Background: Brain regions critical to episodic memory are altered during the preclinical stages of Alzheimer's disease (AD). However, reliable means of identifying cognitively-normal individuals at higher risk to develop AD have not been established.
Objective: To examine whether functional MRI can detect early functional changes associated with scene encoding in a group of presymptomatic presenilin-1 (PSEN1) E280A mutation carriers.
Methods: Participants were 39 young, cognitively-normal individuals from an autosomal dominant early-onset AD kindred, located in Antioquia, Colombia. Participants performed a functional MRI scene encoding task and a post-scan subsequent memory test.
Results: PSEN1 mutation carriers exhibited hyperactivation within medial temporal lobe regions (hippocampus,parahippocampal formation) during successful scene encoding compared to age-matched non-carriers.
Conclusion: Hyperactivation in medial temporal lobe regions during scene encoding is seen in individuals genetically-determined to develop AD years before their clinical onset. Our findings will guide future research with the ultimate goal of using functional neuroimaging in the early detection of preclinical AD.
Keywords: Alzheimer’s disease; autosomal-dominant; functional MRI; memory encoding; presenilin-1.