Neurovascular coupling and functional connectivity changes through the Alzheimer's disease spectrum: Effects of simvastatin treatment.

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.