Choosing for Me or Choosing for You: Value in Medial Prefrontal Cortex
Our understanding of the neural mechanisms of value-based decision making has increased dramatically in the last decade. Much of this progress has been achieved with the adoption of formal mathematical models that can be used to explain the process by which we compute values for stimuli in the world and use those values to guide our choices (Montague et al., 1996; Glimcher and Rustichini, 2004; Daw et al., 2005). By mapping components of these mathematical models to neural activity (a technique called computational fMRI; O'Doherty et al., 2007), it has been possible not only to determine whether a region is engaged under a condition of interest, but also to make inferences about the nature of the computations being implemented. More recently, efforts have been made to expand the application of this method to choice problems with a social component (Hampton et al., 2008; Suzuki et al., 2012) These studies have reaffirmed the roles of key areas of prefrontal cortex such as dorsomedial prefrontal cortex (dmPFC), known previously to be engaged in tasks requiring social cognition (Amodio and Frith, 2006), and ventromedial prefrontal cortex (vmPFC), known to be involved in value-based choice (Hare et al., 2008). But, more importantly, such studies are beginning to yield insights into the specific components of the choice processes in which these areas are implicated. In a new study published in the current issue of Neuron, Nicolle et al. (2012) used computational fMRI to investigate whether the neural substrates of value are sensitive to the distinction between actions evaluated based on their direct value to the self and those evaluated based on their value to others.