Cool b65 a p coil

All TBS protocols were applied to the individual participant’s motor hotspot at 80% of AMT in each participant. The iTBS and cTBS protocols consisted of 600 pulses in total given over 200 s and 40 s time periods correspondingly. The iTBS protocol included trains of 3-pulse bursts (duration of trains 2 s, burst frequency 50 Hz, inter-burst interval 200 ms) spaced by 8 s ITIs. The cTBS protocol used 3 pulse bursts (frequency 50 Hz, inter-burst interval 200 ms) that were delivered continuously. In addition to iTBS and cTBS, each volunteer was randomly assigned to receive either sham iTBS or sham cTBS during the initial visit series, and the same sham stimulation during retest visit series. For administration of the sham TBS protocols, the placebo side of the Cool-B65 A/P coil with a 3D printed 3.3 cm spacer (MagVenture A/S, Farum, Denmark) attached to the placebo side was used. Single positive triangle electrical pulses (pulse width 2.2 ms, intensity 2–3 mA) were given synchronously with TMS and sham TMS for additional blinding of the participants by an attempt to match the sensory experience of the active and sham protocols. For this purpose, a pair of self-adhesive surface electrodes (Ambu Neuroline 715, Ambu A/S Baltorpbakken 13, DK-2750 Ballerup) were placed approximately 1 cm below the inion. The electrical stimulation was applied synchronously with all TBS protocols.

TBS procedures were performed using a figure-of-eight Cool B-65 A/P coil (Magventure). At baseline, individual resting motor threshold was determined using Parameter Estimation by Sequential Training, an automated algorithm used to determine TMS thresholds (22 (link)). The TMS coil was positioned at the FP1 using the standard electroencephalography 10–20 landmark location. TBS was administered at 110% of each participant’s resting motor threshold. Pulses were administered in a burst-firing pattern (3 pulse burst, 50 Hz; 5 Hz [200-ms] interburst intervals; 1800 pulses/train with a 60-second intertrain interval [3600 pulses/day]). To enhance tolerability of FP1 TBS, stimulation intensity was gradually escalated from 30% to 110% of resting motor threshold over the first 30 seconds of each train.
This double-blind study used the MagVenture MagPro integrated active-sham system, wherein a USB key coded with participant numbers was inserted into the machine prior to each participant’s visit and electrodes (Natus Inc.) are placed on the left frontalis muscle under the coil. During stimulation, current was passed through the surface electrodes at an intensity scaled to their motor threshold. Following each TMS treatment, individuals were asked to note whether they received real or sham and their level of confidence (Likert scale, 1–10).