Functional Dissociations of Risk and Reward Processing in the Medial Prefrontal Cortex

Abstract

Making a risky decision is a complex process that involves evaluation of both the value of the options and the associated risk level. Yet the neural processes underlying these processes have not so far been clearly identified. Using functional magnetic resonance imaging and a task that simulates risky decisions, we found that the dorsal region of the medial prefrontal cortex (MPFC) was activated whenever a risky decision was made, but the degree of this activity across subjects was negatively correlated with their risk preference. In contrast, the ventral MPFC was parametrically modulated by the received gain/loss, and the activation in this region was positively correlated with an individual's risk preference. These results extend existing neurological evidence by showing that the dorsal and ventral MPFC convey different decision signals (i.e., aversion to uncertainty vs. approach to rewarding outcomes), where the relative strengths of these signals determine behavioral decisions involving risk and uncertainty.

A cross-sectional and longitudinal analysis of reward-related brain activation: Effects of age, pubertal stage, and reward sensitivity

“…That is, participants who generally played more often showed, as expected, increased activation in VS, but also increased activation in medial PFC after rewards compared to losses. Previous studies demonstrated that activation in medial PFC regions during decision-making was related to increased risk-taking tendencies (Van Leijenhorst, Gunther Moor, et al, 2010;Xue et al, 2009;but see Eshel, Nelson, Blair, Pine, & Ernst, 2007), which is consistent with its role in reward-related action tendencies (Rushworth et al, 2011;Rushworth et al, 2012). The current study extends previous findings by showing that medial PFC activation during outcome processing was positively related to the tendency to choose a risky option in a cross-sectional sample.…”

“…Alternatively, parametric modulation of rewards and losses (e.g. Tom et al, 2007;Xue et al, 2009) may be a promising approach in distinguishing reward versus loss-related activation across development.…”

Fiber connectivity between the striatum and cortical and subcortical regions is associated with temperaments in Chinese males

“…It is believed to form relative reward values to guide or top-down regulate human RD-oriented behaviors during reward processing (Rolls, 2000;Wallis, 2007). The medial frontal cortex was proposed to integrate and transmit representations of reward to the mesolimbic and mesocortical dopamine systems, to modulate striatal reward encoding during reappraisal of reward anticipation and to contribute to successful regulation of reward (Glascher et al, 2009;Xue et al, 2009). Human electrophysiological studies showed a dynamic interaction between the striatum and medial frontal cortex underlying reward-guided learning and decision-making (Cohen, 2007;Cohen et al, 2009).…”

Can neuroimaging inform economic theories of decision making?

“…Take for example the idea that people vary greatly in their risk-taking tendencies. In one study, 59 dorsal MPFC activity was recruited when participants engaged in risky decisions, but the magnitude of this activation was predicted by risk aversion. However, ventral MPFC activity was modulated by actual gains, and the magnitude of this modulation was correlated with higher levels of risk tolerance.…”