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Bridging the Gap in Neuroelectronic Interfaces

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

Front. Neurosci. | doi: 10.3389/fnins.2019.00413

Mediating retinal ganglion cell spike rates using high-frequency electrical stimulation

 Tianruo GUO1, David Tsai1, 2, Chih Yu Yang1,  Amr Al Abed1, Perry Twyford3,  Shelley I. Fried3, 4, John W. Morely5,  Gregg J. Suaning6,  Socrates Dokos1 and  Nigel H. Lovell1*
  • 1University of New South Wales, Australia
  • 2Columbia University, United States
  • 3VA Boston Healthcare System, United States
  • 4Massachusetts General Hospital, Harvard Medical School, United States
  • 5School of Medicine, Western Sydney University, Australia
  • 6University of Sydney, Australia

Recent retinal studies have directed more attention to sophisticated stimulation strategies based on high-frequency (> 1.0 kHz) electrical stimulation (HFS). In these studies, each RGC type demonstrated a characteristic stimulus-strength-dependent response to HFS, offering the intriguing possibility of focally targeting retinal neurons to provide useful visual information by retinal prosthetics. Ionic mechanisms are known to affect the responses of electrogenic cells during electrical stimulation. However, how these mechanisms affect retinal ganglion cell (RGC) responses is not well understood at present, particularly when applying HFS. Here, we investigate this issue via an in silico model of the RGC and confirm and calibrate the model using an in vitro retinal preparation. An RGC model based on accurate biophysics and realistic representation of cell morphology, was used to investigate how RGCs respond to HFS. The model was able to closely replicate the stimulus-strength-dependent suppression of RGC action potentials observed experimentally. Our results suggest that the cellular inhibition to HFS is due to local membrane hyperpolarization caused by outward membrane currents near the stimulus electrode. In addition, the extent of HFS-induced inhibition can be largely altered by the intrinsic properties of the inward sodium current. Finally, stimulus-strength-dependent suppression can be modulated by a wide range of stimulation frequencies, under generalized electrode placement conditions. In vitro experiments verified the computational modeling data. This modeling and experimental approach can be extended to further our understanding of the effects of novel stimulus strategies by simulating RGC stimulus-response profiles over a larger range of stimulation frequencies and electrode locations than have previously been explored.

Keywords: Neuromodulation, high-frequency electrical stimulation, Retinal implant, retinal ganglion cell, computational modeling, in vitro patch-clamp

Received: 20 Dec 2018; Accepted: 11 Apr 2019.

Edited by:

Jeffrey R. Capadona, Case Western Reserve University, United States

Reviewed by:

Robert A. Gaunt, University of Pittsburgh, United States
Juan Álvaro Gallego, Northwestern University, United States  

Copyright: © 2019 GUO, Tsai, Yang, Al Abed, Twyford, Fried, Morely, Suaning, Dokos and Lovell. 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. Nigel H. Lovell, University of New South Wales, Sydney, Australia,