ReviewElectrical stimulation of the brain and the development of cortical visual prostheses: An historical perspective

•We revisit the discovery of visual cortex and of the brain׳s electrical excitability.•We detail early experiences with electrical stimulation of visual cortex.•Subsequent attempts to develop a cortical visual prosthesis are explored.•We detail the development of technologies critical to current prosthesis designs.

Rapid advances are occurring in neural engineering, bionics and the brain-computer interface. These milestones have been underpinned by staggering advances in micro-electronics, computing, and wireless technology in the last three decades. Several cortically-based visual prosthetic devices are currently being developed, but pioneering advances with early implants were achieved by Brindley followed by Dobelle in the 1960s and 1970s. We have reviewed these discoveries within the historical context of the medical uses of electricity including attempts to cure blindness, the discovery of the visual cortex, and opportunities for cortex stimulation experiments during neurosurgery. Further advances were made possible with improvements in electrode design, greater understanding of cortical electrophysiology and miniaturisation of electronic components. Human trials of a new generation of prototype cortical visual prostheses for the blind are imminent.This article is part of a Special Issue entitled Hold Item.