Subcortical amyloid relates to cortical morphology in cognitively normal individuals
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European journal of nuclear medicine and molecular imaging ; vol. 46, p. 2358-2369.Éditeur·s
SpringerAuteur·e·s
Résumé·s
Purpose Amyloid (Aβ) brain deposition can occur in cognitively normal individuals and is associated with cortical volume
abnormalities. Aβ-related volume changes are inconsistent across studies. Since volume is composed of surface area and
thickness, the relative contribution of Aβ deposition on each of these metrics remains to be understood in cognitively normal
individuals.
Methods A group of 104 cognitively normal individuals underwent neuropsychological assessment, PiB-PET scan, and MRI
acquisition. Surface-based cortical analyses were performed to investigate the effects of cortical and subcortical Aβ burden on
cortical volume, thickness, and surface area. Mediation analyses were used to study the effect of thickness and surface area on
Aβ-associated volume changes. We also investigated the relationships between structural metrics in clusters with abnormal
morphology and regions underlying resting-state functional networks and cognitive performance.
Results Cortical Aβ was not associated with cortical morphology. Subcortical Aβ burden was associated with changes in cortical
volume, thickness, and surface area. Aβ-associated volume changes were driven by cortical surface area with or without
thickness but never by thickness alone. Aβ-associated changes overlapped greatly with regions from the default mode network
and were associated with lower performance in visuospatial abilities, episodic memory, and working memory.
Conclusions In cognitively normal individuals, subcortical Aβ is associated with cortical volume, and this effect was driven by
surface area with or without thickness. Aβ-associated cortical changes were found in the default mode network and affected
cognitive performance. Our findings demonstrate the importance of studying subcortical Aβ and cortical surface area in normal
ageing
Autre·s localisation·s
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