Cerebrospinal Fluid Flow is Locked to Spontaneous BOLD Signal Fluctuations in the Subarachnoid Space and Ventricles

Motivation: Cerebrospinal fluid (CSF) is essential in the central nervous system for transporting metabolic waste. Previous research has shown CSF inflow in the 4th ventricle is coupled with neural activity. Goal(s): We investigated how spontaneous BOLD fluctuations influence CSF flow in both subarachnoid space and large ventricles. Approach: We used 7 Tesla echo-planar time-resolved imaging (EPTI) to spatially map CSF flow dynamics simultaneously with BOLD signals. Results: Significant changes in CSF dynamics were observed during spontaneous BOLD fluctuations both in subarachnoid space and ventricles, highlighting the role of neural activity and cerebrovascular dynamics in driving directional CSF flow in the human brain at rest. Impact: Using a novel technique obtaining simultaneous CSF flow and BOLD signals, we observed significant CSF flow changes in subarachnoid space and ventricles during spontaneous BOLD fluctuations, establishing the role of low-frequency hemodynamics in driving whole-brain directional CSF flow.