Title : 1 Neural basis of decision - making guided by emotional outcomes

37 Emotional events resulting from a choice influence an individual’s subsequent 38 decision-making. Although the relationship between emotion and decision-making has 39 been widely discussed, previous studies have mainly investigated decision outcomes 40 that can easily be mapped to reward and punishment, including monetary gain/loss, 41 gustatory stimuli, and pain. These studies regard emotion as a modulator of 42 decision-making that can be made rationally in the absence of emotions. In our daily 43 lives, however, we often encounter various emotional events that affect decisions by 44 themselves, and mapping the events to a reward or punishment is often not 45 straightforward. In this study, we investigated the neural substrates of how such 46 emotional decision outcomes affect subsequent decision-making. By using functional 47 magnetic resonance imaging (fMRI), we measured brain activities of humans during a 48 stochastic decision-making task in which various emotional pictures were presented as 49 decision outcomes. We found that pleasant pictures differentially activated the midbrain, 50 the fusiform gyrus, and the parahippocampal gyrus, whereas unpleasant pictures 51 differentially activated the ventral striatum, compared to neutral pictures. We assumed 52 that the emotional decision outcomes affect the subsequent decision by updating the 53 value of the options, a process modeled by reinforcement learning models, and that the 54 brain regions representing the prediction error that drives the reinforcement learning 55 are involved in guiding subsequent decisions. We found that some regions of the 56 striatum and the insula were separately correlated with the prediction error for either 57 pleasant pictures or unpleasant pictures, whereas the precuneus was correlated with 58 prediction errors for both pleasant and unpleasant pictures. 59 60