gms | German Medical Science

Artificial Vision 2019

The International Symposium on Visual Prosthetics

13.12. - 14.12.2019, Aachen

Location-dependent AIS variations influence activation thresholds in mouse α RGCs

Meeting Abstract

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  • Paul Werginz - Vienna University of Technology, Vienna/A; Massachusetts General Hospital, Boston/USA
  • V. Raghuram - Boston VA Healthcare System, Boston/USA; Massachusetts General Hospital, Boston/USA; Tufts University, Medford/USA
  • S. I. Fried - Boston VA Healthcare System, Boston/USA; Massachusetts General Hospital, Boston/USA

Artificial Vision 2019. Aachen, 13.-14.12.2019. Düsseldorf: German Medical Science GMS Publishing House; 2019. Doc19artvis20

doi: 10.3205/19artvis20, urn:nbn:de:0183-19artvis205

Published: December 10, 2019

© 2019 Werginz et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at



Objective: To evaluate threshold differences between different types of alpha retinal ganglion cells (α RGCs) based on differential axon initial segment (AIS) anatomy.

Materials and methods: Two different methods were used to recover AIS anatomy in α RGCs:

Retinal whole-mounts from Thy-1 GFP mice were stained for AnkyrinG and ChAT.
RGCs were filled in wild-type (C57BL/6J) mouse retinas and stained for streptavidin, AnkyrinG and ChAT. Multi-compartment models based on traced RGC anatomies were generated. AIS properties were varied according to anatomical measurements and activation thresholds in response to electric stimulation were computed.

Results: AIS length and distance from the soma varied depending on retinal location and cell type. Whereas AISs in ON- and OFF-α sustained RGCs displayed a size gradient along the nasal-temporal axis AISs in OFF-α transient RGCs tended to be longer in the dorsal vs. the ventral retina. For a given location, AISs were longer in ON- vs. OFF-α sustained RGCs. Computed activation thresholds were lowest when the AIS and the stimulating electrode were located close to each other. Longest AISs resulted in lowest activation thresholds allowing selective stimulation over cells with shorter AISs.

Discussion: Our results indicate that cell type selective activation of certain α RGC classes may be possible due to differences in AIS anatomy.

Acknowledgment: Research was supported by the VA (1I01RX001663), NINDS (U01-NS099700 & R01-NS110575) and FWF (J3947).