Document Detail


Spatiotemporal interactions in retinal prosthesis subjects.
MedLine Citation:
PMID:  19741248     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: Vision loss due to retinitis pigmentosa affects an estimated 15 million people worldwide. Through collaboration between Second Sight Medical Products, Inc., and the Doheny Eye Institute, six blind human subjects underwent implantation with epiretinal 4 x 4 electrode arrays designed to directly stimulate the remaining cells of the retina, with the goal of restoring functional vision by applying spatiotemporal patterns of stimulation. To better understand spatiotemporal interactions between electrodes during synchronous and asynchronous stimulation, the authors investigated how percepts changed as a function of pulse timing across the electrodes. METHODS: Pulse trains (20, 40, 80, and 160 Hz) were presented on groups of electrodes with 800, 1600, or 2400 microm center-to-center separation. Stimulation was either synchronous (pulses were presented simultaneously across electrodes) or asynchronous (pulses were phase shifted). Using a same-different discrimination task, the authors were able to evaluate how the perceptual quality of the stimuli changed as a function of phase shifts across multiple electrodes. RESULTS: Even after controlling for electric field interactions, subjects could discriminate between spatiotemporal pulse train patterns based on differences of phase across electrodes as small as 3 ms. These findings suggest that the quality of the percept is affected not only by electric field interactions but also by spatiotemporal interactions at the neural level. CONCLUSIONS: During multielectrode stimulation, interactions between electrodes have a significant influence on the quality of the percept. Understanding how these spatiotemporal interactions at the neural level influence percepts during multielectrode stimulation is fundamental to the successful design of a retinal prosthesis.
Authors:
Alan Horsager; Robert J Greenberg; Ione Fine
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2009-09-09
Journal Detail:
Title:  Investigative ophthalmology & visual science     Volume:  51     ISSN:  1552-5783     ISO Abbreviation:  Invest. Ophthalmol. Vis. Sci.     Publication Date:  2010 Feb 
Date Detail:
Created Date:  2010-01-19     Completed Date:  2010-02-17     Revised Date:  2010-09-27    
Medline Journal Info:
Nlm Unique ID:  7703701     Medline TA:  Invest Ophthalmol Vis Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1223-33     Citation Subset:  IM    
Affiliation:
Neuroscience Graduate Program, University of Southern California, Los Angeles, California 90033, USA. horsager@usc.edu
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MeSH Terms
Descriptor/Qualifier:
Blindness / rehabilitation
Electric Stimulation Therapy
Electrodes, Implanted*
Humans
Male
Microelectrodes*
Middle Aged
Prostheses and Implants*
Retina / physiopathology*,  surgery
Retinitis Pigmentosa / physiopathology*,  surgery
Sensory Thresholds / physiology*
Visual Perception / physiology*
Grant Support
ID/Acronym/Agency:
EY012893/EY/NEI NIH HHS
Comments/Corrections

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