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IC‐P‐112: Multicenter stability, diagnostic accuracy and regional specificity of cholinergic forebrain atrophy in Alzheimer's disease: A European Diffusion Tensor Imaging Study in Dementia (EDSD)
Author(s) -
Kilimann Ingo,
Grothe Michel,
Heinsen Helmut,
Alho Eduardo,
Frisoni Giovanni,
Bokde Arun,
Fellgiebel Andreas,
Filippi Massimo,
Hampel Harald,
Klöppel Stefan,
Teipel Stefan
Publication year - 2012
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.2012.05.146
Subject(s) - atrophy , basal forebrain , dementia , pathology , diffusion mri , alzheimer's disease , cholinergic , hippocampus , neuroscience , nuclear medicine , magnetic resonance imaging , medicine , psychology , radiology , disease
related to the non-stationary nature of the connectivity within ICNs. Methods: We performed a large (n 1⁄4 892) high-dimensional independent component analysis decomposition of TF-fMRI data on cognitively normal (CN) subjects drawn from theMayo Clinic Study of Aging. This was used to atlas the brain into 68 regions, categorized based on network of origin, anatomical locations, and a functional meta-analysis. These regions were used to construct dynamic graphical representations of the brain within a sliding timewindow.We calculated dwell time in particular network configurations in 892 CN and 28 AD subjects. Results: The 80,280 graphs displayed a highly modular architecture relative to the null model (Q* 1⁄4 0.55 +/-0.06 vs. null Q*1⁄4 0.16 +/0.01, P<0.001). The number of modules varied between 2 and 5, with 23.63% in a 2module configuration, 72.38% in a 3 modular configuration, 3.98% in a 4 modular configuration, and less than 0.01% in a 5 module configuration. This distribution was similar for the dwell time from single subjects’ scanning sessions. The regions of the brain assigned to the same module resembled the most commonly identified ICNs (Figure). We found that Alzheimer’s subjects form brain states with a lower proportion of strong pDMN contributions and a higher proportion of strong aDMN contributions (Table). Conclusions:We defined a functional parcellation of the brain in a large group of CN subjects.We also demonstrated that the brain’s modular organization is non-stationary over time. Compared to CN, AD subjects had greater dwell time in strong aDMN sub-network modular configurations and less dwell time in pDMN configurations. Thus dwell time in specific modular configurations rather than steady state connectivity magnitude seems to underlie the functional connectivity findings that have routinely been described in AD dementia.