TI simulation

AF3_PO10_and_AF4_Oz

Subject
ernie
Conductivity
vn
Total current
2 mA
Report
2026-09-28 19:58

0.359 V/m peak envelope in grey matter

Temporal interference with AF3–PO10 and AF4–Oz at 1 mA per channel (2 mA total), anisotropic, volume-normalised (vn) from the subject's DTI tensor. In grey matter the envelope reaches 0.359 V/m (99.9th percentile), median 0.169 V/m; its maximum, 0.485 V/m, is at MNI (11, 16, -25) mm.

Grey matter 99.9th pct
0.359V/mpeak envelope
Grey matter median
0.169V/mhalf of grey matter is above this
Grey matter maximum
0.485V/mat MNI (11, 16, -25) mm
Total current
2mA2 channels × 1 mA

Montage and dose

Where the current goes in and how much.

Figure 1. Montage on the EEG cap
Montage on the EEG10-10_UI_Jurak_2007 cap: AF3 to PO10; AF4 to Oz
Ch 1A (blue)
AF3 → PO10, 1 mA
Ch 1B (red)
AF4 → Oz, 1 mA
Top view, nose up. Each colour is one channel, drawn on the EEG10-10_UI_Jurak_2007 layout the app uses.

Dose

Electrodes
ellipse 8×8 mm, gel 4 mm, rubber 2.0 mm
Current
1 mA per channel, 2 mA total (each electrode carries its channel's current)
Carrier frequencies
not part of the field model (quasi-static); set them on the stimulator
EEG net
EEG10-10_UI_Jurak_2007
Conductivity
anisotropic, volume-normalised (vn) from the subject's DTI tensor: DTI_coregT1_tensor.nii.gz

Field

Where the envelope is strongest.

Figure 2. TI envelope amplitude
TI envelope over the T1, through the grey-matter hot spot (top 0.1 %)axial z = +26 mmcoronal y = +37 mmsagittal x = +17 mm
0.170.36 V/m
Slices through the grey-matter hot spot (top 0.1 %). Coloured where the envelope is above the grey-matter median (0.17 V/m), up to its 99.9th percentile; grey and white matter only. Neurological convention: subject left on image left.

Technical details

Carrier fieldsper-carrier grey-matter percentiles
Each high-frequency carrier alone: grey-matter |E| percentiles (V/m) from SimNIBS's field summary.
CarrierChannel99.9 %99.0 %95.0 %
ernie_TDCS_1AF3 → PO100.2550.2100.165
ernie_TDCS_2AF4 → Oz0.2970.2240.171

SimNIBS estimated the electrode current calibration error at 3.4 %, 2.8 %.

Methods and referencesboilerplate generated from this run; check before use

Temporal interference stimulation was simulated in TI-Toolbox with SimNIBS 4.6.0 [Saturnino2019b] on the head model of subject ernie [Puonti2020]. 2 channels (AF3–PO10 and AF4–Oz) each delivered 1 mA through ellipse 8×8 mm electrodes with 4 mm gel; positions from the EEG10-10_UI_Jurak_2007 layout [Jurcak2007]. Tissue conductivities were anisotropic in white and grey matter, derived from diffusion tensors (vn) [Opitz2011].

The TI envelope was taken as the maximal modulation amplitude over field orientations [Grossman2017]; in grey matter its 99.9th percentile was 0.359 V/m and its median 0.169 V/m.

References

  1. Grossman2017Grossman N, Bono D, Dedic N, Kodandaramaiah SB, Rudenko A, Suk HJ, Cassara AM, Neufeld E, Kuster N, Tsai LH, Pascual-Leone A, Boyden ES. Noninvasive deep brain stimulation via temporally interfering electric fields. Cell. 2017;169(6):1029-1041.e16. doi:10.1016/j.cell.2017.05.024
  2. Jurcak2007Jurcak V, Tsuzuki D, Dan I. 10/20, 10/10, and 10/5 systems revisited: their validity as relative head-surface-based positioning systems. NeuroImage. 2007;34(4):1600-1611. doi:10.1016/j.neuroimage.2006.09.024
  3. Opitz2011Opitz A, Windhoff M, Heidemann RM, Turner R, Thielscher A. How the brain tissue shapes the electric field induced by transcranial magnetic stimulation. NeuroImage. 2011;58(3):849-859. doi:10.1016/j.neuroimage.2011.06.069
  4. Puonti2020Puonti O, Van Leemput K, Saturnino GB, Siebner HR, Madsen KH, Thielscher A. Accurate and robust whole-head segmentation from magnetic resonance images for individualized head modeling. NeuroImage. 2020;219:117044. doi:10.1016/j.neuroimage.2020.117044
  5. Saturnino2019bSaturnino GB, Puonti O, Nielsen JD, Antonenko D, Madsen KH, Thielscher A. SimNIBS 2.1: a comprehensive pipeline for individualized electric field modelling for transcranial brain stimulation. In: Makarov SN, Noetscher GM, Nummenmaa A, eds. Brain and Human Body Modeling. Springer; 2019. doi:10.1007/978-3-030-21293-3_1
Run recordversions and the configuration as run
Simulation
AF3_PO10_and_AF4_Oz
Created
2026-09-23 18:41
TI-Toolbox
3.0.1
SimNIBS
4.6.0
Solver
hypre

config.json

{
 "subject_id": "ernie",
 "simulation_name": "AF3_PO10_and_AF4_Oz",
 "simulation_display_name": null,
 "simulation_mode": "TI",
 "montage_mode": "net",
 "eeg_net": "EEG10-10_UI_Jurak_2007.csv",
 "conductivity": "vn",
 "electrode_pairs": [
  [
   "AF3",
   "PO10"
  ],
  [
   "AF4",
   "Oz"
  ]
 ],
 "is_xyz_montage": false,
 "electrode_coordinates": [
  [
   -30.90749936116757,
   103.60814467271162,
   42.86161058908083
  ],
  [
   51.60590485878426,
   -65.61118035813816,
   -29.16119480397702
  ],
  [
   38.283491056928554,
   105.31282365659466,
   43.22186034843143
  ],
  [
   -0.9476220091638726,
   -91.74869214701492,
   8.96142810697856
  ]
 ],
 "electrode_coordinate_source": "eeg_positions/EEG10-10_UI_Jurak_2007.csv",
 "intensities": [
  1,
  1
 ],
 "electrode_geometry": {
  "shape": "ellipse",
  "dimensions": [
   8,
   8
  ],
  "gel_thickness": 4,
  "rubber_thickness": 2.0
 },
 "mapping_options": {
  "map_to_surf": true,
  "map_to_vol": false,
  "map_to_mni": false,
  "map_to_fsavg": false
 },
 "tissues_in_niftis": "all",
 "aniso_maxratio": 10,
 "aniso_maxcond": 2,
 "open_in_gmsh": false,
 "created_at": "2026-09-23T18:41:20.666776"
}