Dataset Information

Oculomotor Responses to Dynamic Stimuli in a 44-Channel Suprachoroidal Retinal Prosthesis.

ABSTRACT:

Purpose

To investigate oculomotor behavior in response to dynamic stimuli in retinal implant recipients.

Methods

Three suprachoroidal retinal implant recipients performed a four-alternative forced-choice motion discrimination task over six sessions longitudinally. Stimuli were a single white bar ("moving bar") or a series of white bars ("moving grating") sweeping left, right, up, or down across a 42? monitor. Performance was compared with normal video processing and scrambled video processing (randomized image-to-electrode mapping to disrupt spatiotemporal structure). Eye and head movement was monitored throughout the task.

Results

Two subjects had diminished performance with scrambling, suggesting retinotopic discrimination was used in the normal condition and made smooth pursuit eye movements congruent to the moving bar stimulus direction. These two subjects also made stimulus-related eye movements resembling optokinetic reflex (OKR) for moving grating stimuli, but the movement was incongruent with stimulus direction. The third subject was less adept at the task, appeared primarily reliant on head position cues (head movements were congruent to stimulus direction), and did not exhibit retinotopic discrimination and associated eye movements.

Conclusions

Our observation of smooth pursuit indicates residual functionality of cortical direction-selective circuits and implies a more naturalistic perception of motion than expected. A distorted OKR implies improper functionality of retinal direction-selective circuits, possibly due to retinal remodeling or the non-selective nature of the electrical stimulation.

Translational relevance

Retinal implant users can make naturalistic eye movements in response to moving stimuli, highlighting the potential for eye tracker feedback to improve perceptual localization and image stabilization in camera-based visual prostheses.

SUBMITTER: Titchener SA

PROVIDER: S-EPMC7757638 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Oculomotor Responses to Dynamic Stimuli in a 44-Channel Suprachoroidal Retinal Prosthesis.

Titchener Samuel A SA Kvansakul Jessica J Shivdasani Mohit N MN Fallon James B JB Nayagam D A X DAX Epp Stephanie B SB Williams Chris E CE Barnes Nick N Kentler William G WG Kolic Maria M Baglin Elizabeth K EK Ayton Lauren N LN Abbott Carla J CJ Luu Chi D CD Allen Penelope J PJ Petoe Matthew A MA

Translational vision science & technology 20201218 13

<h4>Purpose</h4>To investigate oculomotor behavior in response to dynamic stimuli in retinal implant recipients.<h4>Methods</h4>Three suprachoroidal retinal implant recipients performed a four-alternative forced-choice motion discrimination task over six sessions longitudinally. Stimuli were a single white bar ("moving bar") or a series of white bars ("moving grating") sweeping left, right, up, or down across a 42″ monitor. Performance was compared with normal video processing and scrambled vide ...[more]

PMID: 33384885

Similar Datasets

Project description:PurposeTo assess the safety and efficacy of chronic electrical stimulation of the retina with a suprachoroidal visual prosthesis.MethodsSeven normally-sighted feline subjects were implanted for 96-143 days with a suprachoroidal electrode array and six were chronically stimulated for 70-105 days at levels that activated the visual cortex. Charge balanced, biphasic, current pulses were delivered to platinum electrodes in a monopolar stimulation mode. Retinal integrity/function and the mechanical stability of the implant were assessed monthly using electroretinography (ERG), optical coherence tomography (OCT) and fundus photography. Electrode impedances were measured weekly and electrically-evoked visual cortex potentials (eEVCPs) were measured monthly to verify that chronic stimuli were suprathreshold. At the end of the chronic stimulation period, thresholds were confirmed with multi-unit recordings from the visual cortex. Randomized, blinded histological assessments were performed by two pathologists to compare the stimulated and non-stimulated retina and adjacent tissue.ResultsAll subjects tolerated the surgical and stimulation procedure with no evidence of discomfort or unexpected adverse outcomes. After an initial post-operative settling period, electrode arrays were mechanically stable. Mean electrode impedances were stable between 11-15 k? during the implantation period. Visually-evoked ERGs & OCT were normal, and mean eEVCP thresholds did not substantially differ over time. In 81 of 84 electrode-adjacent tissue samples examined, there were no discernible histopathological differences between stimulated and unstimulated tissue. In the remaining three tissue samples there were minor focal fibroblastic and acute inflammatory responses.ConclusionsChronic suprathreshold electrical stimulation of the retina using a suprachoroidal electrode array evoked a minimal tissue response and no adverse clinical or histological findings. Moreover, thresholds and electrode impedance remained stable for stimulation durations of up to 15 weeks. This study has demonstrated the safety and efficacy of suprachoroidal stimulation with charge balanced stimulus currents.

Dataset Information

Oculomotor Responses to Dynamic Stimuli in a 44-Channel Suprachoroidal Retinal Prosthesis.

Purpose

Methods

Results

Conclusions

Translational relevance

Publications

Oculomotor Responses to Dynamic Stimuli in a 44-Channel Suprachoroidal Retinal Prosthesis.

Similar Datasets

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