Increased vasomotor waves inverts electro-hydrodynamic drive over blood-brain-barrier in sleep.

Motivation: Sleep is known to increase slow vasomotor BOLD signal oscillations that are assumed be related to increased in brain solute transport. However, it is unclear what mediates this processess. Goal(s): We set out to investigate how the increased vasomotor waves affect the causal drive of brain water concentration and blood-brain barrier(BBB) permeability using ultrafast MREG multimodal imaging. Approach: We quantified the difference in the causal drive of human brain water, BBB potential and BOLD signal with dynamic phase transfer entropy. Results: We found that sleep regionally reverses the causal drive of vasomotor brain water and BBB signals indicating permeability changes in the cortex. Impact: Sleep induces vasomotor waves that start to drive both brain water and BBB signals in the same posterior/middline areas in sleep adding further proof to the previous findings of increased solute transport in parasagital areas.