Temporal lobe functional activity and connectivity in young adult APOE ɛ4 carriers

Alzheimer's & Dementia - Tập 6 - Trang 303-311 - 2010
Nancy A. Dennis1,2, Jeffrey N. Browndyke3,4,5, Jared Stokes1, Anna Need6, James R. Burke3,7, Kathleen A. Welsh-Bohmer3,4,7, Roberto Cabeza1,5
1Center for Cognitive Neuroscience, Duke University, Durham, NC, USA
2Department of Psychology, Pennsylvania State University, University Park, PA, USA
3Joseph and Kathleen Bryan Alzheimer’s Disease Research Center, Duke University, Durham, NC, USA
4Division of Medical Psychology, Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
5Duke Institute for Brain Sciences, Duke University, Durham, NC, USA
6Institute for Genome Sciences and Policy, Duke University, Durham, NC, USA
7Division of Neurology, Department of Medicine, Duke University Medical Center, Durham, NC, USA

Tóm tắt

BackgroundWe sought to determine if the APOE ε4 allele influences both the functional activation and connectivity of the medial temporal lobes (MTLs) during successful memory encoding in young adults.MethodsTwenty‐four healthy young adults, i.e., 12 carriers and 12 noncarriers of the APOE ε4 allele, were scanned in a subsequent‐memory paradigm, using event‐related functional magnetic resonance imaging. The neuroanatomic correlates of successful encoding were measured as greater neural activity for subsequently remembered versus forgotten task items, or in short, encoding success activity (ESA). Group differences in ESA within the MTLs, as well as whole‐brain functional connectivity with the MTLs, were assessed.ResultsIn the absence of demographic or performance differences, APOE ε4 allele carriers exhibited greater bilateral MTL activity relative to noncarriers while accomplishing the same encoding task. Moreover, whereas ε4 carriers demonstrated a greater functional connectivity of ESA‐related MTL activity with the posterior cingulate and other peri‐limbic regions, reductions in overall connectivity were found across the anterior and posterior cortices.ConclusionsThese results suggest that the APOE ɛ4 allele may influence not only functional activations within the MTL, but functional connectivity of the MTLs to other regions implicated in memory encoding. Enhanced functional connectivity of the MTLs with the posterior cingulate in young adult ε4 carriers suggests that APOE may be expressed early in brain regions known to be involved in Alzheimer's disease, long before late‐onset dementia is a practical risk or consideration. These functional connectivity differences may also reflect pleiotropic effects of APOE during early development.

Tài liệu tham khảo

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Alzheimer's & Dementia

Tập 6

303-311

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