Neural correlates of incidental memory in mild cognitive impairment: An fMRI study

Mandzia, Jennifer L.; McAndrews, Mary Pat; Grady, Cheryl L.; Graham, Simon J.; Black, Sandra E.

doi:10.1016/j.neurobiolaging.2007.08.024

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Volume 30, Issue 5 , Pages 717-730, May 2009

Neural correlates of incidental memory in mild cognitive impairment: An fMRI study

Jennifer L. Mandzia
- L.C. Campbell Cognitive Neurology Research Unit, Neurosciences Research, Sunnybrook Health Sciences Centre, Canada
- Corresponding author at: c/o Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, A421, Toronto, Ontario, Canada M4N 3M5. Tel.: +1 416 480 4551; fax: +1 416 480 4552.
Mary Pat McAndrews
- University Health Network, Toronto Western Hospital and Research Institute, Canada
- Department of Psychology, University of Toronto, Canada
Cheryl L. Grady
- Rotman Research Institute and Baycrest Centre for Geriatric Care, Canada
- Department of Psychology, University of Toronto, Canada
- Department of Psychiatry, University of Toronto, Canada
Simon J. Graham
- Rotman Research Institute and Baycrest Centre for Geriatric Care, Canada
- Department of Medical Biophysics, University of Toronto, Faculty of Medicine, Canada
Sandra E. Black
- L.C. Campbell Cognitive Neurology Research Unit, Neurosciences Research, Sunnybrook Health Sciences Centre, Canada
- Department of Medicine, Division of Neurology, University of Toronto, Canada
- Rotman Research Institute and Baycrest Centre for Geriatric Care, Canada

Received 12 November 2006; received in revised form 28 August 2007; accepted 31 August 2007. published online 26 October 2007.

Abstract

Behaviour and fMRI brain activation patterns were compared during encoding and recognition tasks in mild cognitive impairment (MCI) (n=14) and normal controls (NC) (n=14). Deep (natural vs. man-made) and shallow (color vs. black and white) decisions were made at encoding and pictures from each condition were presented for yes/no recognition 20min later. MCI showed less inferior frontal activation during deep (left only) and superficial encoding (bilaterally) and in both medial temporal lobes (MTL). When performance was equivalent (recognition of words encoded superficially), MTL activation was similar for the two groups, but during recognition testing of deeply encoded items NC showed more activation in both prefrontal and left MTL region. In a region of interest analysis, the extent of activation during deep encoding in the parahippocampi bilaterally and in left hippocampus correlated with subsequent recognition accuracy for those items in controls but not in MCI, which may reflect the heterogeneity of activation responses in conjunction with different degrees of pathology burden and progression status in the MCI group.