New Vision for Visual Prostheses

Farnum, Alexander; Pelled, Galit

doi:10.3389/fnins.2020.00036

Cited by 44 publications

(31 citation statements)

References 145 publications

(166 reference statements)

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“…This technique has been explored both for the retina and the visual cortex. Current clinical trials are testing the feasibility of using optogenetics to render the RP patients sensitive to light ( Farnum and Pelled, 2020 ).…”

Section: Discussionmentioning

confidence: 99%

Brain-Machine Interfaces to Assist the Blind

Ptito

Bleau

Djerourou

et al. 2021

Front. Hum. Neurosci.

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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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Section: Discussionmentioning

confidence: 99%

Brain-Machine Interfaces to Assist the Blind

Ptito

Bleau

Djerourou

et al. 2021

Front. Hum. Neurosci.

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“…Moreover, preventing electrode degradation overtime while optimizing functionality will be necessary in order to sustain visual resolution [ 21 ]. Visual impairments can stem from various conditions along the retina-geniculate-striate pathway, hence a prosthesis that encompasses individuals within this population will also be necessary [ 22 , 23 ]. The aforementioned issues are just a few points that will need to be addressed if ICMS are to become successful [ 22 ].…”

Section: Introductionmentioning

confidence: 99%

Inducing lateralized phosphenes over the occipital lobe using transcranial magnetic stimulation to navigate a virtual environment

2021

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Electrical stimulation involving visual areas of the brain produces artificial light percepts called phosphenes. These visual percepts have been extensively investigated in previous studies involving intracortical microsimulation (ICMS) and serve as the basis for developing a visual prosthesis for the blind. Although advances have been achieved, many challenges still remain with implementing a functional ICMS for visual rehabilitation purposes. Transcranial magnetic stimulation (TMS) over the primary occipital lobe offers an alternative method to produce phosphenes non-invasively. A main challenge facing blind individuals involves navigation. Within the scientific community, methods to evaluate the ability of a visual prosthesis to facilitate in navigation has been neglected. In this study, we investigate the effectiveness of evoking lateralized phosphenes to navigate a computer simulated virtual environment. More importantly, we demonstrate how virtual environments along with the development of a visual prosthesis share a mutual relationship benefiting both patients and researchers. Using two TMS devices, a pair of 40mm figure-of-eight coils were placed over each occipital hemisphere resulting in lateralized phosphene perception. Participants were tasked with making a series of left and right turns using peripheral devices depending on the visual hemifield in which a phosphene is present. If a participant was able to accurately perceive all ten phosphenes, the simulated target is able to advance and fully exit the virtual environment. Our findings demonstrate that participants can interpret lateralized phosphenes while highlighting the integration of computer based virtual environments to evaluate the capability of a visual prosthesis during navigation.

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“…Similarly to electrode stimulation, a phosphene can be induced by magnetic stimulation [58,46] and therefore this strategy could lead to restoration of vision. Other strategies are possible as described in [34].…”

Section: Electrical Stimulation and Electrode Array Design: Challengementioning

confidence: 99%

Visual cortical prosthesis: an electrical perspective

Pio-Lopez

Poulkouras

Depannemaecker

2021

Journal of Medical Engineering & Technology

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The electrical stimulation of the visual cortices has the potential to restore vision to blind individuals. Until now, the results of visual cortical prosthetics has been limited as no prosthesis has restored a full working vision but the field has shown a renewed interest these last years thanks to wireless and technological advances. However, several scientific and technical challenges are still open in order to achieve the therapeutic benefit expected by these new devices. One of the main challenges is the electrical stimulation of the brain itself. In this review, we analyze the results in electrode-based visual cortical prosthetics from the electrical point of view. We first briefly describe what is known about the electrode-tissue interface and safety of electrical stimulation. Then we focus on the psychophysics of prosthetic vision and the state-of-the-art on the interplay between the electrical stimulation of the visual cortex and phosphene perception. Lastly, we discuss the challenges and perspectives of visual cortex electrical stimulation and electrode array design to develop the new generation implantable cortical visual prostheses.

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New Vision for Visual Prostheses

Cited by 44 publications

References 145 publications

Brain-Machine Interfaces to Assist the Blind

Brain-Machine Interfaces to Assist the Blind

Inducing lateralized phosphenes over the occipital lobe using transcranial magnetic stimulation to navigate a virtual environment

Visual cortical prosthesis: an electrical perspective

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