Greater default-mode network abnormalities compared to high order visual processing systems in amnestic mild cognitive impairment: an integrated multi-modal MRI study.

摘要: We conducted an integrated multi-modal magnetic resonance imaging (MRI) study based on functional MRI (fMRI) data during a complex but cognitively preserved visual task in 15 amnestic mild cognitive impairment (a-MCI) patients and Healthy Elders (HE). Independent Component Analysis of fMRI identified network containing Activation Task Related Pattern (ATRP), including regions the dorsal ventral stream, Deactivation (DTRP), with high spatial correspondence default-mode (DMN). Gray matter (GM) volumes underlying ATRP DTRP cortical areas were measured, probabilistic tractography (based diffusion MRI) fiber pathways within each network. For network, a-MCI exhibited increased responses inferior-ventral areas, possibly reflecting compensatory activations for more compromised regions. However, no significant GM or white group differences observed DTRP/DMN, showed deactivation deficits reduced posterior cingulate/precuneus, excessive deactivations inferior parietal lobe, less tract integrity cingulate bundles. performance correlated DTRP-functionality HE group. Besides allowing identification reorganizations directly processing task-stimuli, these findings highlight importance conducting studies MCI spared domains order to identify abnormalities critical DMN their precise anatomical substrates. These latter may reflect early neuroimaging biomarkers dementia.