Note that the term “reward outcome” is used to refer to the particular outcome for each individual trial – not to the reward outcome of the preceding trial. Also we did not analyze penalty or

punishment effects because of the small number of incorrect (or slow) responses (see Table 2). In this sense, the incentive effects are driven largely by the (fictive) reward outcomes – noting that the actually monetary recompense for participating in the study was established in advance and was the same for all subjects. Table 2 Behavior results The ensuring contrast images for each participant were entered into second-level random-effects group analyses, using one sample t-tests to produce statistical parametric Inhibitors,research,lifescience,medical t-maps (SPMs) testing for regionally specific effects. The fMRI results are reported at a corrected significance level of P < 0.05 using a Monte Carlo correction with cluster size threshold of 85 (2 mm3). Group-level interaction effects Inhibitors,research,lifescience,medical between anticipation (reward vs. non-reward) and conflict (congruent vs. incongruent) were determined by a 2 × 2 repeated measures ANOVA. We illustrated the significant interaction effects plotting

the magnitudes of the effects in each SB203580 cost region obtained with an 8-mm radius sphere centered on the peak Inhibitors,research,lifescience,medical voxel of target-related activity in each region. Interaction effects were tested within volumes defined by the (orthogonal) main effects of anticipation. The use of orthogonal localizing contrasts protects against biased sampling (Friston et al. 2006). Results Behavioral results There was a significant main effect of conflict on RT, with RTs significantly

longer for incongruent than Inhibitors,research,lifescience,medical congruent flankers (Table 2, F1,15 = 92.258, P < 0.001). Similarly, there was a significant main effect of anticipation (F1,15 = 5.900, P < 0.028). However, there was no interaction between anticipation and conflict (F1,15 = 3.226, P = 0.93) (Table 2, Fig. 2). Although response accuracy was higher for congruent (98.6%) versus incongruent flankers (96.9%), these differences Inhibitors,research,lifescience,medical were not significant. Post hoc analyses showed that RT2 (mean = 544.30 msec, SD = 92.58 msec) was significantly shorter than RT1 (mean = 556.34 msec, SD = 107.32 msec, P = 0.038), and that RT3 was the longest (mean = 622.97 msec, SD = 215.40 msec). Figure 2 Behavior results. Neuroimaging results Reward anticipation Contrasts for reward minus non-reward cues showed significant activation in components of the attentional network, including Rolziracetam the right superior parietal cortex, the inferior occipital cortexes bilaterally, the left lingual gyrus, the left thalamus, and the left putamen (Table 3, Fig. 3). Figure 3 Activation during reward components of the ACR task. Statistical parametric maps in axial views showing significant blood oxygenation level-dependent (BOLD) signal changes. (A) BOLD signal increase in the left putamen generated by the reward–non-reward …