Modelling the electric field and the current density generated by cerebellar transcranial DC stimulation in humans

• We evaluated the electric field and the current density spatial distribution of cerebellar tDCS in different brain regions.
• We used computation method applied to realistic human model of different age and sex.
• We showed that the strongest electric field and current density amplitudes occur mainly in the cerebellum.

ObjectiveTranscranial Direct Current Stimulation (tDCS) over the cerebellum (or cerebellar tDCS) modulates working memory, changes cerebello-brain interaction, and affects locomotion in humans. Also, the use of tDCS has been proposed for the treatment of disorders characterized by cerebellar dysfunction. Nonetheless, the electric field (E) and current density (J) spatial distributions generated by cerebellar tDCS are unknown. This work aimed to estimate E and J distributions during cerebellar tDCS.MethodsComputational electromagnetics techniques were applied in three human realistic models of different ages and gender.ResultsThe stronger E and J occurred mainly in the cerebellar cortex, with some spread (up to 4%) toward the occipital cortex. Also, changes by ±1 cm in the position of the active electrode resulted in a small effect (up to 4%) in the E and J spatial distribution in the cerebellum. Finally, the E and J spreads to the brainstem and the heart were negligible, thus further supporting the safety of this technique.ConclusionsDespite inter-individual differences, our modeling study confirms that the cerebellum is the structure mainly involved by cerebellar tDCS.SignificanceModeling approach reveals that during cerebellar tDCS the current spread to other structures outside the cerebellum is unlike to produce functional effects.