Search

Menopause is associated with cognitive decline, and previous parity can increase or delay the trajectory of cognitive aging. Furthermore, parity enables the hippocampus to respond to estrogens in middle age. The present study investigated how previous parity and estrogens influence cognition, neurogenesis, and neuronal activation in response to memory retrieval in the hippocampus of middle-aged females. Multiparous and nulliparous rats were ovariectomized (OVX) or received sham surgery and were treated with vehicle, 17β-estradiol, 17α-estradiol, or estrone. Rats were trained on the spatial working and reference memory versions of the Morris water maze. Multiparous rats had a significantly greater density of immature neurons in the hippocampus, enhanced acquisition of working memory, but poorer reference memory compared with nulliparous rats. Furthermore, OVX increased, while treatment with estrogens reduced, the density of immature neurons, regardless of parity. OVX improved reference memory only in nulliparous rats. Thus, motherhood has long-lasting effects on the neuroplasticity and function of the hippocampus. These findings have wide-ranging implications for the treatment of age-associated decline in women. [ABSTRACT FROM AUTHOR]

Objectives: Physical activity (PA) and total sleep time (TST) are each associated with cognition; however, whether these relationships vary by age and biological sex is unclear. We examined the relationships of PA or TST with cognition, and whether age and sex moderated these relationships, using baseline data from the Canadian Longitudinal Study on Aging (CLSA; 2010-2015).Study Design: A cross-sectional analysis of participants from the Comprehensive cohort of the CLSA with complete PA and sleep data (n = 20,307; age range 45-86 years).Main Outcome Measures: PA and TST were measured using the Physical Activity Scale for the Elderly (PASE) and self-reported TST over the past month. Cognition was indexed using a three-factor structural equation model (i.e., memory, executive function, and verbal fluency).Results: Non-linear restricted cubic spline models indicated that PA and TST explained statistically significant (p < 0.01) but modest variance of each cognitive domain (<1 % of 23-24 % variance). Age and sex did not moderate associations of PA with any cognitive domain. However, age and sex moderated relationships of TST with cognition, whereby: 1) associations of TST with memory decreased with age for males and females; and 2) males and females had different age-associated relationships of TST with executive function and verbal fluency.Conclusions: PA and TST modestly contribute to multiple domains of cognition across middle and older adulthood. Importantly, the association of PA with cognition does not appear to vary across middle or older adulthood, nor does it vary by biological sex; however, TST appears to have a complex relationship with multiple domains of cognition which is both age- and sex-dependent. [ABSTRACT FROM AUTHOR]

Abstract: Although controversial, estrogen replacement therapy has been implicated as a possible therapeutic agent for ameliorating age-related cognitive decline in postmenopausal women. We have shown previously that different types of estrogen promote hippocampal neurogenesis in a dose-dependent manner in young adult female rats. However, previous studies have not found a beneficial effect of 17β-estradiol in middle-aged female rats. The aim of the present study was to determine the acute effects of 17β-estradiol, 17α-estradiol, and estrone on hippocampal cell proliferation in middle-aged ovariectomized female rats and to determine whether effects are dependent on previous reproductive experience. Middle-aged multiparous female rats or age-matched virgin female rats were injected subcutaneously with vehicle or 10μg dose of 17β-estradiol, 17α-estradiol, or estrone, and then given BrdU 30min later and perfused 24h later to assess cell proliferation. All estrogens significantly upregulated cell proliferation in the hippocampus in middle-aged multiparous females but none of the estrogens upregulated cell proliferation in the middle-aged virgins. Therefore, previous reproductive experience may make the older brain more responsive to estrogens later in life. We also found that 17α-estradiol upregulated cell proliferation to a greater degree than the other estrogens in the multiparous females. Together these findings may lead to the development of new therapeutic advances in the treatment of symptoms associated with menopause in women. [Copyright &y& Elsevier]