How exactly IFG is involved in the evaluative process itself is still unclear. Our results suggest that, if it has a causal role in promoting nondefault riskier choices, then its disruption would lead to taking safer, default choices. In agreement

with the possibility that IFG or an adjacent lateral frontal region is involved in dynamic, context-dependent changes in decision making, one recent study applied transcranial magnetic stimulation in this vicinity and found that subjects were more likely to make socially unbiased decisions and to integrate considerations of reward magnitudes in the standard manner (Baumgartner et al., 2011), rather than taking the social context into Selleckchem Apoptosis Compound Library consideration. Eighteen subjects (nine women and nine men), aged 22–36 years, completed the task. They were paid £10 plus a performance-dependent

bonus of between £15 and £30. Ethical approval was given by the Oxfordshire National Health Service Research Ethics Committee (local ethics code: 07/Q1603/11). Before fMRI scanning, every subject selleck screening library was instructed in the task and played a shorter version of the task used in the fMRI experiment for about 10 min. The behavioral task in the scanner consisted of 24 blocks, each composed of eight trials (192 decisions in total) in which the subjects had to decide between a safer option with a higher reward probability but a lower reward magnitude and a riskier option with a potentially higher reward magnitude but lower reward probability. MYO10 There were eight decisions, and they were each presented once in each block in a randomized order that varied. In this way, we were conclusively able to show that dynamic changes in decisions occur, because of sensitivity to risk pressure, even when the exact same options were presented. Risk pressure varied because all eight decisions were associated with different values and were presented in different orders, with different outcomes, and in the context of different block target values (which the subjects had to reach in order to keep the points they won during the

block). Four target levels were used in the experiments. The different target levels helped ensure that risk pressure (see Introduction and the following section) had some parametric range. To equalize expected gains at the beginning of a block regardless of target level and to keep motivation relatively stable, we introduced a “multiplier,” which was displayed on top of the “target” line. The multiplier indicated a factor that would be used to multiply the points subjects won before they were added to the subject’s account if they reached the target. We chose the multiplication factor by applying our model (discussed in the next section) to generate equal expected gains at the first trial of a block. Simply put, if a participant had a high target to reach, all his points were multiplied (e.g., by 2) if he managed to reach it.