Differential neural mechanisms underlying temporal discounting of financial gain and loss

Abstract

The decision-making process of humans has been investigated by several disciplines including economics, psychology, neuroscience, and recently collaborated endeavors called neuroeconomics. Among variables involved in the complex process, valence and time play a key role in diverse decision-making situations. Previous studies in neuroscience, in addition to economics, have explored neural mechanisms underlying intertemporal choice, in particular, temporal discounting of primary or secondary rewards. However, it remains elusive whether temporal discounting of financial loss is different from that of financial gain at behavioral and neuronal level. In this study, we used functional Magnetic Resonance Imaging (fMRI) to examine neural mechanisms underpinning the temporal discounting of financial losses with a serial decision-making model. As a result, shape of the discounting function in the aversive frame is hyperbolic as in the appetitive context. However, a decay rate of the hyperbolic discounting function in the domain of loss is smaller than that in the gain domain. In addition, neural activities in posterior cingulate cortex (PCC), medial prefrontal cortex (mPFC), caudate nucleus, and substantia nigra (SN) represent subjective values or their differentials of financial gains. In the aversive frame, mPFC, dorsolateral prefrontal cortex (DLPFC), and ventral striatum (VS) are implicated in the estimation of the subjective values and their differentials. These findings contribute to a better understanding of human economic behavior, and open the door for further studies to dissociate the high-level intertemporal choice from other related behaviors such as self-control, uncertainty, time perception.