title: Spontaneous Neural Dynamics and Multi-scale Network Organization.
abstract: Spontaneous neural activity has historically been viewed as task-irrelevant noise that should be controlled for via experimental design, and removed through data analysis. However, electrophysiology and functional MRI studies of spontaneous activity patterns, which have greatly increased in number over the past decade, have revealed a close correspondence between these intrinsic patterns and the structural network architecture of functional brain circuits. In particular, by analyzing the large-scale covariation of spontaneous hemodynamics, researchers are able to reliably identify functional networks in the human brain. Subsequent work has sought to identify the corresponding neural signatures via electrophysiological measurements, as this would elucidate the neural origin of spontaneous hemodynamics and would reveal the temporal dynamics of these processes across slower and faster timescales. Here we survey common approaches to quantifying spontaneous neural activity, reviewing their empirical success, and their correspondence with the findings of neuroimaging. We emphasize invasive electrophysiological measurements, which are amenable to amplitude- and phase-based analyses, and which can report variations in connectivity with high spatiotemporal precision. After summarizing key findings from the human brain, we survey work in animal models that display similar multi-scale properties. We highlight that, across many spatiotemporal scales, the covariance structure of spontaneous neural activity reflects structural properties of neural networks and dynamically tracks their functional repertoire.
authors.affiliation: Department of Psychology, Stanford University CA, USA.
authors.forename: Brett L
authors.initials: BL
authors.lastname: Foster
authors.affiliation: Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health MD, USA.
authors.forename: Biyu J
authors.initials: BJ
authors.lastname: He
authors.affiliation: Department of Psychology, University of Toronto ON, Canada.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Honey
authors.affiliation: Department of Psychology, University of Montreal QC, Canada.
authors.forename: Karim
authors.initials: K
authors.lastname: Jerbi
authors.affiliation: Department of Psychology, Vanderbilt University TN, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Maier
authors.affiliation: Department of Psychology, University of Wisconsin - Madison WI, USA.
authors.forename: Yuri B
authors.initials: YB
authors.lastname: Saalmann
keywords: brain networks; connectivity; electrocorticography (ECoG); neural dynamics; resting-state fMRI