title: Cortisol and induced cognitive fatigue: effects on memory activation in healthy males.
abstract: We investigated the relationship between individual differences in acute fatigue and endogenous cortisol changes elicited by the sustained performance of cognitively demanding tasks (fatigue condition). Healthy males provided salivary cortisol measurements and subjective fatigue ratings, and were scanned (functional magnetic resonance imaging) during memory encoding and recognition tasks in fatigue and control conditions. A group of 15 'responders' showed significantly higher cortisol levels in the fatigue condition than 12 'non-responders'. Responders showed higher subjective fatigue and reduced encoding and recognition activation than non-responders in the fatigue condition. An interaction in activation changes in the right hippocampus during encoding reflected decreased activation in responders, but somewhat increased activation in non-responders in the fatigue compared to control condition. Moreover, decreased hippocampal activation in responders was associated with increased subjective fatigue. Findings are consistent with a central role for the hippocampus in differences between responders and non-responders and also implicate the right hippocampus in individual differences in induced cognitive fatigue effects.
authors.affiliation: School for Mental Health and Neuroscience (MHeNS), Department of Psychiatry and Neuropsychology, Maastricht University, The Netherlands. e.b.klaassen@vu.nl
authors.forename: Elissa B
authors.initials: EB
authors.lastname: Klaassen
authors.forename: Renate H M
authors.initials: RH
authors.lastname: de Groot
authors.forename: Elisabeth A T
authors.initials: EA
authors.lastname: Evers
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Nicolson
authors.forename: Dick J
authors.initials: DJ
authors.lastname: Veltman
authors.forename: Jelle
authors.initials: J
authors.lastname: Jolles
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000209:etiology*; D005221:Fatigue / Q000150:complications* / Q000473:pathology*; D006624:Hippocampus / Q000098:blood supply; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D007091:Image Processing, Computer-Assisted; D007206:Individuality; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D012463:Saliva / Q000378:metabolism; D013997:Time Factors
chemical_list: D010100:Oxygen; D006854:Hydrocortisone
keywords: Cortisol; Encoding; Functional MRI; Induced cognitive fatigue; Recognition