Design of a Prototype for Vision Prosthesis

2018 ◽  
Vol 7 (2) ◽  
pp. 1-13
Author(s):  
V. Bhujanga Rao ◽  
P. Seetharamaiah ◽  
Nukapeyi Sharmili
Keyword(s):  
Visual Information ◽  
Ganglion Cells ◽  
Electrode Array ◽  
Laboratory Model ◽  
Electric Pulses ◽  
Embedded Computer ◽  
Field Of Vision ◽  
Led Array ◽  
Electrical Pulses ◽  
Computer Based

This article describes how the field of vision prostheses is currently being developed around the world to restore useful vision for people suffering from retinal degenerative diseases. The vision prosthesis system (VPS) maps visual images to electrical pulses and stimulates the surviving healthy parts in the retina of the eye, i.e. ganglion cells, using electric pulses applied through an electrode array. The retinal neurons send visual information to the brain. This article presents the design of a prototype vision prosthesis system which converts images/video into biphasic electric stimulation pulses for the excitation of electrodes simulated by an LED array. The proposed prototype laboratory model has been developed for the design of flexible high-resolution 1024-electrode VPS, using an embedded computer-based efficient control algorithm for better visual prediction. The prototype design for the VPS is verified visually through a video display on an LCD/LED array. The experimental results of VPS are enumerated for the test objects, such as, palm, human face and large font characters. The results were found to be satisfactory.

Design of a Prototype for Vision Prosthesis

2021 ◽  
pp. 492-505
Author(s):  
V. Bhujanga Rao ◽  
P. Seetharamaiah ◽  
Nukapeyi Sharmili
Keyword(s):  
Visual Information ◽  
Ganglion Cells ◽  
Electrode Array ◽  
Laboratory Model ◽  
Electric Pulses ◽  
Embedded Computer ◽  
Field Of Vision ◽  
Led Array ◽  
Electrical Pulses ◽  
Computer Based

This article describes how the field of vision prostheses is currently being developed around the world to restore useful vision for people suffering from retinal degenerative diseases. The vision prosthesis system (VPS) maps visual images to electrical pulses and stimulates the surviving healthy parts in the retina of the eye, i.e. ganglion cells, using electric pulses applied through an electrode array. The retinal neurons send visual information to the brain. This article presents the design of a prototype vision prosthesis system which converts images/video into biphasic electric stimulation pulses for the excitation of electrodes simulated by an LED array. The proposed prototype laboratory model has been developed for the design of flexible high-resolution 1024-electrode VPS, using an embedded computer-based efficient control algorithm for better visual prediction. The prototype design for the VPS is verified visually through a video display on an LCD/LED array. The experimental results of VPS are enumerated for the test objects, such as, palm, human face and large font characters. The results were found to be satisfactory.

Retinal input influences pace of neurogenesis but not cell-type configuration of the visual forebrain

2021 ◽  
Author(s):  
Shachar Sherman ◽  
Koichi Kawakami ◽  
Herwig Baier
Keyword(s):  
Visual Information ◽  
Visual Stimulation ◽  
Ganglion Cells ◽  
Neuronal Cell ◽  
Cell Types ◽  
Vertebrate Brain ◽  
Relative Contribution ◽  
Retinal Input ◽  
And Migration ◽  
The Brain

The brain is assembled during development by both innate and experience-dependent mechanisms1-7, but the relative contribution of these factors is poorly understood. Axons of retinal ganglion cells (RGCs) connect the eye to the brain, forming a bottleneck for the transmission of visual information to central visual areas. RGCs secrete molecules from their axons that control proliferation, differentiation and migration of downstream components7-9. Spontaneously generated waves of retinal activity, but also intense visual stimulation, can entrain responses of RGCs10 and central neurons11-16. Here we asked how the cellular composition of central targets is altered in a vertebrate brain that is depleted of retinal input throughout development. For this, we first established a molecular catalog17 and gene expression atlas18 of neuronal subpopulations in the retinorecipient areas of larval zebrafish. We then searched for changes in lakritz (atoh7-) mutants, in which RGCs do not form19. Although individual forebrain-expressed genes are dysregulated in lakritz mutants, the complete set of 77 putative neuronal cell types in thalamus, pretectum and tectum are present. While neurogenesis and differentiation trajectories are overall unaltered, a greater proportion of cells remain in an uncommitted progenitor stage in the mutant. Optogenetic stimulation of a pretectal area20,21 evokes a visual behavior in blind mutants indistinguishable from wildtype. Our analysis shows that, in this vertebrate visual system, neurons are produced more slowly, but specified and wired up in a proper configuration in the absence of any retinal signals.

scholarly journals Interspike Interval Based Filtering of Directional Selective Retinal Ganglion Cells Spike Trains

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Aurel Vasile Martiniuc ◽  
Alois Knoll
Keyword(s):  
Retinal Ganglion Cells ◽  
Visual Stimulus ◽  
Visual Information ◽  
Ganglion Cells ◽  
Neuronal Response ◽  
Spike Trains ◽  
Retinal Ganglion ◽  
Stimulus Motion ◽  
Information Rates ◽  
Grating Bars

The information regarding visual stimulus is encoded in spike trains at the output of retina by retinal ganglion cells (RGCs). Among these, the directional selective cells (DSRGC) are signaling the direction of stimulus motion. DSRGCs' spike trains show accentuated periods of short interspike intervals (ISIs) framed by periods of isolated spikes. Here we use two types of visual stimulus, white noise and drifting bars, and show that short ISI spikes of DSRGCs spike trains are more often correlated to their preferred stimulus feature (that is, the direction of stimulus motion) and carry more information than longer ISI spikes. Firstly, our results show that correlation between stimulus and recorded neuronal response is best at short ISI spiking activity and decrease as ISI becomes larger. We then used grating bars stimulus and found that as ISI becomes shorter the directional selectivity is better and information rates are higher. Interestingly, for the less encountered type of DSRGC, known as ON-DSRGC, short ISI distribution and information rates revealed consistent differences when compared with the other directional selective cell type, the ON-OFF DSRGC. However, these findings suggest that ISI-based temporal filtering integrates a mechanism for visual information processing at the output of retina toward higher stages within early visual system.

scholarly journals An ultra-low-cost electroporator with microneedle electrodes (ePatch) for SARS-CoV-2 vaccination

2021 ◽  
Vol 118 (45) ◽  
pp. e2110817118
Author(s):  
Dengning Xia ◽  
Rui Jin ◽  
Gaurav Byagathvalli ◽  
Huan Yu ◽  
Ling Ye ◽  
...  
Keyword(s):  
Immune Responses ◽  
Large Scale ◽  
Low Cost ◽  
Electrode Array ◽  
Dna Vaccination ◽  
Intradermal Injection ◽  
Antibody Responses ◽  
Transient Effects ◽  
Electric Pulses ◽  
High Electric Field Strength

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other pathogens with pandemic potential requires safe, protective, inexpensive, and easily accessible vaccines that can be developed and manufactured rapidly at a large scale. DNA vaccines can achieve these criteria, but induction of strong immune responses has often required bulky, expensive electroporation devices. Here, we report an ultra-low-cost (<1 USD), handheld (<50 g) electroporation system utilizing a microneedle electrode array (“ePatch”) for DNA vaccination against SARS-CoV-2. The low cost and small size are achieved by combining a thumb-operated piezoelectric pulser derived from a common household stove lighter that emits microsecond, bipolar, oscillatory electric pulses and a microneedle electrode array that targets delivery of high electric field strength pulses to the skin’s epidermis. Antibody responses against SARS-CoV-2 induced by this electroporation system in mice were strong and enabled at least 10-fold dose sparing compared to conventional intramuscular or intradermal injection of the DNA vaccine. Vaccination was well tolerated with mild, transient effects on the skin. This ePatch system is easily portable, without any battery or other power source supply, offering an attractive, inexpensive approach for rapid and accessible DNA vaccination to combat COVID-19, as well as other epidemics.

scholarly journals A method for single-neuron chronic recording from the retina in awake mice

Science ◽  
2018 ◽  
Vol 360 (6396) ◽  
pp. 1447-1451 ◽  
Author(s):  
Guosong Hong ◽  
Tian-Ming Fu ◽  
Mu Qiao ◽  
Robert D. Viveros ◽  
Xiao Yang ◽  
...  
Keyword(s):  
Retinal Ganglion Cells ◽  
Visual Information ◽  
Single Neuron ◽  
Ganglion Cells ◽  
Ex Vivo ◽  
Neural Circuitry ◽  
Retinal Ganglion ◽  
Chronic Recording ◽  
The Brain

The retina, which processes visual information and sends it to the brain, is an excellent model for studying neural circuitry. It has been probed extensively ex vivo but has been refractory to chronic in vivo electrophysiology. We report a nonsurgical method to achieve chronically stable in vivo recordings from single retinal ganglion cells (RGCs) in awake mice. We developed a noncoaxial intravitreal injection scheme in which injected mesh electronics unrolls inside the eye and conformally coats the highly curved retina without compromising normal eye functions. The method allows 16-channel recordings from multiple types of RGCs with stable responses to visual stimuli for at least 2 weeks, and reveals circadian rhythms in RGC responses over multiple day/night cycles.

Tracking Children's Interactions with Traditional Text and Computer-Based Early Literacy Media

2017 ◽  
pp. 107-121
Author(s):  
Domenica De Pasquale ◽  
Eileen Wood ◽  
Alexandra Gottardo ◽  
Jeffery A. Jones ◽  
Rachel Kaplan ◽  
...  
Keyword(s):  
Eye Tracking ◽  
Early Literacy ◽  
Software Design ◽  
Visual Information ◽  
Literacy Skills ◽  
Computer Mediated ◽  
Key Skills ◽  
Computer Based ◽  
Based Instruction ◽  
Tracking Technology

Early literacy skills have been the focus of considerable research for the past two decades. Many instructional interventions have been developed to help improve children's acquisition of key skills – among the most recent is an array of software programs. In this chapter we review the foundations for software design, instructional theories related to computer media-based instruction and an assessment of how children interact with the visual information provided in children's software. In particular, the chapter will highlight current research examining what features of software design impact children's ability to attend and learn from this media. Eye tracking technology has been used in research on early literary to better understand how learning occurs. This chapter identifies how eye-tracking technology can facilitate understanding of how young children interact with literacy tools in computer-mediated contexts.

scholarly journals Early Feasibility Study of a Neurostimulator to Create Artificial Vision

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Nader Pouratian ◽  
Daniel Yoshor ◽  
Soroush Niketeghad ◽  
Jessy Dornm ◽  
Robert Greenberg
Keyword(s):  
Video Processing ◽  
Visual Information ◽  
Electrode Array ◽  
Video Camera ◽  
Artificial Vision ◽  
Processing Unit ◽  
New Device ◽  
Pediatric Glaucoma ◽  
Functional Vision ◽  
And Performance

Abstract INTRODUCTION Stimulation of human visual cortex is known to elicit visual perceptions that could potentially be used for creating artificial vision. The Orion Visual Cortical Prosthesis is a new device that is intended to restore some functional vision to blind patients. METHODS The device comprises an implant (consisting of an electronics package, receiving antenna, and an electrode array with 60 electrodes); glasses with a video camera; and a video processing unit (VPU). The camera collects real-time visual information, which is then processed by the VPU and converted to stimulation patterns sent to electrode array. The electronics are skull mounted with the subdural array implanted through a posterior interhemispheric approach. This is a 5-yr study of subjects who are bilaterally blind with bare light or no light perception due to non-cortical etiology. RESULTS A total of 6 subjects have been implanted in 2 centers. As of May 1, 2019, average implant duration was 11.1 mo (range 3.4-15.0 mo). Average age at time of implant was 50.3 yr. Cause of blindness included trauma (2), pediatric glaucoma (2), optic neuropathy (1), and endophthalmitis (1). One serious adverse device event (seizure) has been reported. Average thresholds ranged from 1.6 to 3.7 mA across the 6 subjects. At 6 mo postimplant, 3 of 5 subjects performed significantly better with the system on than off on a light localization task; 2 subjects performed better on a direction of motion task, and no subjects had measurable visual acuity. All 5 subjects were rated as receiving “positive” or “mild positive” benefit on a functional vision assessment. One-year adverse event and visual performance data for the first 5 subjects will be presented and compared to results from a commercially-available retinal prosthesis. CONCLUSION Safety and performance results of the first 5 subjects as of 6 mo postimplantation appear encouraging.

scholarly journals Generation, identification and functional characterization of thenob4mutation ofGrm6in the mouse

2007 ◽  
Vol 24 (1) ◽  
pp. 111-123 ◽  
Author(s):  
LAWRENCE H. PINTO ◽  
MARTHA H. VITATERNA ◽  
KAZUHIRO SHIMOMURA ◽  
SANDRA M. SIEPKA ◽  
VICTORIA BALANNIK ◽  
...  
Keyword(s):  
Visual Information ◽  
Metabotropic Glutamate Receptor ◽  
Ganglion Cells ◽  
Functional Characterization ◽  
Chemical Mutagenesis ◽  
Receptor Protein ◽  
Mrna Levels ◽  
Chromosome 11 ◽  
Full Field ◽  
Metabotropic Glutamate

We performed genome-wide chemical mutagenesis of C57BL/6J mice usingN-ethyl-N-nitrosourea (ENU). Electroretinographic screening of the third generation offspring revealed two G3 individuals from one G1 family with a normal a-wave but lacking the b-wave that we namednob4. The mutation was transmitted with a recessive mode of inheritance and mapped to chromosome 11 in a region containing theGrm6gene, which encodes a metabotropic glutamate receptor protein, mGluR6. Sequencing confirmed a single nucleotide substitution from T to C in theGrm6gene. The mutation is predicted to result in substitution of Pro for Ser at position 185 within the extracellular, ligand-binding domain and oocytes expressing the homologous mutation in mGluR6 did not display robust glutamate-induced currents. Retinal mRNA levels forGrm6were not significantly reduced, but no immunoreactivity for mGluR6 protein was found. Histological and fundus evaluations ofnob4showed normal retinal morphology. In contrast, the mutation has severe consequences for visual function. Innob4mice, fewer retinal ganglion cells (RGCs) responded to the onset (ON) of a bright full field stimulus. When ON responses could be evoked, their onset was significantly delayed. Visual acuity and contrast sensitivity, measured with optomotor responses, were reduced under both photopic and scotopic conditions. This mutant will be useful because its phenotype is similar to that of human patients with congenital stationary night blindness and will provide a tool for understanding retinal circuitry and the role of ganglion cell encoding of visual information.

The Biomechanical Response of Normal and Glaucoma Human Sclera

2010 ◽  
Author(s):  
Baptiste Coudrillier ◽  
Kristin M. Myers ◽  
Thao D. Nguyen
Keyword(s):  
Retinal Ganglion Cells ◽  
Material Properties ◽  
Visual Information ◽  
Ganglion Cells ◽  
Retinal Ganglion ◽  
Progressive Degeneration ◽  
Biomechanical Response ◽  
Elevated Intraocular Pressure ◽  
The Relationship ◽  
The Brain

By 2010, 60 million people will have glaucoma, the second leading cause of blindness worldwide [1]. The disease is characterized by a progressive degeneration of the retinal ganglion cells (RGC), a type of neuron that transmits visual information to the brain. It is well know that elevated intraocular pressure (IOP) is a risk factor in the damage to the RGCs [3–5], but the relationship between the mechanical properties of the ocular connective tissue and how it affects cellular function is not well characterized. The cornea and the sclera are collage-rich structures that comprise the outer load-bearing shell of the eye. Their preferentially aligned collagen lamellae provide mechanical strength to resist ocular expansion. Previous uniaxial tension studies suggest that altered viscoelastic material properties of the eye wall play a role in glaucomatous damage [6].

Next-Generation Techniques for Analysis of Lamina Cribrosa Microstructure

2012 ◽  
Author(s):  
C. Ross Ethier ◽  
Richie Abel ◽  
E. A. Sander ◽  
John G. Flanagan ◽  
Michael Girard
Keyword(s):  
Risk Factor ◽  
Intraocular Pressure ◽  
Retinal Ganglion Cells ◽  
Visual Information ◽  
Ganglion Cells ◽  
Lamina Cribrosa ◽  
Retinal Ganglion ◽  
Irreversible Damage ◽  
Ocular Disorders ◽  
The Brain

Glaucoma describes a group of potentially blinding ocular disorders, afflicting c. 60 million people worldwide. Of these, c. 8 million are bilaterally blind, estimated to increase to 11 million by 2020. The central event in glaucoma is slow and irreversible damage of retinal ganglion cells, responsible for carrying visual information from the retina to the brain (Figure 1). Intraocular pressure (IOP) is a risk factor for glaucoma1–4, and significant, sustained IOP reduction is unequivocally beneficial in the clinical management of glaucoma patients2, 3, 5. Unfortunately, we do not understand how elevated IOP leads to the loss of retinal ganglion cells.

Sign in / Sign up

Export Citation Format

Share Document