Despite considerable advances in the field of retinal prosthetics during recent years, significant variability remains in the quality of vision restoration for patients. One target for refinement of prosthetic vision is to selectively activate one or more of the ~20 parallel channels of visual information that are established in the retina and subsequently travel to different visual networks in the brain. These different channels result in different spike train response patterns in the retinal ganglion cells (RGCs) which constitute the sole output neuron population of the retina.
Here we demonstrate, however, that the genuine visual response patterns of retinal ganglion cells can be altered by electrical stimulation, suggesting that the encoding of visual stimuli by retinal prosthesis devices may require consideration of stimulation-induced changes in the retina. Specifically, we demonstrate that ON and OFF response amplitudes increase significantly after stimulation. This leads to changes in the relative weighting of ON and OFF response types on a cell by cell basis – fundamentally altering the visual stimulus encoded by some RGCs.