The role of the human ventral striatum and the medial orbitofrontal cortex in the representation of reward magnitude - an activation likelihood estimation meta-analysis of neuroimaging studies of passive reward expectancy and outcome processing

Reward maximization is a core motivation of every organism. In humans, several brain regions have been implicated in the representation of reward magnitude. Still, it is unclear whether identical brain regions consistently play a role in reward prediction and its consumption. In this study we used coordinate-based ALE meta-analysis to determine the individual roles of the ventral striatum (vSTR) and the medial orbitofrontal cortex (mOFC/VMPFC) in the representation of reward in general and of reward magnitude in particular. Specifically, we wanted to assess commonalities and differences in regional brain activation during the passive anticipation and consumption of rewards. Two independent meta-analyses of neuroimaging data from the past decade revealed a general role for the vSTR in reward anticipation and consumption. This was the case particularly when the consumed rewards occurred unexpectedly or were uncertain. In contrast, for the mOFC/VMPFC the present meta-analytic data suggested a rather specific function in reward consumption as opposed to passive anticipation. Importantly, when considering only coordinates that compared different reward magnitudes, the same parts of the vSTR and the mOFC/VMPFC showed concordant responses across studies, although areas of coherence were regionally more confined. These meta-analytic data suggest that the vSTR may be involved in both prediction and consumption of salient rewards, and may also be sensitive to different reward magnitudes, while the mOFC/VMPFC may rather process the magnitude during reward receipt. Collectively, our meta-analytic data conform with the notion that these two brain regions may subserve different roles in processing of reward magnitude.