Spatial Interactions of Electrically Evoked Potentials in Visual Cortex Induced by Multi-retinal Electrical Stimulation in Rats
Retinal prostheses are designed to electrically stimulate retinal neurons to generate artificial vision in patients with degenerative diseases such as retinitis pigmentosa (RP) or age-related macular degeneration (AMD). Considering hundreds of microelectrodes may be applied in the future retinal prosthesis to provide enough spatial information for precise perception, it is crucial to investigate the spatial properties of the visual cortex in response to retinal electric stimulation via in vivo studies, especially in multi-stimulating manner by adjacent electrodes. In this study, we use retinal multi-stimulating electrodes to stimulate retinal ganglion cells (RGCs) and record electrically evoked potentials (EEPs) in contralateral visual cortex by a 32-channel Utah array. The threshold of eliciting current for EEPs was determined with 20% of the maximum response in visual cortex. The spatial map with 32 grids for single retinal stimulation was obtained firstly, which showed the different spatial distribution to different retinal stimulation. Then the combination of two stimulation from two adjacent retinal stimulating electrode was applied to examine the spatial responses of visual cortex.
The work described in this paper was supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China, through Project CityU 123412 and also supported by Guangdong Innovative and Entrepreneurial Research Team Program (No. 2013S046) and Shenzhen Peacock Plan.
- 1.Hartong, D.T., E.L. Berson, and T.P. Dryja, Retinitis pigmentosa. Lancet, 2006. 368(9549): p. 1795–1809.Google Scholar
- 5.Humayun, M.S., et al., Morphometric analysis of the extramacular retina from postmortem eyes with retinitis pigmentosa. Invest Ophthalmol Vis Sci, 1999. 40(1): p. 143–148.Google Scholar