Estrogens dynamically regulate neurogenesis in the dentate gyrus of adult female rats.

Estrone and estradiol differentially modulate neuroplasticity and cognition. How they influence the maturation of new neurons in the adult hippocampus, however, is not known. The present study assessed the effects of estrone and estradiol on the maturation timeline of neurogenesis in the dentate gyrus (DG) of ovariectomized (a model of surgical menopause) young adult Sprague-Dawley rats using daily subcutaneous injections of 17β-estradiol, estrone or vehicle.

High estradiol reduces adult neurogenesis but strengthens functional connectivity within the hippocampus during spatial pattern separation in adult female rats.

Adult neurogenesis in the dentate gyrus plays an important role for pattern separation, the process of separating similar inputs and forming distinct neural representations. Estradiol modulates neurogenesis and hippocampus function, but to date no examination of estradiol's effects on pattern separation have been conducted. Here, we examined estrogenic regulation of adult neurogenesis and functional connectivity in the hippocampus after the spatial pattern separation task in female rats.

Sex differences in contextual pattern separation, neurogenesis, and functional connectivity within the limbic system.

Background: Females are more likely to present with anxiety disorders such as post-traumatic stress disorder (PTSD) compared to males, which are associated with disrupted hippocampal integrity. Sex differences in the structure and function of hippocampus exist. Here, we examined sex differences in contextual pattern separation, functional connectivity, and activation of new neurons during fear memory.

Sex Differences in Cognition Across Aging.

Sex and gender differences are seen in cognitive disturbances in a variety of neurological and psychiatry diseases. Men are more likely to have cognitive symptoms in schizophrenia whereas women are more likely to have more severe cognitive symptoms with major depressive disorder and Alzheimer's disease. Thus, it is important to understand sex and gender differences in underlying cognitive abilities with and without disease.

Risk-based decision making in rats: Modulation by sex and amphetamine.

Decision-making is a complex process essential to daily adaptation in many species. Risk is an inherent aspect of decision-making and it is influenced by gonadal hormones. Testosterone and 17β-estradiol may modulate decision making and impact the mesocorticolimbic dopamine pathway.

Sex Differences in Maturation and Attrition of Adult Neurogenesis in the Hippocampus.

Sex differences exist in the regulation of adult neurogenesis in the hippocampus in response to hormones and cognitive training. Here, we investigated the trajectory and maturation rate of adult-born neurons in the dentate gyrus (DG) of male and female rats. Sprague Dawley rats were perfused 2 h, 24 h, one week (1w), 2w, or 3w after bromodeoxyuridine (BrdU) injection, a DNA synthesis marker that labels dividing progenitor cells and their progeny.

Effects of aging, high-fat diet, and testosterone treatment on neural and metabolic outcomes in male brown Norway rats.

Risk for Alzheimer's disease (AD) is affected by multiple factors, including aging, obesity, and low testosterone. We previously showed that obesity and low testosterone independently and interactively exacerbate AD-related outcomes in young adult rodents. The goals of the present study are two-fold: to examine whether the effects of an obesogenic diet differ with increasing age and to determine if testosterone treatment in middle-aged and aged animals mitigates negative effects of the diet.

Sex differences in hippocampal cognition and neurogenesis.

Sex differences are reported in hippocampal plasticity, cognition, and in a number of disorders that target the integrity of the hippocampus. For example, meta-analyses reveal that males outperform females on hippocampus-dependent tasks in rodents and in humans, furthermore women are more likely to experience greater cognitive decline in Alzheimer's disease and depression, both diseases characterized by hippocampal dysfunction. The hippocampus is a highly plastic structure, important for processing higher order information and is sensitive to the environmental factors such as stress.

Sex and estrous cycle differences in immediate early gene activation in the hippocampus and the dorsal striatum after the cue competition task.

The hippocampus and dorsal striatum are important structures involved in place and response learning strategies respectively. Both sex and estrous cycle phase differences in learning strategy preference exist following cue competition paradigms. Furthermore, significant effects of sex and learning strategy on hippocampal neural plasticity have been reported.

Sex and strategy use matters for pattern separation, adult neurogenesis, and immediate early gene expression in the hippocampus.

Adult neurogenesis in the dentate gyrus (DG) plays a crucial role for pattern separation, and there are sex differences in the regulation of neurogenesis. Although sex differences, favoring males, in spatial navigation have been reported, it is not known whether there are sex differences in pattern separation. The current study was designed to determine whether there are sex differences in the ability for separating similar or distinct patterns, learning strategy choice, adult neurogenesis, and immediate early gene (IEG) expression in the DG in response to pattern separation training.

Hippocampal learning, memory, and neurogenesis: Effects of sex and estrogens across the lifespan in adults.

This article is part of a Special Issue "Estradiol and Cognition". There are sex differences in hippocampus-dependent cognition and neurogenesis suggesting that sex hormones are involved. Estrogens modulate certain forms of spatial and contextual memory and neurogenesis in the adult female rodent, and to a lesser extent male, hippocampus.