Format

Send to

Choose Destination
J Neural Eng. 2014 Apr;11(2):026008. doi: 10.1088/1741-2560/11/2/026008. Epub 2014 Mar 10.

Selectivity of direct and network-mediated stimulation of the retinal ganglion cells with epi-, sub- and intraretinal electrodes.

Author information

1
Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA. Department of Physics, Stanford University, Stanford, CA 94305, USA.

Abstract

OBJECTIVE:

Intra-retinal placement of stimulating electrodes can provide close and stable proximity to target neurons. We assessed improvement in stimulation thresholds and selectivity of the direct and network-mediated retinal stimulation with intraretinal electrodes, compared to epiretinal and subretinal placements.

APPROACH:

Stimulation thresholds of the retinal ganglion cells (RGCs) in wild-type rat retina were measured using the patch-clamp technique. Direct and network-mediated responses were discriminated using various synaptic blockers.

MAIN RESULTS:

Three types of RGC responses were identified: short latency (SL, τ < 5 ms) originating in RGCs, medium latency (ML, 3 < τ < 70 ms) originating in the inner nuclear layer and long latency (LL, τ > 40 ms) originating in photoreceptors. Cathodic epiretinal stimulation exhibited the lowest threshold for direct RGC response and the highest direct selectivity (network/direct thresholds ratio), exceeding a factor of 3 with pulse durations below 0.5 ms. For network-mediated stimulation, the lowest threshold was obtained with anodic pulses in OPL position, and its network selectivity (direct/network thresholds ratio) increased with pulse duration, exceeding a factor of 4 at 10 ms. Latency of all three types of responses decreased with increasing strength of the stimulus.

SIGNIFICANCE:

These results define the optimal range of pulse durations, pulse polarities and electrode placement for the retinal prostheses aiming at direct or network-mediated stimulation of RGCs.

PMID:
24608166
PMCID:
PMC4082997
DOI:
10.1088/1741-2560/11/2/026008
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for IOP Publishing Ltd. Icon for PubMed Central
Loading ...
Support Center