Effects of Chronic Sleep Restriction on the Brain Functional Network, as Revealed by Graph Theory

• Published in: Frontiers in neuroscience Vol. 13; p. 1087
• Main Authors: Farahani, Farzad V., Fafrowicz, Magdalena, Karwowski, Waldemar, Douglas, Pamela K., Domagalik, Aleksandra, Beldzik, Ewa, Oginska, Halszka, Marek, Tadeusz
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 11.10.2019; Frontiers Media S.A
• Subjects: Amygdala; Brain; Brain mapping; connectome; Diurnal; Experiments; fMRI; functional connectivity; Functional magnetic resonance imaging; graph theory; Homeostasis; Limbic system; Memory; Nervous system; Neuroimaging; Neuroscience; NMR; Nuclear magnetic resonance; Parahippocampal gyrus; Sleep deprivation; sleep restriction; small-world; Studies; Poland; Los Angeles California; United States > US; fMRI; functional connectivity; graph theory; sleep restriction; small-world; connectome; brain networks
• ISSN: 1662-453X; 1662-4548; 1662-453X
• DOI: 10.3389/fnins.2019.01087

Sleep is a complex and dynamic process for maintaining homeostasis, and a lack of sleep can disrupt whole-body functioning. No organ is as vulnerable to the loss of sleep as the brain. Accordingly, we examined a set of task-based functional magnetic resonance imaging (fMRI) data by using graph theory to assess brain topological changes in subjects in a state of chronic sleep restriction, and then identified diurnal variability in the graph-theoretic measures. Task-based fMRI data were collected in a 1.5T MR scanner from the same participants on two days: after a week of fully restorative sleep and after a week with 35% sleep curtailment. Each day included four scanning sessions throughout the day (at approximately 10:00 AM, 2:00 PM, 6:00 PM, and 10:00 PM). A modified spatial cueing task was applied to evaluate sustained attention. After sleep restriction, the characteristic path length significantly increased at all measurement times, and small-worldness significantly decreased. Assortativity, a measure of network fault tolerance, diminished over the course of the day in both conditions. Local graph measures were altered primarily across the limbic system (particularly in the hippocampus, parahippocampal gyrus, and amygdala), default mode network, and visual network.