Influence of postnatal glucocorticoids on hippocampal-dependent learning varies with elevation patterns and administration methods

Abstract

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 eyeblink conditioning. The nature and even direction of these effects varies with the elevation patterns (level, duration, temporal fluctuation) achieved by different administration methods. We present new time course data indicating that constant glucocorticoid elevations generally corresponded with hippocampus-mediated learning deficits, whereas acute, cyclical elevations corresponded with 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.

Investigating the effects of cerebellar transcranial direct current stimulation on saccadic adaptation and cortisol response

“…Trace conditioning, a cerebellar dependent process [ 10 ], has been shown to be impaired in only one study with Cushing’s syndrome patients [ 19 ]. However, similar conditioning impairments in conditioning results have been found following cortisol manipulations in rats [ 11 ]. Finally, numerous imaging studies show cerebellar activations during processing of emotional content [ 56 ].…”

Animal Models for Functional Gastrointestinal Disorders

“…Moreover, the regulation of the hypothalamic expression of the arginine vasopressin gene - that occurs at very early stages ( 61 )—which is involved in the ACTH stress response in young rats has a key role for the control of ACTH release from the pituitary ( 62 ). Furthermore, it is also the most critical period in the development of central structures such as the amygdala ( 63 ) and hippocampus ( 64 ). In those two structures, neurodevelopment is very active with neurogenesis, cell differentiation, and migration ( 65 ).…”

Glucocorticoid‐mediated mechanisms of hippocampal damage: Contribution of subgranular neurogenesis

“…Despite male–female differences in the HPA axis activity, higher levels of GCs and elevated stress responses in female rats, both sexes exhibited similar stress‐induced alterations in AHN (Hulshof et al., 2012). As a rule, constant GCs elevations correspond with hippocampus‐dependent learning deficits, while acute or cyclic GC rises are associated with an improved initial acquisition, the sensitivity being greater for males than for female rats (Claflin et al., 2017). Importantly, changes in the AHN paralleled some but not all effects.…”