fMRI Informed Montage Selection for Transcranial Electrical Stimulation: Frontoparietal Synchronization for Drug Cue Reactivity

Abstract

Background: Frontoparietal network (FPN) with multiple cortical nodes is involved in executive functions. Transcranial electrical stimulation (tES) can potentially modulate interactions between these nodes using frontoparietal synchronization (FPS). Here we used fMRI and computational head models (CHMs) to inform electrode montage and dosage selection in FPS. Methods: Sixty methamphetamine users completed an fMRI drug cue-reactivity task. Two sets of 4x1 HD electrodes with anode over F3 and F4 were simulated and spheres around maximum electric field in each hemisphere were defined as frontal seeds. Using frontal seeds, a task-based functional connectivity analysis was conducted based on a seed-to-whole brain generalized psychophysiological interaction (gPPI). Electrode placement for parietal sites was selected based on gPPI results. Task-based and resting-state connectivity were compared between fMRI-informed and classic F3-P3/F4-P4 montages. Results: Whole-brain gPPI showed two significant clusters (left: 506 voxels P=0.006, right: 455 voxels P=0.016), located in the inferior parietal lobule under the CP5 and CP6 electrode location. Pair-wise ROI-based gPPI comparing informed (F3-CP5/F4-CP6) and classic (F3-P3/F4-P4) montages showed significant increased PPI and resting-state connectivity only in the informed montage. Cue-induced craving score was also correlated with left (F3-CP5) frontoparietal connectivity in the fMRI-informed montage. Conclusion: This study proposes an analytic pipeline to select electrode montage and dosage in dual site tES using CHMs and task-based connectivity. Stimulating F3-F4 can tap into both FPN and saliency network (SN) based on the montage selection. Using CHM and fMRI will be essential to navigating ample parameter space in the stimulation protocols for future tES studies.

Online closed‐loop real‐time tES‐fMRI for brain modulation: A technical report

“…While the present protocol optimized the tACS frequency and phase difference parameters, optimizing the stimulation coordinates (electrodes positions) may further improve the efficacy of the stimulation. Although the stimulation coordinates in the present protocol were determined based on previous tES studies (Jaušovec et al., 2014 ; Violante et al., 2017 ), a newly developed method attempted to optimize the stimulation coordinates utilizing fMRI (Soleimani et al., 2021 ) can be incorporated in the future studies.…”

“…Although the stimulation coordinates in the present protocol were determined based on previous tES studies (Jaušovec et al, 2014;Violante et al, 2017), a newly developed method attempted to optimize the stimulation coordinates utilizing fMRI (Soleimani et al, 2021) can be incorporated in the future studies.…”

Closing the loop between brain and electrical stimulation: Towards precision neuromodulation treatments

“…The center coordinate would be F4 in EEG 10 20 international system, and four surrounding electrodes (F1, F5, AF3, FC3) would be placed around F4, which results in a 4x1 montage with the center over the right DLPFC. The second stimulation site for placing another set of 4x1 electrodes would be defined based on the parietal brain region connected to the right DLPFC, obtained by fMRI using a task, which activates the cognitive process of interest (e.g., the drug cue reactivity task in a group of participants with substance use disorders as suggested by [151]). Stimulation targets are shown by circles in Figure 5.b (circle colors represent frontal (brown) and parietal (purple) regions as the stimulation targets).…”