title: Common intrinsic connectivity states among posteromedial cortex subdivisions: Insights from analysis of temporal dynamics.
abstract: Perspectives of human brain functional connectivity continue to evolve. Static representations of functional interactions between brain regions are rapidly giving way to dynamic perspectives, which emphasize non-random temporal variations in intrinsic functional connectivity (iFC) patterns. Here, we bring this dynamic perspective to our understanding of iFC patterns for posteromedial cortex (PMC), a cortical hub known for its functional diversity. Previous work has consistently differentiated iFC patterns among PMC subregions, though assumed static iFC over time. Here, we assessed iFC as a function of time utilizing a sliding-window correlation approach, and applied hierarchical clustering to detect representative iFC states from the windowed iFC. Across subregions, five iFC states were detected over time. Although with differing frequencies, each subregion was associated with each of the states, suggesting that these iFC states are "common" to PMC subregions. Importantly, each subregion possessed a unique preferred state(s) and distinct transition patterns, explaining previously observed iFC differentiations. These results resonate with task-based fMRI studies suggesting that large-scale functional networks can be flexibly reconfigured in response to changing task-demands. Additionally, we used retest scans (~1week later) to demonstrate the reproducibility of the iFC states identified, and establish moderate to high test-retest reliability for various metrics used to quantify switching behaviors. We also demonstrate the ability of dynamic properties in the visual PMC subregion to index inter-individual differences in a measure of concept formation and mental flexibility. These findings suggest functional relevance of dynamic iFC and its potential utility in biomarker identification over time, as d-iFC methodologies are refined and mature.
authors.affiliation: Center for the Developing Brain, Child Mind Institute, New York, NY 10022, USA; Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; The Phyllis Green and Randolph Cowen Institute for Pediatric Neuroscience, New York University Child Study Center, New York, NY 10016, USA.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Center for the Developing Brain, Child Mind Institute, New York, NY 10022, USA; Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
authors.forename: R Cameron
authors.initials: RC
authors.lastname: Craddock
authors.affiliation: Max Planck Research Group for Neuroanatomy & Connectivity, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Margulies
authors.affiliation: Center for the Developing Brain, Child Mind Institute, New York, NY 10022, USA; Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; The Phyllis Green and Randolph Cowen Institute for Pediatric Neuroscience, New York University Child Study Center, New York, NY 10016, USA.
authors.forename: Chao-Gan
authors.initials: CG
authors.lastname: Yan
authors.affiliation: Center for the Developing Brain, Child Mind Institute, New York, NY 10022, USA; Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA. Electronic address: Michael.Milham@childmind.org.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Milham
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology*; D055815:Young Adult
keywords: Connectivity states; Intrinsic functional connectivity; Resting-state fMRI; Temporal dynamics; The posteromedial cortex