Vascular risk factors, cerebrovascular reactivity, and the default-mode brain network

Abstract

Cumulating evidence from epidemiologic studies implicates cardiovascular health and cerebrovascular function in several brain diseases in late life. We examined vascular risk factors with respect to a cerebrovascular measure of brain functioning in subjects in mid-life, which could represent a marker of brain changes in later life. Breath-hold functional MRI (fMRI) was performed in 541 women and men (mean age 50.4 years) from the Coronary Artery Risk Development in Young Adults (CARDIA) Brain MRI sub-study. Cerebrovascular reactivity (CVR) was quantified as percentage change in blood-oxygen level dependent (BOLD) signal in activated voxels, which was mapped to a common brain template and log-transformed. Mean CVR was calculated for anatomic regions underlying the default-mode network (DMN) - a network implicated in AD and other brain disorders - in addition to areas considered to be relatively spared in the disease (e.g. occipital lobe), which were utilized as reference regions. Mean CVR was significantly reduced in the posterior cingulate/precuneus (β = -0.063, 95% CI: - 0.106, -0.020), anterior cingulate (β = -0.055, 95% CI: -0.101, -0.010), and medial frontal lobe (β = -0.050, 95% CI: -0.092, -0.008) relative to mean CVR in the occipital lobe, after adjustment for age, sex, race, education, and smoking status, in subjects with pre-hypertension/hypertension compared to normotensive subjects. By contrast, mean CVR was lower, but not significantly, in the inferior parietal lobe (β = -0.024, 95% CI: -0.062, 0.014) and the hippocampus (β = -0.006, 95% CI: -0.062, 0.050) relative to mean CVR in the occipital lobe. Similar results were observed in subjects with diabetes and dyslipidemia compared to those without these conditions, though the differences were non-significant. Reduced CVR may represent diminished vascular functionality for the DMN for individuals with prehypertension/ hypertension in mid-life, and may serve as a preclinical marker for brain dysfunction in later life.

Detecting Perfusion Pattern Based on the Background Low-Frequency Fluctuation in Resting-State Functional Magnetic Resonance Imaging Data and Its Influence on Resting-State Networks: An Iterative Postprocessing Approach

“…In particular, the time-shift regression method could enhance the connectivity within the DMN including PCC, medial pre-frontal cortex (mPFC), middle temporal lobe, and angular gyrus. These results are in line with previous works investigating changes in the cerebrovascular reactivity (Golestani et al, 2016;Haight et al, 2015), showing that the BOLD signal is potentially mediated by concomitant alterations in the cerebrovascular response. Our observations support the idea that the presence of varied in cerebro-vascular response may be the major vascular modulator of RS-fMRI (Golestani et al, 2016).…”

Short‐ and long‐term reproducibility of BOLD signal change induced by breath‐holding at 1.5 and 3 T

“…This autoregulation property, better known as cerebrovascular reactivity (CVR), is a critical biomarker of vascular health. Alternations in CVR have been shown to provide valuable information regarding cerebrovascular diseases and neurodegenerative diseases . In addition, vascular insults related to advanced age can be considered the second most common cause of cognitive decline in elderly individuals .…”

Reduced cerebrovascular reactivity among adolescents with bipolar disorder

“…Additionally, our previous study examined regional differences, sex differences, and three modeling techniques for analyzing CVR in a healthy youth sample . Importantly, if present early, CVR could be used as a trait marker, rather than a state marker, in BD . Studies of CVR in high‐risk offspring of parents with BD are warranted to evaluate whether anomalous CVR forebodes the development of BD and other disorders in this group.…”