LAUSR

Sleep is a multiscale phenomenon. It has subjective and objective components often not highly correlated. Given the importance of brain networks for cognition and evidence that sleep deprivation and variability in habitual sleep patterns affects Functional brain Connectivity (FC), we would expect brain networks would be differentially related to subjective and objective markers of sleep. As well as region specific studies, investigating the effect of habitual sleep measures across whole network interactions is important. This study investigates whether overall FC from 3 Intrinsically Connected Networks (ICN); Default mode(DMN), Salience(SN) and Central executive(CEN) network is differentially related to subjective and objective sleep measures from sleep quality questionnaire, sleep diary data and actigraphy metrics. Functional Magnetic Resonance Imaging data acquired from 32 healthy adults (right handed, 14 female, age 23-59 years). Regions of interest (ROI) representing nodes of the ICN created from separate data of 55 subjects (28 male, age 25±4yrs). Seed-based FC analysis performed using in-house MATLAB code. Average FC across all paired connections in each ICN calculated to define overall mean FC. Two-way multiple measures factorial ANOVA split-plot analysis performed with a 2x3x6 design to determine any interaction of 6 sleep measures (Pittsburgh sleep quality index, subjective sleep efficiency, diary total sleep time, wake after sleep onset, total sleep time, sleep efficiency) with the FC of the ICN. Pairwise comparisons for significant interactions and univariate analysis on the linearly independent pairwise comparisons among the estimated marginal means performed to confirm significant interactions between ICN FC and sleep measures. No significant interactions for any of the sleep metrics tested, subjective or quantitative (P=>0.05). Except subjective sleep efficiency (SSE) which demonstrated a significant within subject interaction of overall network FC (F(2,30) = 3.682, P = 0.033, n2=0.109) for CEN. Significant findings of SSE in relation to CEN demonstrate increased FC of the CEN in relation to higher SSE and lower CEN FC in subjects with low SSE. Overall findings suggests FC changes within ICN in relation to chronic habitual sleep status metrics (subjective or quantitative) don’t involve whole network FC, therefore we believe them to be region specific.