Activity in dlPFC and its effective connectivity to vmPFC are associated with temporal discounting

Abstract

There is widespread interest in identifying computational and neurobiological mechanisms that influence the ability to choose long-term benefits over more proximal and readily available rewards in domains such as dietary and economic choice. We present the results of a human fMRI study that examines how neural activity relates to observed individual differences in the discounting of future rewards during an intertemporal monetary choice task. We found that a region of left dorsolateral prefrontal cortex (dlPFC) BA-46 was more active in trials where subjects chose delayed rewards, after controlling for the subjective value of those rewards. We also found that the connectivity from dlPFC BA-46 to a region of ventromedial prefrontal cortex (vmPFC) widely associated with the computation of stimulus values, increased at the time of choice, and especially during trials in which subjects chose delayed rewards. Finally, we found that estimates of effective connectivity between these two regions played a critical role in predicting out-of-sample, between-subject differences in discount rates. Together with previous findings in dietary choice, these results suggest that a common set of computational and neurobiological mechanisms facilitate choices in favor of long-term reward in both settings.

Neural mechanisms underlying the impact of daylong cognitive work on economic decisions

“…Perhaps surprisingly, the MFG cluster was not activated by the contrast between patient and impulsive choice, contrary to observations in some previous studies (5,26). This result might come from a limitation of our design.…”

“…Because choices were too noisy, it was impossible to fit a discounting model and provide a computational characterization of fatigue effects. However, our null result might help sort out different hypotheses that were suggested regarding the role of the LPFC in intertemporal choice (3,(26)(27)(28). More specifically, the increase in choice impulsivity could arise from a failure to inhibit the selection of immediate rewards (6) or from a change in the relative valuation of choice options (7).…”

The mediating role of LPFC–vmPFC functional connectivity in the relation between regulatory mode and delay discounting

“…These results suggested that regulatory mode may be related to the valuation network in goal pursuit. Neuroscience studies have found that vmPFC is a major region that computes the value of various options, suggesting that vmPFC may be an important region that relates to neural representation of valuation in regulatory mode [13,45]. Additionally, cognitive neuroscience research has suggested that successful self-regulation is dependent on top-down control from the prefrontal cortex over subcortical regions involved in reward and emotion [18,19,46,47].…”

Computational and neurobiological foundations of leadership decisions

“…The shrinkage and selection properties of the elastic net serve to reduce the likelihood of over-fitting to the training data set. For the elastic net analysis we used an alpha value of 0.3 following optimization performed in previous work from our lab (93). The leave-oneout cross-validation procedure first uses the data from n-1 participants to estimate model parameters.…”