title: Neuroimaging, cognition, light and circadian rhythms.
abstract: In humans, sleep and wakefulness and the associated cognitive processes are regulated through interactions between sleep homeostasis and the circadian system. Chronic disruption of sleep and circadian rhythmicity is common in our society and there is a need for a better understanding of the brain mechanisms regulating sleep, wakefulness and associated cognitive processes. This review summarizes recent investigations which provide first neural correlates of the combined influence of sleep homeostasis and circadian rhythmicity on cognitive brain activity. Markers of interindividual variations in sleep-wake regulation, such as chronotype and polymorphisms in sleep and clock genes, are associated with changes in cognitive brain responses in subcortical and cortical areas in response to manipulations of the sleep-wake cycle. This review also includes recent data showing that cognitive brain activity is regulated by light, which is a powerful modulator of cognition and alertness and also directly impacts sleep and circadian rhythmicity. The effect of light varied with age, psychiatric status, PERIOD3 genotype and changes in sleep homeostasis and circadian phase. These data provide new insights into the contribution of demographic characteristics, the sleep-wake cycle, circadian rhythmicity and light to brain functioning.
authors: Cyclotron Research Centre, University of Liège Liège, Belgium.
authors: Giulia
authors: G
authors: Gaggioni
authors: Cyclotron Research Centre, University of Liège Liège, Belgium.
authors: Pierre
authors: P
authors: Maquet
authors: Cyclotron Research Centre, University of Liège Liège, Belgium ; Centre for Chronobiology, Psychiatric Hospital of the University of Basel Basel, Switzerland.
authors: Christina
authors: C
authors: Schmidt
authors: Surrey Sleep Research Centre, University of Surrey Guildford, UK.
authors: Derk-Jan
authors: DJ
authors: Dijk
authors: Cyclotron Research Centre, University of Liège Liège, Belgium.
authors: Gilles
authors: G
authors: Vandewalle
keywords: circadian; cognition; fMRI; inter-individual differences in sleep-wake regulation; light; non-image-forming; non-visual; sleep