title: Complexity of low-frequency blood oxygen level-dependent fluctuations covaries with local connectivity.
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.
authors: Division of Neuroradiology, University of Utah, Salt Lake City, Utah; Program in Neuroscience, University of Utah, Salt Lake City, Utah; The Brain Institute at the University of Utah, Salt Lake City, Utah; Department of Bioengineering, University of Utah, Salt Lake City, Utah.
authors: Jeffrey S
authors: JS
authors: Anderson
authors: Brandon A
authors: BA
authors: Zielinski
authors: Jared A
authors: JA
authors: Nielsen
authors: Michael A
authors: MA
authors: Ferguson
mesh_terms: D000293:Adolescent; D000328:Adult; D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002648:Child; D016208:Databases, Factual; D005260:Female; D006257:Head; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009038:Motion; D036421:Nerve Fibers, Unmyelinated / Q000502:physiology; D009434:Neural Pathways / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology; D010100:Oxygen / Q000097:blood*; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: 1/f; avalanche dynamics; brain development; chaos theory; complexity; fMRI; fcMRI; long memory; power law; regional homogeneity; resting state fMRI