The 2.75 J stimulus elicited a mean rating of 3.5 ± 1.0 J, and the 3.25 J stimulus a mean rating of 5.7 ± 1.2 J. Stimuli were delivered to the left hand dorsum, at either a proximal or a distal locus. The proximal and distal loci were separated by 15 mm with approximately 8 mm between the centres

of each site on the proximal or distal line (see Fig. 1). This distance was selected both on the basis of previous studies (Porro et al., 2007; Schlereth et al., 2001) and our pilot study, to elicit an intermediate level of accuracy, avoiding both floor and ceiling effects. After each stimulus Ponatinib cost participants had to judge whether it was of ‘high’ or ‘medium’ intensity, or whether it was on the ‘proximal’ or ‘distal’ locus (see Experimental procedure for details). TMS mapping was conducted in an initial session prior to the main experiment. The motor threshold for each participant was determined by delivering single TMS pulses with a Magstim 200 magnetic stimulator (Magstim, Whitland, Dyfed, UK) using a figure-of-eight

coil. The hand motor ‘hotspot’ in the right hemisphere was located by first marking 5 cm lateral and 1 cm posterior to the vertex. The coil was then moved in anterioposterior and mediolateral directions LY2109761 from this location in a 1 × 1 cm grid, delivering single TMS pulses at each site, until motor twitches were obtained in the resting left hand in three out of five successive trials (confirmed by participants’ report and experimenter’s observation). The mean stimulator output required to elicit motor twitches was 44.8 ± 6.0% of maximum.

For the experimental conditions an intensity Bay 11-7085 of 110% of the resting motor threshold was used for all stimulated brain areas (S1, S2 and vertex). The skull vertex was used as a sham stimulation site, to control for the nonspecific effects of TMS such as auditory and sensory artefacts. In sham stimulation, the coil was rotated vertically so that no actual magnetic stimulation was delivered to the brain. S1 was located by moving the coil posteriorly from M1 until no detectable motor twitches occurred, based on both experimenter observation and reports by the participant. This location was on average 2.4 ± .6 cm posterior to the M1 hotspot. A number of previous studies have localised S1 using this method (Bolognini et al., 2011; Porro et al., 2007). S2 was located as 2.5 cm anterior and 6.5 cm superior to the right preauricular point, again in accordance with previous studies (Bolognini et al., 2011; Kanda et al., 2003). In addition, in nine participants these locations were confirmed by using high-resolution structural scans and a neuronavigation system (Brainsight, Magstim, Whitland, Dyfed, UK). We checked in these participants that the stimulated locations corresponded to the Talairach co-ordinates of S1 and S2 previously localised through functional procedures (see Fig. 2).