Abstract
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.
