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Spatial dynamics within and between brain functional domains: A hierarchical approach to study time-varying brain function
Journal article   Open access   Peer reviewed

Spatial dynamics within and between brain functional domains: A hierarchical approach to study time-varying brain function

Armin Iraji, Zening Fu, Eswar Damaraju, Thomas P DeRamus, Noah Lewis, Juan R Bustillo, Rhoshel K Lenroot, Aysneil Belger, Judith M Ford, Sarah McEwen, …
Human brain mapping, Vol.40(6), pp.1969-1986
04/15/2019
DOI: 10.1002/hbm.24505
PMCID: PMC6692083
PMID: 30588687
url
https://doi.org/10.1002/hbm.24505View
Published (Version of record) Open Access

Abstract

The analysis of time-varying activity and connectivity patterns (i.e., the chronnectome) using resting-state magnetic resonance imaging has become an important part of ongoing neuroscience discussions. The majority of previous work has focused on variations of temporal coupling among fixed spatial nodes or transition of the dominant activity/connectivity pattern over time. Here, we introduce an approach to capture spatial dynamics within functional domains (FDs), as well as temporal dynamics within and between FDs. The approach models the brain as a hierarchical functional architecture with different levels of granularity, where lower levels have higher functional homogeneity and less dynamic behavior and higher levels have less homogeneity and more dynamic behavior. First, a high-order spatial independent component analysis is used to approximate functional units. A functional unit is a pattern of regions with very similar functional activity over time. Next, functional units are used to construct FDs. Finally, functional modules (FMs) are calculated from FDs, providing an overall view of brain dynamics. Results highlight the spatial fluidity within FDs, including a broad spectrum of changes in regional associations, from strong coupling to complete decoupling. Moreover, FMs capture the dynamic interplay between FDs. Patients with schizophrenia show transient reductions in functional activity and state connectivity across several FDs, particularly the subcortical domain. Activity and connectivity differences convey unique information in many cases (e.g., the default mode) highlighting their complementarity information. The proposed hierarchical model to capture FD spatiotemporal variations provides new insight into the macroscale chronnectome and identifies changes hidden from existing approaches.
Young Adult Magnetic Resonance Imaging Brain - diagnostic imaging Humans Middle Aged Adolescent Adult Female Male Brain Mapping - methods Models, Neurological Brain - physiology

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