Thus far, we have reviewed motivational effects that appear to be more transient in nature; however, although relatively little is known about sustained motivational signals, such modulations have also been observed. For instance, in our experiment discussed above, we employed an experimental design in which incentive was manipulated in a blocked fashion, allowing us to investigate sustained responses throughout the block of trials and how they were modulated by motivation. State-like effects were observed in several brain regions, including sites in the prefrontal cortex (PFC; e.g., FEF, middle frontal gyrus), parietal cortex (e.g., IPS), in addition to the PCC. Related findings were also reported by Locke and Braver (2008) who reported increased sustained fMRI activity during rewarded blocks of a cognitive control task in a network of regions including the right lateral PFC, right parietal cortex, and dorsal medial frontal cortex. Importantly, in a recent study, Jimura et al. (in press) showed that the effect of an individual's sensitivity to reward on working memory performance was mediated by sustained effects of reward observed in the right lateral PFC. These studies highlight the importance of studying sustained effects of motivation, which may be more closely related to arousal processes. Indeed, future investigations seeking to unravel the contributions of both transient and sustained responses to behavioral performance are greatly needed.