Fig 1.
After baseline data acquisition, subjects were removed from the MRI gantry and taken into a separate room for continuous theta-burst stimulation (cTBS), which was administered at 80% AMT for 600 pulses. MEPs were measured at 120% RMT before and after cTBS. The subjects were then transferred to the MRI room. Data for post-cTBS GABA-MRS were obtained approximately 15 min after the TMS protocol, with right and left data collected in a randomized order.
Fig 2.
A typical GABA-MRS spectrum, where peaks of GABA, NAA, and combined glutamate and glutamine (Glx) are measured.
A voxel measuring 25 × 25 × 25 mm placed in bilateral M1 of a typical subject.
Fig 3.
A) The %change in GABA level in the left and right M1. GABA level increased by 7.35% ± 14.26% in the left M1 and decreased by 3.38% ± 13.9% in the right M1 following cTBS. B) GABA levels before and after cTBS. GABA levels were significantly lower in the left hemisphere (dominant side) than on the right hemisphere (nondominant side) before and after stimulation but were significantly increased in the left hemisphere after stimulation.
Fig 4.
The %change in GABA level had a trend correlation with MEP amplitude in the left sensorimotor area (R = −0.43002, R2 = 0.1849, t = 1.844717, p = 0.082575).
Data points reflect individual subjects.
Fig 5.
Visualization of the primary motor network analyzed using FSL MELODIC.
A) Pre-cTBS primary motor network. B) Post-cTBS primary motor network.