Selective Activation of Retinal Ganglion Cell Subtypes Through Targeted Electrical Stimulation Parameters

Paknahad, Javad; Humayun, Mark S.; Lazzi, Gianluca

doi:10.1109/tnsre.2022.3149967

Cited by 2 publications

(2 citation statements)

References 64 publications

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“…In addition, a more recent retinal study [55] of the ON and OFF mosaic characteristics suggested the importance of multi-type RGC encoding for perceptual performance. Other studies also suggested the preferential stimulation parameter spaces for activating functionally distinct RGCs [79][80][81][82][83][84][85]. In the future, we can better explore retinal outputs by adding network-mediated factors and multiple RGC pathways [86].…”

Section: Limitations and Future Directionmentioning

confidence: 98%

An in-silico analysis of electrically evoked responses of midget and parasol retinal ganglion cells in different retinal regions

et al. 2022

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Background: Visual outcomes provided by present retinal prostheses that primarily target retinal ganglion cells (RGCs) through epiretinal stimulation remain rudimentary, partly due to the limited knowledge of retinal responses under electrical stimulation. Better understanding of how different retinal regions can be quantitatively controlled with high spatial accuracy, will be beneficial to the design of micro-electrode arrays (MEAs) and stimulation strategies for next-generation wide-view, high-resolution epiretinal implants. Methods: A computational model was developed to assess neural activity at different eccentricities (2 mm and 5 mm) within the human retina. This model included midget and parasol RGCs with anatomically accurate cell distribution and cell-specific morphological information. We then performed in silico investigations of region-specific RGC responses to epiretinal electrical stimulation using varied electrode sizes (5 µm – 210 µm diameter), emulating both commercialized retinal implants and recently-developed prototype devices. Results: Our model of epiretinal stimulation predicted RGC population excitation analogous to the complex percepts reported in human subjects. Following this, our simulations suggest that midget and parasol RGCs have characteristic regional differences in excitation under preferred electrode sizes. Relatively central (2 mm) regions demonstrated higher number of excited RGCs but lower overall activated receptive field (RF) areas under the same stimulus amplitudes (two-way ANOVA, p < 0.05). Furthermore, the activated RGC numbers per unit active RF area (number-RF ratio) were significantly higher in central than in peripheral regions, and higher in the midget than in the parasol population under all tested electrode sizes (two-way ANOVA, p < 0.05). Our simulations also suggested that smaller electrodes exhibit a higher range of controllable stimulation parameters to achieve pre-defined performance of RGC excitation. ..

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Section: Limitations and Future Directionmentioning

confidence: 98%

An in-silico analysis of electrically evoked responses of midget and parasol retinal ganglion cells in different retinal regions

et al. 2022

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“…The reversal potential and conductance values of the leak ion channel were − 60 mV and 0.05 mS/cm 2 , respectively. Further details can be found in our previous studies 11 , 15 , 18 , 19 .…”

Section: Methodsmentioning

confidence: 99%

An extraocular electrical stimulation approach to slow down the progression of retinal degeneration in an animal model

Gonzalez Calle,

Paknahad,

Pollalis

et al. 2023

Sci Rep

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Retinal diseases such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD) are characterized by unrelenting neuronal death. However, electrical stimulation has been shown to induce neuroprotective changes in the retina capable of slowing down the progression of retinal blindness. In this work, a multi-scale computational model and modeling platform were used to design electrical stimulation strategies to better target the bipolar cells (BCs), that along with photoreceptors are affected at the early stage of retinal degenerative diseases. Our computational findings revealed that biphasic stimulus pulses of long pulse duration could decrease the activation threshold of BCs, and the differential stimulus threshold between ganglion cells (RGCs) and BCs, offering the potential of targeting the BCs during the early phase of degeneration. In vivo experiments were performed to evaluate the electrode placement and parameters found to target bipolar cells and evaluate the safety and efficacy of the treatment. Results indicate that the proposed transcorneal Electrical Stimulation (TES) strategy can attenuate retinal degeneration in a Royal College of Surgeon (RCS) rodent model, offering the potential to translate this work to clinical practice.

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Selective Activation of Retinal Ganglion Cell Subtypes Through Targeted Electrical Stimulation Parameters

Cited by 2 publications

References 64 publications

An in-silico analysis of electrically evoked responses of midget and parasol retinal ganglion cells in different retinal regions

An in-silico analysis of electrically evoked responses of midget and parasol retinal ganglion cells in different retinal regions

An extraocular electrical stimulation approach to slow down the progression of retinal degeneration in an animal model

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