DOCSLIB.ORG

Visual Prosthesis

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Visual Prosthesis INVITED PAPER 1 Visual Prosthesis 2 Microelectronic implants that provide identification of simple objects and motion 3 detection for blind patients have been tested and evaluated; further development is 4 needed for face recognition and reading implants. 5 By James D. Weiland and Mark S. Humayun 6 ABSTRACT | Electronic visual prostheses have demonstrated requirements for a parallel neural interface and power 37 7 the ability to restore a rudimentary sense of vision to blind efficiency that make certain engineering challenges impor- 38 8 individuals. This review paper will highlight past and recent tant to all visual implants. This paper will review the causes 39 9 progress in this field as well as some technical challenges to of blindness, the microelectronic approaches to treating 40 10 further advancement. Retinal implants have now been tested in blindness, and technology needs to enable future implants. 41 11 humans by four independent groups. Optic nerve and cortical 12 implants have been also been evaluated in humans. The first 42 13 implants have achieved remarkable results, including detection II. CAUSES OF BLINDNESS 14 of motion and distinguishing objects from a set. To improve on Blindness can result from damage to the optical pathway 43 15 these results, a number of research groups have performed (cornea, aqueous humor, crystalline lens, and vitreous 44 16 simulations that predict up to 1000 individual pixels may be Fig. 3) that focuses light on the retina or damage to the 45 17 needed to restore significant functions such as face recognition visual neurons that sense light and send visual information 46 18 and reading. In order to achieve a device that can stimulate the to the brain. We will review only the neural diseases, but it is 47 19 visual system in this many locations, issues of power con- worth noting that cataracts (opacities in the crystalline lens) 48 1 20 sumption and electronic packaging must be resolved. are a major cause of blindness worldwide. An excellent 49 2 review of the retina and vision can be found online. 50 21 KEYWORDS | Electrical stimulation; implantable medical pack- Blindness has a significant impact on the economy. 51 22 aging; medical implants; neural prosthesis; retinal prosthesis Recent studies have found that only 29% of severely 52 visually impaired persons are gainfully employed, com- 53 pared with a national average of 84% [1]. Persons with 54 23 I. INTRODUCTION severe visual impairment earn 37% per year less than their 55 24 Photoreceptors are the specialized neurons in the eye that able bodied counterparts [2]. The total economic impact 56 25 convert photons into a neural signal (Fig. 1). The of vision loss in the United States is estimated at nearly 57 3 26 photoreceptors are part of the retina, a multilayer neural $68 billion annually. 58 27 structure about 200 m thick that lines the backIEEE of the eye. The two most common retinal degenerative diseases that 59 28 Other cells in the retina process the signal from the result in blindness secondary to photoreceptor loss are age- 60 29 photoreceptors. Retinal ganglion cells send the processed related macular degeneration (AMD) and retinitis pigmen- 61 30 signal from the retina to the brain via the optic nerve. tosa (RP). RP is generally more severe, and its symptoms 62 31 Blindness can result when any part of this visual pathway is appear earlier in life, but AMD is more prevalent. In the 63 32 damaged by injury or disease. Electronic visual prostheses United States, there are approximately 700 000 new AMD 64 33 are being developed that can be implanted in different patients; each year, 70 000 of these patients will become 65 34 anatomical locations along the visual pathway (Fig. 2). While legally blind,Proof with many more suffering significant vision 66 35 the final implementation of the implant will depend on the loss [3]. AMD results from a slow degeneration of the 67 36 anatomy of the targeted area, visual prostheses have common photoreceptor cells of the retina, ultimately culminating in 68 photoreceptor cell death. This is sometimes accompanied by 69 Manuscript received August 14, 2007; revised January 14, 2008. 1See World Health Organization, www.who.int/mediacentre/ The authors are with Doheny Eye Institute, University of Southern California, factsheets/fs282/en/. Los Angeles, CA 90033 USA (e-mail: [email protected]; [email protected]). 2www.webvision.med.utah.edu/. 3 Digital Object Identifier: 10.1109/JPROC.2008.922589 See http://www.silverbook.org/visionloss. 0018-9219/$25.00 Ó2008 IEEE Vol. 96, No. 7, July 2008 | Proceedings of the IEEE 1 Weiland and Humayun: Visual Prosthesis Fig. 1. Cross-section of the retina. The photoreceptors (rods and cones) convert photons into neurochemical energy, which is relayed through the retina. The different layers of the retina processing the image signal. The output of the retina comes from the retinal ganglion cells, whose axons gather at the optic disc to form the optic nerve. In retinitis pigmentosa and age-related macular degeneration, the photoreceptors are degenerated but the other layers of the retina remain. (Image courtesy of Webvision, webvision.med.utah.edu.) IEEE Proof Fig. 2. Human visual system. The optic nerve transmits retinal information to the lateral geniculate, which relays the information to the primary visual cortex (striate cortex or V1). (Image courtesy of Webvision, webvision.med.utah.edu.) 2 Proceedings of the IEEE | Vol. 96, No. 7, July 2008 Weiland and Humayun: Visual Prosthesis lating electrode array. Implants in humans have been 102 tested in the retina, visual cortex, and optic nerve. 103 Recent clinical trials of retinal implants have included 104 epiretinal implants [7]–[10], a passive subretinal device [11], 105 and an active subretinal device [12] (see Fig. 3). Passive 106 devices rely on incident light for power, whereas active 107 devices have an external power source. All of the devices 108 currently being tested are manufactured by companies, 109 which have the required quality systems and manufacturing 110 skills to produce robust, medical-grade implants. The trials 111 reviewed below will be referred to by the company that 112 produced the implant. 113 The first clinical trial of a permanently implanted 114 retinal prosthesis was initiated by Optobionics, Inc., in 115 2000. The device was a passive microphotodiode array 116 with 3500 elements. Subjects in the passive subretinal trial 117 Fig. 3. Cross-section of a human eye. Light is focused by the cornea do not report pixelized vision, as might be expected if each 118 and lens on the retina. The retina lines the posterior of the eye. photodiode were acting as a photoreceptor [11]. However, 119 (Image from http://www.nei.nih.gov/health/cataract/ some of the subjects have reported improved visual 120 cataract_facts.asp.) function away from the implant site, suggesting that the 121 presence of the implant alone, or coupled with low-level 122 electrical stimulation, induced a Bneurotrophic effect[ 123 70 the formation of new blood vessels. Individuals afflicted that improved the health of the retina and consequently 124 71 with AMD will start to have distorted central vision and improved visual function. 125 72 eventually will lose most vision in the central 30 of visual A prototype epiretinal implant with 16 electrodes is 126 73 field, rendering them legally blind (less than 20/200 vision). beingtestedbySecondSightMedicalProducts,Inc. 127 74 RP is a collective name for a number of genetic defects that (Sylmar, CA). This trial began in 2002 and has enrolled 128 75 also result in photoreceptor loss [4]. More than 100 genetic six individuals with bare light perception secondary to RP. 129 76 defects have been identified that cause the different forms of Test subjects can use spatial information from the 130 77 RP. The overall incidence of RP is 1 in 3500 live births. In stimulator to detect motion and locate objects [9]. 131 78 general, RP strikes the rod photoreceptor cells first, Subjects demonstrated their ability to distinguish between 132 79 resulting in poor night vision and loss of peripheral vision. three common objects (plate, cup, and knife) at levels 133 80 Eventually, cone photoreceptors, which mediate color and statistically above chance. Subjects have also demonstrat- 134 81 daytime vision, are lost, leading to complete blindness. ed that they can discern the direction of motion of a bar 135 82 Neither AMD nor RP is presently curable through surgery passed in front of the camera. Recent reports involve 136 83 or treatment, but there are some treatments that can slow detection of the orientation of a black and white grating 137 84 the progression of AMD [5]. pattern [13]. A subject was able to detect these gratings at 138 85 Diseases that damage the optic nerve include diabetic 4 increasing spatial frequency up to the theoretical limit 139 86 retinopathy and glaucoma. In diabetic retinopathy, retinal predicted by the electrode spacing on the retina. 140 87 blood vessel abnormalities can prevent nourishment from Perceptual thresholds are in general low, compared to 141 88 reaching neural cells in the retina, leading to ganglion cell IEEEthe earlier short-term implants [8]. Some subjects have 142 89 and optic nerve damage. Glaucoma often includes high shown a majority of electrodes with a perceptual 143 90 intraocular pressure as a symptom. In the past, it was thought threshold below 50 A (1 ms pulse), with a range of 144 91 that high eye pressure was damaging to the retina and led to 24–702 A (1 ms pulse) reported across three subjects. A 145 92 ganglion cell and optic nerve loss, but more recently it has second clinical trial of an epiretinal implant, built by 146 93 been found that even individuals with normal eye pressure Intelligent Medical Implants AG (Zurich, Switzerland), 147 94 can have optic nerve damage from glaucoma [6].
Load more

Recommended publications
  • THE 11TH WORLD CONGRESS on the Relationship Between Neurobiology and Nano-Electronics Focusing on Artificial Vision
    THE 11TH WORLD CONGRESS On the Relationship Between Neurobiology and Nano-Electronics Focusing on Artificial Vision November 10-12, 2019 The Henry, An Autograph Collection Hotel DEPARTMENT OF OPHTHALMOLOGY Detroit Institute of Ophthalmology Thank you to Friends of Vision for your support of the Bartimaeus Dinner The Eye and The Chip 2 DEPARTMENT OF OPHTHALMOLOGY Detroit Institute of Ophthalmology TABLE OF CONTENTS WELCOME LETTER—PAUL A. EDWARDS. M.D. ....................................................... WELCOME LETTER—PHILIP C. HESSBURG, M.D. ..................................................... DETROIT INSTITUTE OF OPHTHALMOLOGY ......................................................... ORGANIZING COMMITTEE/ACCREDITATION STATEMENT ............................................... CONGRESS 3-DAY SCHEDULE ................................................................... PLATFORM SPEAKER LIST ...................................................................... SPEAKER ABSTRACTS .......................................................................... POSTER PRESENTERS’ LIST ..................................................................... POSTER ABSTRACTS ........................................................................... BARTIMAEUS AWARD—PREVIOUS RECIPIENTS ...................................................... SUPPORTING SPONSORS . Audio-Visual Services Provided by Dynasty Media Network http://dynastymedianetwork.com/ The Eye and The Chip Welcome On behalf of the Henry Ford Health System and the Department of Ophthalmology,
    [Show full text]
  • A Review of Retinal Prosthesis Approaches
    International Conference Mathematical and Computational Biology 2011 International Journal of Modern Physics: Conference Series Vol. 9 (2012) 209–231 World Scientific Publishing Company DOI: 10.1142/S2010194512005272 A REVIEW OF RETINAL PROSTHESIS APPROACHES TRAN TRUNG KIEN School of Computer Science, The University of Nottingham Malaysia Campus, Jalan Broga, Semenyih, Selangor 43500, Malaysia [email protected] TOMAS MAUL School of Computer Science, The University of Nottingham Malaysia Campus, Jalan Broga, Semenyih, Selangor 43500, Malaysia [email protected] ANDRZEJ BARGIELA School of Computer Science, The University of Nottingham, Nottingham, NG8 1BB [email protected] Age-related macular degeneration and retinitis pigmentosa are two of the most common diseases that cause degeneration in the outer retina, which can lead to several visual impairments up to blindness. Vision restoration is an important goal for which several different research approaches are currently being pursued. We are concerned with restoration via retinal prosthetic devices. Prostheses can be implemented intraocularly and extraocularly, which leads to different categories of devices. Cortical Prostheses and Optic Nerve Prostheses are examples of extraocular solutions while Epiretinal Prostheses and Subretinal Prostheses are examples of intraocular solutions. Some of the prostheses that are successfully implanted and tested in animals as well as humans can restore basic visual functions but still have limitations. This paper will give an overview of the current state of art of Retinal Prostheses and compare the advantages and limitations of each type. The purpose of this review is thus to summarize the current technologies and approaches used in developing Retinal Prostheses and therefore to lay a foundation for future designs and research directions.
    [Show full text]
  • What Do Blind People “See” with Retinal Prostheses? Observations And
    bioRxiv preprint doi: https://doi.org/10.1101/2020.02.03.932905; this version posted February 4, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 1 What do blind people “see” with retinal prostheses? Observations and qualitative reports of epiretinal 2 implant users 3 4 5 6 Cordelia Erickson-Davis1¶* and Helma Korzybska2¶* 7 8 9 10 11 1 Stanford School of Medicine and Stanford Anthropology Department, Stanford University, Palo Alto, 12 California, United States of America 13 14 2 Laboratory of Ethnology and Comparative Sociology (LESC), Paris Nanterre University, Nanterre, France 15 16 17 18 19 * Corresponding author. 20 E-mail: [email protected], [email protected] 21 22 23 ¶ The authors contributed equally to this work. 24 25 26 1 bioRxiv preprint doi: https://doi.org/10.1101/2020.02.03.932905; this version posted February 4, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 27 Abstract 28 29 Introduction: Retinal implants have now been approved and commercially available for certain 30 clinical populations for over 5 years, with hundreds of individuals implanted, scores of them closely 31 followed in research trials. Despite these numbers, however, few data are available that would help 32 us answer basic questions regarding the nature and outcomes of artificial vision: what do 33 participants see when the device is turned on for the first time, and how does that change over time? 34 35 Methods: Semi-structured interviews and observations were undertaken at two sites in France and 36 the UK with 16 participants who had received either the Argus II or IRIS II devices.
    [Show full text]
  • The Orion Visual Prosthesis System
    Development of a Visual Prosthesis: The Orion Visual Prosthesis System Nader Pouratian, M.D., Ph.D. Daniel Yoshor, M.D., Ph.D. Study partly funded by NIH BRAIN Initiative grant: UH3NS103442 Disclosures Second Sight – Grant Support for this project Consultant BrainLab – Grant Support Medtronic – Fellowship Support Boston Scientific – Consultant, DSMB 2 3 Overall Goal: Cortical Prosthesis for Previously Sighted Patients with No or Bare Light Perception Safe – Implant-related concerns (infection) Seizures Practical – Surgically Practical and Adoptable (microarray “tiles” vs ECoG) Clinically Useful – Perceptions Shadows Edges 4 Visual Cortical Prosthesis: Orion I Implant Leverages existing Argus II technology Bypasses the eyes and optic nerve and directly stimulates the visual cortex Designated a Breakthrough Device by FDA Early Feasibility Study underway in U.S. In planning stages for next phase (pivotal or feasibility study) Orion I Implant Glasses & Antenna Medial View Lateral View Cable Implant coil (receiving Electrode array (60 channels) antenna) Video Processing Unit Cover Early Testing in a Blind Subject with “Off the shelf” Device 30 year old with an 8 year history of bare light perception blindness due to Voght- Koaynagi-Harada Syndrome Implantation of a Neuropace responsive neurostimulation device with 2 parallel 4-contact leads implanted over the right medial occipital lobe via a posterior interhemispheric approach. Systematic manipulation of stimulation intensity, pulse width, frequency, and site of stimulation over 10 months.
    [Show full text]
  • Getting Signals Into the Brain: Visual Prosthetics Through Thalamic Microstimulation
    Neurosurg Focus 27 (1):E6, 2009 Getting signals into the brain: visual prosthetics through thalamic microstimulation JOHN S. PEZARI S , PH.D., AN D EMA D N. ES KAN D AR , M.D. Department of Neurosurgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts Common causes of blindness are diseases that affect the ocular structures, such as glaucoma, retinitis pigmen- tosa, and macular degeneration, rendering the eyes no longer sensitive to light. The visual pathway, however, as a pre- dominantly central structure, is largely spared in these cases. It is thus widely thought that a device-based prosthetic approach to restoration of visual function will be effective and will enjoy similar success as cochlear implants have for restoration of auditory function. In this article the authors review the potential locations for stimulation electrode placement for visual prostheses, assessing the anatomical and functional advantages and disadvantages of each. Of particular interest to the neurosurgical community is placement of deep brain stimulating electrodes in thalamic structures that has shown substantial promise in an animal model. The theory of operation of visual prostheses is discussed, along with a review of the current state of knowledge. Finally, the visual prosthesis is proposed as a model for a general high-fidelity machine-brain interface.(DOI: 10.3171/2009.4.FOCUS0986) KEY WOR ds • visual prosthesis • deep brain stimulation • visual function N this article we review the current state of visual Evaluating Points Along the Early prosthetics with particular attention to the approaches Visual Pathway as Stimulation Targets that include neurosurgical methodologies. I There are 6 locations along the visual pathway with potential for functional restoration of sight through mi- Background: Causes of Blindness crostimulation as depicted in Fig.
    [Show full text]
  • Fabrication of Subretinal 3D Microelectrodes with Hexagonal Arrangement
    micromachines Article Fabrication of Subretinal 3D Microelectrodes with Hexagonal Arrangement Hee Won Seo , Namju Kim and Sohee Kim * Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea; [email protected] (H.W.S.); [email protected] (N.K.) * Correspondence: [email protected]; Tel.: +82-53-785-6217 Received: 29 March 2020; Accepted: 27 April 2020; Published: 29 April 2020 Abstract: This study presents the fabrication of three-dimensional (3D) microelectrodes for subretinal stimulation, to accommodate adjacent return electrodes surrounding a stimulating electrode. For retinal prosthetic devices, the arrangement of return electrodes, the electrode size and spacing should be considered together, to reduce the undesired dissipation of electric currents. Here, we applied the hexagonal arrangement to the microelectrode array for the localized activation of retinal cells and better visual acuity. To provide stimuli more efficiently to non-spiking neurons, a 3D structure was created through a customized pressing process, utilizing the elastic property of the materials used in the fabrication processes. The diameter and pitch of the Pt-coated electrodes were 150 µm and 350 µm, respectively, and the height of the protruded electrodes was around 20 µm. The array consisted of 98 hexagonally arranged electrodes, supported by a flexible and transparent polydimethylsiloxane (PDMS) base, with a thickness of 140 µm. Also, the array was coated with 2 µm-thick parylene-C, except the active electrode sites, for more focused stimulation. Finally, the electrochemical properties of the fabricated microelectrodes were characterized, resulting in the mean impedance of 384.87 kW at 1 kHz and the charge storage capacity (CSC) of 2.83 mC cm 2.
    [Show full text]
  • Sensors 2009, 9, 9073-9093; Doi:10.3390/S91109073 OPEN ACCESS Sensors ISSN 1424-8220
    Sensors 2009, 9, 9073-9093; doi:10.3390/s91109073 OPEN ACCESS sensors ISSN 1424-8220 www.mdpi.com/journal/sensors Review Implantable CMOS Biomedical Devices Jun Ohta 1,2,*, Takashi Tokuda 1,2, Kiyotaka Sasagawa 1,2 and Toshihiko Noda 1,2 1 Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0101, Japan 2 CREST, Japan Science and Technology Agency, 3-5 Sanban, Chiyoda, Tokyo 102-0075, Japan; E-Mails: [email protected] (T.T.); [email protected] (K.S.); [email protected] (T.N.) * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +81-743-72-6051; Fax: +81-743-72-6059. Received: 5 August 2009; in revised form: 6 November 2009 / Accepted: 9 November 2009/ Published: 17 November 2009 Abstract: The results of recent research on our implantable CMOS biomedical devices are reviewed. Topics include retinal prosthesis devices and deep-brain implantation devices for small animals. Fundamental device structures and characteristics as well as in vivo experiments are presented. Keywords: biomedical devices; retinal prosthesis; image sensors; CMOS; brain implantation 1. Introduction The trend toward ultra-fine scale in CMOS technologies has not only increased chip integration density but has also enabled the widespread application of CMOS technologies in areas such as image sensors, wireless, micro-electro-mechanical systems (MEMS), and micro total analysis system (µTAS). These features are suitable for biomedical applications. For example, implantable devices require small volume and low power consumption, which are realized by ultra-fine fabrication technology. MEMS are effective technologies for biomedical applications, because MEMS easily form three- dimensional structured which are useful in the applications.
    [Show full text]
  • "Visual Prostheses"
    530 VISUAL PROSTHESES VISUAL PROSTHESES JEAN DELBEKE CLAUDE VERAART Catholic University of Louvain Brussels, Belgium INTRODUCTION Minute electrical stimuli delivered to the retina, the optic nerve, or the occipital cortex can induce light perceptions called phosphenes. The visual prosthesis aims at exploiting these phosphenes to restore a form of vision in some cases of blindness. Very schematically, a camera or a picture capturing device transforms images into electrical signals that are then adapted and passed on to some still functional part of the visual pathways, thus bridging the defective structures. The system has at least some parts implanted, including electrodes and their stimulator circuits. A photo- sensitive array in the eye could provide the necessary image input, but most approaches use an external minia- ture camera. Typically, the visual data handling requires an external processor and the power supply as well as the data are provided to the implant by a transcutaneous transmission system. Despite a first pioneering attempt by Brindley and Lewin as early as 1968 (1) only very few experimental visual prostheses have been implanted in humans so far. The limited accessibility of the involved anatomical struc- tures, the poorly understood neural encoding, and the huge amount of information handled by the visual nervous system have clearly hampered a development that can not yet be compared with the far more advanced evolution of cochlear implants (see article on Cochlear Implants in this encyclopedia). The visual prosthesis is still at a very Encyclopedia of Medical Devices and Instrumentation, Second Edition, edited by John G. Webster Copyright # 2006 John Wiley & Sons, Inc.
    [Show full text]
  • Visual Prostheses for the Blind
    Review Visual prostheses for the blind 1,2 1,2 1,2,3 Robert K. Shepherd , Mohit N. Shivdasani , David A.X. Nayagam , 1,2 1,2 Christopher E. Williams , and Peter J. Blamey 1 Bionics Institute, 384-388 Albert St East Melbourne, 3002, Victoria, Australia 2 Medical Bionics Department, University of Melbourne, 384-388 Albert St East Melbourne, 3002, Victoria, Australia 3 Department of Pathology, University of Melbourne, Parkville, 3010, Victoria, Australia After more than 40 years of research, visual prostheses It is estimated that 285 million people are visually are moving from the laboratory into the clinic. These impaired worldwide; 39 million of whom are blind [2]. devices are designed to provide prosthetic vision to the Although uncorrected refractive errors are the main cause blind by stimulating localized neural populations in one of visual impairment, diseases associated with degenera- of the retinotopically organized structures of the visual tion of the retinal photoreceptors result in severe visual pathway – typically the retina or visual cortex. The long loss with few or no therapeutic options for ongoing clinical gestation of this research reflects the many significant management. Importantly, significant numbers of RGCs technical challenges encountered including surgical ac- are spared following the loss of photoreceptors. Although cess, mechanical stability, hardware miniaturization, there are major alterations to the neural circuitry of these hermetic encapsulation, high-density electrode arrays, surviving neurons [3], their presence provides the potential and signal processing. This review provides an introduc- to restore vision using electrical stimulation delivered by tion to the pathophysiology of blindness; an overview of an electrode array located close to the retina (Box 1).
    [Show full text]
  • Neurobionics and the Brain-Computer Interface: Current Applications And
    Narrative review Neurobionics and the brainecomputer interface: current applications and future horizons Jeffrey V Rosenfeld1,2, Yan Tat Wong3 eurobionics is the science of directly integrating electronics Summary with the nervous system to repair or substitute impaired e e The brain computer interface (BCI) is an exciting advance in Nfunctions. The brain computer interface (BCI) is the linkage neuroscience and engineering. of the brain to computers through scalp, subdural or intracortical In a motor BCI, electrical recordings from the motor cortex of electrodes (Box 1). Development of neurobionic technologies paralysed humans are decoded by a computer and used to requires interdisciplinary collaboration between specialists in drive robotic arms or to restore movement in a paralysed medicine, science, engineering and information technology, and hand by stimulating the muscles in the forearm. large multidisciplinary teams are needed to translate the findings of Simultaneously integrating a BCI with the sensory cortex will high performance BCIs from animals to humans.1 further enhance dexterity and fine control. ’ BCIs are also being developed to: Neurobionics evolved out of Brindley and Lewin s work in the < provide ambulation for paraplegic patients through 1960s, in which electrodes were placed over the cerebral cortex of a controlling robotic exoskeletons; 2-4 blind woman. Wireless stimulation of the electrodes induced < restore vision in people with acquired blindness; — fi phosphenes spots of light appearing in the visual elds. This < detect and control epileptic seizures; and was followed in the 1970s by the work of Dobelle and colleagues, < improve control of movement disorders and memory who provided electrical input to electrodes placed on the visual enhancement.
    [Show full text]
  • How to Write for Technical Periodicals & Conferences As a Researcher Or Practicing Engineer, You Know How Important It Is to Publish the Results of Your Work
    IEEE AUTHORSHIP SERieS HOW TO WRITE FOR TECHNICAL PERIODICALS & CONFERENCES As a researcher or practicing engineer, you know how important it is to publish the results of your work. It is not just about career advancement or getting recognition. Publication is a critical step in the scientific process. Your discoveries will foster innovation and help advance technology for public good. But that can only happen if your research can be read, understood, and built upon by your fellow researchers and engineers. This guide is designed to help you succeed as an author. CONTENTS SECTION 1 SECTION 7 INTRODUCTION ............................................................................2 IMPROVING AND ReVISING ................................................... 16 How to Revise .................................................................................16 SECTION 2 Polishing ..............................................................................................16 BEFORE YOU BEGIN ....................................................................3 Tips for Non-English Speakers ....................................................19 Conducting Your Literature Search ............................................ 3 Internal Review .................................................................................19 Next Steps ............................................................................................ 4 SECTION 8 SECTION 3 SUBMISSIONS ............................................................................ 20 ETHICS
    [Show full text]
  • Visual Cortical Prosthesis : an Electrical Perspective
    Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 22 December 2020 doi:10.20944/preprints202012.0562.v1 Visual cortical prosthesis : an electrical perspective L´eo Pio-Lopez1, Romanos Poulkouras2,3, and Damien Depannemaecker4 1Independent researcher, 13006, Marseille, France 2Department of Bioelectronics, Ecole Nationale Sup´erieure des Mines, CMP-EMSE, 13541 Gardanne, France 3Institut de Neurosciences de la Timone, UMR 7289, CNRS, Aix-Marseille Universit´e,Marseille, France 4Department of Integrative and Computational Neuroscience, Paris-Saclay Institute of Neuroscience, Centre National de la Recherche Scientifique, France Abstract The electrical stimulation of the visual cortices has the potential to restore vision to blind individuals. Until now, the results of visual cortical prosthetics has been limited as no prosthesis has restored a full working vision but the field has shown a renewed interest these last years thanks to wireless and technological advances. However, several scientific and technical challenges are still open in order to achieve the therapeutic benefit expected by these new devices. One of the main challenges is the electrical stimulation of the brain itself. In this review, we analyze the results in electrode-based visual cortical prosthetics from the electrical point of view. We first briefly describe what is known about the electrode-tissue interface and safety of electrical stimulation. Then we focus on the psychophysics of prosthetic vision and the state-of-the-art on the interplay between the electrical stimulation of the visual cortex and phosphene perception. Lastly, we discuss the challenges and perspectives of visual cortex electrical stimulation and electrode array design to develop the new generation implantable cortical visual prostheses.
    [Show full text]