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β-Amyloid affects frontal and posterior brain networks in normal aging
Hwamee Oh1, Elizabeth C Mormino, Cindee Madison
1Helen Wills Neuroscience Institute, University of California-Berkeley, Berkeley, CA 94720-3190, USA. hwameeoh@berkeley.edu
Neuroimage
|October 23, 2010
Summary
Amyloid-beta (Aβ) deposition in healthy older adults is linked to brain structure changes. Reduced frontal gray matter volume associated with Aβ correlates with poorer working memory, suggesting Aβ
Area of Science:
- Neuroscience
- Neurology
- Gerontology
Background:
- Alzheimer's disease (AD) hallmark, beta-amyloid (Aβ) deposition, is found in cognitively normal individuals, but its impact on aging brains is debated.
- Understanding Aβ's effects in normal aging is crucial for early AD detection and intervention strategies.
Purpose of the Study:
- To investigate the relationship between Aβ deposition, brain structure (gray matter volume), and cognitive function in cognitively intact older adults.
- To explore how Aβ affects distinct brain networks and their association with cognitive performance.
Main Methods:
- Utilized Positron Emission Tomography (PET) with Pittsburgh Compound B (PIB) to measure Aβ deposition.
- Employed structural Magnetic Resonance Imaging (MRI) and voxel-based morphometry (VBM) for brain structure analysis.
- Conducted comprehensive neuropsychological tests to assess cognitive functions, including working memory.
Main Results:
- Negative association found between Aβ deposition and gray matter volume in the left inferior frontal cortex across all participants.
- Reduced gray matter volume in the posterior cingulate was observed in individuals with high Aβ deposition.
- Structural covariance analysis revealed distinct frontal and posterior brain networks associated with Aβ.
- Reduced gray matter volume in the frontal network correlated with poorer working memory, while the posterior network showed no such association.
Conclusions:
- Aβ deposition is associated with structural brain changes and cognitive alterations even in cognitively normal elderly individuals.
- Aβ-dependent gray matter loss in frontal networks differentially impacts cognitive functions like working memory during normal aging.
- Findings suggest distinct roles for frontal and posterior brain networks in mediating the effects of Aβ on cognition in aging.
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