Biomedical subjects

Elizabeth Hampson

Publications and source records attributed to Elizabeth Hampson.

9 recordsLinked to original sources

PubMed2006

A female advantage in the serial production of non-representational learned gestures.

Clinical research has demonstrated a sex difference in the neuroanatomical organization of the limb praxis system. To test for a corresponding sex difference in the functioning of this system, we compared healthy men and women on a gesture production task modeled after those used in apraxia research. In two separate studies, participants were taught to perform nine non-representational gestures in response to computer-generated color cues. After extensive practice with the gestures, the color cues were placed on a timer and presented in randomized sequences at progressively faster speeds. A detailed videotape analysis revealed that women in both studies committed significantly fewer 'praxic' errors than men (i.e., errors that resembled those seen in limb apraxia). This was true during both the untimed practice trials and the speeded trials of the task, despite equivalent numbers of errors between the sexes in the 'non-praxic' (i.e., executory) error categories. Women in both studies also performed the task at significantly faster speeds than men. This finding was not accounted for by a female advantage in extraneous elements of the task, i.e., speed of color processing, associative retrieval, or motor execution. Together, the two studies provide convergent support for a female advantage in the efficiency of forelimb gesture production. They are consistent with emerging evidence of a sex difference in the anatomical organization of the praxis system.

Adolescent↗

PubMed2006

Seasonality, waist-to-hip ratio, and salivary testosterone.

Patterns of seasonal variation in testosterone (T) and T-dependent measures are poorly understood in humans and particularly in women, despite their importance in other animals. We examined seasonal fluctuations in salivary T in women and men, and waist-to-hip ratio (WHR) in women. Participants were 220 women and 127 men from central and West Coast North America. Results showed that T was significantly highest in autumn for both women and men, and that WHR in women closely matched the seasonal variation in T, with high values in the fall and summer. This suggests that T does show a reliable fluctuation over the seasons, which may result in meaningful fluctuations in behavioral, cognitive, and somatic variables associated with T.

Adult↗

PubMed2005

Menstrual cycle effects on perceptual closure mediate changes in performance on a fragmented objects test of implicit memory.

Healthy premenopausal women with regular menstrual cycles were assessed on a fragmented objects test of implicit memory. Testing took place at either the low estrogen (n=17) or the high estrogen (n=16) stages of the menstrual cycle. Concentrations of ovarian hormones were confirmed by saliva assays. Both groups of women exhibited a priming effect, in that primed objects were identified faster and at greater fragmentation than unprimed objects. There was no evidence that high estrogen inhibits perceptual object priming. However, women at the menstrual phase were able to identify both primed and unprimed objects at a more degraded level of fragmentation. Changes in perceptual closure over the menstrual cycle may be the basis for the changes in performance on the fragmented objects test observed in previous studies.

Adult↗

PubMed2005

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.

Adolescent↗

PubMed2004

Strategies and methods for research on sex differences in brain and behavior.

Female and male brains differ. Differences begin early during development due to a combination of genetic and hormonal events and continue throughout the lifespan of an individual. Although researchers from a myriad of disciplines are beginning to appreciate the importance of considering sex differences in the design and interpretation of their studies, this is an area that is full of potential pitfalls. A female's reproductive status and ovarian cycle have to be taken into account when studying sex differences in health and disease susceptibility, in the pharmacological effects of drugs, and in the study of brain and behavior. To investigate sex differences in brain and behavior there is a logical series of questions that should be answered in a comprehensive investigation of any trait. First, it is important to determine that there is a sex difference in the trait in intact males and females, taking into consideration the reproductive cycle of the female. Then, one must consider whether the sex difference is attributable to the actions of gonadal steroids at the time of testing and/or is sexually differentiated permanently by the action of gonadal steroids during development. To answer these questions requires knowledge of how to assess and/or manipulate the hormonal condition of the subjects in the experiment appropriately. This article describes methods and procedures to assist scientists new to the field in designing and conducting experiments to investigate sex differences in research involving both laboratory animals and humans.

Animals↗

PubMed2004

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.

Adrenalectomy↗

PubMed2002

A sex difference in reliance on vision during manual sequencing tasks.

The manual praxis system is a left-hemisphere based motor programming system that is involved in the selection of hand and arm movements and is particularly important for the control of movements made with minimal external sensory guidance. Few studies have explored the parameters surrounding normal praxic function, but preliminary data suggest that men may rely less heavily on praxic control than women. To further investigate this possibility, we tested healthy individuals on two tasks designed to recruit the praxis system and on a visually-guided control measure. Participants performed each task with vision and without. We hypothesized that, if men are less fully reliant on the praxis system than women, then their performance should be more adversely affected by the removal of vision on tasks that are ostensibly praxic. Consistent with this prediction, we found a significantly larger drop in men's scores than in women's when vision was occluded. Importantly, this pattern was selective to the praxic measures. In contrast, men were no more impaired by the loss of vision than were women on an externally-guided pegboard task. These findings may reflect an anatomical sex difference in the organization of the praxis system within the left cerebral hemisphere.

Adolescent↗

PubMedDate not supplied

Preliminary clinical experience with androgen administration for pre- and postmenopausal women with hypoactive sexual desire.

The present study examined effects of testosterone on hypoactive sexual desire in pre- and postmenopausal women (treated) compared with an age-matched reference group (reference). Treated participants received 100 mg of testosterone cypionate in oil injected intramuscularly (i.m.) monthly for 3 months. We measured salivary testosterone and scores on the Sexual Desire Inventory pretreatment and posttreatment. Treated and reference participants' baseline testosterone was equivalent, however, treated participants exhibited higher testosterone levels than did reference participants posttreatment. As expected, treated participants exhibited lower baseline sexual desire than did reference participants and showed a significant increase in sexual desire posttreatment. This research suggests that testosterone may effectively alleviate hypoactive sexual desire, even in women with normal testosterone levels.

Adult↗

PubMedDate not supplied

Waist-to-hip ratio is positively associated with bioavailable testosterone but negatively associated with sexual desire in healthy premenopausal women.

OBJECTIVE: We examined whether high waist-to-hip ratio (WHR) in women is a biomarker for increased testosterone (T) and higher levels of sexual desire. METHODS: Participants were 99 healthy nonobese premenopausal women. Trait levels of mean bioavailable T were estimated from three saliva samples collected at 8:00 am, 9:30 am, and 6:00 pm to 9:00 pm, controlling for phase of the menstrual cycle. Sexual desire was measured with the Sexual Desire Inventory. RESULTS: WHR was positively, although moderately, correlated with bioavailable T. WHR, but not T, was negatively correlated with level of sexual desire. CONCLUSIONS: These results confirm that the positive association between WHR and androgens seen in clinical populations also exists in the general population of healthy adult women. However, the relationship may not be strong enough in healthy women for WHR to serve as a useful biomarker of androgen levels in sexuality studies, especially given its association with other, perhaps negatively valued, morphologic attributes.

Adult↗