Replicating the Role of the Human Retina for a Cortical Visual Neuroprosthesis

Replicating the Role of the Human Retina for a Cortical Visual Neuroprosthesis

Samuel Romero (University of Granada, Spain), Christian Morillas (University of Granada, Spain), Antonio Martínez (University of Alicante, Spain), Begoña del Pino (University of Granada, Spain), Francisco Pelayo (University of Granada, Spain) and Eduardo Fernández (University Miguel Hernández, Spain)
DOI: 10.4018/978-1-4666-2539-6.ch014


Neuroengineering is an emerging research field combining the latest findings from neuroscience with developments in a variety of engineering disciplines to create artificial devices, mainly for therapeutical purposes. In this chapter, an application of this field to the development of a visual neuroprosthesis for the blind is described. Electrical stimulation of the visual cortex in blind subjects elicits the perception of visual sensations called phosphenes, a finding that encourages the development of future electronic visual prostheses. However, direct stimulation of the visual cortex would miss a significant degree of image processing that is carried out by the retina. The authors describe a biologically-inspired retina-like processor designed to drive the implanted stimulator using visual inputs from one or two cameras. This includes dynamic response modeling with minimal latency. The outputs of the retina-like processor are comparable to those recorded in biological retinas that are exposed to the same stimuli and allow estimation of the original scene
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Visual Neuroprosthetics

Currently, there are three major approaches for restoring sight to the blind by electrical neurostimulation. The major difference between these approaches lies in the location at which the neural interface for electrical stimulation is implanted, as represented in Figure 1.

Figure 1.

Representation showing the complexity of the primary visual system in humans, including a number of structures conforming the visual pathways. The big arrows mark the location of the electrode arrays for stimulation according to the three kinds of implants (retinal, optic nerve and cortical prostheses). Image modified from a plate from Gray’s Anatomy (Gray, 1918).


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