Hair cortisol concentrations are associated with hippocampal subregional volumes in children

Attila Keresztes,Laurel Raffington,Katharina Bögl,Yee Lee Shing,Andrew R Bender,Christine Heim

doi:10.1038/s41598-020-61131-x

Abstract

The human hippocampus, a brain structure crucial for memory across the lifespan, is highly sensitive to adverse life events. Stress exposures during childhood have been linked to altered hippocampal structure and memory performance in adulthood. Animal studies suggest that these differences are in part driven by aberrant glucocorticoid secretion during development, with strongest effects on the CA3 region and the dentate gyrus (CA3-DG) of the hippocampus, alongside associated memory impairments. However, only few pediatric studies have examined glucocorticoid associations with hippocampal subfield volumes and their functional relevance. In 84 children (age range: 6–7 years), we assessed whether volumes of hippocampal subregions were related to cumulative glucocorticoid levels (hair cortisol), parenting stress, and performance on memory tasks known to engage the hippocampus. We found that higher hair cortisol levels were specifically related to lower CA3-DG volume. Parenting stress did not significantly correlate with hair cortisol, and there was no evidence to suggest that individual differences in hippocampal subregional volumes manifest in memory performance. Our results suggest that the CA3-DG may be the hippocampal region most closely associated with hair cortisol levels in childhood. Establishing causal pathways underlying this association and its relation to environmental stress and memory development necessitates longitudinal studies.

Highlights

The human hippocampus, a brain structure crucial for memory across the lifespan, is highly sensitive to adverse life events
It is plausible that there were significant covariances among the residual variances of the indicators that were not specified. Because of their close anatomical relationship, this was likely for hippocampal subregions in the same hemisphere
We allowed the residual variances of subiculum, CA1-2, and CA3 region and the dentate gyrus (CA3-DG) within each hemisphere to be correlated

Summary

Introduction

The human hippocampus, a brain structure crucial for memory across the lifespan, is highly sensitive to adverse life events. The hippocampus, a bilateral brain structure in the medial temporal lobes, is crucial for learning and memory in humans[1] It supports recalling highly specific details of events in our lives[2,3], constructing memories[4], associative or relational binding of information, and extracting knowledge from repeated experiences through generalization[5,6]. Extremely high glucocorticoid concentrations can directly result in neuronal damage, as evidenced by reductions in cell numbers and dendritic arborization[54,55,57], with glucocorticoid-induced dendritic atrophy in the CA3 observed in rodents[58] suggested as a potential mechanism in humans[34] These effects can, in addition, underlie observations of stress-induced decreases in neurogenesis[59]

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Conclusion