Breakdown of long-range temporal dependence in default mode and attention networks during deep sleep

ENZO TAGLIAZUCCHI; FREDERIC VON WEGNER; ASTRID MORZELEWSKI; VERENA BRODBECK; KOLJA JAENKE; HELMUT LAUFS

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

NATL ACAD SCIENCES

Lugar: Washington DC, USA; Año: 2013

0027-8424

The integration of segregated brain functional modules is a prerequisitefor conscious awareness during wakeful rest. Here, wetest the hypothesis that temporal integration, measured as longtermmemory in the history of neural activity, is another importantquality underlying conscious awareness. For this aim, we study thetemporal memory of blood oxygen level-dependent signals acrossthe human nonrapid eye movement sleep cycle. Results reveal thatthis property gradually decreases from wakefulness to deep nonrapideye movement sleep and that such decreases affect areas identifiedwith default mode and attention networks. Although blood oxygenlevel-dependent spontaneous fluctuations exhibit nontrivial spatialorganization, even during deep sleep, they also display a decreasedtemporal complexity in specific brain regions. Conversely, this resultsuggests that long-range temporal dependence might be an attributeof the spontaneous conscious mentation performed duringwakeful rest.