P.S.M. and M.P. contributed equally to this work.
Structure and function of medial temporal and posteromedial cortices in early Alzheimer’s disease
Version of Record online: 21 JUN 2011
European Journal of Neuroscience © 2011 Federation of European Neuroscience Societies and Blackwell Publishing Ltd. No claim to original US government works
European Journal of Neuroscience
Volume 34, Issue 2, pages 320–330, July 2011
How to Cite
Miettinen, P. S., Pihlajamäki, M., Jauhiainen, A. M., Niskanen, E., Hänninen, T., Vanninen, R. and Soininen, H. (2011), Structure and function of medial temporal and posteromedial cortices in early Alzheimer’s disease. European Journal of Neuroscience, 34: 320–330. doi: 10.1111/j.1460-9568.2011.07745.x
- Issue online: 18 JUL 2011
- Version of Record online: 21 JUN 2011
- Received 5 May 2010, revised 4 April 2011, accepted 25 April 2011
- magnetic resonance imaging;
- mild cognitive impairment;
- parahippocampal cortex;
- posterior cingulate
Medial temporal lobe (MTL) atrophy and posteromedial cortical hypometabolism are consistent imaging findings in Alzheimer’s disease (AD). As the MTL memory structures are affected early in the course of AD by neurofibrillary tangle pathology, the posteromedial metabolic abnormalities have been postulated to represent remote effects of MTL alterations. In this study, we investigated with functional MRI (fMRI) the structure–function relationship between the MTL and posteromedial regions, including the retrosplenial, posterior cingulate and precuneal cortices, in 21 older controls (OCs), 18 subjects with amnestic mild cognitive impairment (MCI) and 16 AD patients during a word list learning task. In the voxel-based morphometric and volumetric analyses, the MCI subjects showed smaller entorhinal volume than OCs (P = 0.0001), whereas there was no difference in the hippocampal or posteromedial volume. AD patients, as compared with MCI patients, showed pronounced loss of volume in the entorhinal (P = 0.0001), hippocampal (P = 0.01) and posteromedial (P = 0.001) regions. The normal pattern of posteromedial fMRI task-induced deactivation during active encoding of words was observed bilaterally in the OCs, but only in restricted unilateral left posteromedial areas in the MCI and AD patients. Across all subjects, more extensive impairment of the retrosplenial and posterior cingulate function was significantly related to smaller entorhinal (P = 0.001) and hippocampal (P = 0.0002) volume. These findings demonstrate that entorhinal atrophy and posteromedial cortical dysfunction are early characteristics of prodromal AD, and precede and/or overwhelm atrophy of the hippocampus and posteromedial cortices. Disturbances in posteromedial cortical function are associated with morphological changes in the MTL across the continuum from normal aging to clinical AD.