EXPRESS: Ultralow frequency vaso-oscillations in human cerebral arteries occur independently from Mayer waves

Abstract This study tests the hypothesis that vasomotion, an ∼ 0.1 Hz oscillation in arteriole diameter, is generated by intrinsic oscillations within the arterioles that perfuse the brain, and not by external drive from systemic blood pressure oscillations (Mayer waves). During cardio-pulmonary bypass that transiently eliminated systemic blood pressure oscillations in 14 patients, we observed that vasomotor oscillations persist with normal amplitudes and frequencies over the one- to three-hour time course of surgery. In contrast, ∼ 0.1 Hz oscillations in peripheral blood pressure were predominantly absent. This implies that cerebral arterioles generate their own rhythmic vaso-dynamics, although we cannot discount that vasomotion can phase-lock with ∼ 0.1 Hz systemic physiological rhythms in the awake, healthy state. We discuss the impact of this finding on the role of vasomotion in modulating the perfusion of blood and the transport of interstitial fluid in the brain.