1), parallel to the effect already seen in Experiment 1. The results

showed the expected effect of higher MEPs in the $5 condition (t14 = 2.085, P = 0.028; Fig. 2B). Correspondingly, the average RT was smaller in the strong urge condition compared with the weak urge condition by 9 ms, although the difference was not statistically significant (t14 < 1). A verification analysis of root mean square pre-TMS EMG activity showed that the muscle was equally at ‘rest’ for these conditions (t14 = 1.3, n.s.). In contrast, the MEPs in Experiment 2b for the strong urge condition were not found to be larger than the MEPs for the weak urge condition (t14 = −0.178, n.s.; Fig. 2C). A verification analysis of root mean square pre-TMS EMG activity showed that the muscle was equally at ‘rest’ for these conditions (t14 < 1, n.s.). In both Experiments 2a and 2b, on the 10% of trials in which the yellow LBH589 clinical trial border was presented, participants satisfactorily reported this occurrence (< 2 errors for each subject). This showed that the subjects were paying attention to the stimuli in Experiment 2b even though no manual motor response

was required. We recorded HSP inhibitor TMS-induced MEPs from the right index finger to measure the level of urges for food and money. In Experiment 1, using the food paradigm, we found that MEPs increased with increasing urge for food, specifically at the late but not at the early time-point. Importantly, these measurements were made before the participant even knew which motor response to make. The effect was replicated for money (Experiment 2a), proving reliability and generalizability. Next, by removing the response requirement diglyceride (Experiment 2b), we show that a critical element of the ‘urge effect’ measured here is the need for subjects to take action. Our results agree with the findings of

Pessiglione et al. (2007) who showed that even subliminal high-value stimuli lead to behavioral and BOLD activation. However, because that study relied on (slow) fMRI measures, it could not dissociate the preparation of movement from the actual movement. Here, the high temporal resolution of TMS points to urge-related motor excitability before movement. Moreover, in the study by Pessiglione et al. (2007), when the stimulus occurred participants knew which response to prepare. In our experiment, we changed the mapping of Yes and No choices to left and right hand randomly on each trial, and thus recorded MEPs before the participants even knew which response they would need to make. By doing this, we rule out the possibility that the observed increases of MEPs merely relates to the preparation of a particular motor response. Instead, it must also reflect motivational processing that is upstream from the corticospinal system.