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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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Monaco A, Cattaneo R, Di Nicolantonio S, Strada M, Altamura S, Ortu E. Central effects of trigeminal electrical stimulation. Cranio 2023:1-24. [PMID: 38032105 DOI: 10.1080/08869634.2023.2280153] [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: 12/01/2023]
Abstract
This is a review of the literature on the main neuromodulation techniques, focusing on the possibility of introducing sensory threshold ULFTENS into them. Electro neuromodulation techniques have been in use for many years as promising methods of therapy for cognitive and emotional disorders. One of the most widely used forms of stimulation for orofacial pain is transcutaneous trigeminal stimulation on three levels: supraorbital area, dorsal surface of the tongue, and anterior skin area of the tragus. The purpose of this review is to trigger interest on using dental ULFTENS as an additional trigeminal neurostimulation and neuromodulation technique in the context of TMD. In particular, we point out the possibility of using ULFTENS at a lower activation level than that required to trigger a muscle contraction that is capable of triggering effects at the level of the autonomic nervous system, with extreme ease of execution and few side effects.
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Affiliation(s)
- Annalisa Monaco
- MeSVA Department, Dental Unit, University of L'Aquila, L'Aquila, Italy
| | - Ruggero Cattaneo
- MeSVA Department, Dental Unit, University of L'Aquila, L'Aquila, Italy
| | | | - Marco Strada
- MeSVA Department, Dental Unit, University of L'Aquila, L'Aquila, Italy
| | - Serena Altamura
- MeSVA Department, Dental Unit, University of L'Aquila, L'Aquila, Italy
| | - Eleonora Ortu
- MeSVA Department, Dental Unit, University of L'Aquila, L'Aquila, Italy
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Harrar V, Le Trung W, Malienko A, Khan AZ. A nonvisual eye tracker calibration method for video-based tracking. J Vis 2018; 18:13. [PMID: 30208432 DOI: 10.1167/18.9.13] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Video-based eye trackers have enabled major advancements in our understanding of eye movements through their ease of use and their non-invasiveness. One necessity to obtain accurate eye recordings using video-based trackers is calibration. The aim of the current study was to determine the feasibility and reliability of alternative calibration methods for scenarios in which the standard visual-calibration is not possible. Fourteen participants were tested using the EyeLink 1000 Plus video-based eye tracker, and each completed the following 5-point calibration methods: 1) standard visual-target calibration, 2) described calibration where participants were provided with verbal instructions about where to direct their eyes (without vision of the screen), 3) proprioceptive calibration where participants were asked to look at their hidden finger, 4) replacement calibration, where the visual calibration was performed by 3 different people; the calibrators were temporary substitutes for the participants. Following calibration, participants performed a simple visually-guided saccade task to 16 randomly presented targets on a grid. We found that precision errors were comparable across the alternative calibration methods. In terms of accuracy, compared to the standard calibration, non-visual calibration methods (described and proprioception) led to significantly larger errors, whilst the replacement calibration method had much smaller errors. In conditions where calibration is not possible, for example when testing blind or visually impaired people who are unable to foveate the calibration targets, we suggest that using a single stand-in to perform the calibration is a simple and easy alternative calibration method, which should only cause a minimal decrease in accuracy.
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Affiliation(s)
- Vanessa Harrar
- Vision, Attention, and Action Laboratory (VISATTAC), School of Optometry, University of Montreal, Montreal, Quebec, Canada
| | - William Le Trung
- Vision, Attention, and Action Laboratory (VISATTAC), School of Optometry, University of Montreal, Montreal, Quebec, Canada
| | - Anton Malienko
- Vision, Attention, and Action Laboratory (VISATTAC), School of Optometry, University of Montreal, Montreal, Quebec, Canada
| | - Aarlenne Zein Khan
- Vision, Attention, and Action Laboratory (VISATTAC), School of Optometry, University of Montreal, Montreal, Quebec, Canada
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Cideciyan AV, Aguirre GK, Jacobson SG, Butt OH, Schwartz SB, Swider M, Roman AJ, Sadigh S, Hauswirth WW. Pseudo-fovea formation after gene therapy for RPE65-LCA. Invest Ophthalmol Vis Sci 2014; 56:526-37. [PMID: 25537204 DOI: 10.1167/iovs.14-15895] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The purpose of this study was to evaluate fixation location and oculomotor characteristics of 15 patients with Leber congenital amaurosis (LCA) caused by RPE65 mutations (RPE65-LCA) who underwent retinal gene therapy. METHODS Eye movements were quantified under infrared imaging of the retina while the subject fixated on a stationary target. In a subset of patients, letter recognition under retinal imaging was performed. Cortical responses to visual stimulation were measured using functional magnetic resonance imaging (fMRI) in two patients before and after therapy. RESULTS All patients were able to fixate on a 1° diameter visible target in the dark. The preferred retinal locus of fixation was either at the anatomical fovea or at an extrafoveal locus. There were a wide range of oculomotor abnormalities. Natural history showed little change in oculomotor abnormalities if target illuminance was increased to maintain target visibility as the disease progressed. Eleven of 15 study eyes treated with gene therapy showed no differences from baseline fixation locations or instability over an average of follow-up of 3.5 years. Four of 15 eyes developed new pseudo-foveas in the treated retinal regions 9 to 12 months after therapy that persisted for up to 6 years; patients used their pseudo-foveas for letter identification. fMRI studies demonstrated that preservation of light sensitivity was restricted to the cortical projection zone of the pseudo-foveas. CONCLUSIONS The slow emergence of pseudo-foveas many months after the initial increases in light sensitivity points to a substantial plasticity of the adult visual system and a complex interaction between it and the progression of underlying retinal disease. The visual significance of pseudo-foveas suggests careful consideration of treatment zones for future gene therapy trials. (ClinicalTrials.gov number, NCT00481546.).
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Affiliation(s)
- Artur V Cideciyan
- Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Geoffrey K Aguirre
- Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Samuel G Jacobson
- Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Omar H Butt
- Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Sharon B Schwartz
- Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Malgorzata Swider
- Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Alejandro J Roman
- Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Sam Sadigh
- Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - William W Hauswirth
- Department of Ophthalmology, University of Florida, Gainesville, Florida, United States
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Abstract
Eye injuries are common in warfare with an incidence of approximately 10%. They carry a high morbidity, as they can determine an injured person’s future independence and employability. The majority are a combination of primary and secondary blast mechanisms, though tertiary and quaternary types are common. There is some evidence of quinary types from toxic elements from the explosion. Eye protection significantly reduces the incidence and severity of ballistic eye injury but does not eliminate it. Thermal ocular burns are relatively common in warfare. The treatment goal is to minimise limbal stem cell damage. Human amniotic membrane can be used to promote this. Retinal and optic nerve injury following closed eye trauma are currently untreatable, but neuroprotective and neuroregenerative agents are being developed to improve outcomes. Sensory substitution of the sense of touch for sight can help orientate blinded individual in their surroundings. Ophthalmology has a major impact on the lives of the war wounded.
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Affiliation(s)
- Robert AH Scott
- Royal Centre for Defence Medicine, New Queen Elizabeth Hospital, Birmingham, UK
- Section of Neurotrauma and Neurodegeneration, School of Clinical and Experimental Medicine, University of Birmingham, UK
- Birmingham and Midland Eye Centre, Birmingham, UK
| | - Richard J Blanch
- Royal Centre for Defence Medicine, New Queen Elizabeth Hospital, Birmingham, UK
- Section of Neurotrauma and Neurodegeneration, School of Clinical and Experimental Medicine, University of Birmingham, UK
| | - Peter J Morgan-Warren
- Royal Centre for Defence Medicine, New Queen Elizabeth Hospital, Birmingham, UK
- Section of Neurotrauma and Neurodegeneration, School of Clinical and Experimental Medicine, University of Birmingham, UK
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Abstract
Children who receive treatment for medulloblastoma have a high survival rate, but also a high likelihood of developing posterior fossa syndrome, a condition that includes devastating balance and motor problems. This case series used 2 novel neuromodulation devices in conjunction with an intensive physical therapy intervention for 2 children who were 5 years post tumor treatment with a diagnosis of posterior fossa syndrome. Pre- and postclinical measures, in addition to magnetoencephalography brain imaging, describe positive behavioral and neuroplastic changes resulting from the intervention. The positive outcomes in these cases suggest that further study is needed using neuromodulatory devices and long-term rehabilitation in children with balance and movement disorders resulting from cancer treatment.
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Abstract
When considering the burden of visual impairment on aging individuals and society at large, it is important to bear in mind that vision changes are a natural aspect of aging. In this article, we consider vision changes that are part of normal aging, the prevalence of abnormal vision changes caused by disorders of the visual system, and the anticipated incidence and impact of visual impairment as the US population ages. We then discuss the services available to reduce the impact of vision loss, and the extent to which those services can and should be improved, not only to be better prepared for the anticipated increase in low vision over the coming decades, but also to increase the awareness of interactions between visual impairment and comorbidities that are common among the elderly. Finally, we consider how to promote improved quality, availability, and acceptance of low vision care to lessen the impact of visual impairment on individuals, and its burden on society.
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Affiliation(s)
- Gislin Dagnelie
- Johns Hopkins University, Wilmer Eye Institute, Baltimore, Maryland
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Schneider RM, Thurtell MJ, Eisele S, Lincoff N, Bala E, Leigh RJ. Neurological basis for eye movements of the blind. PLoS One 2013; 8:e56556. [PMID: 23441203 PMCID: PMC3575504 DOI: 10.1371/journal.pone.0056556] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 01/10/2013] [Indexed: 11/23/2022] Open
Abstract
When normal subjects fix their eyes upon a stationary target, their gaze is not perfectly still, due to small movements that prevent visual fading. Visual loss is known to cause greater instability of gaze, but reported comparisons with normal subjects using reliable measurement techniques are few. We measured binocular gaze using the magnetic search coil technique during attempted fixation (monocular or binocular viewing) of 4 individuals with childhood-onset of monocular visual loss, 2 individuals with late-onset monocular visual loss due to age-related macular degeneration, 2 individuals with bilateral visual loss, and 20 healthy control subjects. We also measured saccades to visual or somatosensory cues. We tested the hypothesis that gaze instability following visual impairment is caused by loss of inputs that normally optimize the performance of the neural network (integrator), which ensures both monocular and conjugate gaze stability. During binocular viewing, patients with early-onset monocular loss of vision showed greater instability of vertical gaze in the eye with visual loss and, to a lesser extent, in the normal eye, compared with control subjects. These vertical eye drifts were much more disjunctive than upward saccades. In individuals with late monocular visual loss, gaze stability was more similar to control subjects. Bilateral visual loss caused eye drifts that were larger than following monocular visual loss or in control subjects. Accurate saccades could be made to somatosensory cues by an individual with acquired blindness, but voluntary saccades were absent in an individual with congenital blindness. We conclude that the neural gaze-stabilizing network, which contains neurons with both binocular and monocular discharge preferences, is under adaptive visual control. Whereas monocular visual loss causes disjunctive gaze instability, binocular blindness causes both disjunctive and conjugate gaze instability (drifts and nystagmus). Inputs that bypass this neural network, such as projections to motoneurons for upward saccades, remain conjugate.
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Affiliation(s)
- Rosalyn M. Schneider
- Veterans Affairs Medical Center, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Matthew J. Thurtell
- Department of Ophthalmology & Visual Sciences, University of Iowa, Iowa City, Iowa, United States of America
- Neurology Service and Center for the Prevention and Treatment of Visual Loss, Veterans Affairs Medical Center, Iowa City, Iowa, United States of America
| | - Sylvia Eisele
- Veterans Affairs Medical Center, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Norah Lincoff
- Jacobs Neurological Institute, State University of New York, Buffalo, New York, United States of America
| | - Elisa Bala
- Department of Ophthalmology, Cleveland Clinic Foundation, Cleveland, Ohio, United States of America
| | - R. John Leigh
- Veterans Affairs Medical Center, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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