Reward and Novelty Enhance Imagination of Future Events in a Motivational-Episodic Network.

Lisa Bulganin,Bianca C Wittmann

doi:10.1371/journal.pone.0143477

Abstract

Thinking about personal future events is a fundamental cognitive process that helps us make choices in daily life. We investigated how the imagination of episodic future events is influenced by implicit motivational factors known to guide decision making. In a two-day functional magnetic resonance imaging (fMRI) study, we controlled learned reward association and stimulus novelty by pre-familiarizing participants with two sets of words in a reward learning task. Words were repeatedly presented and consistently followed by monetary reward or no monetary outcome. One day later, participants imagined personal future events based on previously rewarded, unrewarded and novel words. Reward association enhanced the perceived vividness of the imagined scenes. Reward and novelty-based construction of future events were associated with higher activation of the motivational system (striatum and substantia nigra/ ventral tegmental area) and hippocampus, and functional connectivity between these areas increased during imagination of events based on reward-associated and novel words. These data indicate that implicit past motivational experience contributes to our expectation of what the future holds in store.

Highlights

When we envision our personal future, we often imagine events as coherent scenarios unfolding in a specific place at a specific time
Post-hoc t-tests on vividness ratings showed higher vividness for the reward compared to the novelty condition (t20 = 3.17, p = .01, d = 0.32) and a trend towards higher vividness for the reward compared to the neutral condition (t20 = 2.07, p = .051, d = 0.16), with no difference between the novelty and neutral conditions (t20 = -1.55, p = .14)
These results are consistent with the hypothesis that the imagination of personal future events is enhanced for events constructed around novel stimuli and stimuli associated with past reward experience

Summary

Introduction

When we envision our personal future, we often imagine events as coherent scenarios unfolding in a specific place at a specific time. Imagining the future has been shown to depend on our capacity to remember past episodes, and an overlapping network of brain regions support the construction of future episodes and the recollection of the past (for a review, see [1]). While the importance of episodic memory to the imagination of future events is well supported, the role of implicit memory has not been addressed yet. A central component of learned motivational value is the expectation of reward elicited by stimuli associated with reward in the past. These reward-predicting stimuli activate a network of regions

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Results

Conclusion