Deficiency in anterior-posterior connectivity of default-mode network in amnestic mild cognitive impairment: A combined task-related and resting-state fMRI study

Mild cognitive impairment (MCI) is a transitional stage between normal aging and Alzheimer´s disease (AD). Recent functional imaging studies have demonstrated regional deactivation magnitudes changes of default-mode network (DMN) in patients, accompanied by a defect of memory function. However, functional connectivity in the DMN during task performance was rarely investigated. METHODS : 26 amnestic MCI and 27 healthy controls underwent functional magnetic resonance imaging (fMRI) during an episodic memory task. Resting-state fMRI data were also collected. The changes in default-mode networks under both task-related and resting-state fMRI were obtained with a temporal correlation analysis. RESULTS: Significantly decreased functional connectivity was found mainly in anterior-posterior connectivity of DMN in aMCI groups. And a correlation existed between the anterior-posterior functional connectivity and MMSE scores. CONCLUSIONS: This study showed that disconnectivity of DMN could be used as an imaging biomarker for predicting the future cognitive decline of aMCI patients.