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Theoretical background:
The Apolipoprotein E (APOE) ε4 genotype is known to be one of the strongest single-gene predictors for Alzheimer disease, which is characterized by widespread brain structural degeneration progressing along with cognitive impairment. The ε4 allele status has been associated with brain structural alterations and lower cognitive ability in non-demented subjects. However, it remains unclear to what extent the visuospatial cognitive domain is affected, from what age onward changes are detectable and if alterations may interact with cognitive deficits in major depressive disorder (MDD). The current work investigated the effect of APOE ε4 homozygosity on visuospatial working memory (vWM) capacity, and on hippocampal morphometry. Furthermore, potential moderating roles of age and MDD were assessed.
Methods:
A sample of
n
= 31 homozygous ε4 carriers was contrasted with
n
= 31 non-ε4 carriers in a cross-sectional design. The sample consisted of non-demented, young to mid-age participants (mean age = 34.47;
SD
= 13.48; 51.6% female). Among them were
n
= 12 homozygous ε4 carriers and
n
= 12 non-ε4 carriers suffering from MDD (39%). VWM was assessed using the Corsi block-tapping task. Region of interest analyses of hippocampal gray matter density and volume were conducted using voxel-based morphometry (CAT12), and Freesurfer, respectively.
Results:
Homozygous ε4 carriers showed significantly lower Corsi span capacity than non-ε4 carriers did, and Corsi span capacity was associated with higher gray matter density of the hippocampus. APOE group differences in hippocampal volume could be detected but were no longer present when controlling for total intracranial volume. Hippocampal gray matter density did not differ between APOE groups. We did not find any interaction effects of age and MDD diagnosis on hippocampal morphometry.
Conclusion:
Our results point toward a negative association of homozygous ε4 allele status with vWM capacity already during mid-adulthood, which emerges independently of MDD diagnosis and age. APOE genotype seems to be associated with global brain structural rather than hippocampus specific alterations in young- to mid-age participants.
Organisation de Coopération et de Développement Économiques Organisation for Economic Cooperation and Development 19-Oct-2016 ___________________________________________________________________________________________ _____________ English-Or. English STATISTICS DIRECTORATE A REVIEW OF GENERAL SOCIAL SURVEYS WORKING PAPER No.75
La confiance entre les citoyens et leur administration est-elle en train de s'effondrer ? C'est l'idée même du « contrat social » cher à Jean-Jacques Rousseau, par lequel les citoyens libres acceptent volontairement, dans leur propre intérêt, de remettre le pouvoir entre les mains de l'État, qui pourrait être en jeu. Selon l'édition 2017 du rapport de l'OCDE Comment va la vie ?, 38 % seulement des citoyens des pays de l'OCDE déclarent avoir confiance en l'État ; contre environ 42 % en 2006. Pourquoi une telle « déconnexion » les citoyens et leurs élus ?
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