Aβ-related hyperactivation in frontoparietal control regions in cognitively normal elderly

Area of Science:

• Neuroscience
• Neurology
• Cognitive Science

Background:

• Amyloid-beta (Aβ) peptide accumulation is a key hallmark of Alzheimer's disease.
• Aβ deposition is associated with functional changes, particularly in episodic memory and medial temporal lobes.
• Aβ deposition also overlaps with frontoparietal control (FPC) regions crucial for cognitive control and working memory.

Purpose of the Study:

• To investigate Aβ-related functional alterations in FPC regions during a working memory task.
• To examine the relationship between amyloid positivity, age, and brain activity in cognitively normal elderly individuals.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to study 42 young and 57 cognitively normal elderly participants.
• Participants performed a letter Sternberg task with varying cognitive loads.
• (18)F-florbetaben-positron emission tomography (PET) scans determined amyloid positivity (Aβ+) status in older subjects.

Main Results:

• Both age and Aβ deposition were independently associated with increased load-dependent frontoparietal hyperactivation.
• Compensatory hyperactivity related to Aβ was observed beyond the FPC regions.
• Aβ-related hyperactivation was found in FPC regions during working memory tasks.

Conclusions:

• Aβ-related hyperactivation is not confined to the episodic memory system but also occurs in frontoparietal control regions.
• These findings suggest that Aβ accumulation impacts cognitive control networks in aging and preclinical Alzheimer's disease.
• The study highlights the widespread effects of Aβ on brain function beyond traditional memory-associated areas.