rewards did not provoke significant ventral striatal BOLD responses, whereas the anticipation of making an instrumental response to obtain money did— particularly if the reward contingency was uncertain. Similarly, Elliott et al. (2004) found that instrumental acts for rewards modulated the putamen’s response to monetary gain, with greater activity when the instrumental response was required. Interestingly, however, ventral striatal activity was not elicited under any condition in the Elliott et al. study. Second, ventral striatal (and midbrain) responses may be more closely associated with unanticipated events (appetitive or aversive) and reward prediction, while medial frontal cortex is more directly involved in coding for the reinforcing value represented by the stimulus (Hare et al., 2008; Imperato et al., 1992; Imperato, Cabib, & Puglisi-Allegra, 1993; Jensen et al., 2007; Joshua et al., 2008; Kalivas & Duffy, 1995).
