The primary analysis was performed Y27632 on baseline-normalized rather than raw MEPs (as the variance was generally smaller for the former). Analysis used PASW Statistics 17.0.2 (SPSS, Chicago, IL, USA). In a verification procedure, we computed root mean square pre-TMS EMG activity for each condition in order to establish if the muscle of interest was at rest at the time of stimulation. The key hypothesis in Experiment 1 was that MEPs would increase with urge. Accordingly, we tested whether there was a linear increase from neutral to weakly wanted to strongly wanted items at early and late time-points separately. The same analysis was also done for RT. In addition, we used aversive food stimuli to both increase the range of

subjective urge measurements and to examine the relationship between MEP and ‘negative’ urges (i.e. motor system responses for items the participant

did not Selleckchem Dabrafenib want to consume). We did not have any prediction about how MEPs would relate to the strength of the negative urges. The key hypothesis for Experiment 2a was that MEPs would be greater for the $5 stimulus than the 10 cent stimulus. For Experiment 2b, we were interested to see if the absence of action would produce the same or different results from Experiment 2a. For Experiment 1, a linear contrast across wanting levels showed that normalized MEPs increased significantly with increasing urge for the late period (F1,15 = 6.536, P = 0.022), but not for the early period (F1,15 = 0.191, n.s.; Fig. 1C). Post hoc, Bonferroni-corrected tests for the late period showed a significant difference in normalized MEPs between the strongly wanted and the neutral conditions (t15 = 2.557, P < 0.0167), and for the strongly wanted and the weakly wanted conditions (t15 = 2.371, P < 0.0167), but not for the weakly wanted compared with the neutral condition (t15 < 1). These effects remained unaltered when raw (rather than baseline-normalized) MEPs were used in the analysis. A linear contrast across wanting levels

also showed that RT got faster with increasing consumption urge (F1,15 = 8.072, P = 0.012). Post hoc, Bonferroni-corrected tests revealed a significant ever decrease in RT for the strongly wanted compared with the neutral condition (t15 = 2.841, P < 0.0167), and for the weakly wanted compared with the neutral condition (t15 = 2.619, P < 0.0167), but not for the strongly wanted compared with the weakly wanted condition (t15 < 1). A verification analysis of root mean square pre-TMS EMG activity showed that the muscle was equally at ‘rest’ for the comparison of strongly wanted and neutral conditions (t15 < 1, n.s.). To analyse ‘negative urges’, for which we had no predictions, we performed a repeated-measures anova for the neutral, the weakly unwanted and the strongly unwanted conditions for the early and late periods separately. This did not reveal any significant effect of ‘negative urges’ on normalized MEPs, for the early (F2,30 = 2.35, n.s.) or the late (F2,30 < 1, n.s.) stimulation periods.