Reduced cortical thickness in hippocampal subregions among cognitively normal apolipoprotein E e4 carriers

A.C. Burggren, M.M. Zeineh, A.D. Ekstrom, M.N. Braskie, P.M. Thompson, G.W. Small, S.Y. Bookheimer
2008 NeuroImage  
Our objective was to investigate whether asymptomatic carriers of apolipoprotein E ε4 [APOE-4] demonstrate pathological differences and atrophy in medial temporal lobe (MTL) sub-regions. We measured cortical thickness and volume in MTL sub-regions (hippocampal CA fields 1, 2 and 3; dentate gyrus; entorhinal cortex; subiculum; perirhinal cortex; parahippocampal cortex; and fusiform gyrus) using a high-resolution in-plane (.4×.4mm) MRI sequence in 30 cognitively normal volunteers (14 APOE-4
more » ... rs, 16 non-carriers, mean age 57 years). A cortical unfolding procedure maximized visibility of this convoluted cortex, providing cortical ribbon thickness measures throughout individual subregions of the hippocampus and surrounding cortex. APOE-4 carriers had reduced cortical thickness compared with non-carriers in entorhinal cortex (ERC) and the subiculum (Sub), but not in the main hippocampal body or perirhinal cortex. Average cortical thickness was 14.8% lower (p=1.0e −6 ) for ERC and 12.6% lower (p=6.8e −5 ) for Sub in APOE-4 carriers. Standard volumetric measures of the same regions showed similar, but non-significant trends. Cognitively intact carriers of APOE-4 show regionally specific thinning of the cortical ribbon compared to APOE-3 carriers; cortical thickness may be a more sensitive measure of pathological differences in genetic risk subjects than standard volumetry.
doi:10.1016/j.neuroimage.2008.03.039 pmid:18486492 pmcid:PMC2601686 fatcat:m2rt3rbx2vc4bhwjm3ypdhp674