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Updated: Sep 13, 2025

Application of Granger Causality Analysis of the Directed Functional Connection in Alzheimer's Disease and Mild Cognitive Impairment
Published on: August 7, 2017
Neurovascular coupling and functional connectivity changes through the Alzheimer's disease spectrum: Effects of
Aline R Zimmer1,2, Miled Bourourou2, Frédéric Lesage3
1Graduate Program in Pharmaceutical Science, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
Introduction:
Alzheimer's disease (AD) is a leading cause of dementia, with vascular dysfunction being an early pathogenic event. Cardiovascular interventions show therapeutic promise, hence may improve neurovascular coupling (NVC) and resting-state functional connectivity (RSFC) hemodynamic responses.
Methods:
NVC and RSFC were recorded longitudinally in control and AD transgenic mice treated or not with simvastatin (SV) using optical imaging of intrinsic signals (OIS), together with memory testing.
Results:
AD mice showed early decreases in NVC and bilateral connectivity (BC) in motor and cingulate cortex, and hypoconnectivity within the sensory-motor network. Early default-mode network (DMN) hyperconnectivity was followed by hypoconnectivity, together with a decreased BC in somatosensory (S) cortex. SV restored NVC, prevented aberrant DMN hyperconnectivity, improved BC of S, and preserved memory.
Discussion:
Our results indicate that OIS can detect early AD-related changes in NVC and RSFC, and that a preventive cardiovascular strategy may bear therapeutic promise in at-risk individuals.
Highlights:
Optical imaging of intrinsic signals captures Alzheimer's disease (AD) progression and response to therapy. Neurovascular coupling (NVC) and resting-state functional connectivity (RSFC) disruptions precede memory decline in AD transgenic mice. Simvastatin prevented NVC and AD-specific RSFC disruptions and protected memory. This study supports translational value of hemodynamic signal in early AD detection.
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