اثرات چرخه قاعدگی بر روی بستن ادراکی واسطه تغییرات در عملکرد آزمون اجسام تکه تکه حافظه ضمنی

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.

There is increasing evidence that estrogen modulates neuropsychological functioning in women. Naturalistic studies of cognitive performance across the menstrual cycle and studies of postmenopausal women taking estrogen replacement therapy are two methods used to investigate estrogen effects. Observational studies and randomized controlled trials have shown a favorable effect of estrogen on tests of explicit and implicit memory (e.g., Maki, Rich, & Rosenbaum, 2002; Sherwin & Tulandi, 1996). In contrast, more than a dozen studies have shown that performance on tests of mental rotation and other spatial abilities is decreased at phases of the menstrual cycle characterized by high estrogen and improved at phases of low estrogen (Hampson, 1990; Maki et al., 2002). Thus estrogen’s effects on cognition are complex and multi-faceted. In a recent report, Maki et al. (2002) argued that high levels of ovarian hormones might inhibit perceptual object priming. Women tested in the early follicular phase of the menstrual cycle, when estrogen is low, performed better on a fragmented object identification (FOI) task than did women tested at the midluteal phase, when estrogen is high. This paradoxical finding does not fit with the emerging picture of estrogen’s favorable effects on a variety of memory tasks, nor with performance on a test of conceptual implicit memory reported in the same study (Maki et al., 2002), and suggests that there may be another explanation for the findings. In the present report, we show that changes in performance across the menstrual cycle on a test of implicit memory, the FOI task, may be explained by cycle-related changes in the ability to synthesize visual-perceptual information, i.e., by changes in perceptual closure.