Structural hippocampal network alterations during healthy aging: a multi-modal MRI study.
Front. Aging Neurosci.. 2013-01-01; 5:
DOI: 10.3389/fnagi.2013.00084
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1. Front Aging Neurosci. 2013 Dec 5;5:84. doi: 10.3389/fnagi.2013.00084. eCollection
2013.
Structural hippocampal network alterations during healthy aging: a multi-modal
MRI study.
Pelletier A(1), Periot O(2), Dilharreguy B(3), Hiba B(4), Bordessoules M(2),
Pérès K(5), Amieva H(5), Dartigues JF(5), Allard M(6), Catheline G(1).
Author information:
(1)University of Bordeaux, INCIA, UMR 5287 Talence, France ; CNRS, INCIA, UMR
5287 Talence, France ; EPHE Bordeaux, France.
(2)University of Bordeaux, INCIA, UMR 5287 Talence, France ; CNRS, INCIA, UMR
5287 Talence, France ; CHU de Bordeaux, Service de Médecine Nucléaire Bordeaux,
France.
(3)University of Bordeaux, INCIA, UMR 5287 Talence, France ; CNRS, INCIA, UMR
5287 Talence, France.
(4)RMSB, UMR 5536 Bordeaux, France.
(5)Université de Bordeaux, ISPED, Centre ISPED, INSERM U 897 Bordeaux, France.
(6)University of Bordeaux, INCIA, UMR 5287 Talence, France ; CNRS, INCIA, UMR
5287 Talence, France ; EPHE Bordeaux, France ; CHU de Bordeaux, Service de
Médecine Nucléaire Bordeaux, France.
While hippocampal atrophy has been described during healthy aging, few studies
have examined its relationship with the integrity of White Matter (WM) connecting
tracts of the limbic system. This investigation examined WM structural damage
specifically related to hippocampal atrophy in healthy aging subjects (n = 129),
using morphological MRI to assess hippocampal volume and Diffusion Tensor Imaging
(DTI) to assess WM integrity. Subjects with Mild Cognitive Impairment (MCI) or
dementia were excluded from the analysis. In our sample, increasing age was
significantly associated with reduced hippocampal volume and reduced Fractional
Anisotropy (FA) at the level of the fornix and the cingulum bundle. The findings
also demonstrate that hippocampal atrophy was specifically associated with
reduced FA of the fornix bundle, but it was not related to alteration of the
cingulum bundle. Our results indicate that the relationship between hippocampal
atrophy and fornix FA values is not due to an independent effect of age on both
structures. A recursive regression procedure was applied to evaluate sequential
relationships between the alterations of these two brain structures. When both
hippocampal atrophy and fornix FA values were included in the same model to
predict age, fornix FA values remained significant whereas hippocampal atrophy
was no longer significantly associated with age. According to this latter
finding, hippocampal atrophy in healthy aging could be mediated by a loss of
fornix connections. Structural alterations of this part of the limbic system,
which have been associated with neurodegeneration in Alzheimer’s disease, result
at least in part from the aging process.
DOI: 10.3389/fnagi.2013.00084
PMCID: PMC3852215
PMID: 24367331