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Huang Y, Yao K, Zhang Q, Huang X, Chen Z, Zhou Y, Yu X. Bioelectronics for electrical stimulation: materials, devices and biomedical applications. Chem Soc Rev 2024; 53:8632-8712. [PMID: 39132912 DOI: 10.1039/d4cs00413b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Bioelectronics is a hot research topic, yet an important tool, as it facilitates the creation of advanced medical devices that interact with biological systems to effectively diagnose, monitor and treat a broad spectrum of health conditions. Electrical stimulation (ES) is a pivotal technique in bioelectronics, offering a precise, non-pharmacological means to modulate and control biological processes across molecular, cellular, tissue, and organ levels. This method holds the potential to restore or enhance physiological functions compromised by diseases or injuries by integrating sophisticated electrical signals, device interfaces, and designs tailored to specific biological mechanisms. This review explains the mechanisms by which ES influences cellular behaviors, introduces the essential stimulation principles, discusses the performance requirements for optimal ES systems, and highlights the representative applications. From this review, we can realize the potential of ES based bioelectronics in therapy, regenerative medicine and rehabilitation engineering technologies, ranging from tissue engineering to neurological technologies, and the modulation of cardiovascular and cognitive functions. This review underscores the versatility of ES in various biomedical contexts and emphasizes the need to adapt to complex biological and clinical landscapes it addresses.
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Affiliation(s)
- Ya Huang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Kuanming Yao
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Qiang Zhang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Xingcan Huang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Zhenlin Chen
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Yu Zhou
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
| | - Xinge Yu
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
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2
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Raghuram V, Datye AD, Fried SI, Timko BP. Transparent and Conformal Microcoil Arrays for Spatially Selective Neuronal Activation. DEVICE 2024; 2:100290. [PMID: 39184953 PMCID: PMC11343507 DOI: 10.1016/j.device.2024.100290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
Micromagnetic stimulation (μMS) using small, implantable microcoils is a promising method for achieving neuronal activation with high spatial resolution and low toxicity. Herein, we report a microcoil array for localized activation of cortical neurons and retinal ganglion cells. We developed a computational model to relate the electric field gradient (activating function) to the geometry and arrangement of microcoils, and selected a design that produced an anisotropic region of activation <50 μm wide. The device was comprised of an SU-8/Cu/SU-8 tri-layer structure, which was flexible, transparent and conformal and featured four individually-addressable microcoils. Interfaced with cortex or retina explants from GCaMP6-expressing mice, we observed that individual neurons localized within 40 μm of a microcoil tip could be activated repeatedly and in a dose- (power-) dependent fashion. These results demonstrate the potential of μMS devices for brain-machine interfaces and could enable routes toward bioelectronic therapies including prosthetic vision devices.
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Affiliation(s)
- Vineeth Raghuram
- Dept. of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
- Boston Veterans Affairs Healthcare System, Boston, MA 02130, USA
- Dept. of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Aditya D. Datye
- Dept. of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Shelley I. Fried
- Dept. of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
- Boston Veterans Affairs Healthcare System, Boston, MA 02130, USA
- Dept. of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Brian P. Timko
- Dept. of Biomedical Engineering, Tufts University, Medford, MA 02155, USA
- Lead Contact
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3
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de Ruyter van Steveninck J, Nipshagen M, van Gerven M, Güçlü U, Güçlüturk Y, van Wezel R. Gaze-contingent processing improves mobility, scene recognition and visual search in simulated head-steered prosthetic vision. J Neural Eng 2024; 21:026037. [PMID: 38502957 DOI: 10.1088/1741-2552/ad357d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 03/19/2024] [Indexed: 03/21/2024]
Abstract
Objective.The enabling technology of visual prosthetics for the blind is making rapid progress. However, there are still uncertainties regarding the functional outcomes, which can depend on many design choices in the development. In visual prostheses with a head-mounted camera, a particularly challenging question is how to deal with the gaze-locked visual percept associated with spatial updating conflicts in the brain. The current study investigates a recently proposed compensation strategy based on gaze-contingent image processing with eye-tracking. Gaze-contingent processing is expected to reinforce natural-like visual scanning and reestablished spatial updating based on eye movements. The beneficial effects remain to be investigated for daily life activities in complex visual environments.Approach.The current study evaluates the benefits of gaze-contingent processing versus gaze-locked and gaze-ignored simulations in the context of mobility, scene recognition and visual search, using a virtual reality simulated prosthetic vision paradigm with sighted subjects.Main results.Compared to gaze-locked vision, gaze-contingent processing was consistently found to improve the speed in all experimental tasks, as well as the subjective quality of vision. Similar or further improvements were found in a control condition that ignores gaze-dependent effects, a simulation that is unattainable in the clinical reality.Significance.Our results suggest that gaze-locked vision and spatial updating conflicts can be debilitating for complex visually-guided activities of daily living such as mobility and orientation. Therefore, for prospective users of head-steered prostheses with an unimpaired oculomotor system, the inclusion of a compensatory eye-tracking system is strongly endorsed.
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Affiliation(s)
| | - Mo Nipshagen
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Marcel van Gerven
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Umut Güçlü
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Yağmur Güçlüturk
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Richard van Wezel
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
- Biomedical Signals and Systems Group, University of Twente, Enschede, The Netherlands
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Johnson TV, Baranov P, Di Polo A, Fortune B, Gokoffski KK, Goldberg JL, Guido W, Kolodkin AL, Mason CA, Ou Y, Reh TA, Ross AG, Samuels BC, Zack DJ. The Retinal Ganglion Cell Repopulation, Stem Cell Transplantation, and Optic Nerve Regeneration Consortium. OPHTHALMOLOGY SCIENCE 2023; 3:100390. [PMID: 38025164 PMCID: PMC10630665 DOI: 10.1016/j.xops.2023.100390] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/24/2023] [Accepted: 08/18/2023] [Indexed: 12/01/2023]
Abstract
Purpose The Retinal Ganglion Cell (RGC) Repopulation, Stem Cell Transplantation, and Optic Nerve Regeneration (RReSTORe) consortium was founded in 2021 to help address the numerous scientific and clinical obstacles that impede development of vision-restorative treatments for patients with optic neuropathies. The goals of the RReSTORe consortium are: (1) to define and prioritize the most critical challenges and questions related to RGC regeneration; (2) to brainstorm innovative tools and experimental approaches to meet these challenges; and (3) to foster opportunities for collaborative scientific research among diverse investigators. Design and Participants The RReSTORe consortium currently includes > 220 members spanning all career stages worldwide and is directed by an organizing committee comprised of 15 leading scientists and physician-scientists of diverse backgrounds. Methods Herein, we describe the structure and organization of the RReSTORe consortium, its activities to date, and the perceived impact that the consortium has had on the field based on a survey of participants. Results In addition to helping propel the field of regenerative medicine as applied to optic neuropathies, the RReSTORe consortium serves as a framework for developing large collaborative groups aimed at tackling audacious goals that may be expanded beyond ophthalmology and vision science. Conclusions The development of innovative interventions capable of restoring vision for patients suffering from optic neuropathy would be transformative for the ophthalmology field, and may set the stage for functional restoration in other central nervous system disorders. By coordinating large-scale, international collaborations among scientists with diverse and complementary expertise, we are confident that the RReSTORe consortium will help to accelerate the field toward clinical translation. Financial Disclosures Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Thomas V. Johnson
- Wilmer Eye Institute and Cellular & Molecular Medicine Program, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Petr Baranov
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, Maryland
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada, Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, QC, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, Oregon
| | | | - Jeffrey L. Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California
| | - William Guido
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky
| | - Alex L. Kolodkin
- Solomon H Snyder Department of Neuroscience and Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Carol A. Mason
- Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Department of Pathology & Cell Biology, and Department of Ophthalmology, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Yvonne Ou
- Department of Ophthalmology, University of California, San Francisco, California
| | - Thomas A. Reh
- Department of Biological Structure, University of Washington, Seattle, Washington
| | - Ahmara G. Ross
- Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Brian C. Samuels
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, Alabama
| | - Donald J. Zack
- Departments of Ophthalmology (Wilmer Eye Institute), Neuroscience, Molecular Biology and Genetics, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Kim YH, Koo H, Kim MS, Jung SD. Fabrication of a photo-crosslinkable fluoropolymer-passivated flexible neural probe and acute recording and stimulation performances in vivo. BIOMATERIALS ADVANCES 2023; 154:213629. [PMID: 37742557 DOI: 10.1016/j.bioadv.2023.213629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 08/25/2023] [Accepted: 09/16/2023] [Indexed: 09/26/2023]
Abstract
Herein, we fabricated fluorine-containing, polymer-based, flexible neural probes with fluorinated ethylene propylene (FEP) films as the substrates and photo-crosslinkable fluoropolymers as the passivation material. For fabrication, metal-free Au layer formation on the FEP film, the simultaneous photo-adhesion and photo-patterning technique, and the pulsed-laser scanning probe shaping technique were combined, followed by Au electrode surface modification. The resultant probes achieved a charge injection limit equal to 5.18 mC cm-2 by implementing iridium oxide-modified nanoporous Au (IrOx/NPG) structures. We performed simultaneous in vivo micro-stimulations of the Schaffer collateral fibres and recorded the evoked field excitatory postsynaptic potentials (fEPSPs) in the stratum radiatum layer of the hippocampal Cornu Ammonis 1 region using a single probe. Inducing the fEPSP at very low charge per pulse settings (3.2-3.6 nC/pulse) indicates the efficient charge injection capability of the IrOx/NPG electrode, thereby enabling safe, prolonged, and thrifty micro-stimulations. Furthermore, the single probe-induced and recorded long-term potentiation persisted for periods longer than 60 min following theta-burst stimulation. The materials used in this study are all biocompatible and chemically robust. The fabricated neural probes can be applied in chronic clinical trials in vivo.
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Affiliation(s)
- Yong Hee Kim
- Cybre Brain Research Section, Electronics and Telecommunications Research Institute, 218 Gajeong-ro, Yuseong-gu, Daejeon 305-700, Republic of Korea
| | - Ho Koo
- Department of Neuroscience, Cell Biology, and Anatomy, University of Texas Medical Branch, Galveston, TX, United States
| | - Min Sun Kim
- Department of Physiology, Wonkwang University School of Medicine, 895 Munwang-ro, Iksan 570-711, Jeollabuk-do, Republic of Korea
| | - Sang-Don Jung
- Cybre Brain Research Section, Electronics and Telecommunications Research Institute, 218 Gajeong-ro, Yuseong-gu, Daejeon 305-700, Republic of Korea.
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Wang J, Azimi H, Zhao Y, Kaeser M, Vaca Sánchez P, Vazquez-Guardado A, Rogers JA, Harvey M, Rainer G. Optogenetic activation of visual thalamus generates artificial visual percepts. eLife 2023; 12:e90431. [PMID: 37791662 PMCID: PMC10593406 DOI: 10.7554/elife.90431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 10/03/2023] [Indexed: 10/05/2023] Open
Abstract
The lateral geniculate nucleus (LGN), a retinotopic relay center where visual inputs from the retina are processed and relayed to the visual cortex, has been proposed as a potential target for artificial vision. At present, it is unknown whether optogenetic LGN stimulation is sufficient to elicit behaviorally relevant percepts, and the properties of LGN neural responses relevant for artificial vision have not been thoroughly characterized. Here, we demonstrate that tree shrews pretrained on a visual detection task can detect optogenetic LGN activation using an AAV2-CamKIIα-ChR2 construct and readily generalize from visual to optogenetic detection. Simultaneous recordings of LGN spiking activity and primary visual cortex (V1) local field potentials (LFPs) during optogenetic LGN stimulation show that LGN neurons reliably follow optogenetic stimulation at frequencies up to 60 Hz and uncovered a striking phase locking between the V1 LFP and the evoked spiking activity in LGN. These phase relationships were maintained over a broad range of LGN stimulation frequencies, up to 80 Hz, with spike field coherence values favoring higher frequencies, indicating the ability to relay temporally precise information to V1 using light activation of the LGN. Finally, V1 LFP responses showed sensitivity values to LGN optogenetic activation that were similar to the animal's behavioral performance. Taken together, our findings confirm the LGN as a potential target for visual prosthetics in a highly visual mammal closely related to primates.
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Affiliation(s)
- Jing Wang
- Department of Medicine, University of FribourgFribourgSwitzerland
- Department of Neurobiology, School of Basic Medical Sciences, Nanjing Medical UniversityNanjingChina
| | - Hamid Azimi
- Department of Medicine, University of FribourgFribourgSwitzerland
| | - Yilei Zhao
- Department of Medicine, University of FribourgFribourgSwitzerland
| | - Melanie Kaeser
- Department of Medicine, University of FribourgFribourgSwitzerland
| | | | | | - John A Rogers
- Querrey Simpson Institute for Bioelectronics, Northwestern UniversityEvanstonUnited States
| | - Michael Harvey
- Department of Medicine, University of FribourgFribourgSwitzerland
| | - Gregor Rainer
- Department of Medicine, University of FribourgFribourgSwitzerland
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Wang HZ, Wong YT. A novel simulation paradigm utilising MRI-derived phosphene maps for cortical prosthetic vision. J Neural Eng 2023; 20:046027. [PMID: 37531948 PMCID: PMC10594539 DOI: 10.1088/1741-2552/aceca2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 07/13/2023] [Accepted: 08/01/2023] [Indexed: 08/04/2023]
Abstract
Objective.We developed a realistic simulation paradigm for cortical prosthetic vision and investigated whether we can improve visual performance using a novel clustering algorithm.Approach.Cortical visual prostheses have been developed to restore sight by stimulating the visual cortex. To investigate the visual experience, previous studies have used uniform phosphene maps, which may not accurately capture generated phosphene map distributions of implant recipients. The current simulation paradigm was based on the Human Connectome Project retinotopy dataset and the placement of implants on the cortices from magnetic resonance imaging scans. Five unique retinotopic maps were derived using this method. To improve performance on these retinotopic maps, we enabled head scanning and a density-based clustering algorithm was then used to relocate centroids of visual stimuli. The impact of these improvements on visual detection performance was tested. Using spatially evenly distributed maps as a control, we recruited ten subjects and evaluated their performance across five sessions on the Berkeley Rudimentary Visual Acuity test and the object recognition task.Main results.Performance on control maps is significantly better than on retinotopic maps in both tasks. Both head scanning and the clustering algorithm showed the potential of improving visual ability across multiple sessions in the object recognition task.Significance.The current paradigm is the first that simulates the experience of cortical prosthetic vision based on brain scans and implant placement, which captures the spatial distribution of phosphenes more realistically. Utilisation of evenly distributed maps may overestimate the performance that visual prosthetics can restore. This simulation paradigm could be used in clinical practice when making plans for where best to implant cortical visual prostheses.
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Affiliation(s)
- Haozhe Zac Wang
- Department of Electrical and Computer Systems Engineering, Monash University, Melbourne, Australia
| | - Yan Tat Wong
- Department of Electrical and Computer Systems Engineering, Monash University, Melbourne, Australia
- Department of Physiology, Monash University, Melbourne, Australia
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Margalit SN, Slovin H. Spatio-temporal activation patterns of neuronal population evoked by optostimulation and the comparison to electrical microstimulation. Sci Rep 2023; 13:12689. [PMID: 37542091 PMCID: PMC10403613 DOI: 10.1038/s41598-023-39808-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 07/31/2023] [Indexed: 08/06/2023] Open
Abstract
Optostimulation and electrical microstimulation are well-established techniques that enable to artificially stimulate the brain. While the activation patterns evoked by microstimulation in cortical network are well characterized, much less is known for optostimulation. Specifically, the activation maps of neuronal population at the membrane potential level and direct measurements of these maps were barely reported. In addition, only a few studies compared the activation patterns evoked by microstimulation and optostimulation. In this study we addressed these issues by applying optostimulation in the barrel cortex of anesthetized rats after a short (ShortExp) or a long (LongExp) opsin expression time and compared it to microstimulation. We measured the membrane potential of neuronal populations at high spatial (meso-scale) and temporal resolution using voltage-sensitive dye imaging. Longer optostimulation pulses evoked higher neural responses spreading over larger region relative to short pulses. Interestingly, similar optostimulation pulses evoked stronger and more prolonged population response in the LongExp vs. the ShortExp condition. Finally, the spatial activation patterns evoked in the LongExp condition showed an intermediate state, with higher resemblance to the microstimulation at the stimulation site. Therefore, short microstimulation and optostimulation can induce wide spread activation, however the effects of optostimulation depend on the opsin expression time.
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Affiliation(s)
| | - Hamutal Slovin
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel.
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Karadima V, Pezaris EA, Pezaris JS. Attitudes of potential recipients toward emerging visual prosthesis technologies. Sci Rep 2023; 13:10963. [PMID: 37414798 PMCID: PMC10325978 DOI: 10.1038/s41598-023-36913-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 06/12/2023] [Indexed: 07/08/2023] Open
Abstract
With the advent of multiple visual prosthesis devices to treat blindness, the question of how potential patients view such interventions becomes important in order to understand the levels of expectation and acceptance, and the perceived risk-reward balance across the different device approaches. Building on previous work on single device approaches done with blind individuals in Chicago and Detroit, USA, Melbourne, Australia, and Bejing, China, we investigated attitudes in blind individuals in Athens, Greece with coverage expanded to three of the contemporary approaches, Retinal, Thalamic, and Cortical. We presented an informational lecture on the approaches, had potential participants fill out a preliminary Questionnaire 1, then organized selected subjects into focus groups for guided discussion on visual prostheses, and finally had these subjects fill out a more detailed Questionnaire 2. We report here the first quantitative data that compares multiple prosthesis approaches. Our primary findings are that for these potential patients, perceived risk continues to outweigh perceived benefits, with the Retinal approach having the least negative overall impression and the Cortical approach the most negative. Concerns about the quality of restored vision were primary. Factors that drove the choice of hypothetical participation in a clinical trial were age and years of blindness. Secondary factors focused on positive clinical outcomes. The focus groups served to swing the impressions of each approach from neutrality toward the extremes of a Likert scale, and shifted the overall willingness to participate in a clinical trial from neutral to negative. These results, coupled with informal assessment of audience questions after the informational lecture, suggest that a substantial improvement in performance over currently available devices will be necessary before visual prostheses gain wide acceptance.
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Affiliation(s)
- Vicky Karadima
- Multisensory and Temporal Processing Lab (MultiTimeLab), Department of Psychology, Panteion University of Social and Political Sciences, Athens, Greece
| | | | - John S Pezaris
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA.
- Department of Neurosurgery, Harvard Medical School, Boston, MA, USA.
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Wang HZ, Wong YT. Utilization of brain scans to create realistic phosphene maps for cortical visual prosthesis simulation studies. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38083444 DOI: 10.1109/embc40787.2023.10341189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
It has been shown that we can restore sensations of light by stimulating the visual cortex. Cortical prosthetic vision consists of light perception in the visual field named phosphenes. Phosphenes are like pixels on a monitor which we can control to form the desired perception. However, the locations of phosphenes evoked vary between individuals. One of the biggest challenges is how to utilize phosphenes to present recognizable patterns that represent real-world scenes. Because of the difficulties of recruiting participants, and the risks of neurosurgery, researchers have used computer simulations to investigate the outcome of cortical visual prostheses. Previous simulations used regular phosphene maps, which may overestimate the visual ability cortical visual prosthesis can provide. This study aims to develop a more realistic simulation for cortical visual prostheses. We derived realistic phosphene maps using an existing cortical retinotopy dataset and decided implant placement by considering neurosurgery restrictions. We rendered some visual stimuli to evaluate the usability of those phosphene maps. The results indicate that presenting information on phosphenes maps may be more challenging than previously estimated.
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Cadoni S, Demené C, Alcala I, Provansal M, Nguyen D, Nelidova D, Labernède G, Lubetzki J, Goulet R, Burban E, Dégardin J, Simonutti M, Gauvain G, Arcizet F, Marre O, Dalkara D, Roska B, Sahel JA, Tanter M, Picaud S. Ectopic expression of a mechanosensitive channel confers spatiotemporal resolution to ultrasound stimulations of neurons for visual restoration. NATURE NANOTECHNOLOGY 2023; 18:667-676. [PMID: 37012508 DOI: 10.1038/s41565-023-01359-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
Remote and precisely controlled activation of the brain is a fundamental challenge in the development of brain-machine interfaces for neurological treatments. Low-frequency ultrasound stimulation can be used to modulate neuronal activity deep in the brain, especially after expressing ultrasound-sensitive proteins. But so far, no study has described an ultrasound-mediated activation strategy whose spatiotemporal resolution and acoustic intensity are compatible with the mandatory needs of brain-machine interfaces, particularly for visual restoration. Here we combined the expression of large-conductance mechanosensitive ion channels with uncustomary high-frequency ultrasonic stimulation to activate retinal or cortical neurons over millisecond durations at a spatiotemporal resolution and acoustic energy deposit compatible with vision restoration. The in vivo sonogenetic activation of the visual cortex generated a behaviour associated with light perception. Our findings demonstrate that sonogenetics can deliver millisecond pattern presentations via an approach less invasive than current brain-machine interfaces for visual restoration.
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Affiliation(s)
- Sara Cadoni
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Charlie Demené
- Physics for Medicine Paris, INSERM, CNRS, École Supérieure de Physique et de Chimie Industrielles (ESPCI Paris), Paris Sciences et Lettres (PSL) Research University, Paris, France
| | - Ignacio Alcala
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Diep Nguyen
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Dasha Nelidova
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland
| | | | - Jules Lubetzki
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Ruben Goulet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Emma Burban
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Julie Dégardin
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Manuel Simonutti
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Gregory Gauvain
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Fabrice Arcizet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Olivier Marre
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Botond Roska
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland
| | - José Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Ophthalmology and Vitreo-Retinal Diseases, Fondation Ophtalmologique Rothschild, Paris, France
- Centre Hospitalier National d'Ophtalmologie des XV-XX, Paris, France
| | - Mickael Tanter
- Physics for Medicine Paris, INSERM, CNRS, École Supérieure de Physique et de Chimie Industrielles (ESPCI Paris), Paris Sciences et Lettres (PSL) Research University, Paris, France
| | - Serge Picaud
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.
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Thompson C, Evans B, Zhao D, Purcell E. Spatiotemporal Expression of RNA-Seq Identified Proteins at the Electrode Interface. Acta Biomater 2023; 164:209-222. [PMID: 37116634 DOI: 10.1016/j.actbio.2023.04.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 04/14/2023] [Accepted: 04/18/2023] [Indexed: 04/30/2023]
Abstract
Implantation of electrodes in the brain can be used to record from or stimulate neural tissues to treat neurological disease and injury. However, the tissue response to implanted devices can limit their functional longevity. Recent RNA-seq datasets identify hundreds of genes associated with gliosis, neuronal function, myelination, and cellular metabolism that are spatiotemporally expressed in neural tissues following the insertion of microelectrodes. To validate mRNA as a predictor of protein expression, this study evaluates a sub-set of RNA-seq identified proteins (RSIP) at 24-hours, 1-week, and 6-weeks post-implantation using quantitative immunofluorescence methods. This study found that expression of RSIPs associated with glial activation (Glial fibrillary acidic protein (GFAP), Polypyrmidine tract binding protein-1 (Ptbp1)), neuronal structure (Neurofilament heavy chain (Nefh), Proteolipid protein-1 (Plp1), Myelin Basic Protein (MBP)), and iron metabolism (Transferrin (TF), Ferritin heavy chain-1 (Fth1)) reinforce transcriptional data. This study also provides additional context to the cellular distribution of RSIPs using a MATLAB-based approach to quantify immunofluorescence intensity within specific cell types. Ptbp1, TF, and Fth1 were found to be spatiotemporally distributed within neurons, astrocytes, microglia, and oligodendrocytes at the device interface relative to distal and contralateral tissues. The altered distribution of RSIPs relative to distal tissue is largely localized within 100µm of the device injury, which approaches the functional recording range of implanted electrodes. This study provides evidence that RNA-sequencing can be used to predict protein-level changes in cortical tissues and that RSIPs can be further investigated to identify new biomarkers of the tissue response that influence signal quality. STATEMENT OF SIGNIFICANCE: : Microelectrode arrays implanted into the brain are useful tools that can be used to study neuroscience and to treat pathological conditions in a clinical setting. The tissue response to these devices, however, can severely limit their functional longevity. Transcriptomics has deepened the understandings of the tissue response by revealing numerous genes which are differentially expressed following device insertion. This manuscript provides validation for the use of transcriptomics to characterize the tissue response by evaluating a subset of known differentially expressed genes at the protein level around implanted electrodes over time. In additional to validating mRNA-to-protein relationships at the device interface, this study has identified emerging trends in the spatiotemporal distribution of proteins involved with glial activation, neuronal remodeling, and essential iron binding proteins around implanted silicon devices. This study additionally provides a new MATLAB based methodology to quantify protein distribution within discrete cell types at the device interface which may be used as biomarkers for further study or therapeutic intervention in the future.
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Affiliation(s)
- Cort Thompson
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI 48824, United States of America; Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, United States of America
| | - Blake Evans
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI 48824, United States of America; Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, United States of America
| | - Dorothy Zhao
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI 48824, United States of America; Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, United States of America
| | - Erin Purcell
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI 48824, United States of America; Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, United States of America.
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13
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Halgren AS, Siegel Z, Golden R, Bazhenov M. Multielectrode Cortical Stimulation Selectively Induces Unidirectional Wave Propagation of Excitatory Neuronal Activity in Biophysical Neural Model. J Neurosci 2023; 43:2482-2496. [PMID: 36849415 PMCID: PMC10082457 DOI: 10.1523/jneurosci.1784-21.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 12/27/2022] [Accepted: 01/13/2023] [Indexed: 03/01/2023] Open
Abstract
Cortical stimulation is emerging as an experimental tool in basic research and a promising therapy for a range of neuropsychiatric conditions. As multielectrode arrays enter clinical practice, the possibility of using spatiotemporal patterns of electrical stimulation to induce desired physiological patterns has become theoretically possible, but in practice can only be implemented by trial-and-error because of a lack of predictive models. Experimental evidence increasingly establishes traveling waves as fundamental to cortical information-processing, but we lack an understanding of how to control wave properties despite rapidly improving technologies. This study uses a hybrid biophysical-anatomical and neural-computational model to predict and understand how a simple pattern of cortical surface stimulation could induce directional traveling waves via asymmetric activation of inhibitory interneurons. We found that pyramidal cells and basket cells are highly activated by the anodal electrode and minimally activated by the cathodal electrodes, while Martinotti cells are moderately activated by both electrodes but exhibit a slight preference for cathodal stimulation. Network model simulations found that this asymmetrical activation results in a traveling wave in superficial excitatory cells that propagates unidirectionally away from the electrode array. Our study reveals how asymmetric electrical stimulation can easily facilitate traveling waves by relying on two distinct types of inhibitory interneuron activity to shape and sustain the spatiotemporal dynamics of endogenous local circuit mechanisms.SIGNIFICANCE STATEMENT Electrical brain stimulation is becoming increasingly useful to probe the workings of brain and to treat a variety of neuropsychiatric disorders. However, stimulation is currently performed in a trial-and-error fashion as there are no methods to predict how different electrode arrangements and stimulation paradigms will affect brain functioning. In this study, we demonstrate a hybrid modeling approach, which makes experimentally testable predictions that bridge the gap between the microscale effects of multielectrode stimulation and the resultant circuit dynamics at the mesoscale. Our results show how custom stimulation paradigms can induce predictable, persistent changes in brain activity, which has the potential to restore normal brain function and become a powerful therapy for neurological and psychiatric conditions.
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Affiliation(s)
- Alma S Halgren
- Department of Medicine, University of California - San Diego, La Jolla, California 92093-7374
- Department of Integrative Biology, University of California - Berkeley, Berkeley, California 94720
| | - Zarek Siegel
- Department of Medicine, University of California - San Diego, La Jolla, California 92093-7374
- Neurosciences Graduate Program, University of California - San Diego, La Jolla, California 92093-7374
| | - Ryan Golden
- Department of Medicine, University of California - San Diego, La Jolla, California 92093-7374
- Neurosciences Graduate Program, University of California - San Diego, La Jolla, California 92093-7374
| | - Maxim Bazhenov
- Department of Medicine, University of California - San Diego, La Jolla, California 92093-7374
- Neurosciences Graduate Program, University of California - San Diego, La Jolla, California 92093-7374
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14
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Abouelseoud G, Abouelseoud Y, Shoukry A, Ismail N, Mekky J. A mixed integer linear programming framework for improving cortical vision prosthesis designs. Biomed Signal Process Control 2023. [DOI: 10.1016/j.bspc.2022.104253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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15
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Liang I, Spencer B, Scheller M, Proulx MJ, Petrini K. Assessing people with visual impairments’ access to information, awareness and satisfaction with high-tech assistive technology. BRITISH JOURNAL OF VISUAL IMPAIRMENT 2022. [DOI: 10.1177/02646196221131746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Assistive technology (AT) devices are designed to help people with visual impairments (PVIs) perform activities that would otherwise be difficult or impossible. Devices specifically designed to assist PVIs by attempting to restore sight or substitute it for another sense have a very low uptake rate. This study, conducted in England, aimed to investigate why this is the case by assessing accessibility to knowledge, awareness, and satisfaction with AT in general and with sensory restoration and substitution devices in particular. From a sample of 25 PVIs, ranging from 21 to 68 years old, results showed that participants knew where to find AT information; however, health care providers were not the main source of this information. Participants reported good awareness of different ATs, and of technologies they would not use, but reported poor awareness of specific sensory substitution and restoration devices. Only three participants reported using AT, each with different devices and varying levels of satisfaction. The results from this study suggest a possible breakdown in communication between health care providers and PVIs, and dissociation between reported AT awareness and reported access to AT information. Moreover, awareness of sensory restoration and substitution devices is poor, which may explain the limited use of such technology.
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16
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Oz R, Edelman-Klapper H, Nivinsky-Margalit S, Slovin H. Microstimulation in the primary visual cortex: activity patterns and their relation to visual responses and evoked saccades. Cereb Cortex 2022; 33:5192-5209. [PMID: 36300613 DOI: 10.1093/cercor/bhac409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 09/22/2022] [Accepted: 09/22/2022] [Indexed: 11/12/2022] Open
Abstract
Abstract
Intracortical microstimulation (ICMS) in the primary visual cortex (V1) can generate the visual perception of a small point of light, termed phosphene, and evoke saccades directed to the receptive field of the stimulated neurons. Although ICMS is widely used, a direct measurement of the spatio-temporal patterns of neural activity evoked by ICMS and their relation to the neural responses evoked by visual stimuli or how they relate to ICMS-evoked saccades are still missing. To investigate this, we combined ICMS with voltage-sensitive dye imaging in V1 of behaving monkeys and measured neural activity at a high spatial (meso-scale) and temporal resolution. We then compared the population response evoked by small visual stimuli to those evoked by microstimulation. Both stimulation types evoked population activity that spread over few millimeters in V1 and propagated to extrastriate areas. However, the population responses evoked by ICMS have shown faster dynamics for the activation transients and the horizontal propagation of activity revealed a wave-like propagation. Finally, neural activity in the ICMS condition was higher for trials with evoked saccades as compared with trials without saccades. Our results uncover the spatio-temporal patterns evoked by ICMS and their relation to visual processing and saccade generation.
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Affiliation(s)
- Roy Oz
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University , Ramat Gan 5290002, Israel
| | - Hadar Edelman-Klapper
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University , Ramat Gan 5290002, Israel
| | - Shany Nivinsky-Margalit
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University , Ramat Gan 5290002, Israel
| | - Hamutal Slovin
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University , Ramat Gan 5290002, Israel
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17
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Roy S, Nagrale P. Encoding the Photoreceptors of the Human Eye. Cureus 2022; 14:e30125. [PMID: 36381896 PMCID: PMC9644661 DOI: 10.7759/cureus.30125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 10/10/2022] [Indexed: 01/25/2023] Open
Abstract
This review aims to assess the anatomy of the human eye with a focus on exploring opportunities to mimic certain functionalities of photoreceptors in the optical system. This can help restore vision issues in people who had normal vision earlier, but their vision was impaired due to reasons that damaged parts of the eye; however, the functionality of the optic nerve remained intact. It is a conceptual article where the methodology to simulate artificial photoreceptors is discussed.
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Affiliation(s)
- Shreya Roy
- Medical Student, Jawaharlal Nehru Medical College, Datta Meghe Institute of Medical Sciences, Wardha, IND
| | - Prachi Nagrale
- Ophthalmology, Jawaharlal Nehru Medical College, Datta Meghe Institute of Medical Sciences, Wardha, IND
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18
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Shull G, Shin Y, Viventi J, Jochum T, Morizio J, Seo KJ, Fang H. Design and Simulation of a Low Power 384-channel Actively Multiplexed Neural Interface. IEEE BIOMEDICAL CIRCUITS AND SYSTEMS CONFERENCE : HEALTHCARE TECHNOLOGY : [PROCEEDINGS]. IEEE BIOMEDICAL CIRCUITS AND SYSTEMS CONFERENCE 2022; 2022:477-481. [PMID: 37431519 PMCID: PMC10331316 DOI: 10.1109/biocas54905.2022.9948553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/12/2023]
Abstract
Brain computer interfaces (BCIs) provide clinical benefits including partial restoration of lost motor control, vision, speech, and hearing. A fundamental limitation of existing BCIs is their inability to span several areas (> cm2) of the cortex with fine (<100 μm) resolution. One challenge of scaling neural interfaces is output wiring and connector sizes as each channel must be independently routed out of the brain. Time division multiplexing (TDM) overcomes this by enabling several channels to share the same output wire at the cost of added noise. This work leverages a 130-nm CMOS process and transfer printing to design and simulate a 384-channel actively multiplexed array, which minimizes noise by adding front end filtering and amplification to every electrode site (pixel). The pixels are 50 μm × 50 μm and enable recording of all 384 channels at 30 kHz with a gain of 22.3 dB, noise of 9.57 μV rms, bandwidth of 0.1 Hz - 10 kHz, while only consuming 0.63 μW/channel. This work can be applied broadly across neural interfaces to create high channel-count arrays and ultimately improve BCIs.
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Affiliation(s)
- Gabriella Shull
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Yieljae Shin
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Jonathan Viventi
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Thomas Jochum
- Department of Biomedical Engineering, Duke University, Durham, North Carlonia
| | - James Morizio
- Department of Electrical Engineering, Duke University, Durham, North Carolina
| | - Kyung Jin Seo
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Hui Fang
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
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19
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Hayashida Y, Kameda S, Umehira Y, Ishikawa S, Yagi T. Multichannel stimulation module as a tool for animal studies on cortical neural prostheses. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 4:927581. [PMID: 36176924 PMCID: PMC9513350 DOI: 10.3389/fmedt.2022.927581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 08/08/2022] [Indexed: 11/13/2022] Open
Abstract
Intracortical microstimulation to the visual cortex is thought to be a feasible technique for inducing localized phosphenes in patients with acquired blindness, and thereby for visual prosthesis. In order to design effective stimuli for the prosthesis, it is important to elucidate relationships between the spatio-temporal patterns of stimuli and the resulting neural responses and phosphenes through pre-clinical animal studies. However, the physiological basis of effective spatial patterns of the stimuli for the prosthesis has been little investigated in the literature, at least partly because that the previously developed multi-channel stimulation systems were designed specifically for the clinical use. In the present, a 64-channel stimulation module was developed as a scalable tool for animal experiments. The operations of the module were verified by not only dry-bench tests but also physiological animal experiments in vivo. The results demonstrated its usefulness for examining the stimulus-response relationships in a quantitative manner, and for inducing the multi-site neural excitations with a multi-electrode array. In addition, this stimulation module could be used to generate spatially patterned stimuli with up to 4,096 channels in a dynamic way, in which the stimulus patterns can be updated at a certain frame rate in accordance with the incoming visual scene. The present study demonstrated that our stimulation module is applicable to the physiological and other future studies in animals on the cortical prostheses.
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Affiliation(s)
- Yuki Hayashida
- Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, Suita, Japan
- Department of Information Engineering, Graduate School of Engineering, Mie University, Tsu, Japan
| | - Seiji Kameda
- Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, Suita, Japan
| | - Yuichi Umehira
- Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, Suita, Japan
| | - Shinnosuke Ishikawa
- Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, Suita, Japan
| | - Tetsuya Yagi
- Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, Suita, Japan
- Department of Electrical and Electronic Engineering, School of Engineering, Fukui University of Technology, Fukui, Japan
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20
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Lee SW, Fried SI. Micro-magnetic stimulation of primary visual cortex induces focal and sustained activation of secondary visual cortex. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20210019. [PMID: 35658677 DOI: 10.1098/rsta.2021.0019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/01/2021] [Indexed: 06/15/2023]
Abstract
Cortical visual prostheses that aim to restore sight to the blind require the ability to create neural activity in the visual cortex. Electric stimulation delivered via microelectrodes implanted in the primary visual cortex (V1) has been the most common approach, although conventional electrodes may not effectively confine activation to focal regions and thus the acuity they create may be limited. Magnetic stimulation from microcoils confines activation to single cortical columns of V1 and thus may prove to be more effective than conventional microelectrodes, but the ability of microcoils to drive synaptic connections has not been explored. Here, we show that magnetic stimulation of V1 using microcoils induces spatially confined activation in the secondary visual cortex (V2) in mouse brain slices. Single-loop microcoils were fabricated using platinum-iridium flat microwires, and their effectiveness was evaluated using calcium imaging and compared with that of monopolar and bipolar electrodes. Our results show that compared to the electrodes, the microcoils better confined activation to a small region in V1. In addition, they produced more precise and sustained activation in V2. The finding that microcoil-based stimulation propagates to higher visual centres raises the possibility that complex visual perception, e.g. that requiring sustained synaptic inputs, may be achievable. This article is part of the theme issue 'Advanced neurotechnologies: translating innovation for health and well-being'.
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Affiliation(s)
- Seung Woo Lee
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Shelley I Fried
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Boston VA Healthcare System, Boston, MA, USA
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21
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van Velthoven EAM, van Stuijvenberg OC, Haselager DRE, Broekman M, Chen X, Roelfsema P, Bredenoord AL, Jongsma KR. Ethical implications of visual neuroprostheses-a systematic review. J Neural Eng 2022; 19. [PMID: 35475424 DOI: 10.1088/1741-2552/ac65b2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 04/08/2022] [Indexed: 11/12/2022]
Abstract
Objective. The aim of this review was to systematically identify the ethical implications of visual neuroprostheses.Approach. A systematic search was performed in both PubMed and Embase using a search string that combined synonyms for visual neuroprostheses, brain-computer interfaces (BCIs), cochlear implants (CIs), and ethics. We chose to include literature on BCIs and CIs, because of their ethically relavant similarities and functional parallels with visual neuroprostheses.Main results. We included 84 articles in total. Six focused specifically on visual prostheses. The other articles focused more broadly on neurotechnologies, on BCIs or CIs. We identified 169 ethical implications that have been categorized under seven main themes: (a) benefits for health and well-being; (b) harm and risk; (c) autonomy; (d) societal effects; (e) clinical research; (f) regulation and governance; and (g) involvement of experts, patients and the public.Significance. The development and clinical use of visual neuroprostheses is accompanied by ethical issues that should be considered early in the technological development process. Though there is ample literature on the ethical implications of other types of neuroprostheses, such as motor neuroprostheses and CIs, there is a significant gap in the literature regarding the ethical implications of visual neuroprostheses. Our findings can serve as a starting point for further research and normative analysis.
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Affiliation(s)
- E A M van Velthoven
- Department of Medical Humanities, Julius Center, University Medical Center Utrecht, PO Box 85500, Utrecht, 3508 GA, The Netherlands
| | - O C van Stuijvenberg
- Department of Medical Humanities, Julius Center, University Medical Center Utrecht, PO Box 85500, Utrecht, 3508 GA, The Netherlands
| | - D R E Haselager
- Department of Medical Humanities, Julius Center, University Medical Center Utrecht, PO Box 85500, Utrecht, 3508 GA, The Netherlands
| | - M Broekman
- Department of Neurosurgery, Haaglanden Medical Center, The Hague, The Netherlands.,Department of Neurosurgery, Leiden Medical Center, Leiden, The Netherlands
| | - X Chen
- Department of Vision & Cognition, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
| | - P Roelfsema
- Department of Vision & Cognition, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.,Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, The Netherlands.,Department of Psychiatry, Academic Medical Center, Amsterdam, The Netherlands
| | - A L Bredenoord
- Erasmus School of Philosophy, Erasmus University Rotterdam, Rotterdam, The Netherlands
| | - K R Jongsma
- Department of Medical Humanities, Julius Center, University Medical Center Utrecht, PO Box 85500, Utrecht, 3508 GA, The Netherlands
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22
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de Ruyter van Steveninck J, Güçlü U, van Wezel R, van Gerven M. End-to-end optimization of prosthetic vision. J Vis 2022; 22:20. [PMID: 35703408 PMCID: PMC8899855 DOI: 10.1167/jov.22.2.20] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Neural prosthetics may provide a promising solution to restore visual perception in some forms of blindness. The restored prosthetic percept is rudimentary compared to normal vision and can be optimized with a variety of image preprocessing techniques to maximize relevant information transfer. Extracting the most useful features from a visual scene is a nontrivial task and optimal preprocessing choices strongly depend on the context. Despite rapid advancements in deep learning, research currently faces a difficult challenge in finding a general and automated preprocessing strategy that can be tailored to specific tasks or user requirements. In this paper, we present a novel deep learning approach that explicitly addresses this issue by optimizing the entire process of phosphene generation in an end-to-end fashion. The proposed model is based on a deep auto-encoder architecture and includes a highly adjustable simulation module of prosthetic vision. In computational validation experiments, we show that such an approach is able to automatically find a task-specific stimulation protocol. The results of these proof-of-principle experiments illustrate the potential of end-to-end optimization for prosthetic vision. The presented approach is highly modular and our approach could be extended to automated dynamic optimization of prosthetic vision for everyday tasks, given any specific constraints, accommodating individual requirements of the end-user.
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Affiliation(s)
- Jaap de Ruyter van Steveninck
- Department of Artificial Intelligence, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
- Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Umut Güçlü
- Department of Artificial Intelligence, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Richard van Wezel
- Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
- Biomedical Signal and Systems, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Marcel van Gerven
- Department of Artificial Intelligence, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
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23
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de Ruyter van Steveninck J, van Gestel T, Koenders P, van der Ham G, Vereecken F, Güçlü U, van Gerven M, Güçlütürk Y, van Wezel R. Real-world indoor mobility with simulated prosthetic vision: The benefits and feasibility of contour-based scene simplification at different phosphene resolutions. J Vis 2022; 22:1. [PMID: 35103758 PMCID: PMC8819280 DOI: 10.1167/jov.22.2.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 12/28/2021] [Indexed: 11/24/2022] Open
Abstract
Neuroprosthetic implants are a promising technology for restoring some form of vision in people with visual impairments via electrical neurostimulation in the visual pathway. Although an artificially generated prosthetic percept is relatively limited compared with normal vision, it may provide some elementary perception of the surroundings, re-enabling daily living functionality. For mobility in particular, various studies have investigated the benefits of visual neuroprosthetics in a simulated prosthetic vision paradigm with varying outcomes. The previous literature suggests that scene simplification via image processing, and particularly contour extraction, may potentially improve the mobility performance in a virtual environment. In the current simulation study with sighted participants, we explore both the theoretically attainable benefits of strict scene simplification in an indoor environment by controlling the environmental complexity, as well as the practically achieved improvement with a deep learning-based surface boundary detection implementation compared with traditional edge detection. A simulated electrode resolution of 26 × 26 was found to provide sufficient information for mobility in a simple environment. Our results suggest that, for a lower number of implanted electrodes, the removal of background textures and within-surface gradients may be beneficial in theory. However, the deep learning-based implementation for surface boundary detection did not improve mobility performance in the current study. Furthermore, our findings indicate that, for a greater number of electrodes, the removal of within-surface gradients and background textures may deteriorate, rather than improve, mobility. Therefore, finding a balanced amount of scene simplification requires a careful tradeoff between informativity and interpretability that may depend on the number of implanted electrodes.
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Affiliation(s)
- Jaap de Ruyter van Steveninck
- Department of Artificial Intelligence, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
- Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Tom van Gestel
- Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Paula Koenders
- Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Guus van der Ham
- Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Floris Vereecken
- Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Umut Güçlü
- Department of Artificial Intelligence, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Marcel van Gerven
- Department of Artificial Intelligence, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Yagmur Güçlütürk
- Department of Artificial Intelligence, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Richard van Wezel
- Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
- Biomedical Signal and Systems, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, the Netherlands
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24
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Lear A, Baker SN, Clarke HF, Roberts AC, Schmid MC, Jarrett W. Understanding them to understand ourselves: The importance of NHP research for translational neuroscience. CURRENT RESEARCH IN NEUROBIOLOGY 2022; 3:100049. [PMID: 36518342 PMCID: PMC9743051 DOI: 10.1016/j.crneur.2022.100049] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 04/20/2022] [Accepted: 07/22/2022] [Indexed: 10/15/2022] Open
Abstract
Studying higher brain function presents fundamental scientific challenges but has great potential for impactful translation to the clinic, supporting the needs of many patients suffering from conditions that relate to neuronal dysfunction. For many key questions relevant to human neurological conditions and clinical interventions, non-human primates (NHPs) remain the only suitable model organism and the only effective way to study the relationship between brain structure and function with the knowledge and tools currently available. Here we present three exemplary studies of current research yielding important findings that are directly translational to human clinical patients but which would be impossible without NHP studies. Our first example shows how studies of the NHP prefrontal cortex are leading to clinically relevant advances and potential new treatments for human neuropsychiatric disorders such as depression and anxiety. Our second example looks at the relevance of NHP research to our understanding of visual pathways and the visual cortex, leading to visual prostheses that offer treatments for otherwise blind patients. Finally, we consider recent advances in treatments leading to improved recovery of movement and motor control in stroke patients, resulting from our improved understanding of brain stem parallel pathways involved in movement in NHPs. The case for using NHPs in neuroscience research, and the direct benefits to human patients, is strong but has rarely been set out directly. This paper reviews three very different areas of neuroscience research, expressly highlighting the unique insights offered to each by NHP studies and their direct applicability to human clinical conditions.
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Affiliation(s)
- Annabella Lear
- Understanding Animal Research, Abbey House, 74-76 St John Street, London, EC1M 4DZ, United Kingdom
| | - Stuart N Baker
- Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Hannah F Clarke
- Department of Physiology, Development, and Neuroscience, University of Cambridge, CB2 3DY, Cambridge, United Kingdom.,Behavioural and Clinical Neuroscience Institute, University of Cambridge, CB2 3EB, Cambridge, United Kingdom
| | - Angela C Roberts
- Department of Physiology, Development, and Neuroscience, University of Cambridge, CB2 3DY, Cambridge, United Kingdom.,Behavioural and Clinical Neuroscience Institute, University of Cambridge, CB2 3EB, Cambridge, United Kingdom
| | - Michael C Schmid
- Department of Neuroscience and Movement Science, Faculty of Science and Medicine, University of Fribourg, 1700, Fribourg, Switzerland.,Biosciences Institute, Faculty of Medical Sciences, Newcastle University, NE2 4HH, United Kingdom
| | - Wendy Jarrett
- Understanding Animal Research, Abbey House, 74-76 St John Street, London, EC1M 4DZ, United Kingdom
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Bosking WH, Oswalt DN, Foster BL, Sun P, Beauchamp MS, Yoshor D. Percepts evoked by multi-electrode stimulation of human visual cortex. Brain Stimul 2022; 15:1163-1177. [PMID: 35985472 PMCID: PMC9831085 DOI: 10.1016/j.brs.2022.08.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/11/2022] [Accepted: 08/11/2022] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Direct electrical stimulation of early visual cortex evokes the perception of small spots of light known as phosphenes. Previous studies have examined the location, size, and brightness of phosphenes evoked by stimulation of single electrodes. While it has been envisioned that concurrent stimulation of many electrodes could be used as the basis for a visual cortical prosthesis, the percepts resulting from multi-electrode stimulation have not been fully characterized. OBJECTIVE To understand the rules governing perception of phosphenes evoked by multi-electrode stimulation of visual cortex. METHODS Multi-electrode stimulation was conducted in human epilepsy patients. We examined the number and spatial arrangement of phosphenes evoked by stimulation of individual multi-electrode groups (n = 8), and the ability of subjects to discriminate between the pattern of phosphenes generated by stimulation of different multi-electrode groups (n = 7). RESULTS Simultaneous stimulation of pairs of electrodes separated by greater than 4 mm tended to produce perception of two distinct phosphenes. Simultaneous stimulation of three electrodes gave rise to a consistent spatial pattern of phosphenes, but with significant variation in the absolute location, size, and orientation of that pattern perceived on each trial. Although multi-electrode stimulation did not produce perception of recognizable forms, subjects could use the pattern of phosphenes evoked by stimulation to perform simple discriminations. CONCLUSIONS The number of phosphenes produced by multi-electrode stimulation can be predicted using a model for spread of activity in early visual cortex, but there are additional subtle effects that must be accounted for.
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Affiliation(s)
- William H. Bosking
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, 19104, USA,Corresponding author. Department of Neurosurgery, University of Pennsylvania, 3700 Hamilton Walk, Richards Room 6A, Philadelphia, PA, 19104, USA. (W.H. Bosking)
| | - Denise N. Oswalt
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Brett L. Foster
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Ping Sun
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Michael S. Beauchamp
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Daniel Yoshor
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, 19104, USA
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Kravchenko SV, Sakhnov SN, Myasnikova VV. Modern concepts of bionic vision. Vestn Oftalmol 2022; 138:95-101. [PMID: 35801887 DOI: 10.17116/oftalma202213803195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Loss of vision is a pressing medical and social problem leading to profound disability, loss of ability to work, serious alterations in the psycho-emotional state, and a decline of the quality of life. When conservative or surgical treatment can not help restore vision, the use of visual prosthesis - bionic eye - can be an effective solution. This review covers the main modern approaches to the development of visual prosthetic systems. Analysis of publications revealed that there are several main approaches to visual prosthesis differing primarily by the anatomical structure targeted for stimulation in order to activate visual sensations. The most significant among them are retinal prostheses, optic nerve stimulation, and cortical visual prostheses. Currently, retinal prostheses such as ARGUS II demonstrate the most successful results, since the stimulation of the surviving neural structures of the retina is a relatively easy task, but their field of application is limited to diseases associated with pathological changes in photoreceptors. The development of cortical visual prostheses is more difficult, but in the future they may allow using more stimulation channels to obtain a more detailed visual perception. In addition, cortical visual prostheses are universal, as they do not require preservation of any structures of the visual organ, only the primary visual cortex.
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Affiliation(s)
- S V Kravchenko
- Krasnodar branch of S.N. Fedorov National Medical Research Center «MNTK «Eye Microsurgery», Krasnodar, Russia
| | - S N Sakhnov
- Krasnodar branch of S.N. Fedorov National Medical Research Center «MNTK «Eye Microsurgery», Krasnodar, Russia
- Kuban State Medical University, Krasnodar, Russia
| | - V V Myasnikova
- Krasnodar branch of S.N. Fedorov National Medical Research Center «MNTK «Eye Microsurgery», Krasnodar, Russia
- Kuban State Medical University, Krasnodar, Russia
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Elnabawy RH, Abdennadher S, Hellwich O, Eldawlatly S. Electrode Dropout Compensation in Visual Prostheses: An Optimal Object Placement Approach. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:6515-6518. [PMID: 34892602 DOI: 10.1109/embc46164.2021.9630991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Visual prostheses provide promising solution to the blind through partial restoration of their vision via electrical stimulation of the visual system. However, there are some challenges that hinder the ability of subjects implanted with visual prostheses to correctly identify an object. One of these challenges is electrode dropout; the malfunction of some electrodes resulting in consistently dark phosphenes. In this paper, we propose a dropout handling algorithm for better and faster identification of objects. In this algorithm, phosphenes representing the object are translated to another location within the same image that has the minimum number of dropouts. Using simulated prosthetic vision, experiments were conducted to test the efficacy of our proposed algorithm. Electrode dropout rates of 10%, 20% and 30% were examined. Our results demonstrate significant increase in the object recognition accuracy, reduction in the recognition time and increase in the recognition confidence level using the proposed approach compared to presenting the images without dropout handling.Clinical Relevance- These results demonstrate the utility of dropout handling in enhancing the perception of images in prosthetic vision.
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Oswalt D, Bosking W, Sun P, Sheth SA, Niketeghad S, Salas MA, Patel U, Greenberg R, Dorn J, Pouratian N, Beauchamp M, Yoshor D. Multi-electrode stimulation evokes consistent spatial patterns of phosphenes and improves phosphene mapping in blind subjects. Brain Stimul 2021; 14:1356-1372. [PMID: 34482000 DOI: 10.1016/j.brs.2021.08.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 08/11/2021] [Accepted: 08/31/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Visual cortical prostheses (VCPs) have the potential to restore visual function to patients with acquired blindness. Successful implementation of VCPs requires the ability to reliably map the location of the phosphene produced by stimulation of each implanted electrode. OBJECTIVE To evaluate the efficacy of different approaches to phosphene mapping and propose simple improvements to mapping strategy. METHODS We stimulated electrodes implanted in the visual cortex of five blind and fifteen sighted patients. We tested two fixation strategies, unimanual fixation, where subjects placed a single index finger on a tactile fixation point and bimanual fixation, where subjects overlaid their right index finger over their left on the tactile point. In addition, we compared absolute mapping in which a single electrode was stimulated on each trial, and relative mapping with sequences containing stimulation of three to five phosphenes on each trial. Trial-to-trial variability present in relative mapping sequences was quantified. RESULTS Phosphene mapping was less precise in blind subjects than in sighted subjects (2DRMS, 16 ± 2.9° vs. 1.9 ± 0.93°; t (18) = 18, p = <0.001). Within blind subjects, bimanual fixation resulted in more consistent phosphene localization than unimanual fixation (BS1: 4.0 ± 2.6° vs. 19 ± 4.7°, t (79) = 24, p < 0.001; BS2 4.1 ± 2.0° vs. 12 ± 2.7°, t (65) = 19, p < 0.001). Multi-point relative mapping had similar baseline precision to absolute mapping (BS1: 4.7 ± 2.6° vs. 3.9 ± 2.0°; BS2: 4.1 ± 2.0° vs. 3.2 ± 1.1°) but improved significantly when trial-to-trial translational variability was removed. Although multi-point mapping methods did reveal more of the functional organization expected in early visual cortex, subjects tended to artificially regularize the spacing between phosphenes. We attempt to address this issue by fitting a standard logarithmic map to relative multi-point sequences. CONCLUSIONS Relative mapping methods, combined with bimanual fixation, resulted in the most precise estimates of phosphene organization. These techniques, combined with use of a standard logarithmic model of visual cortex, may provide a practical way to improve the implementation of a VCP.
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Affiliation(s)
- Denise Oswalt
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA.
| | - William Bosking
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Ping Sun
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA
| | - Sameer A Sheth
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA
| | - Soroush Niketeghad
- Department of Neurosurgery, University of California Los Angeles, Los Angeles, CA, USA
| | | | - Uday Patel
- Second Sight Medical Products, Sylmar, CA, USA
| | | | - Jessy Dorn
- Second Sight Medical Products, Sylmar, CA, USA
| | - Nader Pouratian
- Department of Neurological Surgery, University of Texas Southwestern, Dallas, TX, USA
| | - Michael Beauchamp
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Daniel Yoshor
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA
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Abboud H, Salazar-Camelo A, George N, Planchon SM, Matiello M, Mealy MA, Goodman A. Symptomatic and restorative therapies in neuromyelitis optica spectrum disorders. J Neurol 2021; 269:1786-1801. [PMID: 34482456 PMCID: PMC8940781 DOI: 10.1007/s00415-021-10783-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 08/27/2021] [Accepted: 08/28/2021] [Indexed: 02/06/2023]
Abstract
Neuromyelitis optica spectrum disorders (NMOSD) are a group of autoimmune inflammatory conditions that primarily target the optic nerves, spinal cord, brainstem, and occasionally the cerebrum. NMOSD is characterized by recurrent attacks of visual, motor, and/or sensory dysfunction that often result in severe neurological deficits. In recent years, there has been a significant progress in relapse treatment and prevention but the residual disability per attack remains high. Although symptomatic and restorative research has been limited in NMOSD, some therapeutic approaches can be inferred from published case series and evidence from multiple sclerosis literature. In this review, we will discuss established and emerging therapeutic options for symptomatic treatment and restoration of function in NMOSD. We highlight NMOSD-specific considerations and identify potential areas for future research. The review covers pharmacologic, non-pharmacologic, and neuromodulatory approaches to neuropathic pain, tonic spasms, muscle tone abnormalities, sphincter dysfunction, motor and visual impairment, fatigue, sleep disorders, and neuropsychological symptoms. In addition, we briefly discuss remyelinating agents and mesenchymal stem cell transplantation in NMOSD.
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Affiliation(s)
- Hesham Abboud
- Multiple Sclerosis and Neuroimmunology Program, Parkinson's and Movement Disorders Center, University Hospitals of Cleveland, Case Western Reserve University, Bolwell, 5th floor, 11100 Euclid Avenue, Cleveland, OH, 44106, USA.
| | - Andrea Salazar-Camelo
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Naveen George
- Multiple Sclerosis and Neuroimmunology Program, Parkinson's and Movement Disorders Center, University Hospitals of Cleveland, Case Western Reserve University, Bolwell, 5th floor, 11100 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Sarah M Planchon
- The Mellen Center for Multiple Sclerosis, Cleveland Clinic, Cleveland, OH, USA
| | - Marcelo Matiello
- Neurology Department, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Maureen A Mealy
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Horizon Therapeutics Plc, Deerfield, IL, USA
| | - Andrew Goodman
- Neuroimmunology Division, Department of Neurology, University of Rochester Medical Center, Rochester, NY, USA
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EPIRETINAL FIBROSIS REMOVAL IN AN ARGUS II-IMPLANTED EYE: Histological Characteristics and Functional Results. Retina 2021; 40:2403-2409. [PMID: 32195788 DOI: 10.1097/iae.0000000000002780] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE 1) To investigate morphologic and histochemical characteristics of an epiretinal fibrosis removed in an Argus II-implanted eye; 2) to evaluate the Argus II function before and after the fibrosis removal, and 3) to compare morphologic and functional data. METHODS Fibrosis, which developed between the Argus II prosthesis and the retina two years after implant, was surgically removed. Its morphologic and histochemical characteristics were evaluated both in light and transmission electron microscopy, with special stains and immunohistochemistry. The Argus II function was evaluated during the follow-up before surgical removal and 1 month later. RESULTS Fibrosis was successfully removed. It was composed of a fibrotic tissue with spindle cells arranged in nodular aggregates with a symmetric distribution, mixed with an inflammatory infiltrate. Extra- and intracellular, irregular, small iron particles were found and confirmed ultrastructural characterization with degenerative cellular changes. The repositioned Argus II restored, and its function was partially nearly to normal values 1 month after surgery. CONCLUSION Fibrosis can develop between the Argus II and the retina with increasing reduced function. Morphologic characteristics of the removed fibrosis suggested a pathogenesis based on an inflammatory process involved in a foreign body reaction with progressing connective tissue deposition leading to sclerosis. Adequate clinical follow-up is critical to successful removal of the fibrosis with reactivation of the Argus II function.
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Mohana Devi S, Abishek Kumar B, Mahalaxmi I, Balachandar V. Leber's hereditary optic neuropathy: Current approaches and future perspectives on Mesenchymal stem cell-mediated rescue. Mitochondrion 2021; 60:201-218. [PMID: 34454075 DOI: 10.1016/j.mito.2021.08.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 08/03/2021] [Accepted: 08/23/2021] [Indexed: 12/19/2022]
Abstract
Leber's Hereditary Optic Neuropathy (LHON) is an inherited optic nerve disorder. It is a mitochondrially inherited disease due to point mutation in the MT-ND1, MT-ND4, and MT-ND6 genes of mitochondrial DNA (mtDNA) coding for complex I subunit proteins. These mutations affect the assembly of the mitochondrial complex I and hence the electron transport chain leading to mitochondrial dysfunction and oxidative damage. Optic nerve cells like retinal ganglion cells (RGCs) are more sensitive to mitochondrial loss and oxidative damage which results in the progressive degeneration of RGCs at the axonal region of the optic nerve leading to bilateral vision loss. Currently, gene therapy using Adeno-associated viral vector (AAV) is widely studied for the therapeutics application in LHON. Our review highlights the application of cell-based therapy for LHON. Mesenchymal stem cells (MSCs) are known to rescue cells from the pre-apoptotic stage by transferring healthy mitochondria through tunneling nanotubes (TNT) for cellular oxidative function. Empowering the transfer of healthy mitochondria using MSCs may replace the mitochondria with pathogenic mutation and possibly benefit the cells from progressive damage. This review discusses the ongoing research in LHON and mitochondrial transfer mechanisms to explore its scope in inherited optic neuropathy.
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Affiliation(s)
- Subramaniam Mohana Devi
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, India.
| | - B Abishek Kumar
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, India
| | - Iyer Mahalaxmi
- Livestock Farming and Bioresource Technology, Tamil Nadu, India
| | - Vellingiri Balachandar
- Department of Human Genetics and Molecular Biology, Bharathiar University, Coimbatore, India
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Silva AE, Tsang K, Hasan SJ, Thompson B. Precise oculocentric mapping of transcranial magnetic stimulation-evoked phosphenes. Neuroreport 2021; 32:913-917. [PMID: 34102648 PMCID: PMC8253501 DOI: 10.1097/wnr.0000000000001683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 05/10/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Transcranial magnetic stimulation (TMS)-evoked phosphenes are oculocentric; their perceived location depends upon eye position. We investigated the accuracy and precision of TMS-evoked phosphene oculocentric mapping. METHODS We evoked central phosphenes by stimulating early visual cortical areas with TMS, systematically examining the effect of eye position by asking participants to report the location of the evoked phosphene. We tested whether any systematic differences in the precision or accuracy of responses occurred as a function of eye position. RESULTS Perceived phosphene locations map veridically to eye position, although there are considerable individual differences in the reliability of this mapping. CONCLUSIONS Our results emphasize the need to carefully control eye movements when carrying out phosphene localization studies and suggest that individual differences in the reliability of the reported position of individual phosphenes must be considered.
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Affiliation(s)
- Andrew E. Silva
- School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada
| | - Katelyn Tsang
- School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada
| | - Syeda Javeria Hasan
- School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada
| | - Benjamin Thompson
- School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada
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Mailhot N, Cheriton R, Vyas K, Cook J, Prawer S, Hinzer K, Spinello D. Eighty-Five Percent of Improved Optical Power Delivery to Epiretinal Prostheses Using Rigid Body Compensation Algorithm. J Biomech Eng 2021; 143:061009. [PMID: 33537711 DOI: 10.1115/1.4050026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Indexed: 11/08/2022]
Abstract
Vision impairment caused by degenerative retinal pathologies such as age-related macular degeneration can be treated using retinal implants. Such devices receive power and data using cables passing through a permanent surgical incision in the eye wall (sclera), which increases the risk to patients and surgical costs. A recently developed retinal implant design eliminates the necessity of the implant cable using a photonic power converter (PPC), which receives optical power and data through the pupil and is directed by an ellipsoidal reflector and micro-electromechanical mirror. We present a misalignment compensation algorithm model that accounts for rigid-body motions of the reflector relative to the eye and applies the correction to the mirror coordinates in the presence of angular misalignment of the reflector. We demonstrate that up to 85% of the nominal optical power can be delivered to the implant with axial reflector misalignments up to 30 deg using the compensation algorithm.
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Affiliation(s)
- Nathaniel Mailhot
- Department of Mechanical Engineering, University of Ottawa, Ottawa, ON K1N 6M6, Canada
| | - Ross Cheriton
- National Research Council of Canada, Ottawa, ON K1N 6M6, Canada
| | - Kaustubh Vyas
- Electrical Engineering and Computer Science, University of Ottawa, Ottawa, ON K1N 6M6, Canada
| | - John Cook
- Electrical Engineering and Computer Science, University of Ottawa, Ottawa, ON K1N 6M6, Canada
| | - Steven Prawer
- Department of Physics, University of Melbourne, Melbourne VIC 3010, Australia
| | - Karin Hinzer
- Electrical Engineering and Computer Science, University of Ottawa, Ottawa, ON K1N 6M6, Canada
| | - Davide Spinello
- Department of Mechanical Engineering, University of Ottawa, Ottawa, ON K1N 6M6, Canada
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Full gaze contingency provides better reading performance than head steering alone in a simulation of prosthetic vision. Sci Rep 2021; 11:11121. [PMID: 34045485 PMCID: PMC8160142 DOI: 10.1038/s41598-021-86996-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 03/23/2021] [Indexed: 11/08/2022] Open
Abstract
The visual pathway is retinotopically organized and sensitive to gaze position, leading us to hypothesize that subjects using visual prostheses incorporating eye position would perform better on perceptual tasks than with devices that are merely head-steered. We had sighted subjects read sentences from the MNREAD corpus through a simulation of artificial vision under conditions of full gaze compensation, and head-steered viewing. With 2000 simulated phosphenes, subjects (n = 23) were immediately able to read under full gaze compensation and were assessed at an equivalent visual acuity of 1.0 logMAR, but were nearly unable to perform the task under head-steered viewing. At the largest font size tested, 1.4 logMAR, subjects read at 59 WPM (50% of normal speed) with 100% accuracy under the full-gaze condition, but at 0.7 WPM (under 1% of normal) with below 15% accuracy under head-steering. We conclude that gaze-compensated prostheses are likely to produce considerably better patient outcomes than those not incorporating eye movements.
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Antolik J, Sabatier Q, Galle C, Frégnac Y, Benosman R. Assessment of optogenetically-driven strategies for prosthetic restoration of cortical vision in large-scale neural simulation of V1. Sci Rep 2021; 11:10783. [PMID: 34031442 PMCID: PMC8144184 DOI: 10.1038/s41598-021-88960-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/01/2021] [Indexed: 02/04/2023] Open
Abstract
The neural encoding of visual features in primary visual cortex (V1) is well understood, with strong correlates to low-level perception, making V1 a strong candidate for vision restoration through neuroprosthetics. However, the functional relevance of neural dynamics evoked through external stimulation directly imposed at the cortical level is poorly understood. Furthermore, protocols for designing cortical stimulation patterns that would induce a naturalistic perception of the encoded stimuli have not yet been established. Here, we demonstrate a proof of concept by solving these issues through a computational model, combining (1) a large-scale spiking neural network model of cat V1 and (2) a virtual prosthetic system transcoding the visual input into tailored light-stimulation patterns which drive in situ the optogenetically modified cortical tissue. Using such virtual experiments, we design a protocol for translating simple Fourier contrasted stimuli (gratings) into activation patterns of the optogenetic matrix stimulator. We then quantify the relationship between spatial configuration of the imposed light pattern and the induced cortical activity. Our simulations in the absence of visual drive (simulated blindness) show that optogenetic stimulation with a spatial resolution as low as 100 [Formula: see text]m, and light intensity as weak as [Formula: see text] photons/s/cm[Formula: see text] is sufficient to evoke activity patterns in V1 close to those evoked by normal vision.
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Affiliation(s)
- Jan Antolik
- Faculty of Mathematics and Physics, Charles University, Malostranské nám. 25, 118 00, Prague 1, Czechia.
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012, Paris, France.
| | - Quentin Sabatier
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012, Paris, France
| | - Charlie Galle
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012, Paris, France
| | - Yves Frégnac
- Unité de Neurosciences, Information et Complexité (UNIC), NeuroPSI, Gif-sur-Yvette, France
| | - Ryad Benosman
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012, Paris, France
- University of Pittsburgh, McGowan Institute, 3025 E Carson St, Pittsburgh, PA, USA
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Lešták J. NEUROTRANSMISSION IN VISUAL ANALYZER AND BIONIC EYE. A REVIEW. CESKA A SLOVENSKA OFTALMOLOGIE : CASOPIS CESKE OFTALMOLOGICKE SPOLECNOSTI A SLOVENSKE OFTALMOLOGICKE SPOLECNOSTI 2021; 77:55-59. [PMID: 33985334 DOI: 10.31348/2020/28] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS The aim of the work is to point out the transmission of electrical voltage changes in the visual analyser and thus the efficiency of the bionic eye. MATERIAL AND METHODS The review deals with the question of the transmission of electrical changes in visual path voltage under physiological and pathological conditions. In particular, it points to feedback autoregulatory damage not only of primarily altered cellular structures, but of all other, both horizontally and vertically localized. Based on the results of functional magnetic resonance imaging and electrophysiological methods, it shows the pathology of the entire visual pathway in three eye diseases: retinitis pigmentosa, age-related macular degeneration and glaucoma. RESULTS The thesis also provides an overview of possible systems that are used to replace lost vision, from epiretinal, subretinal, suprachoroidal implants, through stimulation of the optic nerve, corpus geniculatum laterale to the visual cortex. CONCLUSION Due to the pathology of neurotransmission, bionic eye systems cannot be expected to be restored after stabilization of binocular functions.
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Gebrehiwot AN, Kato T, Nakazawa K. Inducing lateralized phosphenes over the occipital lobe using transcranial magnetic stimulation to navigate a virtual environment. PLoS One 2021; 16:e0249996. [PMID: 33852643 PMCID: PMC8046218 DOI: 10.1371/journal.pone.0249996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 03/29/2021] [Indexed: 11/19/2022] Open
Abstract
Electrical stimulation involving visual areas of the brain produces artificial light percepts called phosphenes. These visual percepts have been extensively investigated in previous studies involving intracortical microsimulation (ICMS) and serve as the basis for developing a visual prosthesis for the blind. Although advances have been achieved, many challenges still remain with implementing a functional ICMS for visual rehabilitation purposes. Transcranial magnetic stimulation (TMS) over the primary occipital lobe offers an alternative method to produce phosphenes non-invasively. A main challenge facing blind individuals involves navigation. Within the scientific community, methods to evaluate the ability of a visual prosthesis to facilitate in navigation has been neglected. In this study, we investigate the effectiveness of evoking lateralized phosphenes to navigate a computer simulated virtual environment. More importantly, we demonstrate how virtual environments along with the development of a visual prosthesis share a mutual relationship benefiting both patients and researchers. Using two TMS devices, a pair of 40mm figure-of-eight coils were placed over each occipital hemisphere resulting in lateralized phosphene perception. Participants were tasked with making a series of left and right turns using peripheral devices depending on the visual hemifield in which a phosphene is present. If a participant was able to accurately perceive all ten phosphenes, the simulated target is able to advance and fully exit the virtual environment. Our findings demonstrate that participants can interpret lateralized phosphenes while highlighting the integration of computer based virtual environments to evaluate the capability of a visual prosthesis during navigation.
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Affiliation(s)
| | - Tatsuya Kato
- Department of Life Sciences, The University of Tokyo, Tokyo, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Kimitaka Nakazawa
- Department of Life Sciences, The University of Tokyo, Tokyo, Japan
- * E-mail:
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Pio-Lopez L, Poulkouras R, Depannemaecker D. Visual cortical prosthesis: an electrical perspective. J Med Eng Technol 2021; 45:394-407. [PMID: 33843427 DOI: 10.1080/03091902.2021.1907468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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 have 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 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 analyse the results in electrode-based visual cortical prosthetics from the electrical point of view. We first 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 the 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.
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Affiliation(s)
| | - Romanos Poulkouras
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, Gardanne, France.,Institut de Neurosciences de la Timone, UMR 7289, CNRS, Aix-Marseille Université, Marseille, France
| | - Damien Depannemaecker
- Department of Integrative and Computational Neuroscience, Paris-Saclay Institute of Neuroscience, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
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Virtual Reality for Neurorehabilitation and Cognitive Enhancement. Brain Sci 2021; 11:brainsci11020221. [PMID: 33670277 PMCID: PMC7918687 DOI: 10.3390/brainsci11020221] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/23/2021] [Accepted: 02/06/2021] [Indexed: 02/06/2023] Open
Abstract
Our access to computer-generated worlds changes the way we feel, how we think, and how we solve problems. In this review, we explore the utility of different types of virtual reality, immersive or non-immersive, for providing controllable, safe environments that enable individual training, neurorehabilitation, or even replacement of lost functions. The neurobiological effects of virtual reality on neuronal plasticity have been shown to result in increased cortical gray matter volumes, higher concentration of electroencephalographic beta-waves, and enhanced cognitive performance. Clinical application of virtual reality is aided by innovative brain–computer interfaces, which allow direct tapping into the electric activity generated by different brain cortical areas for precise voluntary control of connected robotic devices. Virtual reality is also valuable to healthy individuals as a narrative medium for redesigning their individual stories in an integrative process of self-improvement and personal development. Future upgrades of virtual reality-based technologies promise to help humans transcend the limitations of their biological bodies and augment their capacity to mold physical reality to better meet the needs of a globalized world.
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Ptito M, Bleau M, Djerourou I, Paré S, Schneider FC, Chebat DR. Brain-Machine Interfaces to Assist the Blind. Front Hum Neurosci 2021; 15:638887. [PMID: 33633557 PMCID: PMC7901898 DOI: 10.3389/fnhum.2021.638887] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 01/19/2021] [Indexed: 12/31/2022] Open
Abstract
The loss or absence of vision is probably one of the most incapacitating events that can befall a human being. The importance of vision for humans is also reflected in brain anatomy as approximately one third of the human brain is devoted to vision. It is therefore unsurprising that throughout history many attempts have been undertaken to develop devices aiming at substituting for a missing visual capacity. In this review, we present two concepts that have been prevalent over the last two decades. The first concept is sensory substitution, which refers to the use of another sensory modality to perform a task that is normally primarily sub-served by the lost sense. The second concept is cross-modal plasticity, which occurs when loss of input in one sensory modality leads to reorganization in brain representation of other sensory modalities. Both phenomena are training-dependent. We also briefly describe the history of blindness from ancient times to modernity, and then proceed to address the means that have been used to help blind individuals, with an emphasis on modern technologies, invasive (various type of surgical implants) and non-invasive devices. With the advent of brain imaging, it has become possible to peer into the neural substrates of sensory substitution and highlight the magnitude of the plastic processes that lead to a rewired brain. Finally, we will address the important question of the value and practicality of the available technologies and future directions.
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Affiliation(s)
- Maurice Ptito
- École d’Optométrie, Université de Montréal, Montréal, QC, Canada
- Department of Nuclear Medicine, University of Southern Denmark, Odense, Denmark
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Maxime Bleau
- École d’Optométrie, Université de Montréal, Montréal, QC, Canada
| | - Ismaël Djerourou
- École d’Optométrie, Université de Montréal, Montréal, QC, Canada
| | - Samuel Paré
- École d’Optométrie, Université de Montréal, Montréal, QC, Canada
| | - Fabien C. Schneider
- TAPE EA7423 University of Lyon-Saint Etienne, Saint Etienne, France
- Neuroradiology Unit, University Hospital of Saint-Etienne, Saint-Etienne, France
| | - Daniel-Robert Chebat
- Visual and Cognitive Neuroscience Laboratory (VCN Lab), Department of Psychology, Faculty of Social Sciences and Humanities, Ariel University, Ariel, Israël
- Navigation and Accessibility Research Center of Ariel University (NARCA), Ariel, Israël
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41
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Beauchamp MS, Oswalt D, Sun P, Foster BL, Magnotti JF, Niketeghad S, Pouratian N, Bosking WH, Yoshor D. Dynamic Stimulation of Visual Cortex Produces Form Vision in Sighted and Blind Humans. Cell 2021; 181:774-783.e5. [PMID: 32413298 DOI: 10.1016/j.cell.2020.04.033] [Citation(s) in RCA: 107] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 09/27/2019] [Accepted: 04/17/2020] [Indexed: 11/28/2022]
Abstract
A visual cortical prosthesis (VCP) has long been proposed as a strategy for restoring useful vision to the blind, under the assumption that visual percepts of small spots of light produced with electrical stimulation of visual cortex (phosphenes) will combine into coherent percepts of visual forms, like pixels on a video screen. We tested an alternative strategy in which shapes were traced on the surface of visual cortex by stimulating electrodes in dynamic sequence. In both sighted and blind participants, dynamic stimulation enabled accurate recognition of letter shapes predicted by the brain's spatial map of the visual world. Forms were presented and recognized rapidly by blind participants, up to 86 forms per minute. These findings demonstrate that a brain prosthetic can produce coherent percepts of visual forms.
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Affiliation(s)
- Michael S Beauchamp
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA
| | - Denise Oswalt
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ping Sun
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA
| | - Brett L Foster
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA
| | - John F Magnotti
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA
| | - Soroush Niketeghad
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Nader Pouratian
- Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - William H Bosking
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA
| | - Daniel Yoshor
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA.
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Desroches PE, Silva SM, Gietman SW, Quigley AF, Kapsa RMI, Moulton SE, Greene GW. Lubricin (PRG4) Antiadhesive Coatings Mitigate Electrochemical Impedance Instabilities in Polypyrrole Bionic Electrodes Exposed to Fouling Fluids. ACS APPLIED BIO MATERIALS 2020; 3:8032-8039. [DOI: 10.1021/acsabm.0c01109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Pauline E. Desroches
- Institute for Frontier Materials and ARC Centre of Excellence for Electromaterials Science, Deakin University, Melbourne, Victoria 3216, Australia
- BioFab3D@ACMD, St Vincent’s Hospital Melbourne, Melbourne, Victoria 3065, Australia
| | - Saimon M. Silva
- ARC Centre of Excellence for Electromaterials Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
- BioFab3D@ACMD, St Vincent’s Hospital Melbourne, Melbourne, Victoria 3065, Australia
| | - Shaun W. Gietman
- ARC Centre of Excellence for Electromaterials Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
- BioFab3D@ACMD, St Vincent’s Hospital Melbourne, Melbourne, Victoria 3065, Australia
| | - Anita F. Quigley
- School of Electrical and Biomedical Engineering, RMIT University, Melbourne, Victoria 3001, Australia
- BioFab3D@ACMD, St Vincent’s Hospital Melbourne, Melbourne, Victoria 3065, Australia
| | - Robert M. I. Kapsa
- School of Electrical and Biomedical Engineering, RMIT University, Melbourne, Victoria 3001, Australia
- BioFab3D@ACMD, St Vincent’s Hospital Melbourne, Melbourne, Victoria 3065, Australia
| | - Simon E. Moulton
- ARC Centre of Excellence for Electromaterials Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
- Iverson Health Innovation Research Institute, Swinburne University of Technology, Victoria 3122, Australia
| | - George W. Greene
- Institute for Frontier Materials and ARC Centre of Excellence for Electromaterials Science, Deakin University, Melbourne, Victoria 3216, Australia
- ARC Centre of Excellence for Electromaterials Science, Faculty of Science, Engineering and Technology, Deakin University, Burwood, Victoria 3125, Australia
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Ryu SB, Paulk AC, Yang JC, Ganji M, Dayeh SA, Cash SS, Fried SI, Lee SW. Spatially confined responses of mouse visual cortex to intracortical magnetic stimulation from micro-coils. J Neural Eng 2020; 17:056036. [PMID: 32998116 PMCID: PMC8923513 DOI: 10.1088/1741-2552/abbd22] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Electrical stimulation via microelectrodes implanted in cortex has been suggested as a potential treatment for a wide range of neurological disorders. Despite some success however, the effectiveness of conventional electrodes remains limited, in part due to an inability to create specific patterns of neural activity around each electrode and in part due to challenges with maintaining a stable interface. The use of implantable micro-coils to magnetically stimulate the cortex has the potential to overcome these limitations because the asymmetric fields from coils can be harnessed to selectively activate some neurons, e.g. vertically-oriented pyramidal neurons while avoiding others, e.g. horizontally-oriented passing axons. In vitro experiments have shown that activation is indeed confined with micro-coils but their effectiveness in the intact brain of living animals has not been evaluated. APPROACH To assess the efficacy of stimulation, a 128-channel custom recording microelectrode array was positioned on the surface of the visual cortex (ECoG) in anesthetized mice and responses to magnetic and electric stimulation were compared. Stimulation was delivered from electrodes or micro-coils implanted through a hole in the center of the recording array at a rate of 200 pulses per second for 100 ms. MAIN RESULTS Both electric and magnetic stimulation reliably elicited cortical responses, although activation from electric stimulation was spatially expansive, often extending more than 1 mm from the stimulation site, while activation from magnetic stimulation was typically confined to a ∼300 µm diameter region around the stimulation site. Results were consistent for stimulation of both cortical layer 2/3 and layer 5 as well as across a range of stimulus strengths. SIGNIFICANCE The improved focality with magnetic stimulation suggests that the effectiveness of cortical stimulation can be improved. Improved focality may be particularly attractive for cortical prostheses that require high spatial resolution, e.g. devices that target sensory cortex, as it may lead to improved acuity.
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Affiliation(s)
- Sang Baek Ryu
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Angelique C. Paulk
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jimmy C. Yang
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Mehran Ganji
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Shadi A. Dayeh
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA
| | - Sydney S. Cash
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Shelley I. Fried
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Boston VA Healthcare System, Boston, MA, USA
| | - Seung Woo Lee
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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Hou Z, Al-Atabany W, Farag R, Vuong QC, Mokhov A, Degenaar P. A scalable data transmission scheme for implantable optogenetic visual prostheses. J Neural Eng 2020; 17:055001. [DOI: 10.1088/1741-2552/abaf2e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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45
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Neural implant for the treatment of multiple sclerosis. Med Hypotheses 2020; 145:110324. [PMID: 33038587 DOI: 10.1016/j.mehy.2020.110324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/06/2020] [Accepted: 09/26/2020] [Indexed: 11/20/2022]
Abstract
The methods used to treat various neurological diseases are evolving. The facilities provided by the technology have led to creation of new treatment opportunities. Neuromodulation is one of these important methods. By definition, the neuromodulation is a change in neural activity which occurs by stimulating a specific area of nervous system. The mentioned stimulation can be electrical, magnetic, or chemical. This method is used in various diseases, such as stroke, Parkinson's, Alzheimer's, and amyotrophic lateral sclerosis (ALS). Multiple sclerosis (MS) is no exception in this regard and methods including the neurofeedback and transcranial magnetic stimulation (TMS) are used to treat various complications of the MS. One aspect of neuromodulation is the use of neural implant, which is applied nowadays, especially in the Parkinson's disease, and the use of microchips and prostheses to treat various symptoms in different neurological diseases has received significant attention. Although neural implant has been exploited to improve the symptoms of MS, they appear to have much greater potential to improve the condition of patients with MS. It seems that more attention to the symptoms of MS, on the one hand, and a new approach to the pathogenesis of this disease and considering it as a connectomopathy, on the other hand, can provide new opportunities for application of this method in the treatment of MS.
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French P. In-Vivo Microsystems: A Review. SENSORS (BASEL, SWITZERLAND) 2020; 20:E4953. [PMID: 32883011 PMCID: PMC7506850 DOI: 10.3390/s20174953] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 12/25/2022]
Abstract
In-vivo sensors yield valuable medical information by measuring directly on the living tissue of a patient. These devices can be surface or implant devices. Electrical activity in the body, from organs or muscles can be measured using surface electrodes. For short term internal devices, catheters are used. These include cardiac catheter (in blood vessels) and bladder catheters. Due to the size and shape of the catheters, silicon devices provided an excellent solution for sensors. Since many cardiac catheters are disposable, the high volume has led to lower prices of the silicon sensors. Many catheters use a single sensor, but silicon offers the opportunity to have multi sensors in a single catheter, while maintaining small size. The cardiac catheter is usually inserted for a maximum of 72 h. Some devices may be used for a short-to-medium period to monitor parameters after an operation or injury (1-4 weeks). Increasingly, sensing, and actuating, devices are being applied to longer term implants for monitoring a range of parameters for chronic conditions. Devices for longer term implantation presented additional challenges due to the harshness of the environment and the stricter regulations for biocompatibility and safety. This paper will examine the three main areas of application for in-vivo devices: surface devices and short/medium-term and long-term implants. The issues of biocompatibility and safety will be discussed.
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Affiliation(s)
- Paddy French
- Laboratory for Bioelectronics, Faculty of Electrical Engineering, Mathematics and Computer Science, TU Delft, Mekelweg 4, 2628CD Delft, The Netherlands
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Fernández E, Alfaro A, González-López P. Toward Long-Term Communication With the Brain in the Blind by Intracortical Stimulation: Challenges and Future Prospects. Front Neurosci 2020; 14:681. [PMID: 32848535 PMCID: PMC7431631 DOI: 10.3389/fnins.2020.00681] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 06/03/2020] [Indexed: 11/15/2022] Open
Abstract
The restoration of a useful visual sense in a profoundly blind person by direct electrical stimulation of the visual cortex has been a subject of study for many years. However, the field of cortically based sight restoration has made few advances in the last few decades, and many problems remain. In this context, the scientific and technological problems associated with safe and effective communication with the brain are very complex, and there are still many unresolved issues delaying its development. In this work, we review some of the biological and technical issues that still remain to be solved, including long-term biotolerability, the number of electrodes required to provide useful vision, and the delivery of information to the implants. Furthermore, we emphasize the possible role of the neuroplastic changes that follow vision loss in the success of this approach. We propose that increased collaborations among clinicians, basic researchers, and neural engineers will enhance our ability to send meaningful information to the brain and restore a limited but useful sense of vision to many blind individuals.
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Affiliation(s)
- Eduardo Fernández
- Institute of Bioengineering, Universidad Miguel Hernández, Elche, Spain
- Center for Biomedical Research in the Network in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, United States
| | - Arantxa Alfaro
- Center for Biomedical Research in the Network in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
- Hospital Vega Baja, Orihuela, Spain
| | - Pablo González-López
- Institute of Bioengineering, Universidad Miguel Hernández, Elche, Spain
- Hospital General Universitario de Alicante, Alicante, Spain
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Abouelseoud G, Abouelseoud Y, Shoukry A, Ismail N, Mekky J. On the use of time division multiplexing to improve electrical brain stimulation focality. Biomed Signal Process Control 2020. [DOI: 10.1016/j.bspc.2020.102048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lozano A, Suárez JS, Soto-Sánchez C, Garrigós J, Martínez-Alvarez JJ, Ferrández JM, Fernández E. Neurolight: A Deep Learning Neural Interface for Cortical Visual Prostheses. Int J Neural Syst 2020; 30:2050045. [DOI: 10.1142/s0129065720500458] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Visual neuroprosthesis, that provide electrical stimulation along several sites of the human visual system, constitute a potential tool for vision restoration for the blind. Scientific and technological progress in the fields of neural engineering and artificial vision comes with new theories and tools that, along with the dawn of modern artificial intelligence, constitute a promising framework for the further development of neurotechnology. In the framework of the development of a Cortical Visual Neuroprosthesis for the blind (CORTIVIS), we are now facing the challenge of developing not only computationally powerful tools and flexible approaches that will allow us to provide some degree of functional vision to individuals who are profoundly blind. In this work, we propose a general neuroprosthesis framework composed of several task-oriented and visual encoding modules. We address the development and implementation of computational models of the firing rates of retinal ganglion cells and design a tool — Neurolight — that allows these models to be interfaced with intracortical microelectrodes in order to create electrical stimulation patterns that can evoke useful perceptions. In addition, the developed framework allows the deployment of a diverse array of state-of-the-art deep-learning techniques for task-oriented and general image pre-processing, such as semantic segmentation and object detection in our system’s pipeline. To the best of our knowledge, this constitutes the first deep-learning-based system designed to directly interface with the visual brain through an intracortical microelectrode array. We implement the complete pipeline, from obtaining a video stream to developing and deploying task-oriented deep-learning models and predictive models of retinal ganglion cells’ encoding of visual inputs under the control of a neurostimulation device able to send electrical train pulses to a microelectrode array implanted at the visual cortex.
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Affiliation(s)
- Antonio Lozano
- Departamento de Electrónica, Tecnología de Computadoras y Proyectos, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain
| | - Juan Sebastián Suárez
- Instituto de Bioingeniería, Universidad Miguel Hernández, 03202 Alicante, Spain
- CIBER-BBN, 28029 Madrid, Spain
| | - Cristina Soto-Sánchez
- Instituto de Bioingeniería, Universidad Miguel Hernández, 03202 Alicante, Spain
- CIBER-BBN, 28029 Madrid, Spain
| | - Javier Garrigós
- Departamento de Electrónica, Tecnología de Computadoras y Proyectos, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain
| | - J. Javier Martínez-Alvarez
- Departamento de Electrónica, Tecnología de Computadoras y Proyectos, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain
| | - J. Manuel Ferrández
- Departamento de Electrónica, Tecnología de Computadoras y Proyectos, Universidad Politécnica de Cartagena, 30202 Cartagena, Spain
| | - Eduardo Fernández
- Instituto de Bioingeniería, Universidad Miguel Hernández, 03202 Alicante, Spain
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50
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Kvansakul J, Hamilton L, Ayton LN, McCarthy C, Petoe MA. Sensory augmentation to aid training with retinal prostheses. J Neural Eng 2020; 17:045001. [PMID: 32554868 DOI: 10.1088/1741-2552/ab9e1d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Retinal prosthesis recipients require rehabilitative training to learn the non-intuitive nature of prosthetic 'phosphene vision'. This study investigated whether the addition of auditory cues, using The vOICe sensory substitution device (SSD), could improve functional performance with simulated phosphene vision. APPROACH Forty normally sighted subjects completed two visual tasks under three conditions. The phosphene condition converted the image to simulated phosphenes displayed on a virtual reality headset. The SSD condition provided auditory information via stereo headphones, translating the image into sound. Horizontal information was encoded as stereo timing differences between ears, vertical information as pitch, and pixel intensity as audio intensity. The third condition combined phosphenes and SSD. Tasks comprised light localisation from the Basic Assessment of Light and Motion (BaLM) and the Tumbling-E from the Freiburg Acuity and Contrast Test (FrACT). To examine learning effects, twenty of the forty subjects received SSD training prior to assessment. MAIN RESULTS Combining phosphenes with auditory SSD provided better light localisation accuracy than either phosphenes or SSD alone, suggesting a compound benefit of integrating modalities. Although response times for SSD-only were significantly longer than all other conditions, combined condition response times were as fast as phosphene-only, highlighting that audio-visual integration provided both response time and accuracy benefits. Prior SSD training provided a benefit to localisation accuracy and speed in SSD-only (as expected) and Combined conditions compared to untrained SSD-only. Integration of the two modalities did not improve spatial resolution task performance, with resolution limited to that of the higher resolution modality (SSD). SIGNIFICANCE Combining phosphene (visual) and SSD (auditory) modalities was effective even without SSD training and led to an improvement in light localisation accuracy and response times. Spatial resolution performance was dominated by auditory SSD. The results suggest there may be a benefit to including auditory cues when training vision prosthesis recipients.
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Affiliation(s)
- Jessica Kvansakul
- Bionics Institute, East Melbourne, VIC, Australia. Department of Medical Bionics, University of Melbourne, Parkville, VIC, Australia
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