Frontoparietal structural properties mediate adult life span differences in executive function

Zai-Fu Yao,Meng-Heng Yang,Kai Hwang,Shulan Hsieh

doi:10.1038/s41598-020-66083-w

Abstract

Executive function (EF) refers to a set of cognitive functions that support goal-directed behaviors. Recent findings have suggested that the frontoparietal network (FPN) subserves neural processes that are related to EF. However, the FPN structural and functional network properties that mediate age-related differences in EF components remain unclear. To this end, we used three experimental tasks to test the component processes of EF based on Miyake and Friedman’s model: one common EF component process (incorporating inhibition, shifting, and updating) and two specific EF component processes (shifting and updating). We recruited 126 healthy participants (65 females; 20 to 78 years old) who underwent both structural and functional MRI scanning. We tested a mediation path model of three structural and functional properties of the FPN (i.e., gray matter volume, white matter fractional anisotropy, and intra/internetwork functional connectivity) as mediators of age-related differences in the three EF components. The results indicated that age-related common EF component differences are mediated by regional gray matter volume changes in both hemispheres of the frontal lobe, which suggests that structural changes in the frontal lobe may have an indirect influence on age-related general elements of EF. These findings suggest that the FPN mediates age-related differences in specific components of EF.

Highlights

Executive function (EF) refers to a set of cognitive functions that support goal-directed behaviors
Given the substantial evidence that has implicated the frontoparietal cortices in EF23–25,35, we focused on the properties of the frontoparietal cortices
We sought to determine whether the structural and network properties of the frontoparietal cortices mediate age-related changes in EF and, further, to determine whether the mediation effect was selective for a specific EF component or whether it was a generalized pattern for all EF components

Summary

Introduction

Executive function (EF) refers to a set of cognitive functions that support goal-directed behaviors. The FPN structural and functional network properties that mediate age-related differences in EF components remain unclear To this end, we used three experimental tasks to test the component processes of EF based on Miyake and Friedman’s model: one common EF component process (incorporating inhibition, shifting, and updating) and two specific EF component processes (shifting and updating). We tested a mediation path model of three structural and functional properties of the FPN (i.e., gray matter volume, white matter fractional anisotropy, and intra/internetwork functional connectivity) as mediators of age-related differences in the three EF components. Studies that putatively test specific EFs, such as updating-specific EF26,27, shifting-specific EF28–32, and inhibitory-specific EF27,33,34, have consistently reported increased frontal and/or parietal activities This reliable relationship between EF and frontoparietal activities strongly suggests that frontoparietal properties may mediate age-related declines in EF. We sought to examine whether the aforementioned age-related declines in structural and functional brain changes are dissociable depending upon the EF component process being tested

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Conclusion