title: Decreased Inter-Hemispheric Functional Connectivity in Cognitively Intact Elderly APOE ɛ4 Carriers: A Preliminary Study.
abstract: The apolipoprotein E (APOE) ɛ4 allele is the best-known genetic risk factor for developing sporadic Alzheimer's disease (AD). According to neuroimaging studies, the APOE ɛ4 allele is associated with localized altered brain function. However, in long-range circuitry, APOE ɛ4 allele-related alterations in functional communication between hemispheres have rarely been directly investigated. We examined the alteration of resting-state functional connectivity (RSFC) between inter-hemispheric homotopic regions in cognitively intact, elderly APOE ɛ4 carriers. The voxel-mirrored homotopic connectivity method was used to assess the inter-hemispheric RSFC. The current study included 13 cognitively intact, elderly APOE ɛ4 carriers (with at least one copy of APOE ɛ4 allele) and 22 well-matched ɛ3 homozygotes. Comparisons between the two groups were conducted, and subsequently, the correlation between the differential inter-hemispheric RSFC and cognitive ability was analyzed. Compared with ɛ3 homozygotes, APOE ɛ4 carriers showed decreased inter-hemispheric RSFC in the bilateral medial temporal lobe (MTL) and orbital frontal cortex (OFC). Moreover, in APOE ɛ4 carriers, the inter-hemispheric RSFC of the MTL correlated with the Wechsler Memory Scale-Logical Memory (WMS-LM) (immediate and delayed performance, r = 0.64, p <  0.05; r = 0.65, p <  0.05, respectively), and the inter-hemispheric RSFC of the OFC correlated with the WMS-LM delayed performance (r = 0.71, p <  0.05). In our study, the presence of the APOE ɛ4 allele was linked with decreased inter-hemispheric RSFC, which was attributed to memory performance in carriers.
authors.forename: Xiao
authors.initials: X
authors.lastname: Luo
authors.forename: Tiantian
authors.initials: T
authors.lastname: Qiu
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Xu
authors.forename: Peiyu
authors.initials: P
authors.lastname: Huang
authors.forename: Quanquan
authors.initials: Q
authors.lastname: Gu
authors.forename: Zhujing
authors.initials: Z
authors.lastname: Shen
authors.forename: Xinfeng
authors.initials: X
authors.lastname: Yu
authors.forename: YunLu
authors.initials: Y
authors.lastname: Jia
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Guan
authors.forename: Ruirui
authors.initials: R
authors.lastname: Song
authors.forename: Minming
authors.initials: M
authors.lastname: Zhang
mesh_terms: D000368:Aged; D000375:Aging / Q000235:genetics* / Q000502:physiology* / Q000523:psychology; D053327:Apolipoprotein E4 / Q000235:genetics*; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D060005:Genotyping Techniques; D006579:Heterozygote; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory / Q000502:physiology; D009483:Neuropsychological Tests; D012146:Rest
chemical_list: D053327:Apolipoprotein E4
keywords: Alzheimer’s disease; apolipoprotein E; corpus callosum; functional magnetic resonance imaging; memory