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Zuk P. Mental integrity, autonomy, and fundamental interests. JOURNAL OF MEDICAL ETHICS 2024:jme-2023-109732. [PMID: 39137962 DOI: 10.1136/jme-2023-109732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 04/25/2024] [Indexed: 08/15/2024]
Abstract
Many technology ethicists hold that the time has come to articulate neurorights: our normative claims vis-à-vis our brains and minds. One such claim is the right to mental integrity ('MI'). I begin by considering some paradigmatic threats to MI (§1) and how the dominant autonomy-based conception ('ABC') of MI attempts to make sense of them (§2). I next consider the objection that the ABC is overbroad in its understanding of what threatens MI and suggest a friendly revision to the ABC that addresses the objection (§3). I then consider a second objection: that the ABC cannot make sense of the MI of the non-autonomous This objection appears fatal even to the revised ABC (§4). On that basis, I develop an alternative conception on which MI is grounded in a plurality of simpler capacities, namely, those for affect, cognition, and volition Each of these more basic capacities grounds a set of fundamental interests, and they are for that reason worthy of protection even when they do not rise to the level of complexity necessary for autonomy (§5). This yields a fully general theory of MI that accounts for its manifestations in both the autonomous and the non-autonomous.
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Affiliation(s)
- Peter Zuk
- Center for Bioethics, Harvard Medical School, Boston, Massachusetts, USA
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2
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Levy L, Ebadi H, Smith AP, Taiclet L, Pouratian N, Feinsinger A. Disentangling Function from Benefit: Participant Perspectives from an Early Feasibility Trial for a Novel Visual Cortical Prosthesis. AJOB Neurosci 2024; 15:158-176. [PMID: 37812142 PMCID: PMC11001790 DOI: 10.1080/21507740.2023.2257152] [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] [Indexed: 10/10/2023]
Abstract
Visual cortical prostheses (VCPs) have the potential to provide artificial vision for visually impaired persons. However, the nature and utility of this form of vision is not yet fully understood. Participants in the early feasibility trial for the Orion VCP were interviewed to gain insight into their experiences using artificial vision, their motivations for participation, as well as their expectations and assessments of risks and benefits. Analyzed using principles of grounded theory and an interpretive description approach, these interviews yielded six themes, including: the irreducibility of benefit to device functionality, mixed expectations for short-term device functionality and long-term technological advancement of visual prostheses, and a broad range of risks, concerns, and fears related to trial participation. We argue that these narratives motivate a nuanced set of ethical considerations related to the complex relationship between functionality and benefit, the intersection of user experience with disability justice, and the import of expectations and indirect risks on consent.
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Affiliation(s)
- Lilyana Levy
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Hamasa Ebadi
- Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Ally Peabody Smith
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Lauren Taiclet
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Nader Pouratian
- Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Ashley Feinsinger
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
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Stiles NRB, Choupan J, Ameri H, Patel VR, Shi Y. Visual Cortical Thickness Increases with Prolonged Artificial Vision Restoration. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.06.26.24309493. [PMID: 38978654 PMCID: PMC11230327 DOI: 10.1101/2024.06.26.24309493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
The Argus II retinal prosthesis restores visual perception to late blind patients. It has been shown that structural changes occur in the brain due to late-onset blindness, including cortical thinning in visual regions of the brain. Following vision restoration, it is not yet known whether these visual regions are reinvigorated and regain a normal cortical thickness or retain the diminished thickness from blindness. We evaluated the cortical thicknesses of ten Argus II Retinal Prostheses patients, ten blind patients, and thirteen sighted participants. The Argus II patients on average had a thicker left Cuneus Cortex and Lateral Occipital Cortex relative to the blind patients. The duration of the Argus II use (time since implant in active users) significantly partially correlated with thicker visual cortical regions in the left hemisphere. Furthermore, in the two case studies (scanned before and after implantation), the patient with longer device use (44.5 months) had an increase in the cortical thickness of visual regions, whereas the shorter-using patient did not (6.5 months). Finally, a third case, scanned at three time points post-implantation, showed an increase in cortical thickness in the Lateral Occipital Cortex between 43.5 and 57 months, which was maintained even after 3 years of disuse (106 months). Overall, the Argus II patients' cortical thickness was on average significantly rejuvenated in two higher visual regions and, patients using the implant for a longer duration had thicker visual regions. This research raises the possibility of structural plasticity reversing visual cortical atrophy in late-blind patients with prolonged vision restoration.
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Zhang B, Zhang R, Zhao J, Yang J, Xu S. The mechanism of human color vision and potential implanted devices for artificial color vision. Front Neurosci 2024; 18:1408087. [PMID: 38962178 PMCID: PMC11221215 DOI: 10.3389/fnins.2024.1408087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 05/31/2024] [Indexed: 07/05/2024] Open
Abstract
Vision plays a major role in perceiving external stimuli and information in our daily lives. The neural mechanism of color vision is complicated, involving the co-ordinated functions of a variety of cells, such as retinal cells and lateral geniculate nucleus cells, as well as multiple levels of the visual cortex. In this work, we reviewed the history of experimental and theoretical studies on this issue, from the fundamental functions of the individual cells of the visual system to the coding in the transmission of neural signals and sophisticated brain processes at different levels. We discuss various hypotheses, models, and theories related to the color vision mechanism and present some suggestions for developing novel implanted devices that may help restore color vision in visually impaired people or introduce artificial color vision to those who need it.
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Affiliation(s)
- Bingao Zhang
- Key Laboratory for the Physics and Chemistry of Nanodevices, Institute of Physical Electronics, Department of Electronics, Peking University, Beijing, China
| | - Rong Zhang
- Key Laboratory for the Physics and Chemistry of Nanodevices, Institute of Physical Electronics, Department of Electronics, Peking University, Beijing, China
| | - Jingjin Zhao
- Key Laboratory for the Physics and Chemistry of Nanodevices, Institute of Physical Electronics, Department of Electronics, Peking University, Beijing, China
| | - Jiarui Yang
- Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Department of Ophthalmology, Peking University Third Hospital, Beijing, China
| | - Shengyong Xu
- Key Laboratory for the Physics and Chemistry of Nanodevices, Institute of Physical Electronics, Department of Electronics, Peking University, Beijing, China
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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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Várkuti B, Halász L, Hagh Gooie S, Miklós G, Smits Serena R, van Elswijk G, McIntyre CC, Lempka SF, Lozano AM, Erōss L. Conversion of a medical implant into a versatile computer-brain interface. Brain Stimul 2024; 17:39-48. [PMID: 38145752 DOI: 10.1016/j.brs.2023.12.011] [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: 10/13/2023] [Revised: 12/19/2023] [Accepted: 12/20/2023] [Indexed: 12/27/2023] Open
Abstract
BACKGROUND Information transmission into the human nervous system is the basis for a variety of prosthetic applications. Spinal cord stimulation (SCS) systems are widely available, have a well documented safety record, can be implanted minimally invasively, and are known to stimulate afferent pathways. Nonetheless, SCS devices are not yet used for computer-brain-interfacing applications. OBJECTIVE Here we aimed to establish computer-to-brain communication via medical SCS implants in a group of 20 individuals who had been operated for the treatment of chronic neuropathic pain. METHODS In the initial phase, we conducted interface calibration with the aim of determining personalized stimulation settings that yielded distinct and reproducible sensations. These settings were subsequently utilized to generate inputs for a range of behavioral tasks. We evaluated the required calibration time, task training duration, and the subsequent performance in each task. RESULTS We could establish a stable spinal computer-brain interface in 18 of the 20 participants. Each of the 18 then performed one or more of the following tasks: A rhythm-discrimination task (n = 13), a Morse-decoding task (n = 3), and/or two different balance/body-posture tasks (n = 18; n = 5). The median calibration time was 79 min. The median training time for learning to use the interface in a subsequent task was 1:40 min. In each task, every participant demonstrated successful performance, surpassing chance levels. CONCLUSION The results constitute the first proof-of-concept of a general purpose computer-brain interface paradigm that could be deployed on present-day medical SCS platforms.
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Affiliation(s)
| | - László Halász
- Albert-Szentgyörgyi Medical School, Doctoral School of Clinical Medicine, Clinical and Experimental Research for Reconstructive and Organ-Sparing Surgery, University of Szeged, Szeged, Hungary
| | | | - Gabriella Miklós
- CereGate GmbH, München, Germany; National Institute of Mental Health, Neurology, and Neurosurgery, Budapest, Hungary; János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Ricardo Smits Serena
- CereGate GmbH, München, Germany; Department of Orthopaedics and Sports Orthopaedics, Klinikum Rechts der Isar, Technical University of Munich, München, Germany
| | | | - Cameron C McIntyre
- Department of Biomedical Engineering and Department of Neurosurgery, Duke University, Durham, NC, USA
| | - Scott F Lempka
- Department of Biomedical Engineering, Department of Anesthesiology and the Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Andres M Lozano
- Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Loránd Erōss
- National Institute of Mental Health, Neurology, and Neurosurgery, Budapest, Hungary
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Zueva MV, Neroeva NV, Zhuravleva AN, Bogolepova AN, Kotelin VV, Fadeev DV, Tsapenko IV. Fractal Phototherapy in Maximizing Retina and Brain Plasticity. ADVANCES IN NEUROBIOLOGY 2024; 36:585-637. [PMID: 38468055 DOI: 10.1007/978-3-031-47606-8_31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
The neuroplasticity potential is reduced with aging and impairs during neurodegenerative diseases and brain and visual system injuries. This limits the brain's capacity to repair the structure and dynamics of its activity after lesions. Maximization of neuroplasticity is necessary to provide the maximal CNS response to therapeutic intervention and adaptive reorganization of neuronal networks in patients with degenerative pathology and traumatic injury to restore the functional activity of the brain and retina.Considering the fractal geometry and dynamics of the healthy brain and the loss of fractality in neurodegenerative pathology, we suggest that the application of self-similar visual signals with a fractal temporal structure in the stimulation therapy can reactivate the adaptive neuroplasticity and enhance the effectiveness of neurorehabilitation. This proposition was tested in the recent studies. Patients with glaucoma had a statistically significant positive effect of fractal photic therapy on light sensitivity and the perimetric MD index, which shows that methods of fractal stimulation can be a novel nonpharmacological approach to neuroprotective therapy and neurorehabilitation. In healthy rabbits, it was demonstrated that a long-term course of photostimulation with fractal signals does not harm the electroretinogram (ERG) and retina structure. Rabbits with modeled retinal atrophy showed better dynamics of the ERG restoration during daily stimulation therapy for a week in comparison with the controls. Positive changes in the retinal function can indirectly suggest the activation of its adaptive plasticity and the high potential of stimulation therapy with fractal visual stimuli in a nonpharmacological neurorehabilitation, which requires further study.
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Affiliation(s)
- Marina V Zueva
- Department of Clinical Physiology of Vision, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Natalia V Neroeva
- Department of Pathology of the Retina and Optic Nerve, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Anastasia N Zhuravleva
- Department of Glaucoma, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Anna N Bogolepova
- Department of neurology, neurosurgery and medical genetics, Pirogov Russian National Research Medical University, Moscow, Russia
| | - Vladislav V Kotelin
- Department of Clinical Physiology of Vision, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Denis V Fadeev
- Scientific Experimental Center Department, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Irina V Tsapenko
- Department of Clinical Physiology of Vision, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
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Sharif NA. Electrical, Electromagnetic, Ultrasound Wave Therapies, and Electronic Implants for Neuronal Rejuvenation, Neuroprotection, Axonal Regeneration, and IOP Reduction. J Ocul Pharmacol Ther 2023; 39:477-498. [PMID: 36126293 DOI: 10.1089/jop.2022.0046] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The peripheral nervous system (PNS) of mammals and nervous systems of lower organisms possess significant regenerative potential. In contrast, although neural plasticity can provide some compensation, the central nervous system (CNS) neurons and nerves of adult mammals generally fail to regenerate after an injury or damage. However, use of diverse electrical, electromagnetic and sonographic energy waves are illuminating novel ways to stimulate neuronal differentiation, proliferation, neurite growth, and axonal elongation/regeneration leading to various levels of functional recovery in animals and humans afflicted with disorders of the CNS, PNS, retina, and optic nerve. Tools such as acupuncture, electroacupuncture, electroshock therapy, electrical stimulation, transcranial magnetic stimulation, red light therapy, and low-intensity pulsed ultrasound therapy are demonstrating efficacy in treating many different maladies. These include wound healing, partial recovery from motor dysfunctions, recovery from ischemic/reperfusion insults and CNS and ocular remyelination, retinal ganglion cell (RGC) rejuvenation, and RGC axonal regeneration. Neural rejuvenation and axonal growth/regeneration processes involve activation or intensifying of the intrinsic bioelectric waves (action potentials) that exist in every neuronal circuit of the body. In addition, reparative factors released at the nerve terminals and via neuronal dendrites (transmitter substances), extracellular vesicles containing microRNAs and neurotrophins, and intercellular communication occurring via nanotubes aid in reestablishing lost or damaged connections between the traumatized tissues and the PNS and CNS. Many other beneficial effects of the aforementioned treatment paradigms are mediated via gene expression alterations such as downregulation of inflammatory and death-signal genes and upregulation of neuroprotective and cytoprotective genes. These varied techniques and technologies will be described and discussed covering cell-based and animal model-based studies. Data from clinical applications and linkage to human ocular diseases will also be discussed where relevant translational research has been reported.
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Affiliation(s)
- Najam A Sharif
- Global Alliances and External Research, Ophthalmology Innovation Center, Santen Inc., Emeryville, California, USA
- Singapore Eye Research Institute (SERI), Singapore
- SingHealth Duke-NUS Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-National University of Singapore Medical School, Singapore
- Department of Surgery and Cancer, Imperial College of Science and Technology, London, United Kingdom
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Texas Southern University, Houston, Texas, USA
- Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center, Fort Worth, Texas, USA
- Department of Pharmacy Sciences, Creighton University, Omaha, Nebraska, USA
- Insitute of Ophthalmology, University College London (UCL), London, United Kingdom
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Wang J, Zou L, Jiang X, Wang D, Mao L, Yang X. Visual stimulation rehabilitation for cortical blindness after vertebral artery interventional surgery: A case report and literature review. Int J Surg Case Rep 2023; 110:108753. [PMID: 37651808 PMCID: PMC10509878 DOI: 10.1016/j.ijscr.2023.108753] [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: 07/28/2023] [Revised: 08/24/2023] [Accepted: 08/25/2023] [Indexed: 09/02/2023] Open
Abstract
INTRODUCTION AND IMPORTANCE Cortical blindness (CB) after vertebral artery interventional surgery is not a frequently reported complication. In this study, the efficacy of visual stimulation rehabilitation consisting of visual recovery training and repetitive transcranial magnetic stimulation (rTMS) for cortical blindness was investigated by clinical evaluation, ophthalmologic examination, and electroencephalography (EEG). CASE PRESENTATION This study reports on a 55-year-old male who showed partial bilateral posterior cerebral artery cortical branch occlusion after timely embolectomy due to thrombus dislodgement during right vertebral artery opening, stenting resulting in basilar artery tip occlusion. The lesions were mainly located in the right cerebellar hemisphere and bilateral occipital lobes, and the patient suffered from bilateral loss of vision, with only light perception preserved. The patient began to receive visual recovery training and 15 sessions of right occipital high-frequency transcranial magnetic stimulation 5 days after the onset. CLINICAL DISCUSSION After treatment, the patient's capacity to identify things improved, allowing him to watch television, as did the precision and fluency of random hand movements, walking, and self-care. CONCLUSION Visual stimulation rehabilitation composed of visual recovery training and rTMS is a promising therapy option for cortical blindness, and our case report provides clinical experience with vision recovery for patients with cortical blindness.
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Affiliation(s)
- Juehan Wang
- Department of Rehabilitation Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Liliang Zou
- Department of Rehabilitation Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaorui Jiang
- Department of Rehabilitation Medicine, The First People's Hospital of Yuhang District, Hangzhou, China
| | - Daming Wang
- Department of Rehabilitation Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lin Mao
- Department of Rehabilitation Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
| | - Xiaofeng Yang
- Emergency and Trauma Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
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Chew LA, Iannaccone A. Gene-agnostic approaches to treating inherited retinal degenerations. Front Cell Dev Biol 2023; 11:1177838. [PMID: 37123404 PMCID: PMC10133473 DOI: 10.3389/fcell.2023.1177838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 03/31/2023] [Indexed: 05/02/2023] Open
Abstract
Most patients with inherited retinal degenerations (IRDs) have been waiting for treatments that are "just around the corner" for decades, with only a handful of seminal breakthroughs happening in recent years. Highlighting the difficulties in the quest for curative therapeutics, Luxturna required 16 years of development before finally obtaining United States Food and Drug Administration (FDA) approval and its international equivalents. IRDs are both genetically and phenotypically heterogeneous. While this diversity offers many opportunities for gene-by-gene precision medicine-based approaches, it also poses a significant challenge. For this reason, alternative (or parallel) strategies to identify more comprehensive, across-the-board therapeutics for the genetically and phenotypically diverse IRD patient population are very appealing. Even when gene-specific approaches may be available and become approved for use, many patients may have reached a disease stage whereby these approaches may no longer be viable. Thus, alternate visual preservation or restoration therapeutic approaches are needed at these stages. In this review, we underscore several gene-agnostic approaches that are being developed as therapeutics for IRDs. From retinal supplementation to stem cell transplantation, optogenetic therapy and retinal prosthetics, these strategies would bypass at least in part the need for treating every individual gene or mutation or provide an invaluable complement to them. By considering the diverse patient population and treatment strategies suited for different stages and patterns of retinal degeneration, gene agnostic approaches are very well poised to impact favorably outcomes and prognosis for IRD patients.
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Affiliation(s)
- Lindsey A. Chew
- Duke Center for Retinal Degenerations and Ophthalmic Genetic Diseases, Department of Ophthalmology, Duke Eye Center, Duke University School of Medicine, Durham, NC, United States
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, United States
| | - Alessandro Iannaccone
- Duke Center for Retinal Degenerations and Ophthalmic Genetic Diseases, Department of Ophthalmology, Duke Eye Center, Duke University School of Medicine, Durham, NC, United States
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11
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Paré S, Bleau M, Dricot L, Ptito M, Kupers R. Brain structural changes in blindness: a systematic review and an anatomical likelihood estimation (ALE) meta-analysis. Neurosci Biobehav Rev 2023; 150:105165. [PMID: 37054803 DOI: 10.1016/j.neubiorev.2023.105165] [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: 09/22/2022] [Revised: 03/23/2023] [Accepted: 04/09/2023] [Indexed: 04/15/2023]
Abstract
In recent decades, numerous structural brain imaging studies investigated purported morphometric changes in early (EB) and late onset blindness (LB). The results of these studies have not yielded very consistent results, neither with respect to the type, nor to the anatomical locations of the brain morphometric alterations. To better characterize the effects of blindness on brain morphometry, we performed a systematic review and an Anatomical-Likelihood-Estimation (ALE) coordinate-based-meta-analysis of 65 eligible studies on brain structural changes in EB and LB, including 890 EB, 466 LB and 1257 sighted controls. Results revealed atrophic changes throughout the whole extent of the retino-geniculo-striate system in both EB and LB, whereas changes in areas beyond the occipital lobe occurred in EB only. We discuss the nature of some of the contradictory findings with respect to the used brain imaging methodologies and characteristics of the blind populations such as the onset, duration and cause of blindness. Future studies should aim for much larger sample sizes, eventually by merging data from different brain imaging centers using the same imaging sequences, opt for multimodal structural brain imaging, and go beyond a purely structural approach by combining functional with structural connectivity network analyses.
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Affiliation(s)
- Samuel Paré
- School of Optometry, University of Montreal, Montreal, Qc, Canada
| | - Maxime Bleau
- School of Optometry, University of Montreal, Montreal, Qc, Canada
| | - Laurence Dricot
- Institute of NeuroScience (IoNS), Université catholique de Louvain (UCLouvain), Bruxelles, Belgium
| | - Maurice Ptito
- School of Optometry, University of Montreal, Montreal, Qc, Canada; Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Qc, Canada; Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Ron Kupers
- School of Optometry, University of Montreal, Montreal, Qc, Canada; Institute of NeuroScience (IoNS), Université catholique de Louvain (UCLouvain), Bruxelles, Belgium; Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark.
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12
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Cehajic-Kapetanovic J, Singh MS, Zrenner E, MacLaren RE. Bioengineering strategies for restoring vision. Nat Biomed Eng 2023; 7:387-404. [PMID: 35102278 DOI: 10.1038/s41551-021-00836-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 11/30/2021] [Indexed: 12/15/2022]
Abstract
Late-stage retinal degenerative disease involving photoreceptor loss can be treated by optogenetic therapy, cell transplantation and retinal prostheses. These approaches aim to restore light sensitivity to the retina as well as visual perception by integrating neuronal responses for transmission to the cortex. In age-related macular degeneration, some cell-based therapies also aim to restore photoreceptor-supporting tissue to prevent complete photoreceptor loss. In the earlier stages of degeneration, gene-replacement therapy could attenuate retinal-disease progression and reverse loss of function. And gene-editing strategies aim to correct the underlying genetic defects. In this Review, we highlight the most promising gene therapies, cell therapies and retinal prostheses for the treatment of retinal disease, discuss the benefits and drawbacks of each treatment strategy and the factors influencing whether functional tissue is reconstructed and repaired or replaced with an electronic device, and summarize upcoming technologies for enhancing the restoration of vision.
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Affiliation(s)
- Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK.
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
| | | | - Eberhart Zrenner
- Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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13
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Bergeron D, Iorio-Morin C, Bonizzato M, Lajoie G, Orr Gaucher N, Racine É, Weil AG. Use of Invasive Brain-Computer Interfaces in Pediatric Neurosurgery: Technical and Ethical Considerations. J Child Neurol 2023; 38:223-238. [PMID: 37116888 PMCID: PMC10226009 DOI: 10.1177/08830738231167736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 02/11/2023] [Accepted: 03/17/2023] [Indexed: 04/30/2023]
Abstract
Invasive brain-computer interfaces hold promise to alleviate disabilities in individuals with neurologic injury, with fully implantable brain-computer interface systems expected to reach the clinic in the upcoming decade. Children with severe neurologic disabilities, like quadriplegic cerebral palsy or cervical spine trauma, could benefit from this technology. However, they have been excluded from clinical trials of intracortical brain-computer interface to date. In this manuscript, we discuss the ethical considerations related to the use of invasive brain-computer interface in children with severe neurologic disabilities. We first review the technical hardware and software considerations for the application of intracortical brain-computer interface in children. We then discuss ethical issues related to motor brain-computer interface use in pediatric neurosurgery. Finally, based on the input of a multidisciplinary panel of experts in fields related to brain-computer interface (functional and restorative neurosurgery, pediatric neurosurgery, mathematics and artificial intelligence research, neuroengineering, pediatric ethics, and pragmatic ethics), we then formulate initial recommendations regarding the clinical use of invasive brain-computer interfaces in children.
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Affiliation(s)
- David Bergeron
- Division of Neurosurgery, Université de Montréal, Montreal, Québec, Canada
| | | | - Marco Bonizzato
- Electrical Engineering Department, Polytechnique Montréal, Montreal, Québec, Canada
- Neuroscience Department and Centre
interdisciplinaire de recherche sur le cerveau et l’apprentissage (CIRCA), Université de Montréal, Montréal, Québec, Canada
| | - Guillaume Lajoie
- Mathematics and Statistics Department, Université de Montréal, Montreal, Québec, Canada
- Mila - Québec AI Institute, Montréal,
Québec, Canada
| | - Nathalie Orr Gaucher
- Department of Pediatric Emergency
Medicine, CHU Sainte-Justine, Montréal, Québec, Canada
- Bureau de l’Éthique clinique, Faculté
de médecine de l’Université de Montréal, Montreal, Québec, Canada
| | - Éric Racine
- Pragmatic Research Unit, Institute de
Recherche Clinique de Montréal (IRCM), Montreal, Québec, Canada
- Department of Medicine and Department
of Social and Preventative Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Alexander G. Weil
- Division of Neurosurgery, Department
of Surgery, Centre Hospitalier Universitaire Sainte-Justine (CHUSJ), Département de
Pédiatrie, Université de Montréal, Montreal, Québec, Canada
- Department of Neuroscience, Université de Montréal, Montréal, Québec, Canada
- Brain and Development Research Axis,
CHU Sainte-Justine Research Center, Montréal, Québec, Canada
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14
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Spencer M, Kameneva T, Grayden DB, Burkitt AN, Meffin H. Quantifying visual acuity for pre-clinical testing of visual prostheses. J Neural Eng 2023; 20. [PMID: 36270430 DOI: 10.1088/1741-2552/ac9c95] [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: 05/26/2022] [Accepted: 10/21/2022] [Indexed: 01/31/2023]
Abstract
Objective.Visual prostheses currently restore only limited vision. More research and pre-clinical work are required to improve the devices and stimulation strategies that are used to induce neural activity that results in visual perception. Evaluation of candidate strategies and devices requires an objective way to convert measured and modelled patterns of neural activity into a quantitative measure of visual acuity.Approach.This study presents an approach that compares evoked patterns of neural activation with target and reference patterns. A d-prime measure of discriminability determines whether the evoked neural activation pattern is sufficient to discriminate between the target and reference patterns and thus provides a quantified level of visual perception in the clinical Snellen and MAR scales. The magnitude of the resulting value was demonstrated using scaled standardized 'C' and 'E' optotypes.Main results.The approach was used to assess the visual acuity provided by two alternative stimulation strategies applied to simulated retinal implants with different electrode pitch configurations and differently sized spreads of neural activity. It was found that when there is substantial overlap in neural activity generated by different electrodes, an estimate of acuity based only upon electrode pitch is incorrect; our proposed method gives an accurate result in both circumstances.Significance.Quantification of visual acuity using this approach in pre-clinical development will allow for more rapid and accurate prototyping of improved devices and neural stimulation strategies.
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Affiliation(s)
- Martin Spencer
- Department of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia.,Greame Clark Institute of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Tatiana Kameneva
- Department of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia.,School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - David B Grayden
- Department of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia.,Greame Clark Institute of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Anthony N Burkitt
- Department of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia.,Greame Clark Institute of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Hamish Meffin
- Department of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia.,Greame Clark Institute of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia.,National Vision Research Institute, Australian College of Optometry, Carlton, Victoria, Australia
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15
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Caravaca-Rodriguez D, Gaytan SP, Suaning GJ, Barriga-Rivera A. Implications of Neural Plasticity in Retinal Prosthesis. Invest Ophthalmol Vis Sci 2022; 63:11. [PMID: 36251317 DOI: 10.1167/iovs.63.11.11] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Retinal degenerative diseases such as retinitis pigmentosa cause a progressive loss of photoreceptors that eventually prevents the affected person from perceiving visual sensations. The absence of a visual input produces a neural rewiring cascade that propagates along the visual system. This remodeling occurs first within the retina. Then, subsequent neuroplastic changes take place at higher visual centers in the brain, produced by either the abnormal neural encoding of the visual inputs delivered by the diseased retina or as the result of an adaptation to visual deprivation. While retinal implants can activate the surviving retinal neurons by delivering electric current, the unselective activation patterns of the different neural populations that exist in the retinal layers differ substantially from those in physiologic vision. Therefore, artificially induced neural patterns are being delivered to a brain that has already undergone important neural reconnections. Whether or not the modulation of this neural rewiring can improve the performance for retinal prostheses remains a critical question whose answer may be the enabler of improved functional artificial vision and more personalized neurorehabilitation strategies.
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Affiliation(s)
- Daniel Caravaca-Rodriguez
- Department of Applied Physics III, Technical School of Engineering, Universidad de Sevilla, Sevilla, Spain
| | - Susana P Gaytan
- Department of Physiology, Universidad de Sevilla, Sevilla, Spain
| | - Gregg J Suaning
- School of Biomedical Engineering, University of Sydney, Sydney, Australia
| | - Alejandro Barriga-Rivera
- Department of Applied Physics III, Technical School of Engineering, Universidad de Sevilla, Sevilla, Spain.,School of Biomedical Engineering, University of Sydney, Sydney, Australia
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16
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Wang J, Zhao R, Li P, Fang Z, Li Q, Han Y, Zhou R, Zhang Y. Clinical Progress and Optimization of Information Processing in Artificial Visual Prostheses. SENSORS (BASEL, SWITZERLAND) 2022; 22:6544. [PMID: 36081002 PMCID: PMC9460383 DOI: 10.3390/s22176544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/22/2022] [Accepted: 08/26/2022] [Indexed: 06/15/2023]
Abstract
Visual prostheses, used to assist in restoring functional vision to the visually impaired, convert captured external images into corresponding electrical stimulation patterns that are stimulated by implanted microelectrodes to induce phosphenes and eventually visual perception. Detecting and providing useful visual information to the prosthesis wearer under limited artificial vision has been an important concern in the field of visual prosthesis. Along with the development of prosthetic device design and stimulus encoding methods, researchers have explored the possibility of the application of computer vision by simulating visual perception under prosthetic vision. Effective image processing in computer vision is performed to optimize artificial visual information and improve the ability to restore various important visual functions in implant recipients, allowing them to better achieve their daily demands. This paper first reviews the recent clinical implantation of different types of visual prostheses, summarizes the artificial visual perception of implant recipients, and especially focuses on its irregularities, such as dropout and distorted phosphenes. Then, the important aspects of computer vision in the optimization of visual information processing are reviewed, and the possibilities and shortcomings of these solutions are discussed. Ultimately, the development direction and emphasis issues for improving the performance of visual prosthesis devices are summarized.
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Affiliation(s)
- Jing Wang
- School of Information, Shanghai Ocean University, Shanghai 201306, China
- Key Laboratory of Fishery Information, Ministry of Agriculture, Shanghai 200335, China
| | - Rongfeng Zhao
- School of Information, Shanghai Ocean University, Shanghai 201306, China
| | - Peitong Li
- School of Information, Shanghai Ocean University, Shanghai 201306, China
| | - Zhiqiang Fang
- School of Information, Shanghai Ocean University, Shanghai 201306, China
| | - Qianqian Li
- School of Information, Shanghai Ocean University, Shanghai 201306, China
| | - Yanling Han
- School of Information, Shanghai Ocean University, Shanghai 201306, China
| | - Ruyan Zhou
- School of Information, Shanghai Ocean University, Shanghai 201306, China
| | - Yun Zhang
- School of Information, Shanghai Ocean University, Shanghai 201306, China
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17
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Peterson SM, Rao RPN, Brunton BW. Learning neural decoders without labels using multiple data streams. J Neural Eng 2022; 19. [PMID: 35905727 DOI: 10.1088/1741-2552/ac857c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 07/29/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Recent advances in neural decoding have accelerated the development of brain-computer interfaces aimed at assisting users with everyday tasks such as speaking, walking, and manipulating objects. However, current approaches for training neural decoders commonly require large quantities of labeled data, which can be laborious or infeasible to obtain in real-world settings. Alternatively, self-supervised models that share self-generated pseudo-labels between two data streams have shown exceptional performance on unlabeled audio and video data, but it remains unclear how well they extend to neural decoding. APPROACH We learn neural decoders without labels by leveraging multiple simultaneously recorded data streams, including neural, kinematic, and physiological signals. Specifically, we apply cross-modal, self-supervised deep clustering to train decoders that can classify movements from brain recordings. After training, we then isolate the decoders for each input data stream and compare the accuracy of decoders trained using cross-modal deep clustering against supervised and unimodal, self-supervised models. MAIN RESULTS We find that sharing pseudo-labels between two data streams during training substantially increases decoding performance compared to unimodal, self-supervised models, with accuracies approaching those of supervised decoders trained on labeled data. Next, we extend cross-modal decoder training to three or more modalities, achieving state-of-the-art neural decoding accuracy that matches or slightly exceeds the performance of supervised models. Significance: We demonstrate that cross-modal, self-supervised decoding can be applied to train neural decoders when few or no labels are available and extend the cross-modal framework to share information among three or more data streams, further improving self-supervised training.
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Affiliation(s)
- Steven M Peterson
- Biology, University of Washington, 4000 15th Ave NE, Seattle, Washington, 98195, UNITED STATES
| | - Rajesh P N Rao
- Department of Computer Science and Engineering College of Engineering, University of Washington, Box 352350, Seattle, Washington, 98195, UNITED STATES
| | - Bingni W Brunton
- University of Washington, 4000 15th Ave NE, Seattle, Washington, 98195, UNITED STATES
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18
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Wang C, Yang J, Sawan M. NeuroSEE: A Neuromorphic Energy Efficient Processing Framework for Visual Prostheses. IEEE J Biomed Health Inform 2022; 26:4132-4141. [PMID: 35503849 DOI: 10.1109/jbhi.2022.3172306] [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: 11/08/2022]
Abstract
Visual prostheses with both comprehensive visual signal processing capability and energy efficiency are becoming increasingly demanded in the age of intelligent personal healthcare, particularly with the rise of wearable and implantable devices. To address this trend, we propose NeuroSEE, a neuromorphic energy-efficient processing framework that combines a spike representation encoding technique and a bio-inspired processing method. This framework first utilizes sparse spike trains to represent visual information, and then a bio-inspired spiking neural network (SNN) is adopted to process the spike trains. The SNN model makes use of an IF neuron with multiple spikefiring rates to decrease the energy consumption without compensating for prediction performance. The experimental results indicate that when predicting the response of the primary visual cortex, the framework achieves a state-ofthe- art Pearson correlation coefficient performance. Spikebased recording and processing methods simplify the storage and transmission of redundant scene information and complex calculation processes. It could reduce power consumption by 15 times compared with the existing Convolutional neural network (CNN) processing framework. The proposed NeuroSEE framework predicts the response of the primary visual cortex in an energy efficient manner, making it a powerful tool for visual prostheses.
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19
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Sharf T, Kalakuntla T, J Lee D, Gokoffski KK. Electrical devices for visual restoration. Surv Ophthalmol 2022; 67:793-800. [PMID: 34487742 PMCID: PMC9241872 DOI: 10.1016/j.survophthal.2021.08.008] [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: 03/25/2021] [Revised: 08/24/2021] [Accepted: 08/30/2021] [Indexed: 11/21/2022]
Abstract
Given the rising number of patients with blindness from macular, optic nerve, and visual pathway disease, there is considerable interest in the potential of electrical stimulation devices to restore vision. Electrical devices for restoration of visual function can be grouped into three categories: (1) visual prostheses whose goal is to bypass damaged areas and directly activate downstream intact portions of the visual pathway; (2) electric field stimulation whose goal is to activate endogenous transcriptional and molecular signaling pathways to promote neuroprotection and neuro-regeneration; and (3) neuromodulation whose stimulation would resuscitate neural circuits vital to coordinating responses to visual input. In this review, we discuss these three approaches, describe advances made in the different fields, and comment on limitations and potential future directions.
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Affiliation(s)
- Tamara Sharf
- Keck School of Medicine, University of Southern California, CA, USA
| | - Tej Kalakuntla
- Keck School of Medicine, University of Southern California, CA, USA
| | - Darrin J Lee
- Department of Neurological Surgery, University of Southern California, CA, USA
| | - Kimberly K Gokoffski
- Department of Ophthalmology, Roski Eye Institute, University of Southern California, CA, USA.
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20
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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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21
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Salas MA, Bell J, Niketeghad S, Oswalt D, Bosking W, Patel U, Dorn JD, Yoshor D, Greenberg R, Bari A, Pouratian N. Sequence of visual cortex stimulation affects phosphene brightness in blind subjects. Brain Stimul 2022; 15:605-614. [DOI: 10.1016/j.brs.2022.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 03/12/2022] [Accepted: 03/29/2022] [Indexed: 11/02/2022] Open
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22
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Stiles NRB, Weiland JD, Patel VR. Visual-tactile shape perception in the visually restored with artificial vision. J Vis 2022; 22:14. [PMID: 35195673 PMCID: PMC8883179 DOI: 10.1167/jov.22.2.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Retinal prostheses partially restore vision to late blind patients with retinitis pigmentosa through electrical stimulation of still-viable retinal ganglion cells. We investigated whether the late blind can perform visual–tactile shape matching following the partial restoration of vision via retinal prostheses after decades of blindness. We tested for visual–visual, tactile–tactile, and visual–tactile two-dimensional shape matching with six Argus II retinal prosthesis patients, ten sighted controls, and eight sighted controls with simulated ultra-low vision. In the Argus II patients, the visual–visual shape matching performance was significantly greater than chance. Although the visual–tactile shape matching performance of the Argus II patients was not significantly greater than chance, it was significantly higher with longer duration of prosthesis use. The sighted controls using natural vision and the sighted controls with simulated ultra-low vision both performed the visual–visual and visual–tactile shape matching tasks significantly more accurately than the Argus II patients. The tactile–tactile matching was not significantly different between the Argus II patients and sighted controls with or without simulated ultra-low vision. These results show that experienced retinal prosthesis patients can match shapes across the senses and integrate artificial vision with somatosensation. The correlation of retinal prosthesis patients’ crossmodal shape matching performance with the duration of device use supports the value of experience to crossmodal shape learning. These crossmodal shape matching results in Argus II patients are the first step toward understanding crossmodal perception after artificial visual restoration.
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Affiliation(s)
- Noelle R B Stiles
- Department of Ophthalmology, University of Southern California, Los Angeles, CA, USA.,
| | - James D Weiland
- Departments of Biomedical Engineering and Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA.,
| | - Vivek R Patel
- Department of Ophthalmology, University of California, Irvine, Irvine, CA, USA.,
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23
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Etemadi L, Enander JMD, Jörntell H. Remote cortical perturbation dynamically changes the network solutions to given tactile inputs in neocortical neurons. iScience 2022; 25:103557. [PMID: 34977509 PMCID: PMC8689199 DOI: 10.1016/j.isci.2021.103557] [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: 06/14/2021] [Revised: 10/18/2021] [Accepted: 12/01/2021] [Indexed: 11/17/2022] Open
Abstract
The neocortex has a globally encompassing network structure, which for each given input constrains the possible combinations of neuronal activations across it. Hence, its network contains solutions. But in addition, the cortex has an ever-changing multidimensional internal state, causing each given input to result in a wide range of specific neuronal activations. Here we use intracellular recordings in somatosensory cortex (SI) neurons of anesthetized rats to show that remote, subthreshold intracortical electrical perturbation can impact such constraints on the responses to a set of spatiotemporal tactile input patterns. Whereas each given input pattern normally induces a wide set of preferred response states, when combined with cortical perturbation response states that did not otherwise occur were induced and consequently made other response states less likely. The findings indicate that the physiological network structure can dynamically change as the state of any given cortical region changes, thereby enabling a rich, multifactorial, perceptual capability. Tactile sensory input patterns evoke multi-structure cortical neuron responses Multi-structure responses are shown to be impacted by remote cortical regions Highly dynamic neuron responses reflects global cortical information integration Perception hence depends on globally distributed activity at the time of input
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Affiliation(s)
- Leila Etemadi
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University, BMC F10 Tornavägen 10, 221 84 Lund, Sweden
| | - Jonas M D Enander
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University, BMC F10 Tornavägen 10, 221 84 Lund, Sweden
| | - Henrik Jörntell
- Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University, BMC F10 Tornavägen 10, 221 84 Lund, Sweden
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24
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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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25
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Zeng Q, Li X, Zhang S, Deng C, Wu T. Think big, see small—A review of nanomaterials for neural interfaces. NANO SELECT 2021. [DOI: 10.1002/nano.202100256] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Qi Zeng
- Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen P.R. China
- College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen P.R. China
| | - Xiaojian Li
- Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen P.R. China
- Key Laboratory of Brain Connectome and Manipulation Chinese Academy of Sciences Shenzhen‐Hong Kong Institute of Brain Science‐Shenzhen Fundamental Research Institutions Shenzhen P.R. China
| | - Shiyun Zhang
- Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen P.R. China
| | - Chunshan Deng
- Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen P.R. China
- Key Laboratory of Brain Connectome and Manipulation Chinese Academy of Sciences Shenzhen‐Hong Kong Institute of Brain Science‐Shenzhen Fundamental Research Institutions Shenzhen P.R. China
| | - Tianzhun Wu
- Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen P.R. China
- Key Laboratory of Health Bioinformatics Chinese Academy of Sciences Shenzhen P.R. China
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26
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Melanitis N, Nakopoulos G, Lozano A, Soto-Sanchez C, Fernandez E, Nikita KS. Using Biologically-inspired Image Features to Model Retinal Response: Evidence from Biological Datasets. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:3378-3381. [PMID: 34891964 DOI: 10.1109/embc46164.2021.9629869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Retinal models are needed to simulate the translation of visual percepts to Retinal Ganglion Cells (RGCs) neural spike trains, through which visual information is transmitted to the brain. Restoring vision through neural prostheses motivates the development of accurate retinal models. We integrate biologically-inspired image features to RGC models. We trained Linear-Nonlinear models using response data from biological retinae. We show that augmenting raw image input with retina-inspired image features leads to performance improvements: in a smaller (30sec. of retina recordings) set integration of features leads to improved models in approximately $\frac{2}{3}$ of the modeled RGCS; in a larger (4min. recording) we show that utilizing Spike Triggered Average analysis to localize RGCs in input images and extract features in a cell-based manner leads to improved models in all (except two) of the modeled RGCs.
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27
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Wittevrongel B, Holmes N, Boto E, Hill R, Rea M, Libert A, Khachatryan E, Van Hulle MM, Bowtell R, Brookes MJ. Practical real-time MEG-based neural interfacing with optically pumped magnetometers. BMC Biol 2021; 19:158. [PMID: 34376215 PMCID: PMC8356471 DOI: 10.1186/s12915-021-01073-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 04/25/2021] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Brain-computer interfaces decode intentions directly from the human brain with the aim to restore lost functionality, control external devices or augment daily experiences. To combine optimal performance with wide applicability, high-quality brain signals should be captured non-invasively. Magnetoencephalography (MEG) is a potent candidate but currently requires costly and confining recording hardware. The recently developed optically pumped magnetometers (OPMs) promise to overcome this limitation, but are currently untested in the context of neural interfacing. RESULTS In this work, we show that OPM-MEG allows robust single-trial analysis which we exploited in a real-time 'mind-spelling' application yielding an average accuracy of 97.7%. CONCLUSIONS This shows that OPM-MEG can be used to exploit neuro-magnetic brain responses in a practical and flexible manner, and opens up new avenues for a wide range of new neural interface applications in the future.
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Affiliation(s)
- Benjamin Wittevrongel
- Laboratory for Neuro- and Psychophysiology, Department of Neurosciences, KU Leuven, Leuven, Belgium. .,Leuven Institute for Artificial Intelligence (Leuven.AI), Leuven, Belgium. .,Leuven Brain Institute (LBI), Leuven, Belgium.
| | - Niall Holmes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Elena Boto
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Ryan Hill
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Molly Rea
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Arno Libert
- Laboratory for Neuro- and Psychophysiology, Department of Neurosciences, KU Leuven, Leuven, Belgium.,Leuven Brain Institute (LBI), Leuven, Belgium
| | - Elvira Khachatryan
- Laboratory for Neuro- and Psychophysiology, Department of Neurosciences, KU Leuven, Leuven, Belgium.,Leuven Brain Institute (LBI), Leuven, Belgium
| | - Marc M Van Hulle
- Laboratory for Neuro- and Psychophysiology, Department of Neurosciences, KU Leuven, Leuven, Belgium.,Leuven Institute for Artificial Intelligence (Leuven.AI), Leuven, Belgium.,Leuven Brain Institute (LBI), Leuven, Belgium
| | - Richard Bowtell
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Matthew J Brookes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
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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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29
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Wang D, Tan J, Zhu H, Mei Y, Liu X. Biomedical Implants with Charge-Transfer Monitoring and Regulating Abilities. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2004393. [PMID: 34166584 PMCID: PMC8373130 DOI: 10.1002/advs.202004393] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 05/12/2021] [Indexed: 05/06/2023]
Abstract
Transmembrane charge (ion/electron) transfer is essential for maintaining cellular homeostasis and is involved in many biological processes, from protein synthesis to embryonic development in organisms. Designing implant devices that can detect or regulate cellular transmembrane charge transfer is expected to sense and modulate the behaviors of host cells and tissues. Thus, charge transfer can be regarded as a bridge connecting living systems and human-made implantable devices. This review describes the mode and mechanism of charge transfer between organisms and nonliving materials, and summarizes the strategies to endow implants with charge-transfer regulating or monitoring abilities. Furthermore, three major charge-transfer controlling systems, including wired, self-activated, and stimuli-responsive biomedical implants, as well as the design principles and pivotal materials are systematically elaborated. The clinical challenges and the prospects for future development of these implant devices are also discussed.
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Affiliation(s)
- Donghui Wang
- State Key Laboratory of High Performance Ceramics and Superfine MicrostructureShanghai Institutes of CeramicsChinese Academy of SciencesShanghai200050China
- School of Materials Science and EngineeringHebei University of TechnologyTianjin300130China
| | - Ji Tan
- State Key Laboratory of High Performance Ceramics and Superfine MicrostructureShanghai Institutes of CeramicsChinese Academy of SciencesShanghai200050China
| | - Hongqin Zhu
- State Key Laboratory of High Performance Ceramics and Superfine MicrostructureShanghai Institutes of CeramicsChinese Academy of SciencesShanghai200050China
- Department of Materials ScienceFudan UniversityShanghai200433China
| | - Yongfeng Mei
- Department of Materials ScienceFudan UniversityShanghai200433China
| | - Xuanyong Liu
- State Key Laboratory of High Performance Ceramics and Superfine MicrostructureShanghai Institutes of CeramicsChinese Academy of SciencesShanghai200050China
- School of Chemistry and Materials ScienceHangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou310024China
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30
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Valero-Vello M, Peris-Martínez C, García-Medina JJ, Sanz-González SM, Ramírez AI, Fernández-Albarral JA, Galarreta-Mira D, Zanón-Moreno V, Casaroli-Marano RP, Pinazo-Duran MD. Searching for the Antioxidant, Anti-Inflammatory, and Neuroprotective Potential of Natural Food and Nutritional Supplements for Ocular Health in the Mediterranean Population. Foods 2021; 10:1231. [PMID: 34071459 PMCID: PMC8229954 DOI: 10.3390/foods10061231] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 12/14/2022] Open
Abstract
Adherence to a healthy diet offers a valuable intervention to compete against the increasing cases of ocular diseases worldwide, such as dry eye disorders, myopia progression, cataracts, glaucoma, diabetic retinopathy, or age macular degeneration. Certain amounts of micronutrients must be daily provided for proper functioning of the visual system, such as vitamins, carotenoids, trace metals and omega-3 fatty acids. Among natural foods, the following have to be considered for boosting eye/vision health: fish, meat, eggs, nuts, legumes, citrus fruits, nuts, leafy green vegetables, orange-colored fruits/vegetables, olives-olive oil, and dairy products. Nutritional supplements have received much attention as potential tools for managing chronic-degenerative ocular diseases. A systematic search of PubMed, Web of Science, hand-searched publications and historical archives were performed by the professionals involved in this study, to include peer-reviewed articles in which natural food, nutrient content, and its potential relationship with ocular health. Five ophthalmologists and two researchers collected the characteristics, quality and suitability of the above studies. Finally, 177 publications from 1983 to 2021 were enclosed, mainly related to natural food, Mediterranean diet (MedDiet) and nutraceutic supplementation. For the first time, original studies with broccoli and tigernut (chufa de Valencia) regarding the ocular surface dysfunction, macular degeneration, diabetic retinopathy and glaucoma were enclosed. These can add value to the diet, counteract nutritional defects, and help in the early stages, as well as in the course of ophthalmic pathologies. The main purpose of this review, enclosed in the Special Issue "Health Benefits and Nutritional Quality of Fruits, Nuts and Vegetables," is to identify directions for further research on the role of diet and nutrition in the eyes and vision, and the potential antioxidant, anti-inflammatory and neuroprotective effects of natural food (broccoli, saffron, tigernuts and walnuts), the Mediterranean Diet, and nutraceutic supplements that may supply a promising and highly affordable scenario for patients at risk of vision loss. This review work was designed and carried out by a multidisciplinary group involved in ophthalmology and ophthalmic research and especially in nutritional ophthalmology.
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Affiliation(s)
- Mar Valero-Vello
- Ophthalmic Research Unit “Santiago Grisolía” Foundation for the Promotion of Health and Biomedical Research of Valencia FISABIO, 46017 Valencia, Spain; (M.V.-V.); (J.J.G.-M.); (S.M.S.-G.); (M.D.P.-D.)
| | - Cristina Peris-Martínez
- Ophthalmic Medical Center (FOM), Foundation for the Promotion of Health and Biomedical Research of Valencia (FISABIO), 46015 Valencia, Spain;
- Department of Surgery, University of Valencia, 46019 Valencia, Spain
- Spanish Net of Ophthalmic Research “OFTARED” RD16/0008/0022, Institute of Health Carlos III, 28029 Madrid, Spain; (A.I.R.); (D.G.-M.); (R.P.C.-M.)
| | - José J. García-Medina
- Ophthalmic Research Unit “Santiago Grisolía” Foundation for the Promotion of Health and Biomedical Research of Valencia FISABIO, 46017 Valencia, Spain; (M.V.-V.); (J.J.G.-M.); (S.M.S.-G.); (M.D.P.-D.)
- Spanish Net of Ophthalmic Research “OFTARED” RD16/0008/0022, Institute of Health Carlos III, 28029 Madrid, Spain; (A.I.R.); (D.G.-M.); (R.P.C.-M.)
- Department of Ophthalmology, General University Hospital “Morales Meseguer”, 30007 Murcia, Spain
- Department of Ophthalmology and Optometry, University of Murcia, 30120 Murcia, Spain
| | - Silvia M. Sanz-González
- Ophthalmic Research Unit “Santiago Grisolía” Foundation for the Promotion of Health and Biomedical Research of Valencia FISABIO, 46017 Valencia, Spain; (M.V.-V.); (J.J.G.-M.); (S.M.S.-G.); (M.D.P.-D.)
- Spanish Net of Ophthalmic Research “OFTARED” RD16/0008/0022, Institute of Health Carlos III, 28029 Madrid, Spain; (A.I.R.); (D.G.-M.); (R.P.C.-M.)
- Cellular and Molecular Ophthalmobiology Group, Department of Surgery, Faculty of Medicine and Odontology, University of Valencia, 46010 Valencia, Spain
| | - Ana I. Ramírez
- Spanish Net of Ophthalmic Research “OFTARED” RD16/0008/0022, Institute of Health Carlos III, 28029 Madrid, Spain; (A.I.R.); (D.G.-M.); (R.P.C.-M.)
- Department of Immunology, Ophthalmology and Otorrinolaringology, Institute of Ophthalmic Research “Ramón Castroviejo”, Complutense University of Madrid, 28040 Madrid, Spain;
| | - José A. Fernández-Albarral
- Department of Immunology, Ophthalmology and Otorrinolaringology, Institute of Ophthalmic Research “Ramón Castroviejo”, Complutense University of Madrid, 28040 Madrid, Spain;
| | - David Galarreta-Mira
- Spanish Net of Ophthalmic Research “OFTARED” RD16/0008/0022, Institute of Health Carlos III, 28029 Madrid, Spain; (A.I.R.); (D.G.-M.); (R.P.C.-M.)
- Department of Ophthalmology. University Clinic Hospital of Valladolid, 47003 Valladolid, Spain
| | - Vicente Zanón-Moreno
- Ophthalmic Research Unit “Santiago Grisolía” Foundation for the Promotion of Health and Biomedical Research of Valencia FISABIO, 46017 Valencia, Spain; (M.V.-V.); (J.J.G.-M.); (S.M.S.-G.); (M.D.P.-D.)
- Spanish Net of Ophthalmic Research “OFTARED” RD16/0008/0022, Institute of Health Carlos III, 28029 Madrid, Spain; (A.I.R.); (D.G.-M.); (R.P.C.-M.)
- Faculty of Health Sciences, International University of Valencia, 46002 Valencia, Spain
| | - Ricardo P. Casaroli-Marano
- Spanish Net of Ophthalmic Research “OFTARED” RD16/0008/0022, Institute of Health Carlos III, 28029 Madrid, Spain; (A.I.R.); (D.G.-M.); (R.P.C.-M.)
- Departament of Surgery, School of Medicine and Health Sciences, Clinic Hospital of Barcelona, Universitat de Barcelona, 08036 Barcelona, Spain
| | - María D. Pinazo-Duran
- Ophthalmic Research Unit “Santiago Grisolía” Foundation for the Promotion of Health and Biomedical Research of Valencia FISABIO, 46017 Valencia, Spain; (M.V.-V.); (J.J.G.-M.); (S.M.S.-G.); (M.D.P.-D.)
- Spanish Net of Ophthalmic Research “OFTARED” RD16/0008/0022, Institute of Health Carlos III, 28029 Madrid, Spain; (A.I.R.); (D.G.-M.); (R.P.C.-M.)
- Cellular and Molecular Ophthalmobiology Group, Department of Surgery, Faculty of Medicine and Odontology, University of Valencia, 46010 Valencia, Spain
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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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32
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Kosta P, Iseri E, Loizos K, Paknahad J, Pfeiffer RL, Sigulinsky CL, Anderson JR, Jones BW, Lazzi G. Model-based comparison of current flow in rod bipolar cells of healthy and early-stage degenerated retina. Exp Eye Res 2021; 207:108554. [PMID: 33794197 DOI: 10.1016/j.exer.2021.108554] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 03/04/2021] [Accepted: 03/23/2021] [Indexed: 12/27/2022]
Abstract
Retinal degenerative diseases, such as retinitis pigmentosa, are generally thought to initiate with the loss of photoreceptors, though recent work suggests that plasticity and remodeling occurs prior to photoreceptor cell loss. This degeneration subsequently leads to death of other retinal neurons, creating functional alterations and extensive remodeling of retinal networks. Retinal prosthetic devices stimulate the surviving retinal cells by applying external current using implanted electrodes. Although these devices restore partial vision, the quality of restored vision is limited. Further knowledge about the precise changes in degenerated retina as the disease progresses is essential to understand how current flows in retinas undergoing degenerative disease and to improve the performance of retinal prostheses. We developed computational models that describe current flow from rod photoreceptors to rod bipolar cells (RodBCs) in the healthy and early-stage degenerated retina. Morphologically accurate models of retinal cells with their synapses are constructed based on retinal connectome datasets, created using serial section transmission electron microscopy (TEM) images of 70 nm-thick slices of either healthy (RC1) or early-stage degenerated (RPC1) rabbit retina. The passive membrane and active ion currents of each cell are implemented using conductance-based models in the Neuron simulation environment. In response to photocurrent input at rod photoreceptors, the simulated membrane potential at RodBCs in early degenerate tissue is approximately 10-20 mV lower than that of RodBCs of that observed in wild type retina. Results presented here suggest that although RodBCs in RPC1 show early, altered morphology compared to RC1, the lower membrane potential is primarily a consequence of reduced rod photoreceptor input to RodBCs in the degenerated retina. Frequency response and step input analyses suggest that individual cell responses of RodBCs in either healthy or early-degenerated retina, prior to substantial photoreceptor cell loss, do not differ significantly.
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Affiliation(s)
- Pragya Kosta
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT, USA.
| | - Ege Iseri
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Kyle Loizos
- Institute for Technology and Medical Systems Innovation (ITEMS), Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Javad Paknahad
- Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Rebecca L Pfeiffer
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA
| | | | - James R Anderson
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA
| | - Bryan W Jones
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA.
| | - Gianluca Lazzi
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA; Institute for Technology and Medical Systems Innovation (ITEMS), Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA; Department of Ophthalmology, University of Southern California, Los Angeles, CA, USA.
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33
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Abbasi B, Rizzo JF. Advances in Neuroscience, Not Devices, Will Determine the Effectiveness of Visual Prostheses. Semin Ophthalmol 2021; 36:168-175. [PMID: 33734937 DOI: 10.1080/08820538.2021.1887902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Background: Innovations in engineering and neuroscience have enabled the development of sophisticated visual prosthetic devices. In clinical trials, these devices have provided visual acuities as high as 20/460, enabled coarse navigation, and even allowed for reading of short words. However, long-term commercial viability arguably rests on attaining even better vision and more definitive improvements in tasks of daily living and quality of life. Purpose: Here we review technological and biological obstacles in the implementation of visual prosthetics. Conclusions: Research in the visual prosthetic field has tackled significant technical challenges, including biocompatibility, signal spread through neural tissue, and inadvertent activation of passing axons; however, significant gaps in knowledge remain in the realm of neuroscience, including the neural code of vision and visual plasticity. We assert that further optimization of prosthetic devices alone will not provide markedly improved visual outcomes without significant advances in our understanding of neuroscience.
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Affiliation(s)
- Bardia Abbasi
- Neuro-Ophthalmology Service, Department of Ophthalmology, Massachusetts Eye and Ear and Harvard Medical School, Boston, MA, USA
| | - Joseph F Rizzo
- Neuro-Ophthalmology Service, Department of Ophthalmology, Massachusetts Eye and Ear and Harvard Medical School, Boston, MA, USA
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34
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Cracchiolo M, Ottaviani MM, Panarese A, Strauss I, Vallone F, Mazzoni A, Micera S. Bioelectronic medicine for the autonomic nervous system: clinical applications and perspectives. J Neural Eng 2021; 18. [PMID: 33592597 DOI: 10.1088/1741-2552/abe6b9] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 02/16/2021] [Indexed: 12/11/2022]
Abstract
Bioelectronic medicine (BM) is an emerging new approach for developing novel neuromodulation therapies for pathologies that have been previously treated with pharmacological approaches. In this review, we will focus on the neuromodulation of autonomic nervous system (ANS) activity with implantable devices, a field of BM that has already demonstrated the ability to treat a variety of conditions, from inflammation to metabolic and cognitive disorders. Recent discoveries about immune responses to ANS stimulation are the laying foundation for a new field holding great potential for medical advancement and therapies and involving an increasing number of research groups around the world, with funding from international public agencies and private investors. Here, we summarize the current achievements and future perspectives for clinical applications of neural decoding and stimulation of the ANS. First, we present the main clinical results achieved so far by different BM approaches and discuss the challenges encountered in fully exploiting the potential of neuromodulatory strategies. Then, we present current preclinical studies aimed at overcoming the present limitations by looking for optimal anatomical targets, developing novel neural interface technology, and conceiving more efficient signal processing strategies. Finally, we explore the prospects for translating these advancements into clinical practice.
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Affiliation(s)
- Marina Cracchiolo
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Matteo Maria Ottaviani
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Alessandro Panarese
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Ivo Strauss
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Fabio Vallone
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Alberto Mazzoni
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Silvestro Micera
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy.,Bertarelli Foundation Chair in Translational NeuroEngineering, Centre for Neuroprosthetics and Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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35
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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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36
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Affiliation(s)
- Lital Alfonta
- Departments of Life Sciences, Chemistry and Ilse Katz Institute for Nanoscale Science and Technology Ben-Gurion University of the Negev P.O. Box 653 Beer-Sheva 8410501 Israel
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37
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Peterson SM, Steine-Hanson Z, Davis N, Rao RPN, Brunton BW. Generalized neural decoders for transfer learning across participants and recording modalities. J Neural Eng 2021; 18. [PMID: 33418552 DOI: 10.1088/1741-2552/abda0b] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/08/2021] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Advances in neural decoding have enabled brain-computer interfaces to perform increasingly complex and clinically-relevant tasks. However, such decoders are often tailored to specific participants, days, and recording sites, limiting their practical long-term usage. Therefore, a fundamental challenge is to develop neural decoders that can robustly train on pooled, multi-participant data and generalize to new participants. APPROACH We introduce a new decoder, HTNet, which uses a convolutional neural network with two innovations: (1) a Hilbert transform that computes spectral power at data-driven frequencies and (2) a layer that projects electrode-level data onto predefined brain regions. The projection layer critically enables applications with intracranial electrocorticography (ECoG), where electrode locations are not standardized and vary widely across participants. We trained HTNet to decode arm movements using pooled ECoG data from 11 of 12 participants and tested performance on unseen ECoG or electroencephalography (EEG) participants; these pretrained models were also subsequently fine-tuned to each test participant. MAIN RESULTS HTNet outperformed state-of-the-art decoders when tested on unseen participants, even when a different recording modality was used. By fine-tuning these generalized HTNet decoders, we achieved performance approaching the best tailored decoders with as few as 50 ECoG or 20 EEG events. We were also able to interpret HTNet's trained weights and demonstrate its ability to extract physiologically-relevant features. SIGNIFICANCE By generalizing to new participants and recording modalities, robustly handling variations in electrode placement, and allowing participant-specific fine-tuning with minimal data, HTNet is applicable across a broader range of neural decoding applications compared to current state-of-the-art decoders.
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Affiliation(s)
- Steven M Peterson
- Biology, University of Washington, 4000 15th Ave NE, Seattle, Washington, 98195, UNITED STATES
| | - Zoe Steine-Hanson
- Computer Science and Engineering, University of Washington, 4000 15th Ave NE, Seattle, Washington, 98195, UNITED STATES
| | - Nathan Davis
- Computer Science and Engineering, University of Washington, 4000 15th Ave NE, Seattle, Washington, 98195, UNITED STATES
| | - Rajesh P N Rao
- Computer Science and Engineering, University of Washington, 185 E Stevens Way NE, Seattle, Washington, 98195, UNITED STATES
| | - Bingni W Brunton
- Biology, University of Washington, 4000 15th Ave NE, Seattle, Washington, 98195, UNITED STATES
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Chari A, Budhdeo S, Sparks R, Barone DG, Marcus HJ, Pereira EAC, Tisdall MM. Brain-Machine Interfaces: The Role of the Neurosurgeon. World Neurosurg 2020; 146:140-147. [PMID: 33197630 DOI: 10.1016/j.wneu.2020.11.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 12/26/2022]
Abstract
Neurotechnology is set to expand rapidly in the coming years as technological innovations in hardware and software are translated to the clinical setting. Given our unique access to patients with neurologic disorders, expertise with which to guide appropriate treatments, and technical skills to implant brain-machine interfaces (BMIs), neurosurgeons have a key role to play in the progress of this field. We outline the current state and key challenges in this rapidly advancing field, including implant technology, implant recipients, implantation methodology, implant function, and ethical, regulatory, and economic considerations. Our key message is to encourage the neurosurgical community to proactively engage in collaborating with other health care professionals, engineers, scientists, ethicists, and regulators in tackling these issues. By doing so, we will equip ourselves with the skills and expertise to drive the field forward and avoid being mere technicians in an industry driven by those around us.
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Affiliation(s)
- Aswin Chari
- Developmental Neurosciences, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom; Department of Neurosurgery, Great Ormond Street Hospital, London, United Kingdom.
| | - Sanjay Budhdeo
- Department for Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, United Kingdom; Department of Neurology, National Hospital for Neurology and Neurosurgery, London, United Kingdom; OwkinInc, New York, New York, USA
| | - Rachel Sparks
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Damiano G Barone
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Hani J Marcus
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, United Kingdom; Wellcome EPSRC Centre for Interventional and Surgical Sciences, University College London, London, United Kingdom
| | - Erlick A C Pereira
- Neurosciences Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, United Kingdom
| | - Martin M Tisdall
- Developmental Neurosciences, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom; Department of Neurosurgery, Great Ormond Street Hospital, London, United Kingdom
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He Y, Sun SY, Roy A, Caspi A, Montezuma SR. Improved mobility performance with an artificial vision therapy system using a thermal sensor. J Neural Eng 2020; 17:045011. [PMID: 32650330 DOI: 10.1088/1741-2552/aba4fb] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To evaluate the benefit of integrating thermal imaging into an artificial vision therapy system, the Argus II retinal prosthesis, in simplifying a complex scene and improving mobility performance in the presence of other persons. APPROACH Four Argus II retinal implant users were evaluated on two tasks: to locate and approach target persons in a booth, and to navigate a hallway while avoiding people. They completed the tasks using both the original Argus II system (the 'Argus II camera') and a thermal-integrated Argus II system (the 'thermal camera'). The safety and efficiency of their navigation were evaluated by their walking speed, navigation errors, and the number of collisions. MAIN RESULTS Navigation performance was significantly superior when using the thermal camera compared to using the Argus II camera, including 75% smaller angle of deviation (p < 0.001), 48% smaller error of distance (p < 0.05), and 30% fewer collisions (p < 0.05). The thermal camera also brought the additional benefit of allowing the participants to perform the task in the dark as efficiently as in the light. More importantly, these benefits did not come at a cost of reduced walking speed. SIGNIFICANCE Using the thermal camera in the Argus II system, compared to a visible-light camera, could improve the wearers' navigation performance by helping them better approach or avoid other persons. Adding the thermal camera to future artificial vision therapy systems may complement the visible-light camera and improve the users' mobility safety and efficiency, enhancing their quality of life.
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Affiliation(s)
- Yingchen He
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, United States of America. Author to whom any correspondence should be addressed
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Nowik K, Langwińska-Wośko E, Skopiński P, Nowik KE, Szaflik JP. Bionic eye review – An update. J Clin Neurosci 2020; 78:8-19. [DOI: 10.1016/j.jocn.2020.05.041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 05/03/2020] [Indexed: 01/26/2023]
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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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Abstract
PURPOSE OF REVIEW The goal is providing an update to the latest research surrounding optoelectronic devices, highlighting key studies and benefits and limitations of each device. RECENT FINDINGS The Argus II demonstrated long-term safety after five-year follow-up. Due to lack of tack fixation, subretinal implants appear to displace over time. PRIMA's completed primate trial showed initial safety and potential for improved vision, resulting in ongoing clinical trials Bionic Vision Australia developed a new 44-electrode suprachoroidal device currently in a clinical trial. Orion (cortical stimulation) is currently undergoing a clinical trial to demonstrate safety. SUMMARY Devices using external camera for images are unaffected by corneal or lens opacities but disconnect eye movements from image perception, while the opposite is true for implants directly detecting light. Visual acuity provided by devices is more complicated than implant electrode density and new devices aim to target this with innovative approaches.
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Affiliation(s)
- Victor Wang
- University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Ajay E. Kuriyan
- Retina Service, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, PA, USA
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, NY, USA
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Shim S, Seo K, Kim SJ. A preliminary implementation of an active intraocular prosthesis as a new image acquisition device for a cortical visual prosthesis. J Artif Organs 2020; 23:262-269. [PMID: 32342231 DOI: 10.1007/s10047-020-01168-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 04/07/2020] [Indexed: 11/30/2022]
Abstract
An active intraocular prosthesis is herein proposed as a new image acquisition device for a cortical visual prosthesis. A conventional intraocular prosthesis is a passive device that helps blind patients underwent eye enucleation to maintain the shape of an eyeball. In contrast, an active intraocular prosthesis, which works as an implantable wireless camera, can capture real-time images and transmit them to a cortical visual prosthesis to restore partial vision of the patients. This active device has distinct advantages in that it can garner a variety of image information while focusing on objects in accordance with natural eye movements, compared with a glasses-mounted camera and implanted micro-photodiodes in typical artificial vision systems. Coated with an epoxy and sealed by an elastomer for biocompatibility as well as durability, the active intraocular prosthesis was fabricated in a spherical form miniaturized enough to be inserted into the eye. Its operation was evaluated by wireless image acquisition displaying a processed gray-scale image. Furthermore, signal-to-noise ratio measurements were conducted to find a reliable communication range of the fabricated prosthesis, while it was covered by an 8-mm-thick biological medium that mimicked in vivo environments. In conclusion, the feasibility of the active intraocular prosthesis to cooperate with a cortical visual prosthesis is discussed.
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Affiliation(s)
- Shinyong Shim
- Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul, 08826, South Korea.,Inter-university Semiconductor Research Center, College of Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Kangmoon Seo
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea
| | - Sung June Kim
- Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul, 08826, South Korea. .,Inter-university Semiconductor Research Center, College of Engineering, Seoul National University, Seoul, 08826, South Korea. .,Institute on Aging, College of Medicine, Seoul National University, Seoul, 08826, South Korea.
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Kamar S, Howlett MHC, Klooster J, de Graaff W, Csikós T, Rabelink MJWE, Hoeben RC, Kamermans M. Degenerated Cones in Cultured Human Retinas Can Successfully Be Optogenetically Reactivated. Int J Mol Sci 2020; 21:ijms21020522. [PMID: 31947650 PMCID: PMC7014344 DOI: 10.3390/ijms21020522] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/11/2020] [Accepted: 01/13/2020] [Indexed: 12/14/2022] Open
Abstract
Biblical references aside, restoring vision to the blind has proven to be a major technical challenge. In recent years, considerable advances have been made towards this end, especially when retinal degeneration underlies the vision loss such as occurs with retinitis pigmentosa. Under these conditions, optogenetic therapies are a particularly promising line of inquiry where remaining retinal cells are made into "artificial photoreceptors". However, this strategy is not without its challenges and a model system using human retinal explants would aid its continued development and refinement. Here, we cultured post-mortem human retinas and show that explants remain viable for around 7 days. Within this period, the cones lose their outer segments and thus their light sensitivity but remain electrophysiologically intact, displaying all the major ionic conductances one would expect for a vertebrate cone. We optogenetically restored light responses to these quiescent cones using a lentivirus vector constructed to express enhanced halorhodopsin under the control of the human arrestin promotor. In these 'reactivated' retinas, we show a light-induced horizontal cell to cone feedback signal in cones, indicating that transduced cones were able to transmit their light response across the synapse to horizontal cells, which generated a large enough response to send a signal back to the cones. Furthermore, we show ganglion cell light responses, suggesting the cultured explant's condition is still good enough to support transmission of the transduced cone signal over the intermediate retinal layers to the final retinal output level. Together, these results show that cultured human retinas are an appropriate model system to test optogenetic vision restoration approaches and that cones which have lost their outer segment, a condition occurring during the early stages of retinitis pigmentosa, are appropriate targets for optogenetic vision restoration therapies.
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Affiliation(s)
- Sizar Kamar
- Netherlands Institute for Neuroscience, 1105 BA Amsterdam-Zuidoost, The Netherlands; (S.K.); (M.H.C.H.); (J.K.); (W.d.G.); (T.C.)
- Department of Ophthalmology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands
| | - Marcus H. C. Howlett
- Netherlands Institute for Neuroscience, 1105 BA Amsterdam-Zuidoost, The Netherlands; (S.K.); (M.H.C.H.); (J.K.); (W.d.G.); (T.C.)
| | - Jan Klooster
- Netherlands Institute for Neuroscience, 1105 BA Amsterdam-Zuidoost, The Netherlands; (S.K.); (M.H.C.H.); (J.K.); (W.d.G.); (T.C.)
| | - Wim de Graaff
- Netherlands Institute for Neuroscience, 1105 BA Amsterdam-Zuidoost, The Netherlands; (S.K.); (M.H.C.H.); (J.K.); (W.d.G.); (T.C.)
| | - Tamás Csikós
- Netherlands Institute for Neuroscience, 1105 BA Amsterdam-Zuidoost, The Netherlands; (S.K.); (M.H.C.H.); (J.K.); (W.d.G.); (T.C.)
| | - Martijn J. W. E. Rabelink
- Department of Cell and Chemical Biology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands; (M.J.W.E.R.); (R.C.H.)
| | - Rob C. Hoeben
- Department of Cell and Chemical Biology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands; (M.J.W.E.R.); (R.C.H.)
| | - Maarten Kamermans
- Netherlands Institute for Neuroscience, 1105 BA Amsterdam-Zuidoost, The Netherlands; (S.K.); (M.H.C.H.); (J.K.); (W.d.G.); (T.C.)
- Department of Biomedical Engineering & Physics, Amsterdam University Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Correspondence:
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Abstract
In humans high quality, high acuity visual experience is mediated by the fovea, a tiny, specialized patch of retina containing the locus of fixation. Despite this, vision restoration strategies are typically developed in animal models without a fovea. While electrical prostheses have been approved by regulators, as yet they have failed to restore high quality, high acuity vision in patients. Approaches under pre-clinical development include regenerative cell therapies, optogenetics and chemical photosensitizers. All retinal vision restoration therapies require reactivation of inner retina that has lost photoreceptor input and that the restored signals can be interpreted at a behavioural level. A greater emphasis on tackling these challenges at the fovea may accelerate progress toward high quality vision restoration.
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Affiliation(s)
- Juliette E McGregor
- Center for Visual Science, University of Rochester, 601 Crittenden Blvd, Rochester, New York, USA
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Abstract
PURPOSE OF REVIEW This article reviews the anatomy, symptoms, examination findings, and causes of diseases affecting the optic chiasm, optic tracts, optic radiations, and occipital lobes. RECENT FINDINGS Modern ophthalmic imaging can be used to monitor the effects of diseases of the optic chiasm and tract on the retinal ganglion cells. It can also be used to visualize transsynaptic degeneration of the anterior visual pathway in the setting of acquired retrogeniculate lesions. Visual prostheses that directly stimulate the occipital lobe are a potential strategy for rehabilitation that is in active clinical trials. SUMMARY Detecting and characterizing visual deficits due to optic chiasm and retrochiasmal disease are important for the diagnosis, localization, and monitoring of neurologic disease; identifying patient disability; and guiding rehabilitation.
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Affiliation(s)
- R Mark Richardson
- Center for the Neural Basis of Cognition, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
- Epilepsy and Movement Disorders Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
| | - Taylor J Abel
- Center for the Neural Basis of Cognition, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Pediatric Epilepsy Surgery, Children's Hospital of Pittsburgh, Pittsburgh, PA, USA
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