Structural connectivity of the default mode network and cognition in Alzheimer's disease

Author(s)

Weiler, Marina ^[1] ; de Campos, Brunno Machado ^[1] ; Nogueira, Mateus Henrique ^[1] ; Damasceno, Benito Pereira ^[2] ; Cendes, Fernando ^[1] ; Balthazar, Marcio L. F. ^{[1, 2]}

Affiliation

^[1] Univ Campinas Unicamp, Dept Neurol, Neuroimaging Lab, Campinas, SP - Brazil

^[2] Univ Campinas Unicamp, Unit Neuropsychol & Neurolinguist, Depat intent Neurol, Campinas, SP - Brazil

• Document type: Journal article
• Source: PSYCHIATRY RESEARCH-NEUROIMAGING; v. 223, n. 1, p. 15-22, JUL 30 2014.
• Web of Science Citations: 13

Abstract

Disconnectivity between the Default Mode Network (DMN) nodes can cause clinical symptoms and cognitive deficits in Alzheimer's disease (AD). We aimed to examine the structural connectivity between DMN nodes, to verify the extent in which white matter disconnection affects cognitive performance. MRI data of 76 subjects (25 mild AD, 21 amnestic Mild Cognitive Impairment subjects and 30 controls) were acquired on a 3.0 T scanner. ExploreDTI software (fractional Anisotropy threshold = 0.25 and the angular threshold = 60 degrees) calculated axial, radial, and mean diffusivities, fractional anisotropy and streamline count. AD patients showed lower fractional anisotropy (P=0.01) and streamline count (P=0.029), and higher radial diffusivity (P=0.014) than controls in the cingulum. After correction for white matter atrophy, only fractional anisotropy and radial diffusivity remained significantly lower in AD compared to controls (P=0.003 and P=0.05). In the parahippocampal bundle, AD patients had lower mean and radial diffusivities (P=0.048 and P=0.013) compared to controls, from which only radial diffusivity survived for white matter adjustment (P=0.05). Regression models revealed that cognitive performance is also accounted for by white matter microstructural values. Structural connectivity within the DMN is important to the execution of high-complexity tasks, probably due to its relevant role in the integration of the network. (C) 2014 Elsevier Ireland Ltd. All rights reserved. (AU)

• FAPESP's process: 11/17092-0 - Biomarkers in Alzheimer's Disease and mild cognitive impairment: evaluation of functional magnetic resonance imaging methods, plasmatic and cerebrospinal fluid markers
• Grantee: Marcio Luiz Figueredo Balthazar
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 13/10431-9 - Anatomical and functional connectivity in Default Mode and Salience Networks in mild dementia of Alzheimer's Disease and amnestic mild cognitive impairment
• Grantee: Marina Weiler
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)