Visual prostheses for the blind

Shepherd, Robert K.; Shivdasani, Mohit N.; Nayagam, David A. X.; Williams, Christopher E.; Blamey, Peter J.

doi:10.1016/j.tibtech.2013.07.001

Cited by 159 publications

(133 citation statements)

References 63 publications

(83 reference statements)

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“…Development of intraocular implants (Ahuja et al, 2011;Shepherd, Shivdasani, Nayagam, Williams, & Blamey, 2013) to artificially augment vision in blind people provides a unique opportunity for c o r t e x x x x ( 2 0 1 6 ) 1 e3 7 27 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 7...…”

Section: Conclusion and Directions For Further Researchmentioning

confidence: 99%

Visual mismatch negativity (vMMN): A review and meta-analysis of studies in psychiatric and neurological disorders

Kremláček

Kreegipuu

Tales

et al. 2016

Cortex

108

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The visual mismatch negativity (vMMN) response is an event-related potential (ERP) component, which is automatically elicited by events that violate predictions based on prior events. VMMN experiments use visual stimulus repetition to induce predictions, and vMMN is obtained by subtracting the response to rare unpredicted stimuli from those to frequent stimuli. One increasingly popular interpretation of the mismatch response postulates that vMMN, similar to its auditory counterpart (aMMN), represents a prediction error response generated by cortical mechanisms forming probabilistic representations of sensory signals. Here we discuss the physiological and theoretical basis of vMMN and review thirty-three studies from the emerging field of its clinical applications, presenting a meta-analysis of findings in schizophrenia, mood disorders, substance abuse, neurodegenerative disorders, developmental disorders, deafness, panic disorder and hypertension. Furthermore, we include reports on aging and maturation as they bear upon many clinically relevant conditions. Surveying the literature we found that vMMN is altered in several clinical populations which is in line with aMMN findings. An important potential advantage of vMMN however is that it allows the investigation of deficits in predictive processing in cognitive domains which rely primarily on visual information; a principal sensory modality and thus of vital importance in environmental information processing and response, and a modality which arguably may be more sensitive to some pathological changes. However, due to the relative infancy of research in vMMN compared to aMMN in clinical populations its potential for clinical application is not yet fully appreciated. The aim of this review and meta-analysis therefore is to present, in a detailed systematic manner, the findings from clinically-based vMMN studies, to discuss their potential impact and application, to raise awareness of this measure and to improve our understanding of disease upon fundamental aspects of visual information processing. Furthermore, we include reports on aging and maturation as they bear upon many clinically relevant conditions. Surveying the literature we found that vMMN is altered in several 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 clinical populations which is in line with aMMN findings. An important potential advantage of vMMN however is that it allows the investigation of deficits in predictive processing in cognitive domains which rely primarily on visual information; a principal sensor...

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Section: Conclusion and Directions For Further Researchmentioning

confidence: 99%

Visual mismatch negativity (vMMN): A review and meta-analysis of studies in psychiatric and neurological disorders

Kremláček

Kreegipuu

Tales

et al. 2016

Cortex

108

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show abstract

“…Though many different prosthetic strategies and a variety of stimulation modalities have been investigated, retinal-based prostheses that seek to stimulate the surviving neurons electrically are by far the most clinically successful [1][2][3][4][5] . Electrical-based retinal prostheses, typically interfaced with the macula regions of the retina in either epiretinal (front of the retina) or subretinal (behind retina) configuration, are chips comprising an array of microelectrodes that stimulate retinal neurons electrically, theoretically generating a perception of a point of light at each electrode site.…”

Section: Introductionmentioning

confidence: 99%

Prototype chemical synapse chip for spatially patterned neurotransmitter stimulation of the retina ex vivo

et al. 2017

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Biomimetic stimulation of the retina with neurotransmitters, the natural agents of communication at chemical synapses, could be more effective than electrical stimulation for treating blindness from photoreceptor degenerative diseases. Recent studies have demonstrated the feasibility of neurotransmitter stimulation by injecting glutamate, a primary retinal neurotransmitter, into the retina at isolated single sites. Here, we demonstrate spatially patterned multisite stimulation of the retina with glutamate, offering the first experimental evidence for applicability of this strategy for translating visual patterns into afferent neural signals. To accomplish pattern stimulation, we fabricated a special microfluidic device comprising an array of independently addressable microports connected to tiny on-chip glutamate reservoirs via microchannels. The device prefilled with glutamate was interfaced with explanted rat retinas placed over a multielectrode array (MEA) with the retinal ganglion cells (RGC) contacting the electrodes and photoreceptor surface contacting the microports. By independently and simultaneously activating a subset of the microports with modulated pressure pulses, small boluses of glutamate were convectively injected at multiple sites in alphabet patterns over the photoreceptor surface. We found that the glutamate-driven RGC responses recorded through the MEA system were robust and spatially laid out in patterns strongly resembling the injection patterns. The stimulations were also highly localized with spatial resolutions comparable to or better than electrical retinal prostheses. Our findings suggest that surface stimulation of the retina with neurotransmitters in pixelated patterns of visual images is feasible and an artificial chemical synapse chip based on this approach could potentially circumvent the limitations of electrical retinal prostheses.

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“…Retinal prostheses typically consist of arrays of photodiodes that are surgically implanted beneath or above the retina to electrically stimulate the remaining inner retinal cells (Loudin et al 2007;Zrenner et al 2011). Another strategy that is being pursued for patients with very advanced disease is a three-dimensional transplants consisting of stem-cell-derived sheets of photoreceptors and RPE cells grown on a biocompatible polymer scaffold (Zhang et al 2007;Yao et al 2011;Tucker et al 2011a;Shepherd et al 2013). …”

Section: Stem Cells and Genetics Of Retinal Degenerationsmentioning

confidence: 99%

Stem Cells as Tools for Studying the Genetics of Inherited Retinal Degenerations

Wiley

Burnight

Mullins

et al. 2014

Cold Spring Harbor Perspectives in Medicine

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Visual prostheses for the blind

Cited by 159 publications

References 63 publications

Visual mismatch negativity (vMMN): A review and meta-analysis of studies in psychiatric and neurological disorders

Visual mismatch negativity (vMMN): A review and meta-analysis of studies in psychiatric and neurological disorders

Prototype chemical synapse chip for spatially patterned neurotransmitter stimulation of the retina ex vivo

Stem Cells as Tools for Studying the Genetics of Inherited Retinal Degenerations

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