Polarity of uncertainty representation during exploration and exploitation in ventromedial prefrontal cortex

Trudel et al. find that the ventromedial prefrontal cortex carries multiple decision variables, the strength and polarity of which vary according to their relevance to the context of exploration, exploitation and the transition between these states. Environments furnish multiple information sources for making predictions about future events. Here we use behavioural modelling and functional magnetic resonance imaging to describe how humans select predictors that might be most relevant. First, during early encounters with potential predictors, participants' selections were explorative and directed towards subjectively uncertain predictors (positive uncertainty effect). This was particularly the case when many future opportunities remained to exploit knowledge gained. Then, preferences for accurate predictors increased over time, while uncertain predictors were avoided (negative uncertainty effect). The behavioural transition from positive to negative uncertainty-driven selections was accompanied by changes in the representations of belief uncertainty in ventromedial prefrontal cortex (vmPFC). The polarity of uncertainty representations (positive or negative encoding of uncertainty) changed between exploration and exploitation periods. Moreover, the two periods were separated by a third transitional period in which beliefs about predictors' accuracy predominated. The vmPFC signals a multiplicity of decision variables, the strength and polarity of which vary with behavioural context.

Automated summary

In a study conducted by Trudel et al., it was found that the ventromedial prefrontal cortex carries multiple decision variables with varying strength and polarity depending on the behavioral context. Initially, participants tend to select predictors with higher uncertainty, but as time progresses, they shift towards more accurate predictors and avoid uncertain ones. This transition is accompanied by changes in representations of belief uncertainty in the vmPFC.