Cerebellar and Spinal Direct Current Stimulation in Children: Computational Modeling of the Induced Electric Field.

Serena Fiocchi,Alberto Priori,Marta Parazzini,Paolo Ravazzani

doi:10.3389/fnhum.2016.00522

Abstract

Recent studies have shown that the specific application of transcranial direct current stimulation (tDCS) over the cerebellum can modulate cerebellar activity. In parallel, transcutaneous spinal DC stimulation (tsDCS) was found to be able to modulate conduction along the spinal cord and spinal cord functions. Of particular interest is the possible use of these techniques in pediatric age, since many pathologies and injuries, which affect the cerebellar cortex as well as spinal cord circuits, are diffuse in adults as well as in children. Up to now, experimental studies of cerebellar and spinal DC stimulation on children are completely missing and therefore there is a lack of information about the safety of this technique as well as the appropriate dose to be used during the treatment. Therefore, the knowledge of electric quantities induced into the cerebellum and over the spinal cord during cerebellar tDCS and tsDCS, respectively, is required. This work attempts to address this issue by estimating through computational techniques, the electric field distributions induced in the target tissues during the two stimulation techniques applied to different models of children of various ages and gender. In detail, we used four voxel child models, aged between 5- and 8-years. Results revealed that, despite inter-individual differences, the cerebellum is the structure mainly involved by cerebellar tDCS, whereas the electric field generated by tsDCS can reach the spinal cord also in children. Moreover, it was found that there is a considerable spread toward the anterior area of the cerebellum and the brainstem region for cerebellar tDCS and in the spinal nerve for spinal direct current stimulation. Our study therefore predicts that the electric field spreads in complex patterns that strongly depend on individual anatomy, thus giving further insight into safety issues and informing data for pediatric investigations of these stimulation techniques.

Highlights

In the last decade two innovative techniques, cerebellar transcranial direct current stimulation and transcutaneous spinal direct current stimulation, based on the delivery of direct current transcutaneously, have been proven to affect and modulate the neural activity in the cerebellum and in the spinal cord, offering promising therapeutic opportunities for restoring their functions (Priori et al, 2014).cTDCS and tsDCS in ChildrenIt is known that weak electrical currents can induce persisting excitability changes in the stimulated structure (Woods et al, 2016)
We here discussed the first computational modeling study on the electric field distributions induced by cerebellar and cTDCS and tsDCS in Children
This work completes the analysis started by two previous modeling studies conducted on adults (Parazzini et al, 2014a,b) and provides some indications about the electric field distribution that can give further insight into safety issues of pediatric transcranial direct current stimulation (tDCS) investigations

Summary

Introduction

In the last decade two innovative techniques, cerebellar transcranial direct current stimulation (ctDCS) and transcutaneous spinal direct current stimulation (tsDCS), based on the delivery of direct current transcutaneously, have been proven to affect and modulate the neural activity in the cerebellum and in the spinal cord, offering promising therapeutic opportunities for restoring their functions (Priori et al, 2014).cTDCS and tsDCS in ChildrenIt is known that weak electrical currents can induce persisting excitability changes in the stimulated structure (Woods et al, 2016). Given the existing spinal-brain interactions and the need to find a noninvasive neuromodulatory tool to prevent neuronal dysfunctions developed after spinal cord injuries, the possibility to apply transcutaneous direct current over spinal cord was explored. This gave significant insights that tsDCS can effectively modulate conduction along the spinal somatosensory pathways and alter spinal cord functions (for a review see Cogiamanian et al, 2012; Priori et al, 2014). Of particular interest is the possible application of these techniques in pediatric age, since many pathologies and injuries, which affect the cerebellar cortex as well as the spinal cord circuits, are diffuse in adults as well as in children. Up till very few studies have applied tDCS in pediatric population (Schneider and Hopp, 2011; Varga et al, 2011; Yook et al, 2011; Siniatchkin et al, 2012; Gillick et al, 2015; Moliadze et al, 2015), mainly using the classical tDCS montages with both electrodes on the scalp (i.e., the one with the active electrode over the motor cortex-M1 and the reference electrode over the contralateral supraorbital cortex)

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Conclusion