Fig 1.
Schematic illustration of the unidirectional (Figure-of-8 and H7) and multidirectional rotational-field (T360°) TMS coil configurations used in the study. Reprinted by permission from Roth et al. (2023). (B) Study design and crossover experimental setup. Three TMS coils were tested in a randomized, crossover design with counterbalanced order. The rMT and MEP amplitudes were measured for each coil. These tests were conducted on 10 subjects across two sessions, each on a different day.
Table 1.
Median (Q1, Q3) values of resting motor threshold (rMT) in volts (V) categorized by stimulated hemisphere and coil type.
Fig 2.
Adjusted rMT according to hemisphere and coil type.
Adjusted rMT (volts) obtained by spTMS applied over the hand knob of the primary motor cortex with MEPs recruited from the contralateral FDI, comparing unidirectional (Figure-of-8 and H7) and multidirectional (rotational-field, T360°) coil configurations. The boxplots illustrate the median (line), first to third quartiles (Q1–Q3, box), whiskers extending up to 1.5 times the interquartile range (IQR), and dots represent outliers. The colors represent the coil configuration: Figure-of-8 (blue), H7 (green), and T360° (red).
Fig 3.
Population-level input–output curves for three TMS coil types.
Population-level input–output (IO) curves depicting predicted motor evoked potential (MEP) amplitude (in mV) as a function of stimulation intensity (% of maximal stimulator output, MSO) for three TMS coil types: Figure-of-8 (blue), H7 (green), and T360° (red). Curves represent posterior predictions from a Bayesian hierarchical model incorporating fixed effects for coil configuration and hemisphere (left vs. right), and subject-level (10 healthy participants undergoing spTMS with MEPs recruited from the contralateral FDI muscle. Shaded regions indicate the 89% highest posterior density interval (HPDI).