Structural and functional neural correlates of visuospatial information processing in normal aging and amnestic mild cognitive impairment.

Our understanding of cognitive changes related to human aging and their underlying neural processes is challenged by the distinction between normal and pathological aging. In our study, the neural correlates of visuospatial working memory (VSWM) in young persons (YC), healthy older adults (HC) and patients with amnestic mild cognitive impairment (aMCI) were investigated. Effects of the genetic risk factor apolipoprotein E (ApoE) ε4 on a VSWM task were analyzed for HC and aMCI patients. Higher cortical activation in extrastriate occipital regions and significantly decreased brain volumes in frontoparietal areas were observed in HC compared with young persons. Also, reduced cortical activation in the right middle frontal gyrus and superior frontal gyrus was observed in aMCI-patients compared with HC. Thus, attenuated cortical activation during VSWM tasks is related to the formation of aMCI and may serve as an early marker for cognitive decline. In contrast to previous studies, no significant apolipoprotein E-linked differences were found between HC and aMCI groups.