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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Neurosci. | doi: 10.3389/fnins.2019.00773

Investigating the feasibility of epicranial cortical stimulation using concentric-ring electrodes: A novel minimally invasive neuromodulation method

  • 1KU Leuven, Belgium

Background
Invasive cortical stimulation (ICS) is a neuromodulation method in which electrodes are implanted on the cortex to deliver chronic stimulation. ICS has been used to treat neurological disorders such as neuropathic pain, epilepsy, movement disorders and tinnitus. Noninvasive neuromodulation methods such as transcranial magnetic stimulation and transcranial electrical stimulation (TES) show great promise in treating some neurological disorders and require no surgery. However, only acute stimulation can be delivered. Epicranial current stimulation (ECS) is a novel concept for delivering chronic neuromodulation through subcutaneous electrodes implanted on the skull. The use of concentric-ring ECS electrodes may allow spatially focused stimulation and offer a less invasive alternative to ICS.

Objectives
Demonstrate ECS proof-of-concept using concentric-ring electrodes in rats and then use a computational model to explore the feasibility and limitations of ECS in humans.

Methods
ECS concentric-ring electrodes were implanted in 3 rats and pulsatile stimulation delivered to the motor cortex. An MRI based electro-anatomical human head model was used to explore different ECS concentric-ring electrode designs and these were compared with ICS and TES.

Results
Concentric-ring ECS electrodes can selectively stimulate the rat motor cortex. The computational model showed that the concentric-ring ECS electrode design can be optimized to achieve focused cortical stimulation. In general, focality was less than ICS but greater than noninvasive transcranial current stimulation.

Conclusions
ECS could be a promising minimally invasive alternative to ICS. Further work in large animal models and patients is needed to demonstrate feasibility and long-term stability.

Keywords: Transcranial electrical stimulation, Neuromodulation, concentric-ring electrode, Motor cortex stimulation, direct cortical stimulation

Received: 04 Dec 2018; Accepted: 10 Jul 2019.

Edited by:

Kai J. Miller, Mayo Clinic, United States

Reviewed by:

Peter Brunner, Albany Medical College, United States
Robert A. Gaunt, University of Pittsburgh, United States  

Copyright: © 2019 Khatoun, Asamoah and Mc Laughlin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Myles Mc Laughlin, KU Leuven, Leuven, Belgium, myles.mclaughlin@kuleuven.be