title: Functional bimodality in the brain networks of preterm and term human newborns.
abstract: The spontaneous brain activity exhibits long-range spatial correlations detected using functional magnetic resonance imaging (fMRI) signals in newborns when (1) long neuronal pathways are still developing, and (2) the electrical brain activity consists of developmentally unique, intermittent events believed to guide activity-dependent brain wiring. We studied this spontaneous electrical brain activity using multichannel electroencephalography (EEG) of premature and fullterm babies during sleep to assess the development of spatial integration during last months of gestation. Correlations of frequency-specific amplitudes were found to follow a robust bimodality: During low amplitudes (low mode), brain activity exhibited very weak spatial correlations. In contrast, the developmentally essential high-amplitude events (high mode) showed strong spatial correlations. There were no clear spatial patterns in the early preterm, but clear frontal and parieto-occipital modules at term age. A significant fronto-occipital gradient was also seen in the development of the graph measure clustering coefficient. Strikingly, no bimodality was found in the fMRI recordings of the fullterm babies, suggesting that early EEG activity and fMRI signal reflect different mechanisms of spatial coordination. The results are compatible with the idea that early developing human brain exhibits intermittent long-range spatial connections that likely provide the endogenous guidance for early activity-dependent development of brain networks.
authors: The University of Queensland Centre for Clinical Research (UQCCR), Royal Brisbane and Women's Hospital, Brisbane, Australia.
authors: Amir
authors: A
authors: Omidvarnia
authors: Department of Clinical Neuroscience, Karolinska Institute, Stockholm SE-171 76, Sweden.
authors: Peter
authors: P
authors: Fransson
authors: Children's Hospital, Helsinki University Central Hospital and University of Helsinki, Helsinki, HUS 00029, Finland.
authors: Marjo
authors: M
authors: Metsäranta
authors: The University of Queensland Centre for Clinical Research (UQCCR), Royal Brisbane and Women's Hospital, Brisbane, Australia, Department of Children's Clinical Neurophysiology, Helsinki University Central Hospital, Helsinki, HUS 00029, Finland and Department of Neurological Sciences, 00014 University of Helsinki, Helsinki, Finland.
authors: Sampsa
authors: S
authors: Vanhatalo
mesh_terms: D001921:Brain / Q000254:growth & development / Q000502:physiology*; D058256:Brain Waves; D004569:Electroencephalography; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D009415:Nerve Net / Q000254:growth & development / Q000502:physiology*
keywords: early brain activity; fMRI; neonatal EEG; preterm infant; resting-state networks