Raw signals were amplified and band-pass-filtered between 20 and 2000 Hz. EMG signals were sampled at a rate of 5000 Hz. All stimulation (single-pulse TMS and TBS) was delivered using a hand-held figure-of-eight coil attached to a Magstim Super Rapid stimulator. The coil was placed tangentially to the scalp with the handle pointing posteriorly. All stimulation was applied
over the hand area of the left motor cortex and individually localised for each participant based on the optimal position for eliciting MEPs in the right FDI. The stimulation intensity for baseline and post-TBS single pulses was set at 120% of each individual’s resting motor threshold (RMT) while the TBS itself was delivered at 80% of AMT. RMT and AMT were defined following recommendation from the selleck inhibitor International Federation of Clinical Neurophysiology. RMT was defined as the minimum single-pulse TMS intensity required
to induce an MEP in the contralateral FDI of > 50 μV peak-to-peak amplitude on more than five Protein Tyrosine Kinase inhibitor out of ten consecutive trials while the target muscle was at rest. AMT was defined as the minimum single-pulse TMS intensity required to induce an MEP in the contralateral FDI of > 200 μV peak-to-peak amplitude on more than five out of ten consecutive trials while the target muscle was held at approximately 20% of the maximal contraction. In order to precisely target the stimulation site (primary motor cortex) and keep the brain target constant throughout the stimulation session, we used a frameless stereotactic neuronavigation system (Brainsight, Rogue Inc.). For all experiments across both cohorts data were analysed using spss version 17 by an experimenter blind to the identities of the participants. MEP amplitude at a given timepoint was defined as the mean amplitude of the 10 MEPs to single TMS pulses recorded in a given 2-min time window. As an index of the duration of the TBS-induced modulation of corticospinal excitability, we defined, for each participant, the timepoint at which the
average MEP amplitude at a given time following pheromone TBS returned to within the 95% confidence interval of the baseline amplitude and did not return to outside that interval on subsequent timepoint measures. MEP amplitudes were standardised, forming a ratio of MEP amplitudes following TBS relative to average baseline MEP amplitude for each individual. For the first cohort, our primary outcome measure was time to return to baseline; thus a t-test was used to compare the duration of the suppression (to cTBS) or facilitation (to iTBS) of MEP amplitude following cTBS and iTBS respectively. We also evaluated the degree of suppression at all 11 timepoints as a secondary measure of group difference.