Dynamic Electrical Stimulation of Sites in Visual Cortex Produces Form Vision in Sighted and Blind Humans

AbstractVisual cortical prosthetics (VCPs) offer the promise of restoring sight to blind patients. Electrical stimulation of a single site in visual cortex can reliably produce a percept of a spot of light in a fixed visual field location, known as a phosphene. Researchers developing VCPs have assumed that multiple phosphenes produced by concurrent stimulation of multiple sites in visual cortex can combine to form a coherent form, like pixels in a visual display. However, existing data do not support this assumption. Therefore, we developed a novel stimulation paradigm for VCPs termed dynamic current steering in which the visual form to be conveyed is traced on the surface of visual cortex by electrically stimulating electrodes in a dynamic sequence. When tested in sighted and blind subjects, this method of stimulating visual cortex allowed for the immediate recognition of a variety of letter shapes without training and with high accuracy.One Sentence SummaryStimulating human visual cortex using dynamic patterns of activity allows both blind and sighted patients to perceive visual percepts of useful forms.

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Focal Electrical Stimulation of Cortical Functional Networks

Cerebral Cortex ◽

10.1093/cercor/bhaa136 ◽

2020 ◽

Vol 30 (10) ◽

pp. 5532-5543 ◽

Cited By ~ 2

Author(s):

Jia Ming Hu ◽

Mei Zhen Qian ◽

Hisashi Tanigawa ◽

Xue Mei Song ◽

Anna Wang Roe

Keyword(s):

Electrical Stimulation ◽

Visual Cortex ◽

Functional Organization ◽

Visual Stimulation ◽

Prosthetic Design ◽

Single Feature ◽

Selective Targeting ◽

Visual Cortical ◽

The Brain ◽

Stimulation Of

Abstract Traditional electrical stimulation of brain tissue typically affects relatively large volumes of tissue spanning multiple millimeters. This low spatial resolution stimulation results in nonspecific functional effects. In addition, a primary shortcoming of these designs was the failure to take advantage of inherent functional organization in the cerebral cortex. Here, we describe a new method to electrically stimulate the brain which achieves selective targeting of single feature-specific domains in visual cortex. We provide evidence that this paradigm achieves mesoscale, functional network-specificity, and intensity dependence in a way that mimics visual stimulation. Application of this approach to known feature domains (such as color, orientation, motion, and depth) in visual cortex may lead to important functional improvements in the specificity and sophistication of brain stimulation methods and has implications for visual cortical prosthetic design.

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Playing the electric light orchestra—how electrical stimulation of visual cortex elucidates the neural basis of perception

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2014.0206 ◽

2015 ◽

Vol 370 (1677) ◽

pp. 20140206 ◽

Cited By ~ 20

Author(s):

Nela Cicmil ◽

Kristine Krug

Keyword(s):

Electrical Stimulation ◽

Visual Cortex ◽

Information Integration ◽

Cortical Neurons ◽

Extrastriate Cortex ◽

Neural Basis ◽

Electrical Microstimulation ◽

Neuronal Mechanisms ◽

Visual Cortical ◽

Stimulation Of

Vision research has the potential to reveal fundamental mechanisms underlying sensory experience. Causal experimental approaches, such as electrical microstimulation, provide a unique opportunity to test the direct contributions of visual cortical neurons to perception and behaviour. But in spite of their importance, causal methods constitute a minority of the experiments used to investigate the visual cortex to date. We reconsider the function and organization of visual cortex according to results obtained from stimulation techniques, with a special emphasis on electrical stimulation of small groups of cells in awake subjects who can report their visual experience. We compare findings from humans and monkeys, striate and extrastriate cortex, and superficial versus deep cortical layers, and identify a number of revealing gaps in the ‘causal map′ of visual cortex. Integrating results from different methods and species, we provide a critical overview of the ways in which causal approaches have been used to further our understanding of circuitry, plasticity and information integration in visual cortex. Electrical stimulation not only elucidates the contributions of different visual areas to perception, but also contributes to our understanding of neuronal mechanisms underlying memory, attention and decision-making.

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Dynamic Stimulation of Visual Cortex Produces Form Vision in Sighted and Blind Humans

Cell ◽

10.1016/j.cell.2020.04.033 ◽

2020 ◽

Vol 181 (4) ◽

pp. 774-783.e5 ◽

Cited By ~ 16

Author(s):

Michael S. Beauchamp ◽

Denise Oswalt ◽

Ping Sun ◽

Brett L. Foster ◽

John F. Magnotti ◽

...

Keyword(s):

Visual Cortex ◽

Form Vision ◽

Blind Humans ◽

Dynamic Stimulation ◽

Stimulation Of

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Visual Cortical Prosthesis : An Electrical Perspective

10.20944/preprints202012.0562.v1 ◽

2020 ◽

Author(s):

Léo Pio-Lopez ◽

Romanos Poulkouras ◽

Damien Depannemaecker

Keyword(s):

Electrical Stimulation ◽

Visual Cortex ◽

Electrode Array ◽

Therapeutic Benefit ◽

Point Of View ◽

Technological Advances ◽

Visual Cortical ◽

Blind Individuals ◽

New Generation ◽

Stimulation Of

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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A vision prosthesis based on electrical stimulation of the primary visual cortex using epicortical microelectrodes

10.1101/2020.12.15.422891 ◽

2020 ◽

Author(s):

Denise Oswalt ◽

Projag Datta ◽

Neil Talbot ◽

Zaman Mirzadeh ◽

Bradley Greger

Keyword(s):

Electrical Stimulation ◽

Visual Cortex ◽

Primary Visual Cortex ◽

Microelectrode Array ◽

Electrical Current ◽

Electrical Currents ◽

Chronic Electrical Stimulation ◽

Multiple Array ◽

Visual Cortical ◽

Stimulation Of

Prostheses that can restore limited vision in the profoundly blind have been under investigation for several decades. Studies using epicortical macroelectrodes and intracortical microelectrodes have validated that electrical stimulation of primary visual cortical can serve as the basis for a vision prosthesis. However, neither of these approaches has resulted in a clinically viable vision prosthesis. Epicortical macroelectrodes required high levels of electrical current to evoke visual percepts, while intracortical microelectrodes faced challenges with longevity and stability. We hypothesized that epicortical microelectrodes could evoke visual percepts at lower currents than macroelectrodes and provide improved longevity and stability compared with intracortical microelectrodes. To test this hypotheses we implanted epicortical microelectrode arrays over the primary visual cortex of a nonhuman primate. Electrical stimulation via this array was used to evaluate the ability of epicortical microstimulation to evoke differentiable visual percepts. Visual percepts were evoked using the epicortical microelectrode array, and at electrical currents notably lower than those required to evoke visual percepts on macroelectrode arrays. The electrical current thresholds for evoking visual percepts on the epicortical microelectrode array were consistent across multiple array implants and over several months. Normal vision of light perception was not impaired by multiple array implants or chronic electrical stimulation, demonstrating that no gross visual deficit resulted from the experiments. We specifically demonstrate that epicortical microelectrode interfaces can serve as the basis for a vision prosthesis and more generally may provide an approach to evoking perception in multiple sensory modalities.

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Electrical Stimulation of Visual Cortex: Relevance for the Development of Visual Cortical Prosthetics

Annual Review of Vision Science ◽

10.1146/annurev-vision-111815-114525 ◽

2017 ◽

Vol 3 (1) ◽

pp. 141-166 ◽

Cited By ~ 21

Author(s):

William H. Bosking ◽

Michael S. Beauchamp ◽

Daniel Yoshor

Keyword(s):

Electrical Stimulation ◽

Visual Cortex ◽

Visual Cortical ◽

Stimulation Of

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Phosphene perceptions and safety of chronic visual cortex stimulation in a blind subject

Journal of Neurosurgery ◽

10.3171/2019.3.jns182774 ◽

2020 ◽

Vol 132 (6) ◽

pp. 2000-2007 ◽

Cited By ~ 3

Author(s):

Soroush Niketeghad ◽

Abirami Muralidharan ◽

Uday Patel ◽

Jessy D. Dorn ◽

Laura Bonelli ◽

...

Keyword(s):

Visual Cortex ◽

Adverse Events ◽

Clinical Intervention ◽

Occipital Cortex ◽

Neuronal Population ◽

Serious Adverse Events ◽

Stimulation Parameters ◽

The Right ◽

Visual Cortical ◽

Stimulation Of

Stimulation of primary visual cortices has the potential to restore some degree of vision to blind individuals. Developing safe and reliable visual cortical prostheses requires assessment of the long-term stability, feasibility, and safety of generating stimulation-evoked perceptions.A NeuroPace responsive neurostimulation system was implanted in a blind individual with an 8-year history of bare light perception, and stimulation-evoked phosphenes were evaluated over 19 months (41 test sessions). Electrical stimulation was delivered via two four-contact subdural electrode strips implanted over the right medial occipital cortex. Current and charge thresholds for eliciting visual perception (phosphenes) were measured, as were the shape, size, location, and intensity of the phosphenes. Adverse events were also assessed.Stimulation of all contacts resulted in phosphene perception. Phosphenes appeared completely or partially in the left hemifield. Stimulation of the electrodes below the calcarine sulcus elicited phosphenes in the superior hemifield and vice versa. Changing the stimulation parameters of frequency, pulse width, and burst duration affected current thresholds for eliciting phosphenes, and increasing the amplitude or frequency of stimulation resulted in brighter perceptions. While stimulation thresholds decreased between an average of 5% and 12% after 19 months, spatial mapping of phosphenes remained consistent over time. Although no serious adverse events were observed, the subject experienced mild headaches and dizziness in three instances, symptoms that did not persist for more than a few hours and for which no clinical intervention was required.Using an off-the-shelf neurostimulator, the authors were able to reliably generate phosphenes in different areas of the visual field over 19 months with no serious adverse events, providing preliminary proof of feasibility and safety to proceed with visual epicortical prosthetic clinical trials. Moreover, they systematically explored the relationship between stimulation parameters and phosphene thresholds and discovered the direct relation of perception thresholds based on primary visual cortex (V1) neuronal population excitation thresholds.

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Electrical Stimulation of the Human Visual Cortex Preliminary Report

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques ◽

10.1017/s031716710001982x ◽

1974 ◽

Vol 1 (4) ◽

pp. 236-238 ◽

Cited By ~ 10

Author(s):

Andrew Talalla ◽

Leo Bullara ◽

Robert Pudenz

Keyword(s):

Electrical Stimulation ◽

Visual Cortex ◽

Feasibility Study ◽

Preliminary Report ◽

Visual Prosthesis ◽

Human Visual Cortex ◽

Stimulation Of

SUMMARY:A feasibility study for the development of a human visual prosthesis has led several workers to observe the effects of electrical stimulation of the human visual cortex. Experience with such stimulations of three normal-sighted patients is reported. The results confirm some of the findings of other workers, but do not show that multiple phosphenes were experienced by our patients, using strictly limited parameters of stimulation.

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Excitatory amino acid receptor-mediated transmission in geniculocortical and intracortical pathways within visual cortex

Journal of Neurophysiology ◽

10.1152/jn.1991.66.1.293 ◽

1991 ◽

Vol 66 (1) ◽

pp. 293-306 ◽

Cited By ~ 31

Author(s):

L. J. Larson-Prior ◽

P. S. Ulinski ◽

N. T. Slater

Keyword(s):

Visual Cortex ◽

Amino Acid ◽

Cortical Neurons ◽

Excitatory Amino Acid ◽

Nmda Antagonist ◽

Receptor Subtypes ◽

Excitatory Amino Acid Receptor ◽

Visual Cortical ◽

Stimulation Of

1. A preparation of turtle (Chrysemys picta and Pseudemys scripta) brain in which the integrity of the intracortical and geniculocortical pathways in visual cortex are maintained in vitro has been used to differentiate the excitatory amino acid (EAA) receptor subtypes involved in geniculocortical and intracortical synapses. 2. Stimulation of the geniculocortical fibers at subcortical loci produces monosynaptic excitatory postsynaptic potentials (EPSPs) in visual cortical neurons. These EPSPs are blocked by the broad-spectrum EAA receptor antagonist kynurenate (1-2 mM) and the non-N-methyl-D-aspartate (NMDA) antagonist 6, 7-dinitroquinoxaline-2,3-dione (DNQX, 10 microM), but not by the NMDA antagonist D,L-2-amino-5-phosphonovalerate (D,L-AP-5, 100 microM). These results indicate that the geniculocortical EPSP is mediated by EAAs that access principally, if not exclusively, EAA receptors of the non-NMDA subtypes. 3. Stimulation of intracortical fibers evokes compound EPSPs that could be resolved into three components differing in latency to peak. The component with the shortest latency was not affected by any of the EAA-receptor antagonists tested. The second component, of intermediate latency, was blocked by kyurenate and DNQX but not by D,L-AP-5. The component of longest latency was blocked by kynurenate and D,L-AP-5, but not by DNQX. These results indicate that the compound intracortical EPSP is comprised of three pharmacologically distinct components that are mediated by an unknown receptor, by quisqualate/kainate, and by NMDA receptors, respectively. 4. Repetitive stimulation of intracortical pathways at 0.33 Hz produces a dramatic potentiation of the late, D,L-AP-5-sensitive component of the intracortical EPSP. 5. These experiments lead to a hypothesis about the subtypes of EAA receptors that are accessed by the geniculocortical and intracortical pathways within visual cortex.

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