Fig 1.
Model segmentation and electrode placements considered.
A previously developed ultra-high resolution model based on the MIDA dataset was adapted for this study. Select tissue masks along with the seven corresponding electrode positions are shown (A: skin; B: skull with blood vessels; C: Semi-transparent CSF with underlying gray matter; D: gray matter sans CSF or blood vessels). The top view of the brain tissue mask is shown in E to highlight the placement of the electrodes. The electrodes are numbered (1–7) to facilitate electrode configuration description (see manuscript text). Electrode 1 at the left mastoid is plotted in red to highlight the anode (positive) polarity considered for the electrode for simulation of all configurations. The dashed section in D is expanded in F to highlight the segmentation of the cochlea (purple), otolith (blue), and the semicircular canals (green).
Fig 2.
Current flow through the three most common GVS electrode placements (Montages 1–3).
First row: Potential (voltage) streamline plots shown with respect to the bottom view of the brain. This view is chosen to highlight flow through the small vestibular structures. Second row: 3D cutaway plot; Third row: 3D cortical EF plot (lateral view); Fourth row: Induced EF plot on the cochlea, otolith, and SCC pairs. L and R denote left and right respectively.
Fig 3.
Current flow through specialized GVS electrode placements (Montages 4–7).
First row: Potential (voltage) streamline plots shown with respect to the bottom view of the brain. Second row: 3D cutaway plot; Third row: 3D cortical EF plot (lateral view); Fourth row: Induced EF plot on the cochlea, otolith, and SCC pairs. L and R denote left and right respectively.
Table 1.
Induced EF metrics, current intensity, and symmetricity across left and right vestibular networks.
Table 2.
Induced EF (mean) across the vestibule and SCC networks.
Table 3.
Comparison of current density, inter-electrode separation, and current loss.
Table 4.
Relating Motion perception, postural sway, to induced current flow in brain and vestibular structures.
Fig 4.
Star plot of right and left vestibular electric field.
Mean, standard deviation (SD), and peak are compared for the left and right vestibular regions. Mean EF further compared for the vestibular network components (semicircular canals (SCC) and vestibule). Values are normalized to the maximum for each category. Plots of all montages overlaid into one to facilitate easy comparison.