Elsevier

NeuroImage

Volume 47, Supplement 1, July 2009, Page S139
NeuroImage

Distinct patterns of brain activity in young carriers of the APOE e4 allele

https://doi.org/10.1016/S1053-8119(09)71381-3Get rights and content

Introduction

Several reports have documented effects of the apolipoprotein E (APOE) allelic variants on the brain in health and disease. In particular, the APOE ɛ4 allele is considered the best established genetic risk factor for sporadic early and late onset Alzheimer's disease (AD) and it is also associated with a higher risk of age-related cognitive impairment among the elderly. Previous functional imaging studies have reported greater activation in middle age/elderly APOE ɛ4-carriers relative to non-carriers. However, it is not clear whether structural or blood-flow alterations underlie these differences, or at what age they manifest.

Section snippets

Methods

Eighteen subjects carrying the APOE ɛ4 allele and 18 matched controls underwent a neuroimaging protocol involving structural MRI (sMRI), functional MRI (fMRI), using blood oxygen level-dependent (BOLD), both task-based and at rest, and arterial spin labelling (ASL) at rest. An encoding memory task (“familiar” vs “novel”), presented in a blocked design fashion, was used to target medial-temporal (MTL) regions.

Results

Carriers and non-carriers were matched for socio-demographic factors. No differences in memory performance, brain morphology or total cerebral blood flow were found between the two groups. As expected increases in fMRI BOLD signal amplitude were observed in MTL regions and in brain regions located in the parietal and occipital lobes when participants were presented with “novel” images compared with “familiar” images regardless of the APOE allele status. The amplitude of activation in the

Conclusions

Young people with an APOE ɛ4 allele have alterations in brain function relative to non-carriers without obvious differences in morphology, resting blood flow or cognitive performance. Therefore, BOLD fMRI emerges as the most sensitive measure of genotypic differences. Moreover, these data indicate that the APOE ɛ4 allelic variant modulates brain function decades before any clinical or neurophysiological expression of neurodegenerative processes.

References (0)

Cited by (0)

View full text