White matter microstructure underlying default mode network connectivity in the human brain

Abstract

White matter microstructure underlying default mode network connectivity in the human brain, NeuroImage (2009), doi:10.1016/j.neuroimage.2009.10.067 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 AbstractResting state functional magnetic resonance imaging (fMRI) reveals a distinct network of correlated brain function representing a default mode state of the human brain. The underlying structural basis of this functional connectivity pattern is still widely unexplored.We combined fractional anisotropy measures of fiber tract integrity derived from diffusion tensor imaging (DTI) and resting state fMRI data obtained at 3 Tesla from 20 healthy elderly subjects (56 to 83 years of age) to determine white matter microstructure underlying default mode connectivity. We hypothesized that the functional connectivity between the posterior cingulate and hippocampus from resting state fMRI data would be associated with the white matter microstructure in the cingulate bundle and fiber tracts connecting posterior cingulate gyrus with lateral temporal lobes, medial temporal lobes and precuneus. This was demonstrated at the p < 0.001 level using a voxel-based multivariate analysis of covariance (MANCOVA) approach. In addition, we used a data driven technique of joint independent component analysis (ICA) that uncovers spatial pattern that are linked across modalities. It revealed a pattern of white matter tracts including cingulate bundle and associated fiber tracts resembling the findings from the hypothesis-driven analysis and was linked to the pattern of default mode network (DMN) connectivity in the resting state fMRI data. Our findings support the notion that the functional connectivity between the posterior cingulate and hippocampus and the functional connectivity across the entire DMN is based on distinct pattern of anatomical connectivity within the cerebral white matter.

A Review of the Functional and Anatomical Default Mode Network in Schizophrenia

“…B Simplified illustration of the principal regions for the two anticorrelated networks, the DMN (red) and TPN (blue volunteers, and found some regions that have corresponding structural fiber pathways, such as the pCC/ PCUN projection to mPFC and bilateral mTLs that has significant functional connectivity, while some significant functional connections, such as that between mPFC and mTLs, exist without known underlying direct fiber tracts [8]. Of note, fiber tracts in the DMN, such as those connecting pCC to bilateral mTLs [20], and pCC to mPFC [21,22], are also detectable between homologous regions in nonhuman primates using effective tracers, suggesting the effectiveness of in vivo DTI tractography in tracing tracts. Subsequent neuroimaging studies [19] combining DTI tractography and fc-fMRI have confirmed a relationship between functional and anatomical connections within the DMN in agreement with Greicius et al [8], further implying that regions that are connected directly by fiber tracts also have significant functional connections, but the inverse condition need not be true because functional connections might be linked indirectly via multisynaptic connections or more distant cortical regions.…”

Aging and large-scale functional networks: White matter integrity, gray matter volume, and functional connectivity in the resting state

“…One possible reason for altered large-scale network activation with increasing age is that ageing leads to widespread neurobiological changes, which impact the structural organization and integrity on which large-scale networks critically depend (Greicius et al, 2009;Horn et al, 2013;Van den Heuvel et al, 2008;Teipel et al, 2010). Thus, structural changes related to ageing would, in part, account for the functional changes associated with cognitive decline.…”

Disparate Connectivity for Structural and Functional Networks is Revealed When Physical Location of the Connected Nodes is Considered

“…Early research on this topic focused on relating FC to AC within few regions in the brain (Koch et al 2002;Guye et al 2003;Boorman et al 2007;Cohen et al 2008;Zhou et al 2008;Takahashi et al 2008). There is also strong evidence that anatomical networks support the formation of functional patterns of resting state connectivity (van den Heuvel et al 2008;Skudlarski et al 2008;Greicius et al 2009;van den Heuvel et al 2009;Teipel et al 2010). Disruption of this FC-AC dependence has been thought to result in significant behavioural deficits related to disconnection syndromes such as schizophrenia (Skudlarski et al 2010;Camchong et al 2011).…”