Interactions of Motivation and Cognitive Control in Older Adult Decision-Making (Braver, PI) R21AG058206
This project explores the neural and psychological mechanisms that underlie older adult decision-making. Basic research in the cognitive neuroscience of aging has suggested that older adults show declines in the ability to control thoughts and actions based on internal goals, and that this may stem from age-related changes in the function of the lateral prefrontal cortex and mid-brain dopamine system. Yet currently, very little is known about whether and how these cognitive and neural changes associated with advancing age impact different forms of decision-making. The current proposal provides a novel perspective on this issue, by focusing on interactions between motivation and cognitive control. Decisions that are both high in motivational value but also heavy in cognitive demand are likely to be some of the most salient and impactful in every day life for older adults, including health choices (what to eat and drink; whether and how often to exercise; medications, treatments, and drugs to take), social interactions (who to approach and who to avoid, whether to pursue solitary or group activities), and financial decisions (what to purchase, how much to save, whether to gamble or purchase insurance) Yet currently almost nothing is known about how motivation – cognitive control interactions change with advancing age or their impact on decision-making. The proposal relies on a recent theoretical framework, value-based cognitive control (VBCC), which postulates that motivational value serves to counteract the subjective and computational costs of engaging in cognitive control. A key implication of the VBCC framework is that age-related changes in decision-making should be most prominent under conditions that make the highest demands on motivation-cognition integration functions. The project directly tests this hypothesis, utilizing innovative and powerful new experimental paradigms and state-of-the-art neuroimaging methods to provide insight into the core neural mechanisms underlying age-related changes in decision-making. In Aim 1 the focus is on age differences in the control mechanisms that enable motivational integration, using a novel task in which the subjective motivational value of cognitive task performance varies as a function of both the monetary and liquid incentives available. In Aim 2, the focus is on age differences in the control mechanisms that enable delay-of-gratification, using a new task probing self-control in terms of repeated decisions to wait for a delayed reward, while foregoing an immediately available one. In both Aims, the central prediction is that older adults will show a reduced ability to successfully modulate cognitive control processes in lateral prefrontal cortex when this depends on integrating neural signals of current motivational value (arising from dopaminergic circuits involve the ventromedial prefrontal cortex and ventral striatum). This project will provide a necessary basic science foundation that has the potential to translate into a more comprehensive understanding of the key factors that impact older adult decision-making behaviors, and how to address and compensate for these when necessary.