Motor-evoked potentials (MEPs) were then used to determine the coil position that evoked the maximal response in the right FCR. The location and trajectory of the coil over left primary motor cortex (M1) were marked using the BrainSight™ stereotaxic software to minimize variability within and across days. Resting motor threshold (RMT) was determined for each participant as the percentage of stimulator output that elicited an MEP of
≥ 50 μV peak to peak on five out of 10 trials. The site of stimulation Saracatinib chemical structure for the left PMd was marked in Brainsight™ by moving one gyrus forward from the FCR ‘hot spot’ (Boyd & Linsdell, 2009). The PMd location was confirmed as the posterior aspect of the middle frontal gyrus (Munchau et al., 2002; Fridman et al., 2004). Isolation of this area from M1 was verified using single pulses to ensure that: (i) there was no electromyographic record of muscle activity recorded over the FCR, and (ii) there were no visually apparent muscle twitches in the forearm or hand. Once confirmed, the location and trajectory of the coil were recorded using BrainSight™ to ensure the consistent stimulation of the PMd across days (Boyd & Linsdell, 2009). Five hertz stimulation consisted BVD-523 of 1200 pulses delivered in 10-s trains with an inter-train interval of 10 s. Intensity
was set to 110% RMT. 1 Hz stimulation consisted of 1200 pulses delivered in 10-s trains with an inter-train interval of 1 s and an intensity of 110% RMT. Control stimulation was delivered using a custom sham coil that looks and sounds similar to the rTMS coil but does not induce any current fantofarone in the underlying cortex (Magstim Company Ltd.). The parameters of the control stimulation were counterbalanced across participants such
that six participants received control stimulation that mimicked 5 Hz stimulation and five participants received control stimulation that mimicked 1 Hz stimulation. The rTMS parameters employed have been shown to induce an after-effect of approximately 15 min (Chen et al., 2003). To ensure that there was no interference with the effects of the rTMS protocols upon consolidation of motor practice, participants were required to remain quietly seated for 15 min following the end of stimulation. Following the retention test on day 5, participants were shown ten 30-s trials of continuous target movements and asked to decide if they recognized any pattern that they performed during the practice sessions. Out of the 10 trials, three contained the ‘true’ middle sequence, i.e. the same as the repeated practice sequence, and seven were foils. Individuals were considered to have explicit awareness of the repeated sequence if they could both correctly recognize 2 of the 3 repeated sequences and properly label 5 of 7 of the foils as having not been seen before (Boyd & Linsdell, 2009). Motor performance was evaluated across practice and retention in two ways.