Abstract
Human decision making can be influenced by presenting different options with positive or negative connotations. This phenomenon is termed the framing effect. Neuroeconomic studies have found that the amygdala plays a significant role in the framing effect, as it incorporates emotional (or intuitive) information into the decision process, which may lead to bias or irrationality. However, previous studies have focused only on the gain domain, in which the initial state is positive (appetitive). The mechanisms underlying the framing effect in the loss (aversive) domain are less well understood, despite their importance for evolution and survival. In this study, we first replicated the findings of De Martino et al. on the framing effect in the gain domain. We then searched for similarities and differences between the gain and loss domains using a similar experimental design combined with functional magnetic resonance imaging. Behaviorally, the participants showed comparable effects for both frame types, suggesting a frame-indiscriminate decision bias. In contrast, at the neuronal level, we found that the amygdala specifically represented the framing effect in the gain domain, and its connectivity to the ventromedial prefrontal cortex was positively modulated by the framing bias, similar to the findings of De Martino et al. However, the striatum was found to represent the framing effect in the loss domain. Striatal connectivity to the dorsomedial prefrontal cortex was similarly affected by the framing bias, suggesting domain-specific neural substrates. Our study emphasizes the importance of distinguishing between gain and loss domains when studying decision making, and highlights the governing role of the cortical-striatal-limbic network in the framing effect.