Increased functional connectivity within medial temporal lobe in mild cognitive impairment

Area of Science:

• Neuroscience
• Neurology
• Radiology

Background:

• Preclinical and prodromal Alzheimer's disease (AD) pathology may cause functional neuronal network changes before structural alterations.
• Resting-state functional magnetic resonance imaging (fMRI) measures functional connectivity, offering insights into network states affected by disease.

Purpose of the Study:

• To investigate functional connectivity changes in the medial temporal lobe (MTL) in amnestic mild cognitive impairment (aMCI) using high-resolution MRI.
• To characterize early AD-related alterations in brain network connectivity.

Main Methods:

• Utilized high-resolution magnetic resonance imaging (MRI) to delineate subregions within the MTL.
• Assessed resting-state functional connectivity between the entorhinal cortex, MTL subregions (especially the anterior hippocampus), and default mode network (DMN) nodes.

Main Results:

• Observed increased functional connectivity between the entorhinal cortex and MTL subregions in aMCI patients, with the most significant increase in the anterior hippocampus.
• Replicated findings of decreased functional connectivity between the MTL and other DMN nodes.

Conclusions:

• The study reveals a dissociation in functional connectivity changes within the MTL compared to its connections with neocortical structures in early AD.
• These findings enhance the characterization of early-stage AD progression and may serve as potential biomarkers.