The Origin of Vasomotion and Stochastic Resonance in Vasomotion

Abstract

Vasomotion is the spontaneous time-dependent contraction and relaxation of micro arteries and the oscillating frequency is about 0.01–0.1 Hz. The physiological mechanism of vasomotion has not been thoroughly understood. From the dynamics point of view, the heartbeat is the only external loading exerted on the vascular system. We speculate that the nonlinear vascular system and the variable period of the heartbeat might induce the low-frequency vasomotion. In this study, the laser Doppler flowmeter is used to measure the time series of radial artery blood flow and reconstructed modified time series that has the same period as the measured time series but different heartbeat curves. We measured the time series of radial artery blood flow in different conditions by adding different noise disturbances on the forearm, and we decomposed the experiment pulse signal by Hilbert–Huang transform. The wavelet spectral analyses showed that the low-frequency components were induced by the variable period but independent of the shape of the heartbeat curve. Furthermore, we simulated the linear flow in a single pipe and the nonlinear flow in a piping network and found that the nonlinear flow would generate low-frequency components. From the results, we could deduce that the variable period of heartbeat and the nonlinearity of the vascular system induce vasomotion. The noise has effects on the blood signals related to the respiratory activities (∼0.3 Hz) but little influence on that related to the cardiac activities (∼1 Hz). Adding white noise and then stopping would induce an SNR increase in the frequency band related to vasomotion (∼0.1 Hz).

Spectral analysis of laser speckle contrast imaging and infrared thermography to assess skin microvascular reactive hyperemia

“…By using Fourier, Hilbert-Huang or wavelet transforms, several representative frequency ranges were found in skin LDF signals, including heartbeat (0.5-2 Hz), respiration (0.14-0.5 Hz), myogenic activity (0.05-0.14 Hz), neurogenic activity (0.02-0.05 Hz), and NO-mediated endothelial activity (0.0095-0.02 Hz). [9][10][11][12][13] Similar spectral characteristics of oscillations were also found in human skin temperature signals. 14,15 There is some evidence to support that the prevalence of vasomotion was altered in response to stimuli under pathological conditions, including arterial hypertension, peripheral arterial obstructive diseases (PAOD), chronic kidney disease (CKD), and diabetes.…”

“…In recent years, the PORH test with signal spectral analysis coupled, which quantified the periodic oscillations of flowmotion, provided new potential indicators specific to a certain physiological mechanism. By using Fourier, Hilbert‐Huang or wavelet transforms, several representative frequency ranges were found in skin LDF signals, including heartbeat (0.5–2 Hz), respiration (0.14–0.5 Hz), myogenic activity (0.05–0.14 Hz), neurogenic activity (0.02–0.05 Hz), and NO‐mediated endothelial activity (0.0095–0.02 Hz) 9–13 . Similar spectral characteristics of oscillations were also found in human skin temperature signals 14,15 .…”

The impact of vasomotion on analysis of rodent fMRI data

“…We detected HDO in anesthetized rats. Several studies reported similar oscillatory signals in measurements sensitive to blood flow or arterial vessel diameter in various species such as mice (Drew et al, 2010;Mateo et al, 2017;Winder et al, 2017;Fan et al, 2020), rats (Fujii et al, 1990;Mayhew et al, 1996;Kleinfeld et al, 1998), rabbits (Hundley et al, 1988), cats (Rivadulla et al, 2011) and humans (Mitra et al, 1997;Obrig et al, 2000;Rayshubskiy et al, 2014;Liu et al, 2022), and identified vasomotion as their origin. Vasomotion refers to rhythmic oscillations of blood vessel diameter, which causes oscillations of blood flow (Aalkjaer et al, 2011).…”

“…We intended to investigate the prevalence of these oscillations (referred as HDO) in fMRI data and identified oscillations with a frequency around 0.2 Hz in MED sedated animals. In contrast, studies applying other anesthesia or measuring awake subjects often reported a vasomotion frequency around 0.1 Hz (Fujii et al, 1990;Mayhew et al, 1996;Mitra et al, 1997;Kleinfeld et al, 1998;Obrig et al, 2000;Rivadulla et al, 2011;Rayshubskiy et al, 2014;Mateo et al, 2017;Fan et al, 2020;Liu et al, 2022). The higher oscillation frequency under MED sedation can be explained by the fact that MED is a vasoconstrictor (Sinclair, 2003;Fukuda et al, 2013) and vasoconstriction causes an increase in vasomotion frequency (Colantuoni et al, 1984;Fujii et al, 1990).…”