Neuroanatomy accounts for age-related changes in risk preferences.

Michael A Grubb,Agnieszka Tymula,Paul W Glimcher,Sharon Gilaie-Dotan,Ifat Levy

doi:10.1038/ncomms13822

Abstract

Many decisions involve uncertainty, or ‘risk', regarding potential outcomes, and substantial empirical evidence has demonstrated that human aging is associated with diminished tolerance for risky rewards. Grey matter volume in a region of right posterior parietal cortex (rPPC) is predictive of preferences for risky rewards in young adults, with less grey matter volume indicating decreased tolerance for risk. That grey matter loss in parietal regions is a part of healthy aging suggests that diminished rPPC grey matter volume may have a role in modulating risk preferences in older adults. Here we report evidence for this hypothesis and show that age-related declines in rPPC grey matter volume better account for age-related changes in risk preferences than does age per se. These results provide a basis for understanding the neural mechanisms that mediate risky choice and a glimpse into the neurodevelopmental dynamics that impact decision-making in an aging population.

Highlights

Many decisions involve uncertainty, or ‘risk’, regarding potential outcomes, and substantial empirical evidence has demonstrated that human aging is associated with diminished tolerance for risky rewards
Which neurobiological markers of aging might be associated with this change in preference? We recently identified a region in right posterior parietal cortex whose grey matter volume (GMV) accounts for individual variation in risk preferences in young adults, such that decreased rPPC GMV is predictive of increased risk aversion[7]
We modelled the expected utility (EU) of each option using the functional form: EUðv; pÞ1⁄4p Á va where v 1⁄4 value, p 1⁄4 probability, and a 1⁄4 the risk preference parameter, with larger alpha values indicative of increased risk tolerance

Summary

Introduction

‘risk’, regarding potential outcomes, and substantial empirical evidence has demonstrated that human aging is associated with diminished tolerance for risky rewards. We report evidence for this hypothesis and show that age-related declines in rPPC grey matter volume better account for age-related changes in risk preferences than does age per se These results provide a basis for understanding the neural mechanisms that mediate risky choice and a glimpse into the neurodevelopmental dynamics that impact decision-making in an aging population. We recently identified a region in right posterior parietal cortex (rPPC) whose grey matter volume (GMV) accounts for individual variation in risk preferences in young adults, such that decreased rPPC GMV is predictive of increased risk aversion[7]. We tested this hypothesis in a sample of urban adults whose ages span seven decades Though both older age and decreased rPPC GMV are associated with risk tolerance, when the independent contributions of these factors are assessed, rPPC GMV still accounts for changes in risk tolerance, whereas age does not.

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