Sleep and mealtime misalignment alters functional connectivity: A pilot resting state study

Delayed sleep and meal times promote metabolic dysregulation and obesity. Altered coordination of sleeping and eating times may impact food reward valuation and interoception in the brain, yet the independent and collective contributions of sleep and meal times are unknown. This randomized, inpatient crossover study experimentally manipulates sleep and meal times while preserving sleep duration (7.05±0.44h for 5 nights). Resting-state functional MRI scans (2×5-minute runs) were obtained for 4 participants (3 males; 25.3±4.6 y), each completing all study phases (normal sleep/normal meal; late sleep/normal meal; normal sleep/late meal; late sleep/late meal). Normal mealtimes were 1, 5, 11, and 12.5h after awakening; late mealtimes were 4.5, 8.5, 14.5 and 16h after awakening. Seed-based resting-state functional connectivity (RSFC) was computed for a priori regions-of-interest (seeds) and contrasted across conditions. Statistically significant (p<0.05, whole-brain corrected) regionally-specific effects were found for multiple seeds. The strongest effects were linked to the amygdala: increased RSFC for late versus normal mealtimes (equivalent to skipping breakfast). A main effect of sleep and interaction with mealtime were also observed. Preliminary findings support the feasibility of examining the effects of sleep and meal time misalignment, independent of sleep duration, on RSFC in regions relevant to food reward and interoception.