title: Implication of the Slow-5 Oscillations in the Disruption of the Default-Mode Network in Healthy Aging and Stroke.
abstract: The processes of normal aging and aging-related pathologies subject the brain to an active re-organization of its brain networks. Among these, the default-mode network (DMN) is consistently implicated with a demonstrated reduction in functional connectivity within the network. However, no clear stipulation on the underlying mechanisms of the de-synchronization has yet been provided. In this study, we examined the spectral distribution of the intrinsic low-frequency oscillations (LFOs) of the DMN sub-networks in populations of young normals, older subjects, and acute and subacute ischemic stroke patients. The DMN sub-networks were derived using a mid-order group independent component analysis with 117 eyes-closed resting-state functional magnetic resonance imaging (rs-fMRI) sessions from volunteers in those population groups, isolating three robust components of the DMN among other resting-state networks. The posterior component of the DMN presented noticeable differences. Measures of amplitude of low-frequency fluctuation (ALFF) and fractional ALFF (fALFF) of the network component demonstrated a decrease in resting-state cortical oscillation power in the elderly (normal and patient), specifically in the slow-5 (0.01-0.027 Hz) range of oscillations. Furthermore, the contribution of the slow-5 oscillations during the resting state was diminished for a greater influence of the slow-4 (0.027-0.073 Hz) oscillations in the subacute stroke group, not only suggesting a vulnerability of the slow-5 oscillations to disruption but also indicating a change in the distribution of the oscillations within the resting-state frequencies. The reduction of network slow-5 fALFF in the posterior DMN component was found to present a potential association with behavioral measures, suggesting a brain-behavior relationship to those oscillations, with this change in behavior potentially resulting from an altered network integrity induced by a weakening of the slow-5 oscillations during the resting state. The repeated identification of those frequencies in the disruption of DMN stresses a critical role of the slow-5 oscillations in network disruption, and it accentuates the importance of managing those oscillations in the health of the DMN.
authors.affiliation: 1 Neuroscience Training Program, University of Wisconsin-Madison , Madison, Wisconsin.|2 Department of Radiology, University of Wisconsin-Madison , Madison, Wisconsin.
authors.forename: Christian
authors.initials: C
authors.lastname: La
authors.affiliation: 2 Department of Radiology, University of Wisconsin-Madison , Madison, Wisconsin.
authors.forename: Veena A
authors.initials: VA
authors.lastname: Nair
authors.affiliation: 2 Department of Radiology, University of Wisconsin-Madison , Madison, Wisconsin.
authors.forename: Pouria
authors.initials: P
authors.lastname: Mossahebi
authors.affiliation: 1 Neuroscience Training Program, University of Wisconsin-Madison , Madison, Wisconsin.|2 Department of Radiology, University of Wisconsin-Madison , Madison, Wisconsin.
authors.forename: Brittany M
authors.initials: BM
authors.lastname: Young
authors.affiliation: 3 Department of Neurology, University of Wisconsin-Madison , Madison, Wisconsin.
authors.forename: Marcus
authors.initials: M
authors.lastname: Chacon
authors.affiliation: 3 Department of Neurology, University of Wisconsin-Madison , Madison, Wisconsin.
authors.forename: Matthew
authors.initials: M
authors.lastname: Jensen
authors.affiliation: 1 Neuroscience Training Program, University of Wisconsin-Madison , Madison, Wisconsin.|4 Department of Medical Physics, University of Wisconsin-Madison , Madison, Wisconsin.|5 Department of Psychiatry, University of Wisconsin-Madison , Madison, Wisconsin.
authors.forename: Rasmus M
authors.initials: RM
authors.lastname: Birn
authors.affiliation: 1 Neuroscience Training Program, University of Wisconsin-Madison , Madison, Wisconsin.|2 Department of Radiology, University of Wisconsin-Madison , Madison, Wisconsin.|4 Department of Medical Physics, University of Wisconsin-Madison , Madison, Wisconsin.|6 Department of Biomedical Engineering, University of Wisconsin-Madison , Madison, Wisconsin.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Meyerand
authors.affiliation: 1 Neuroscience Training Program, University of Wisconsin-Madison , Madison, Wisconsin.|2 Department of Radiology, University of Wisconsin-Madison , Madison, Wisconsin.|3 Department of Neurology, University of Wisconsin-Madison , Madison, Wisconsin.|4 Department of Medical Physics, University of Wisconsin-Madison , Madison, Wisconsin.|5 Department of Psychiatry, University of Wisconsin-Madison , Madison, Wisconsin.|6 Department of Biomedical Engineering, University of Wisconsin-Madison , Madison, Wisconsin.
authors.forename: Vivek
authors.initials: V
authors.lastname: Prabhakaran
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D001921:Brain / Q000502:physiology* / Q000503:physiopathology*; D002545:Brain Ischemia / Q000503:physiopathology*; D001931:Brain Mapping; D058256:Brain Waves; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020521:Stroke / Q000503:physiopathology*; D055815:Young Adult
keywords: aging; default-mode network; fALFF; posterior DMN; rs-fMRI; slow-5; stroke