Patch clamp data associated with Koppenwallner et al. - Short pulse epiretinal stimulation allows focal activation of retinal ganglion cells

Data, as well as simplified load and plot functions. The data is the basis for figures 2-4 in Koppenwallner et al. (10.1109/TNSRE.2025.3529940). Functionality includes loading results from a specified retinal ganglion cell (RGC) and plotting spiking output (e.g., membrane voltage over time) but does not perform threshold searching or other, more complex, analysis.

Context and methodology

Data was created by patch clamp electrophysiology of mouse retinal ganglion cells

Electrical stimulation was applied to test the effect of 10-μs-long biphasic pulses on RGC activation threshold

Technical details

Data can directly be loaded and plotted in Matlab running plotData.m (tested in Matlab R2024b)

Parameters to be specified:

cellID - identifier of each recorded cell, see list on top of plotData.m. Don't forget to add the folder prefix specifiying healthy (wt) and diseased (rd) animals

loc - location of the stimulating electrode during the experiemtn (soma or axon)

dur - pulse duration (10, 25, 50, 250 or 500, in us)

The Data folder is structured into wild-type (wt, healthy animal) and retinal degneration (rd, blind animal) data

If help is needed feel free to reach out to Paul Werginz

Epiretinal implants suffer from a lack of spatial resolution, which is greatly influenced by the undesired co-activation of distal cells with their axons passing close to targeted somas. Short current pulses in the range of 50μs have been shown to preferentially activate somas, but the low specificity may limit practical applications. In this paper, we explored decreasing pulse durations down to 10μs for achieving focal activation, i.e., a large differentiation between axonal and somatic activation in epiretinal configuration. We determined thresholds for pulses ranging between 10 and 500μs in retinal ganglion cells of both wild-type and photoreceptor-degenerated mouse retina. Ex-vivo stimulation using biphasic rectangular pulses was performed using a custom-built modified Howland-type current-controlled stimulator and a microelectrode. We demonstrate reliable direct activation of retinal ganglion cells using 10μs pulses for both somatic and axonal electrode positions. Cells from wild-type and photoreceptor-degenerated retinas exhibited similar thresholds. Axonal thresholds were significantly higher for all pulse durations, with the ratio between axonal and somatic thresholds strongly increasing with decreasing pulse duration (1.32 and 4.39 for pulse durations of 500 and 10μs, respectively). Computational modeling points to somatic polarization as the underlying mechanism for lower somatic thresholds. Our results demonstrate focal activation with pulses in the range of 10μs as a potential strategy to avoid the long-standing problem of axonal co-activation in epiretinal implants.