Entorhinal cortex structure and functional MRI response during an associative verbal memory task

Authors

  • Meredith N. Braskie,

    1. Ahmanson-Lovelace Brain Mapping Center, David Geffen School of Medicine, University of California, Los Angeles, California
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  • Gary W. Small,

    1. Department of Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, California
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  • Susan Y. Bookheimer

    Corresponding author
    1. Ahmanson-Lovelace Brain Mapping Center, David Geffen School of Medicine, University of California, Los Angeles, California
    2. Department of Psychiatry and Biobehavioral Science, David Geffen School of Medicine, University of California, Los Angeles, California
    3. Department of Psychology, University of California, Los Angeles, California
    • UCLA Department of Psychiatry and Biobehavioral Science, Box 951759, 760 Westwood Plaza, C8-881 Semel Institute, Los Angeles, CA 90095-1759, USA
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  • Disclosure: The authors have no actual or potential conflicts of interest. However, they disclose the following: The University of California, Los Angeles, owns a U.S. patent (6,274,119) entitled “Methods for Labeling Beta-Amyloid Plaques and Neurofibrillary Tangles,” which has been licensed to Siemens. Dr. Small is among the inventors, has received royalties, and will receive royalties on future sales. Dr. Small reports having served as a consultant and/or having received lecture fees from Abbott, Dakim, Eisai, Forest, Mattel, Myriad Genetics, Novartis, Ortho-McNeil, Pfizer, Radica, Siemens, and Medivation. Dr. Small also reports having received stock options from Dakim. M.N.B. was supported by an Individual National Research Service Award (F31 NS45425) from the National Institutes of Health/National Institute of Neurological Disorders and Stroke, and by a scholarship from ARCS Foundation, Inc./The John Douglas French Alzheimer's Foundation (with the Erteszek Foundation)

  • M.N.B. was supported by an Individual National Research Service Award (F31 NS45425) from the National Institutes of Health/National Institute of Neurological Disorders and Stroke, and by a scholarship from ARCS Foundation, Inc./The John Douglas French Alzheimer's Foundation (with the Erteszek Foundation).

Abstract

Entorhinal cortex (ERC) volume in adults with mild cognitive impairment has been shown to predict prodromal Alzheimer's disease (AD). Likewise, neuronal loss in ERC has been associated with AD, but not with normal aging. Because ERC is part of a major pathway modulating input to the hippocampus, structural changes there may result in changes to cognitive performance and functional brain activity during memory tasks. In 32 cognitively intact older adults, we examined the relationship between left ERC thickness and functional magnetic resonance imaging (fMRI) activity during an associative verbal memory task. This task has been shown previously to activate regions that are sensitive to aging and AD risk. ERC was manually defined on native space, high resolution, oblique coronal MRI scans. Subjects having thicker left ERC showed greater activation in anterior cingulate and medial frontal regions during memory retrieval, but not encoding. This result was independent of hippocampal volume. Anterior cingulate cortex is directly connected to ERC, and is, along with medial frontal cortex, implicated in error detection, which is impaired in AD. Our results suggest that in healthy older adults, processes that engage frontal regions during memory retrieval are related to ERC structure. Hum Brain Mapp, 2009. © 2009 Wiley-Liss, Inc.

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