One interpretation is that vmPFC/mOFC reflects not only the expected benefit of the course of action taken (in the positive correlation between the BOLD signal and the chosen option value) but also the opportunity costs associated with the unchosen action (in the negative correlation between the BOLD signal and the unchosen option’s value). The precise nature of the vmPFC/mOFC signal remains to be elucidated but if it is a decision signal then it is important to note that it differs from a parietal cortical

action selection signal (Gold and Shadlen, 2007). While the vmPFC/mOFC signal increases with the difference in value between possible choices the BOLD signal in the parietal cortex and some other motor association areas increases as the choice selection becomes more difficult, as indexed by reaction time. The parietal signal therefore click here often has characteristics that are the opposite of the vmPFC/mOFC

signal; its size is negatively correlated with the difference in value between choices (Basten et al., 2010). Exactly how vmPFC/mOFC and the posterior parietal cortex make different contributions to decision-making remains to be determined. One rather confusing feature of vmPFC activity in fMRI experiments is that it is often more active at rest than during task performance. The area is close to, or part of, the “default network,” a set of brain areas with similar activity (Raichle and Snyder, 2007). “Activations” reported Selleck Tyrosine Kinase Inhibitor Library in vmPFC, therefore, actually correspond to different degrees of deactivation, in comparison to rest, in different

not task conditions. In general, activity in vmPFC decreases monotonically with the level of task engagement, which in turn is a function of a number of task features such as stimulus salience. Salience, however, is often correlated with value; high-value stimuli are often salient. Litt et al. (2011) have recently tried to determine whether the vmPFC BOLD signal is driven by saliency or value. They exploited the fact that salience of a stimulus also increases as it becomes more aversive, and therefore less valuable, as well as when it becomes more appetitive, and therefore more valuable. They examined BOLD activity related to both appetitive and aversive foods so that the impact of value and salience could be separated. vmPFC activity was correlated with value rather than stimulus saliency. One way to test whether vmPFC/mOFC signals are causally important for guiding decision-making is to investigate what happens when vmPFC/mOFC lesions are made. If vmPFC/mOFC is essential for the value comparison process then a lesion should impair the value discrimination process. If the vmPFC/mOFC is critical for deciding and discriminating between potential choices on the basis of their relative values then the impairment should increase as a function of the proximity of the choices’ values.