The predominance of valid trials ensured expectation of prime-target correspondence. The paradigm was presented on an LCD screen (Philips Medical Systems, The Netherlands) located in the rear of the magnet bore, visible to the participants via a mirror mounted on the head coil. Responses were obtained with response grips (Nordic NeuroLab AS, Bergen, Norway) and logged in E-Prime. Paradigm presentation and fMRI scanning were synchronized with a sync-box (Nordic NeuroLab AS, Bergen, Norway). Participants were instructed

to respond as quickly and accurately as possible by pressing a button with their right thumb in response to a target pointing right, and their left thumb to a target pointing left. They practiced the task outside the scanner until complete task compliance. Mean RTs for valid, selleck kinase inhibitor invalid and neutral trials were calculated after excluding all trials with commission errors and RT <100 ms. The excluded trials encompassed 3.1% of all trials and were evenly distributed across participants. ABT-263 price Due to the expectation of prime-target correspondence, cue-primes should decrease the RT in valid relative to neutral trials and increase commission errors in invalid trials. The RT priming effect was estimated by subtracting

RT in valid trials from RT in neutral trials. The percentage commission errors was log-transformed to fit parametric analyses. Right-handed participants respond faster to targets pointing right and make more commission errors with targets pointing left (Avila & Parcet, 2002). Hence, repeated measures ANOVA analyses were used to investigate the effects of both trial type and hand on RT and commission errors, separately, followed by paired t-tests. In linear regression analyses, SR, SR+/SP− and SR+/N− were predictors for RT priming effect and commission errors in invalid trials for each hand separately and for both hands combined.

MR images were acquired on a Philips Intera 3 Tesla scanner (Philips Medical Systems, Best, The Netherlands) with Quasar Dual gradients see more using a six-channel SENSE head-coil (InVivo, Gainesville, USA). The participants’ heads were immobilized using foam padding. During the task, T2∗-weighted gradient-echo single-shot echo-planar-imaging whole brain measurements were obtained with 42 contiguous axial slices, slice thickness = 4.0 mm, TR = 1800 ms, TE = 35 ms, flip angle = 90°, SENSE reduction factor = 2.2, field-of-view = 256, and in plane voxel resolution 2 × 2 mm. Four functional runs, each consisting of 182 volumes, were acquired in each participant. Every run was preceded by four dummy scans which were discarded before analysis. A B0 field map was acquired for fMRI scan distortion correction (unwarping) and a 3D MP-RAGE sequence for anatomical reference. Image analyses were carried out in FSL 4.1.5 (Smith et al., 2004).