Influence of postnatal glucocorticoids on hippocampal-dependent learning varies with elevation patterns and administration methods
Wright State University Dayton United States
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Recent interest in the lasting effects of early-life stress has expanded to include effects on cognitive performance. An increase in circulating glucocorticoids is induced by stress exposure and glucocorticoid effects on the hippocampus likely underlie many of the cognitive consequences. Here we review studies showing that corticosterone administered to young rats at the conclusion of the stress hyporesponsiveness period affects later performance in hippocampally-mediated trace eye blink conditioning. The nature and even direction of these effects varies with the elevation patterns level, duration, temporal fluctuation achieved by different administration methods. In general, constant glucocorticoid elevations resulted in hippocampus-mediated learning deficits, whereas acute, cyclical elevations result in improved initial acquisition. Sensitivity was greater for males than for females. Further, changes in hippocampal neurogenesis paralleled some but not all effects. The findings demonstrate that specific patterns of glucocorticoid elevation produced by different drug administration procedures can have markedly different, sex-specific consequences on basic cognitive performance and underlying hippocampal physiology. Implications of these findings for glucocorticoid medications prescribed in childhood are discussed.
- Medicine and Medical Research
- Stress Physiology