The Role of the Frontoparietal Network in the Effects of Education on Reasoning Ability in Healthy Elders

Abstract

In general, aging has a deleterious effect on cognitive functions such as executive functions and memory. Reasoning ability, one of the executive functions, being supported by problem solving by finding logical relations among given problems in novel situations, has been considered as a key element of adaptable behavior. In accordance with previous research, this ability, which has been known to be central to age-related differences in a wide range of cognitive abilities, is mainly susceptible to aging. There are, however, substantial inter-individual differences in cognitive decline in older adults. In particular, according to the concept of cognitive reserve (CR), years of education plays a protective role in age-related decline in cognitive functions and thus, more educated elders show less vulnerability to such disruptive changes. Based on recent numerous neuroimaging studies, the level of coherent activity within the frontoaprietal network especially at rest preferentially underlies such individual differences in reasoning ability. Unfortunately, there is little evidence of education effect on such temporally coherent activity at rest. However, given that more years of schooling were associated with higher temporal coherence in intrinsic activity as suggested by a recent study, it is expected that variations in the intra-network connectivity strength, possibly induced by formal education, may contribute to individual variability in cognitive decline with advancing age. In this sense, it is strongly hypothesized that formal education may be protective against a decline in reasoning ability with age, depending on the level of coherent activity within the frontoparietal network specifically at rest. In this study, the neural mechanism underlying the protective effect of education on age-related decline in reasoning ability was examined using independent component analysis (ICA) and power spectra analysis. As expected, the results showed that the effects of education on reasoning ability was mediated by the power spectra especially in the frontoparietal network. That is, the protective effect of education from the disruptive aging depends on higher level of coherent activity within the frontoparietal network at rest, showing relatively higher reasoning ability in more educated older adults. These results suggest that intra-network connectivity strength at rest could be one of the neural basis underlying education-related cognitive reserve (CR) in healthy elders, providing important clues to healthy brain aging.