Citation

Virginie G, Micheline M, Richert CF, Sarah L C, Christina S, Vanja H, Christian C, Antoine U V. Behav. Brain Res. 2014; 281: 258-266.

Affiliation

Centre for Chronobiology, Psychiatric Hospital of the University of Basel, 4012 Basel, Switzerland.

Copyright

(Copyright © 2014, Elsevier Publishing)

DOI

10.1016/j.bbr.2014.12.043

PMID

25549858

Abstract

Chronic sleep restriction (SR) has deleterious effects on cognitive performance that can be counteracted by light exposure. However, it is still unknown if naturalistic light settings (dawn simulating light) can enhance daytime cognitive performance in a sustainable matter. Seventeen participants were enrolled in a 24-h balanced cross-over study, subsequent to SR (6-h of sleep). Two different light settings were administered each morning: a) dawn simulating light (DsL; polychromatic light gradually increasing from 0 to 250 lux during 30minutes before wake-up time, with light around 250 lux for 20minutes after wake-up time) and b) control dim light (DL; <8 lux). Cognitive tests were performed every two hours during scheduled wakefulness and questionnaires were completed hourly to assess subjective mood. The analyses yielded a main effect of "light condition" for the motor tracking task, sustained attention to response task and a working memory task (visual 1 and 3-back task), as well as for the Simple Reaction Time Task, such that participants showed better task performance throughout the day after morning DsL exposure compared to DL. Furthermore, low performers benefited more from the light effects compared to high performers. Conversely, no significant influences from the DsL were found for the Psychomotor Vigilance Task and a contrary effect was observed for the digit symbol substitution test. No light effects were observed for subjective perception of sleepiness, mental effort, concentration and motivation. Our data indicate that short exposure to artificial morning light may significantly enhance cognitive performance in a domain-specific manner under conditions of mild SR.

Language: en