to a visible platform in a WM pool due to strongly thigmotaxic swimming by females. In Experiment 2, serum CORT, a physiological measure of stress, was highly elevated during and after WM training, with female > male values and strong inverse correlations between CORT and measures of WM performance in females. Familiarization with the WM pool and test procedures by strategies pretraining prior to spatial training reduced or eliminated the sex differences in the stress response and WM performance. In Experiment 3, adrenalectomy to eliminate the stress response eliminated sex differences in WM performance. Taken together, the results suggest that male and female rats may harbor brain circuitry that is equally capable of accurate spatial navigation and memory in the WM but which may be impaired to different degrees by the differential stress responses triggered by WM testing.

Testing the prenatal androgen hypothesis: measuring digit ratios, sexual orientation, and spatial abilities in adults

The present study examined whether the following variables putatively associated with prenatal androgens are inter-related in women: spatial abilities, sexual orientation, and 2nd to 4th finger (digit) length ratio (2D:4D). Participants were 99 healthy premenopausal women tested in the menstrual phase of the ovarian cycle between 0800 and 0930 hr. Women completed the Kinsey scales of sexual orientation, and were either strictly heterosexual (HS; N=79) or not-strictly heterosexual (NHS; N=20). Photocopies of the two hands were collected, and participants completed the revised Vandenberg Mental Rotations test, the Paper Folding test, and a short version of the Guilford-Zimmerman Spatial Orientation Test. Results showed that NHS women exhibited superior spatial ability relative to HS women. No significant difference was found between the HS and NHS women in the 2D:4D digit ratio. There was no association between the digit ratio and spatial performance. These results support an association between increased spatial abilities and heteroflexible sexual orientation, which may possibly be mediated by high prenatal androgens.

SALIVARY TESTOSTERONE LEVELS IN LEFT- AND RIGHT-HANDED ADULTS

It has been proposed that prenatal testosterone (T) may contribute to the development of hand preference and cerebral functional asymmetry in humans. To investigate any persisting association between T and asymmetry in adulthood, left-handed (LH) and right-handed (RH) men and women were administered a hand preference questionnaire and the Fused Dichotic Words Test. Testosterone was measured in samples of saliva. Results showed that LH subjects of both sexes had lower salivary T concentrations than their RH counterparts. Among LH males, subjects with a right-ear advantage in dichotic listening tended to have lower T concentrations than subjects with a left-ear advantage. These results are consistent with the notion that T may be involved in the development of hand preference and cerebral functional asymmetry.