Altered deactivation in individuals with genetic risk for Alzheimer's disease
2008 (English)In: Neuropsychologia, ISSN 0028-3932, Vol. 46, no 6, 1679-1687 p.Article in journal (Refereed) Published
Regions that show task-induced deactivations may be part of a default-mode network related to processes that are more engaged during passive than active task conditions. Alteration of task-induced deactivations with age and dementia is indicated by atypical engagement of default-mode network regions. Genetic studies show a relation between the apolipoprotein E4 (<i>APOE4</i>) allele and the common form of Alzheimer’s disease (AD), and altered functional brain activation has been observed in non-demented <i>APOE4</i> carriers compared to non-carriers. Here we investigate the hypothesis of altered default-mode network brain responses in individuals with genetic risk for AD. Functional MRI was used to assess task-induced deactivation in 60 subjects of which 30 carried at least one copy of the <i>APOE4</i> allele, and 30 non-carriers. Subjects were scanned while performing a semantic categorization task shown to promote episodic memory encoding. The results show patterns of deactivation consistent with the default-mode network. We also found reduced deactivation in non-demented <i>APOE4</i> carriers compared to non-carriers, suggesting alterations in the default-mode network in the absence of dementia. These results implicate possibilities for investigatin altered properties of task-induced deactivations in individuals with genetic risk for AD, and may prove useful for pre-clinical identification of individuals susceptible to memory problems and AD.
Place, publisher, year, edition, pages
2008. Vol. 46, no 6, 1679-1687 p.
deactivation, aging, APOE, genetics, AD, Alzheimer’s disease, fMRI, compensation, memory encoding
IdentifiersURN: urn:nbn:se:su:diva-14738DOI: doi:10.1016/j.neuropsychologia.2008.01.026ISI: 000257128200010PubMedID: 18346764OAI: oai:DiVA.org:su-14738DiVA: diva2:181258