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Updated: Jun 20, 2026
11:01
Examining the Characteristics of Episodic Memory using Event-related Potentials in Patients with Alzheimer's Disease
Published on: August 30, 2011
Semantic memory activation in individuals at risk for developing Alzheimer disease
M Seidenberg1, L Guidotti, K A Nielson
1Department of Psychology, Rosalind Franklin University of Medicine and Science, Chicago, IL, USA.
Neurology
|August 26, 2009
Summary
Healthy older adults with Alzheimer disease risk factors show increased brain activation during a memory task. This heightened activity, particularly in those with both family history and APOE epsilon4, may indicate a compensatory response.
Area of Science:
- Neuroimaging
- Cognitive Neuroscience
- Alzheimer's Disease Research
Background:
- Identifying early biomarkers for Alzheimer disease (AD) in cognitively asymptomatic individuals is crucial for timely intervention.
- Genetic risk factors, such as family history and the APOE epsilon4 allele, are associated with an increased likelihood of developing AD.
- Functional magnetic resonance imaging (fMRI) offers a non-invasive method to investigate brain activity patterns related to cognitive function and disease risk.
Purpose of the Study:
- To evaluate the utility of whole-brain, event-related fMRI in differentiating healthy older adults with AD risk factors from controls.
- To examine brain activation patterns during a semantic memory task involving the discrimination of famous versus unfamiliar names.
- To determine if AD risk factors influence brain activity in a dose-dependent manner.
Main Methods:
- Sixty-nine cognitively asymptomatic older adults were categorized into three groups based on AD risk: control (no risk factors), family history (FH), and family history plus APOE epsilon4 (FH+epsilon4).
- Participants completed a semantic memory task requiring the discrimination of famous from unfamiliar names.
- Event-related fMRI was employed, and hemodynamic response functions were extracted for famous and unfamiliar names using deconvolution analysis on correct trials.
Main Results:
- Individuals with AD risk factors (FH and FH+epsilon4 groups) exhibited greater brain activation when recognizing famous names compared to unfamiliar names, relative to the control group.
- Increased activation was observed primarily in the posterior cingulate/precuneus, temporoparietal junction, and prefrontal cortex, with a more pronounced effect in the FH+epsilon4 group.
- The control group showed greater activation for unfamiliar names than famous names, predominantly in the supplementary motor area, precentral gyrus, inferior frontal gyrus, insula, precuneus, and angular gyrus.
Conclusions:
- A simple semantic memory task is sensitive to Alzheimer disease risk factors in a dose-related manner among cognitively intact older adults.
- Elevated brain activation in at-risk individuals may represent a compensatory mechanism to maintain task performance despite underlying AD risk.
- fMRI during semantic memory tasks can potentially serve as a biomarker for preclinical Alzheimer disease.
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