June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017
Retinal Hypercircuit Responses to Pattern Reversal Electrical Stimulation by A High Density MEA.
Author Affiliations & Notes
  • Ya-Ting Cheng
    Iridium Medical Technology Co., Ltd., Hsinchu, Taiwan
  • Long-Sheng Fan
    Iridium Medical Technology Co., Ltd., Hsinchu, Taiwan
    Inst. of NEMS, Hsinchu, Taiwan
  • Chang-Hao Yang
    Dept. of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
    School of Medicine, National Taiwan University, Taipei, Taiwan
  • L. J. Lee
    School of Medicine, National Taiwan University, Taipei, Taiwan
  • J. Huang
    Iridium Medical Technology Co., Ltd., Hsinchu, Taiwan
  • Y. J. Lai
    Iridium Medical Technology Co., Ltd., Hsinchu, Taiwan
  • Footnotes
    Commercial Relationships   Ya-Ting Cheng, Iridium Medical Technology Co., Ltd. (E); Long-Sheng Fan, None; Chang-Hao Yang, None; L. J. Lee, None; J. Huang, Iridium Medical Technology Co., Ltd. (E); Y. J. Lai, Iridium Medical Technology Co., Ltd. (E)
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 4187. doi:
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      Ya-Ting Cheng, Long-Sheng Fan, Chang-Hao Yang, L. J. Lee, J. Huang, Y. J. Lai; Retinal Hypercircuit Responses to Pattern Reversal Electrical Stimulation by A High Density MEA.. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4187.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : To investigate the RGC hypercircuit responses to pattern reversal of subretinal electrical stimulation, and the minimum detectable spatial movement of stripe- patterned stimulations.

Methods : A 2,500-electrode microelectrode array with SIROF electrodes arranged hexagonally 30 µm in pitch is used for patterned electrical stimulation covering an area of ~1.5x1.2mm. Whole-cell patch clamping is used to measure the RGC responses of retina tissue from 26 C57/B6 wild-type mice during the stimulation. The biphasic current stimulations from these electrodes are spatially grouped into stripe patterns with the stripe width ranging from 26 µm to 260 µm, and temporally separated into two phases 180 degrees out of phase. The pulse rates ranges from 4 to 20 Hz, and the phases of the stripe pattern are reversed every 500 msec. GABAA and GABAC receptors are blocked with antagonists, bicuculline and TPMPA, to assess the influence mediated by lateral inhibition from amacrine cells in the pattern reversal subretinal electrical stimulation.

Results : At low pulse rates (4~8 Hz), the ON RGC’s can spike with each electrical stimulation pulse; at higher pulse rates (16~20 Hz), the RGC’s only respond to the first reversal pulses of one phase indicating the flicker fusion. Some ON RGC’s can respond to pattern reversal with stripe movements as small as 26 μm. Most of the ON RGC’s have the minimum detectable stripe movements between 26 μm to 104 μm (n = 11/18); most of the OFF RGC’s have lower detectable stripe-movements resolution between 208 to 260 μm (n = 5/8); however, some of the OFF RGC's detect stripe movements between 26 μm to 78 μm (n = 2/8). With GABAA receptor blocked by bicuculline, the patched ON RGC’s have improved stripe movement resolution (from 78 μm to 26 μm). With both GABAA and GABAC receptor blocked by bicuculline and TPMPA, the ON RGC’s have increased sensitivity to electrical stimulation, and the flicker fusion happened at the pulse rate ≥ 40 Hz. RGC's respond to the first pulses of the phase reversal of both phases in both GABA blocked cases.

Conclusions : The minimum detectable stripe movement in subretinal electrical stimulation by RGC’s of C57/B6 wild-type mice is 26 μm. By blocking the GABAA and GABAc receptor, the RGC’s have increased sensitivity to the electrical stimulation; however, the stripe movement spatial resolution and pattern reversal time responses results are mixed.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

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