Neuroscience
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Gestation is a time of profound vulnerability, as insults during pregnancy increase the lifelong risk of morbidity for the offspring. Increasingly, maternal diet is recognized as a key factor influencing the developing fetus. Poor-quality maternal diets, whether they provide an excess or an insufficiency of nutrients, lead to overt gestational growth disturbances in the offspring, and elevated risk for a common cluster of metabolic and mental disorders. ⋯ In contrast, offspring of maternal high-fat and low-protein diets mounted essentially no gene expression response to either stressor. However, male and female offspring of all conditions showed elevated hypothalamic-pituitary-adrenal glucocorticoid responses to both stressors, though the recovery of corticosterone responses after stress termination was significantly impaired in offspring of poor-quality maternal diets. Overall, it appears that the ability of the hypothalamus to respond in the immediate aftermath of stressful experiences is severely impaired in offspring of poor-quality maternal diets, regardless of whether the diet provided insufficient nutrients or excessive nutrients.
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We tested the effect of early-life stress (ELS) - 24h maternal deprivation (MD) at postnatal day (PND) 3 - on cognitive performance and hippocampal structure in 12-17-week-old female rats. Behavioral performance was examined in: the Elevated Plus Maze, as an index for general anxiety; the rodent Iowa gambling test, probing reward-based decision making; and the object recognition and object-in-location task, to assess non-stressful contextual memory performance. We further determined hippocampal dentate gyrus (DG) volume and cell density as well as adult proliferation and neurogenesis rates. ⋯ Lack of structural differences and a behavioral phenotype in non-stressful hippocampus dependent learning tasks fits with the lack of phenotype generally reported after ELS in female but less so in male rodents. As evident from an extensive literature review, female and male animals appear to respond more similarly to early-life adversity when tested in anxiety-related tasks. This agrees with recent findings in humans suggesting that females may be relatively resilient to the structural/hippocampal effects of childhood maltreatment, but not to the anxiety and mood-related psychopathology for which childhood maltreatment is considered a risk factor.