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O2‐01‐01: Beta‐amyloid deposition is related to default mode network connectivity in normal controls
Author(s) -
Mormino Elizabeth C.,
Smiljic Andre,
Baker Suzanne L.,
Hayenga Amynta O.,
Madison Cindee M.,
Jagust William J.
Publication year - 2009
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2009.05.316
Subject(s) - default mode network , voxel , precuneus , posterior cingulate , resting state fmri , nuclear medicine , correlation , neuroscience , psychology , medicine , functional connectivity , cortex (anatomy) , mathematics , functional magnetic resonance imaging , radiology , geometry
Background: To compare beta-amyloid (Ab) deposition to default mode network (DMN) connectivity in cognitively normal control (NC) subjects. Methods: Twenty-nine NC subjects underwent MRI and PIB PET scanning (mean age1⁄473.72, SD1⁄46.4, mean MMSE1⁄429.2, SD1⁄40.9). Eight minutes of resting state BOLD data were collected on a 1.5T MRI scanner (TR/ TE1⁄41890/50ms; 3x3x3.5mm; 24 axial slices). BOLD data were decomposed using an independent components analysis and the DMN was selected based on a template matching procedure. A 1-sample t-test with spatially normalized DMN components was used to identify the DMN and confine subsequent analyses (p<0.001, minimum cluster size 1⁄4 20 voxels). Voxel-to-voxel correlations were conducted on spatially normalized DMN components and PIB distribution volume ratio (DVR) images to explore the local relationship between DMN connectivity and Ab burden (using the WFU BPM toolbox with SPM5). In addition, to assess the impact of global Ab, a single PIB index value for each subject (DVR values averaged across multiple cortical regions) was regressed against voxel-wise DMN. Age was controlled for in both correlation analyses, and significant clusters were identified using height and extent p thresholds of 0.05. Results: The 1-sample t-test revealed regions consistent with previous DMN studies (bilateral medial prefrontal, medial parietal/posterior cingulate, lateral parietal, middle/inferior lateral temporal and medial temporal). Voxel-to-voxel PIB DVRs and PIB index versus voxel-wise DMN connectivty revealed a similar pattern of results: significant negative correlations in bilateral precuneus/posterior cingulate and positive relationships bilaterally in medial prefrontal cortex and middle temporal gyri. Conclusions: These results suggest that Ab deposition in stages preceding dementia coincides with changes in DMN connectivity. Ab deposition may reduce connectivity to the precuneus/posterior cingulate, a region central to the DMN that is highly interconnected to both medial temporal and prefrontal regions. Furthermore, increases in connectivity may reflect the network’s attempt to compensate for disconnection in the precuneus/posterior cingulate. However, the causal relationship between DMN connectivity and Ab is unclear and it is equally possible that changes in network connectivity directly lead to Ab deposition.