Journal of the International Neuropsychological Society

Research Articles

Event-Related Functional Magnetic Resonance Imaging Changes during Relational Retrieval in Normal Aging and Amnestic Mild Cognitive Impairment

Kelly S. Giovanelloa1a2 c1, Felipe De Brigarda1a3, Jaclyn Hennessey Forda1, Daniel I. Kaufera4, James R. Burkea5a6, Jeffrey N. Browndykea5a7 and Kathleen A. Welsh-Bohmera5a6a7

a1 Department of Psychology, The University of North Carolina, Chapel Hill, North Carolina

a2 Biomedical Research Imaging Center, The University of North Carolina, Chapel Hill, North Carolina

a3 Department of Philosophy, The University of North Carolina, Chapel Hill, North Carolina

a4 Department of Neurology, The University of North Carolina, Chapel Hill, North Carolina

a5 Joseph & Kathleen Bryan Alzheimer's Disease Research Center, Duke University Medical Center, Durham, North Carolina

a6 Division of Neurology, Duke University Medical Center, Durham, North Carolina

a7 Department of Psychiatry & Behavioral Sciences, Duke University Medical Center, Durham, North Carolina

Abstract

The earliest cognitive deficits observed in amnestic mild cognitive impairment (aMCI) appear to center on memory tasks that require relational memory (RM), the ability to link or integrate unrelated pieces of information. RM impairments in aMCI likely reflect neural changes in the medial temporal lobe (MTL) and posterior parietal cortex (PPC). We tested the hypothesis that individuals with aMCI, as compared to cognitively normal (CN) controls, would recruit neural regions outside of the MTL and PPC to support relational memory. To this end, we directly compared the neural underpinnings of successful relational retrieval in aMCI and CN groups, using event-related functional magnetic resonance imaging (fMRI), holding constant the stimuli and encoding task. The fMRI data showed that the CN, compared to the aMCI, group activated left precuneus, left angular gyrus, right posterior cingulate, and right parahippocampal cortex during relational retrieval, while the aMCI group, relative to the CN group, activated superior temporal gyrus and supramarginal gyrus for this comparison. Such findings indicate an early shift in the functional neural architecture of relational retrieval in aMCI, and may prove useful in future studies aimed at capitalizing on functionally intact neural regions as targets for treatment and slowing of the disease course. (JINS, 2012, 18, 1–12)

(Received August 31 2011)

(Revised April 18 2012)

(Accepted April 19 2012)

Correspondence:

c1 Correspondence and reprint requests to: Kelly S. Giovanello, Department of Psychology, The University of North Carolina, Campus Box 3270, Chapel Hill, NC 27713. E-mail: kgio@unc.edu