Fig 1.
Colored maps of electric field distribution.
Colored field maps for the D–B80 (a) and for the H7 (b) showing electric field distribution within the brain, when located at the treatment location over the prefrontal cortex, indicating the electric field absolute magnitude in each pixel over 14 coronal slices 1 cm apart. The maps were adjusted to the average percentage of the maximal stimulator output required to achieve 100% of the leg rMT, which are 53% for the D–B80 and 54% for the H7. The red pixels indicate field magnitude ≥ the threshold for neuronal activation, which was set to 100 V/m.
Fig 2.
Distribution of values of EF intensity.
Histograms of distribution of the volume in cm3 according to the induced electric field range within the brain for the D–B80 and H7. Field columns are in bins of 5 V/m. The distribution of field values within the brain is significantly different between the coils (p = 0.002, Wilcoxon matched–pairs test).
Fig 3.
The electric field magnitude measured in a phantom head model as a function of the distance from the coil, is shown for the D–B80 coil and for the H7 coil, when located at the treatment location over the prefrontal cortex. The field was measured along a line in a central sagittal plane starting at the point of inflection of the frontal bone and going at 45° downward and posteriorly (a). The electric field was normalized to the field at the scalp, 0.5 cm from coil surface (b), to the field at the brain surface, 1.5 cm from coil surface (c), and to the field at a depth of 3 cm from coil surface (d).
Table 1.
Stimulation volumes V100 (cm3), stimulated depth d100 (mm) and maximal electric field values Emax (V/m) in the brain for simulations in 22 head models, 2 spherical models and for phantom measurements.
Shown are results of comparison of stimulation volumes V100 in the brain between the D–B80 and H7 coils using Wilcoxon matched–pairs test.
Fig 4.
Distribution of values of EF intensity.
Histograms of distribution of volume in cm3 within the brain according to the induced electric field range for the D–B80 and H7 coils. Field columns are in bins of 10 V/m. Results are shown for the 14 numerical head models and the two spherical models.
Fig 5.
The electric field magnitude as a function of the distance from the coil, is shown for the D–B80 coil and for the H7 coil, when located at the treatment location over the prefrontal cortex. The field was measured along a line in a central sagittal plane starting at the point of inflection of the frontal bone and going at 45° downward and posteriorly (top left). The electric field was normalized to the field at a depth of 3 cm from coil surface. Shown results for the 14 numerical head models.
Fig 6.
Distribution of values of EF intensity within specific brain regions.
Histograms of distribution of the volume in cm3 according to the induced electric field range for the D–B80 and H7 coils, are plotted for five brain regions (dACC, dlPFC, IFG, OFC and pre–SMA). Field columns are in bins of 10 V/m. Shown the averaged results of all the 22 simulated head models.
Fig 7.
Descriptive statistics within specific brain regions.
Descriptive statistics across 22 head models for five brain regions (dACC, dlPFC, IFG, OFC and pre–SMA) of the percentage of EF ≥80 V/m for the D–B80 (a) and the H7 (b), and of the EF amplitude distribution within these regions for the D–B80 (c) and the H7 (d). dACC: dorsal anterior cingulate cortex; dlPFC: dorsolateral prefrontal cortex; IFG: inferior frontal gyrus; OFC: orbitofrontal cortex; pre–SMA: pre–supplementary motor area.