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Graefes Arch Clin Exp Ophthalmol. 2015 Sep;253(9):1515-28. doi: 10.1007/s00417-015-3027-x. Epub 2015 May 16.

Spatial characteristics of evoked potentials elicited by a MEMS microelectrode array for suprachoroidal-transretinal stimulation in a rabbit.

Author information

1
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China, zouro@163.com.

Abstract

BACKGROUND:

Suprachoroidal-transretinal stimulation (STS) can potentially restore vision. This study investigated the spatial characteristics of cortical electrical evoked potentials (EEPs) elicited by STS.

METHODS:

A 4 × 4 thin-film platinum microelectrode stimulating array (200 μm electrode diameter and 400 μm center-to-center distance) was fabricated by a micro-electro-mechanical systems (MEMS) techniques and implanted into the suprachoroidal space of albino rabbits.

RESULTS:

The current threshold to elicit reliable EEPs by a single electrode was 41.6 ± 12.6 μA, corresponding to a 66.2 ± 20.1 μC · cm(-2) charge density per phase, which was lower than the reported safety limits. Spatially differentiated cortical responses could be evoked by STS through different rows or columns of electrical stimulation; furthermore, shifts in the location of the maximum cortical activities were consistent with cortical visuotopic maps; increasing the number of simultaneously stimulating electrodes increased the response amplitudes of EEPs and expanded the spatial spread as well. In addition, long-term implantation and electrical stimulation of the MEMS electrode array in suprachoroidal space are necessary to evaluate systematically the safety and biocompatibility of this approach.

CONCLUSIONS:

This study indicates that the STS approach by a MEMS-based platinum electrode array is a feasible alternative for visual restoration, and relatively high spatial discrimination may be achieved.

PMID:
25981117
DOI:
10.1007/s00417-015-3027-x
[Indexed for MEDLINE]

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