A computational pipeline to determine lobular electric field distribution during cerebellar transcranial direct current stimulation

Abstract

Objective Cerebellar transcranial direct current stimulation (ctDCS) is challenging due to the complexity of the cerebellar structure. Therefore, our objective is to develop a freely available computational pipeline to perform cerebellar atlas-based electric field analysis using magnetic resonance imaging (MRI) guided subject-specific head modeling. Methods We present a freely available computational pipeline to determine subject-specific lobular electric field distribution during ctDCS. The computational pipeline can isolate subject-specific cerebellar lobules based on a spatially unbiased atlas (SUIT) for the cerebellum, and then calculates the lobular electric field distribution during ctDCS. The computational pipeline was tested in a case study using a subject-specific head model as well as using a Colin 27 Average Brain. The 5cmx5cm anode was placed 3 cm lateral to inion, and the same sized cathode was placed on the contralateral supraorbital area (called Manto montage) and buccinators muscle (called Celnik montage). A 4×1 HD-ctDCS electrode montage was also implemented for a comparison using analysis of variance (ANOVA). Results Eta-squared effect size after three-way ANOVA for electric field strength was 0.05 for lobule, 0.00 for montage, 0.04 for head model, 0.01 for lobule*montage interaction, 0.01 for lobule* head model interaction, and 0.00 for montage*head model interaction in case of Enorm. Here, the electric field strength of both the Celnik and the Manto montages affected the lobules Crus II, VIIb, VIII, IX of the targeted cerebellar hemispheres while Manto montage had more bilateral effect. The HD-ctDCS montage primarily affected the lobules Crus I, Crus II, VIIb of the targeted cerebellar hemisphere. Our freely available computational modeling approach to analyze subject-specific lobular electric field distribution during ctDCS provided an insight into healthy human anodal ctDCS results