Now you see it, now you don't: Testing environments modulate the association between hippocampal volume and cortisol levels in young and older adults.

TitleNow you see it, now you don't: Testing environments modulate the association between hippocampal volume and cortisol levels in young and older adults.
Publication TypeJournal Article
Year of Publication2014
AuthorsSindi S, Fiocco AJ, Juster R-P, Lord C, Pruessner J, Lupien SJ
JournalHippocampus
Volume24
Issue12
Pagination1623-32
Date Published2014 Dec
ISSN1098-1063
KeywordsAdolescent, Adult, Aged, Aging, Female, Hippocampus, Humans, Hydrocortisone, Magnetic Resonance Imaging, Male, Middle Aged, Organ Size, Saliva, Stress, Psychological, Young Adult
Abstract

The hypothalamic pituitary adrenal axis production of the stress hormone cortisol interacts with the hippocampal formation and impacts memory function. A growing interest is to determine whether hippocampal volume (HV) predicts basal and/or reactive cortisol levels in young and older adults. Recent evidence shows that contextual features in testing environments might be stressful and inadvertently induce a stress response in young and/or older populations. This latter result suggests that variations in testing environments might influence associations between HV and cortisol levels in young and older adults. To this end, we investigated 28 healthy young adults (ages 18-35) and 32 healthy older adults (ages 60-75) in two different environments constructed to be more or less stressful for each age group (Favoring-Young versus Favoring-Old conditions). Cortisol levels were repeatedly assessed in each environment, and young and older participants underwent an anatomical magnetic resonance imaging scan for subsequent assessment of HV. Results in both age groups showed that HV was significantly associated with cortisol levels only in the unfavorable stressful testing conditions specific for each age group. This association was absent when testing environments were designed to decrease stress for each age group. These findings are fundamental in showing that unless the nature of the testing environment is taken into consideration, detected associations between HV and cortisol levels in both young and older populations might be confounded by environmental stress.

DOI10.1002/hipo.22341
Alternate JournalHippocampus
PubMed ID25112535
Grant List77788 / / Canadian Institutes of Health Research / Canada

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