Complexity of low‐frequency blood oxygen level‐dependent fluctuations covaries with local connectivity |
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Authors: | Jeffrey S Anderson Brandon A Zielinski Jared A Nielsen Michael A Ferguson |
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Institution: | 1. Division of Neuroradiology, University of Utah, Salt Lake City, Utah;2. Program in Neuroscience, University of Utah, Salt Lake City, Utah;3. The Brain Institute at the University of Utah, Salt Lake City, Utah;4. Department of Bioengineering, University of Utah, Salt Lake City, Utah;5. Departments of Pediatrics and Neurology, University of Utah, Salt Lake City, Utah;6. Division of Child Neurology, University of Utah, Salt Lake City, Utah |
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Abstract: | Very low‐frequency blood oxygen level‐dependent (BOLD) fluctuations have emerged as a valuable tool for describing brain anatomy, neuropathology, and development. Such fluctuations exhibit power law frequency dynamics, with largest amplitude at lowest frequencies. The biophysical mechanisms generating such fluctuations are poorly understood. Using publicly available data from 1,019 subjects of age 7–30, we show that BOLD fluctuations exhibit temporal complexity that is linearly related to local connectivity (regional homogeneity), consistently and significantly covarying across subjects and across gray matter regions. This relationship persisted independently of covariance with gray matter density or standard deviation of BOLD signal. During late neurodevelopment, BOLD fluctuations were unchanged with age in association cortex while becoming more random throughout the rest of the brain. These data suggest that local interconnectivity may play a key role in establishing the complexity of low‐frequency BOLD fluctuations underlying functional magnetic resonance imaging connectivity. Stable low‐frequency power dynamics may emerge through segmentation and integration of connectivity during development of distributed large‐scale brain networks. Hum Brain Mapp 35:1273–1283, 2014. © 2013 Wiley Periodicals, Inc. |
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Keywords: | brain development fMRI resting state fMRI chaos theory complexity power law avalanche dynamics regional homogeneity fcMRI 1/f long memory |
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