Rieck J, Rodrigue K, Kennedy K, Hebrank A, Devous, Sr. M, Park D.
Elevated Beta-Amyloid Burden is Associated with Neural Differences in Face Processing in Healthy, Non-Demented Older Adults.Human Amyloid Imaging Abstract.
2012 Jan 1;
Impaired face recognition is a commonly reported deficit in aging and Alzheimer’s disease (AD). The fusiform gyrus is a key region involved in processing facial features (Kanwisher et al.,997). Previous research provides evidence that this region shows less neural selectivity with normal aging (Park et al.,004). The current study investigated the role of in vivo beta-amyloid deposition, a putative biomarker of AD, in the neural processing of faces in a sample of healthy, non-demented older adults.
Participants underwent8F-Florbetapir PET imaging to measure beta-amyloid load and also completed a functional MRI task designed to measure neural activation while viewing faces and other categories of objects. A total of0 cognitively-healthy adults distributed across three groups participated in the study:4 young adult controls (mean age =2.7±2.0 years, mean SUVR =.08),8 low beta-amyloid older adults (mean age =4.0 ±.1 years, mean SUVR =1.14) and8 high beta-amyloid older adults (mean age =74.1 ±.7 years, mean SUVR =1.50).
Multivariate pattern analysis of neural activity in the fusiform gyrus revealed that high beta-amyloid adults showed considerably different patterns of neural activation compared to demographically matched low beta-amyloid adults. Our results suggest these differences are driven by reduced neural activity in the fusiform gyrus for the high beta-amyloid group. Furthermore, these differences in neural activity were strongly associated with greater beta-amyloid burden in the precuneus, anterior cingulate, and posterior cingulate regions, but not occipital region.
Overall, elevated beta-amyloid in older adults is associated with a reduced neural response to human faces, compared to both young adults and older adults with a lower beta-amyloid load. We conclude that elevated beta-amyloid deposition, even in healthy adults, may be one of the mechanisms underpinning the neural changes in face processing that occur with aging.
Supported in part by NIH grantsR37AG-006265-25,R37AG-006265-25S1, and Alzheimer’s Association grant IIRG-09-135087. Radiotracer was generously provided to the study by Avid Radiopharmaceuticals.