Abnormal connectivity in the posterior cingulate and hippocampus in early Alzheimer's disease and mild cognitive impairment

Zhou, Yongxia; Dougherty, John H.; Hubner, Karl F.; Bai, Bing; Cannon, Rex L.; Hutson, R. Kent

doi:10.1016/j.jalz.2008.04.006

« Previous Next »Alzheimer's & Dementia: The Journal of the Alzheimer's Association
Volume 4, Issue 4 , Pages 265-270, July 2008

Abnormal connectivity in the posterior cingulate and hippocampus in early Alzheimer's disease and mild cognitive impairment

Yongxia Zhou
- Department of Radiology, Graduate School of Medicine, University of Tennessee, Knoxville, TN, USA
- Cole Neuroscience Center, Graduate School of Medicine, University of Tennessee, Knoxville, TN, USA
John H. Dougherty Jr
- Department of Radiology, Graduate School of Medicine, University of Tennessee, Knoxville, TN, USA
- Cole Neuroscience Center, Graduate School of Medicine, University of Tennessee, Knoxville, TN, USA
- Division of Neurology, Department of Medicine, Graduate School of Medicine, University of Tennessee, Knoxville, TN, USA
- Corresponding author. Tel.: 865-544-6740; Fax: 865-544-6745.
Karl F. Hubner
- Department of Radiology, Graduate School of Medicine, University of Tennessee, Knoxville, TN, USA
Bing Bai
- Siemens Molecular Imaging, Knoxville, TN, USA
Rex L. Cannon
- Cole Neuroscience Center, Graduate School of Medicine, University of Tennessee, Knoxville, TN, USA
R. Kent Hutson
- Department of Radiology, Graduate School of Medicine, University of Tennessee, Knoxville, TN, USA

Abstract

Background

Brain imaging studies of early Alzheimer's disease (AD) have shown decreased metabolism predominantly in the posterior cingulate cortex (PCC), medial temporal lobe, and inferior parietal lobe. This study investigated functional connectivity between these regions, as well as connectivity between these regions and the whole brain.

Methods

Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) studies were performed in subjects with early AD, mild cognitive impairment (MCI), and normal controls.

Results

The data indicate both decreased fiber connections and disrupted connectivity between the hippocampus and PCC in early AD. The MCI group showed reduced fiber numbers derived from PCC and hippocampus to the whole brain.

Conclusions

The fMRI and DTI results confirmed decreased connectivity from both the PCC and hippocampus to the whole brain in MCI and AD and reduction in connectivity between these two regions, which plausibly represents an early imaging biomarker for AD.

Keywords: Alzheimer's disease, Mild cognitive impairment, Connectivity, Diffusion tensor imaging, Default mode functional MRI, Posterior cingulate cortex