Neurite Degradation Mediates the Impact of Amyloid Deposition on Global Cognition in Unimpaired Older Adults

This study showed amyloid deposition, particularly in the left entorhinal cortex and fusiform gyrus, is linked to microstructural degradation and cognitive decline. Significant negative correlations between amyloid and NDI suggest higher amyloid levels lead to greater neurodegeneration and lower cognitive scores even in asymptomatic individuals. Mediation analysis showed NDI partially mediates this relationship in the left entorhinal cortex and fusiform gyrus. These findings highlight early neurodegenerative changes in cognitively unimpaired individuals and emphasize the importance of amyloid and neurite density in understanding cognitive decline.