Complexity of low-frequency blood oxygen level-dependent fluctuations covaries with local connectivity

• Published in: Human brain mapping Vol. 35; no. 4; pp. 1273 - 1283
• Main Authors: Anderson, Jeffrey S., Zielinski, Brandon A., Nielsen, Jared A., Ferguson, Michael A.
• Format: Journal Article
• Language: English
• Published: New York, NY Blackwell Publishing Ltd 01.04.2014; Wiley-Liss; John Wiley & Sons, Inc; John Wiley and Sons Inc
• Subjects: 1/f; Adolescent; Adult; avalanche dynamics; Biological and medical sciences; Brain - anatomy & histology; Brain - growth & development; Brain - physiology; brain development; Brain Mapping - methods; Cardiovascular system; Cerebrovascular Circulation - physiology; chaos theory; Child; complexity; Databases, Factual; fcMRI; Female; fMRI; Head; Humans; Investigative techniques, diagnostic techniques (general aspects); long memory; Magnetic Resonance Imaging - methods; Male; Medical sciences; Motion; Nerve Fibers, Unmyelinated - physiology; Nervous system; Neural Pathways - anatomy & histology; Neural Pathways - growth & development; Neural Pathways - physiology; Oxygen - blood; power law; Radiodiagnosis. Nmr imagery. Nmr spectrometry; regional homogeneity; resting state fMRI; Signal Processing, Computer-Assisted; Young Adult; Chaos; brain development; chaos theory; Fluctuations; Oxygen; Nervous system diseases; Radiodiagnosis; Theory; Memory; Central nervous system; 1/f; avalanche dynamics; fcMRI; resting state fMRI; Low frequency; Nuclear magnetic resonance imaging; Complexity; Encephalon; power law; fMRI; long memory; regional homogeneity; complexity
• ISSN: 1065-9471; 1097-0193; 1097-0193
• DOI: 10.1002/hbm.22251

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.