Verslag – Rapport – Bericht – Report - GSKE - FMRE

Characterization of Human Sleep/Wake Regulation using
Multimodal Functional Imaging in Populations Stratified on the
Polymorphism of PERIOD3 Gene
1 Introduction
This year was mainly devoted to analysis of the fMRI study conducted last year in normal
volunteers stratified according to their genotype for PER3 gene and who were submitted to a
42-hour constant routine. Preliminary results are more than encouraging and were submitted
as abstracts to the forecoming SLEEP meeting.
In the course of designing this experiment, we investigated an attentional task, which eventually
turned out not to be adapted to our purposes.
The Attention Network Test (ANT) is deemed to assess the alerting, orientating and executive
components of human attention. Capitalizing on the opportunity to investigate three facets of
attention in a single task, we used functional magnetic resonance imaging (fMRI) to assess
the effect of sleep deprivation (SD) on brain responses associated with the three attentional
components elicited by the ANT. Twelve healthy volunteers were scanned in two conditions 1
week apart, after a normal night of sleep (rested wakefulness, RW) or after one night of total
sleep deprivation. Sleep deprivation was associated with a global increase in reaction times,
which did not affect specifically any of the three attention effects. Brain responses associated
with the alerting effect did not differ between RW and SD. Higher-order attention components
(orientating and conflict effects) were associated with significantly larger thalamic responses
during SD than during RW. These results suggest that SD influences different components of
human attention non-selectively, through mechanisms that might either affect centrencephalic
structures maintaining vigilance or ubiquitously perturb neuronal function. Compensatory
responses can counter these effects transiently by recruiting thalamic responses, thereby
supporting thalamocortical function.
Muto V, Shaffii-le Bourdiec A, Matarazzo L, Foret A, Mascetti L, Jaspar M, Vandewalle G, Phillips
C, Degueldre C, Balteau E, Luxen A, Collette F, Maquet P (2012) Influence of acute sleep loss on
the neural correlates of alerting, orientating and executive attention components. J Sleep Res
21:648-658.
We also published a follow up study of our recent Science paper on extreme chronotypes,
using a different cognitive task.
Human morning and evening chronotypes differ in their preferred timing for sleep and
wakefulness, as well as in optimal daytime periods to cope with cognitive challenges. Recent
evidence suggests that these preferences are not a simple by-product of socio-professional
timing constraints, but can be driven by inter-individual differences in the expression of circadian
and homeostatic sleep-wake promoting signals. Chronotypes thus constitute a unique tool to
access the interplay between those processes under normally entrained day-night conditions,
and to investigate how they impinge onto higher cognitive control processes. Using functional
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