ABSTRACT
Methods: In an ongoing study, we recruited 46 individuals who complete three sessions: sleep loss (2 nights of 4h in bed), normal sleep (2 nights of 9h in bed) (within-subjects), and a low-grade inflammation condition (COVID-19 vaccination) preceded by either sleep loss or normal sleep (between subjects). Blood samples were taken (not analyzed), sickness symptoms were assessed (SicknessQ with 10-point scale), and model-based and model-free control was quantified (a sequential decision task). Result(s): Sickness symptoms were highest after vaccination with sleep loss (M = 34.6), followed by vaccination with normal sleep (M = 24.3) and sleep loss (M = 23.8), and normal sleep only (M = 15.3). Model-free control increased in the vaccine as compared to the non-vaccine condition (b = 0.23, 95% CI 0.10, 0.37, p <.001), most clearly in the normal sleep condition. Model-based control decreased after sleep loss versus normal sleep (reward + common: b = -0.47, 95% CI -0.67, -0.28, p <.001, non-reward + rare: b = -0.43, 95% CI -0.63, -0.18, p <.001), which was not modulated by vaccination. Conclusion(s): These results suggest that low-grade inflammation and sleep loss independently attenuate behavioral control towards a cognitively less expensive but inflexible decision style. The potential role of sleep-immune pathways in model-based and model-free control will be discussed. Copyright © 2022