Qihong Zou1,2, JiongJiong Wang3,
Hong Gu1, Yufeng Zang2, Yihong Yang1
1Neuroimaging Research Branch, National
Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United
States; 2State Key Laboratory of Cognitive Neuroscience and
Learning, Beijing Normal University, Beijing, China; 3Center for
Functional Neuroimaging and Department of Radiology and Neurology, School of
Medicine, University of Pennsylvania, Philadelphia, PA, United States
Amplitude
of low-frequency fluctuations (ALFF) has been used to quantify the strength
of spontaneous fluctuations of fMRI signal in the resting state. However, its
underlying physiological/biophysical mechanisms are unknown. In this study,
the relationship between BOLD fluctuation amplitude and resting-state
cerebral blood flow (CBF) were investigated. Our results showed that ALFF of
BOLD and CBF were positively correlated within multiple cortical and subcortical
networks. These findings provided first evidences that ALFF is related to
baseline CBF and likely reflects the level of spontaneous neuronal activity.