Phosphenes produced by electrical stimulation of human occipital cortex, and their application to the development of a prosthesis for the blind

Dobelle, William H.; Mladejovsky, M. G.

doi:10.1113/jphysiol.1974.sp010766

Cited by 424 publications

(335 citation statements)

References 12 publications

(17 reference statements)

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“…9 In 1974, the ES of the visual system was shown to elicit visual perceptions using suprathreshold stimulation. 10 Thirty years later, the therapeutic potential of subthreshold ES of the retina was identified by Chow et al 11 The authors showed that patients having inactive subretinal chips generating only subthreshold currents exhibited visual improvement in areas far from the site of the electrical device, suggesting a generalized neuroprotective effect of ES. This finding was associated with the expression of neurotrophic factors and sparked a research interest in the effects of ES in animal experiments and thereafter in clinical studies for treating blindness.…”

Section: Es In Ophthalmologymentioning

confidence: 99%

Electrical Stimulation as a Means for Improving Vision

Sehic

Guo

Cho

et al. 2016

The American Journal of Pathology

136

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Evolving research has provided evidence that noninvasive electrical stimulation (ES) of the eye may be a promising therapy for either preserving or restoring vision in several retinal and optic nerve diseases. In this review, we focus on minimally invasive strategies for the delivery of ES and accordingly summarize the current literature on transcorneal, transorbital, and transpalpebral ES in both animal experiments and clinical studies. Various mechanisms are believed to underlie the effects of ES, including increased production of neurotrophic agents, improved chorioretinal blood circulation, and inhibition of proinflammatory cytokines. Different animal models have demonstrated favorable effects of ES on both the retina and the optic nerve. Promising effects of ES have also been demonstrated in clinical studies; however, all current studies have a lack of randomization and/or a control group (sham). There is thus a pressing need for a deeper understanding of the underlying mechanisms that govern clinical success and optimization of stimulation parameters in animal studies. In addition, such research should be followed by large, prospective, clinical studies to explore the full potential of ES. Through this review, we aim to provide insight to guide future research on ES as a potential therapy for improving vision. (Am J Pathol 2016 http://dx

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Section: Es In Ophthalmologymentioning

confidence: 99%

Electrical Stimulation as a Means for Improving Vision

Sehic

Guo

Cho

et al. 2016

The American Journal of Pathology

136

View full text Add to dashboard Cite

show abstract

“…The neurons that mediate the delay effect exhibit excitability properties that are similar to those of neurons in V1 of humans that mediate electrically evoked phosphenes (i.e. chronaxies ranging from 0.1 to 0.4 ms; Brindley and Lewin, 1968;Dobelle and Mladejovsky, 1974;Rushton and Brindley, 1978;Tehovnik et al, 2004). Therefore, every time stimulation evokes a delay in visually guided saccades, a phosphene is likely being experienced by the monkey at the time of stimulation, which is then followed by a temporary scotoma of comparable size and shape to that of the phosphene.…”

Section: Magnification Factor and Receptive-field Sizementioning

confidence: 99%

“…Electrical stimulation of primary visual cortex (area V1) in humans has been shown to produce a visual percept, called a phosphene (Brindley and Lewin, 1968;Dobelle and Mladejovsky, 1974;Schmidt et al, 1996). This finding has lead to the suggestion that microstimulation of V1 in behaving monkeys could serve as a model for the implantation of a functional cortical visual prosthesis in clinically blind individuals (Troyk et al, 2003;Bartlett et al 2005;Bradley et al, 2005;DeYoe et al, 2005;Tehovnik et al, 2005a).…”

Section: Introductionmentioning

confidence: 99%

“…When evoked using currents above 10 μA and well into the milliampere range, phosphenes are commonly described as being featureless and circular in shape (Brindley and Lewin, 1968;Dobelle and Mladejovsky, 1974;Schmidt et al, 1996). Furthermore, as the stimulating electrode is positioned more distant from the foveal representation of V1 the size of a phosphene increases from a fraction of a degree when evoked at the fovea to three degrees when evoked at the most extreme eccentricities of the visual field (Brindley and Lewin, 1968;Schmidt et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

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Phosphene induction by microstimulation of macaque V1

Tehovnik

Slocum

2007

Brain Research Reviews

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Non-human primates are being used to develop a cortical visual prosthesis for the blind. We use the properties of electrical microstimulation of striate cortex (area V1) of macaque monkeys to make inferences about phosphene induction. Our analysis is based on well-established properties of V1: retino-cortical magnification factor, receptive-field size, and the characteristics of hypercolumns. We argue that phosphene size is dependent on the amount of current delivered to V1 and on the retino-cortical magnification factor. We suggest that to improve the correspondence between the site of stimulation within V1 and the visual field location of an elicited phosphene both eyes must be put under experimental control given that phosphene location is retinocentric and given that the vergence angle between the eyes might affect the position of a phosphene in depth. Knowing how electrical microstimulation interacts with cortical tissue to evoke percepts in behaving macaque monkeys is fundamental to the establishment of an effective cortical visual prosthesis for the blind.

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“…His experiments and studies, however, fell into oblivion in the following decades at the beginning of the twentieth century, with giant progress of scientific medical practice in many other areas. Electrical stimulation of the visual system was re-discovered in the 1970s for elicitation of visual percepts, or phosphenes, by supra-threshold stimulation [2]. These experiments constituted the basis for retinal implants which today allow patients to recognize letters and shapes in laboratory and natural settings [3,4].…”

Section: Introductionmentioning

confidence: 99%