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Published on: October 30, 2018
Aβ Deposition in aging is associated with increases in brain activation during successful memory encoding
Elizabeth C Mormino1, Michael G Brandel, Cindee M Madison
1Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA. bmormino@berkeley.edu
Elderly individuals with high beta-amyloid (Aβ) show increased brain activation during memory tasks. This heightened activation correlates with memory performance in those with Aβ buildup.
Area of Science:
- Neuroscience
- Cognitive Aging
- Biomarkers of Neurodegeneration
Background:
- Beta-amyloid (Aβ) accumulation is an early event in Alzheimer's disease.
- Understanding Aβ's impact on neuronal function in normal aging is crucial.
- Episodic memory encoding involves distinct brain activation and deactivation patterns.
Purpose of the Study:
- To investigate the early effects of beta-amyloid (Aβ) on neuronal function in elderly normal controls (NCs).
- To assess relationships between Aβ levels and brain activation during an episodic memory-encoding task.
- To compare brain activity in elderly and young NCs.
Main Methods:
- Positron emission tomography (PET) with Pittsburgh Compound-B (PIB) to measure Aβ.
- Functional magnetic resonance imaging (fMRI) to measure brain activation during an episodic memory task.
- Comparison of PIB-positive (PIB+) and PIB-negative (PIB-) elderly NCs, and young NCs.
Main Results:
- Significant task-related activation in memory-related networks (e.g., prefrontal, temporal, hippocampal regions).
- Significant deactivation in default mode network regions.
- Higher task-positive activation in PIB+ compared to PIB- elderly subjects.
- Positive correlation between task-positive activation and memory measures in PIB+ subjects.
- Reduced task deactivation in older versus younger subjects, correlated with memory performance.
Conclusions:
- Heightened brain activation during episodic memory encoding is associated with high Aβ levels in elderly NCs.
- Aβ may influence neuronal function early, even in the absence of cognitive decline.
- Age-related changes in brain deactivation patterns are linked to memory performance.
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