研究目的
To provide a starting point and proof of concept for a computational framework to predict the visual experience that retinal prostheses provide to patients, as well as how that visual experience could potentially improve with learning.
研究成果
The reconstruction approach provides a more complete method for exploring the potential for treating blindness with retinal prostheses than has been available previously. It may also be useful for interpreting patient data in clinical trials, and for improving prosthesis design.
研究不足
The model does not yet explicitly include the role of horizontal and amacrine cells or diverse nonlinear aspects of retinal processing. The simulation produced RGC spikes over time, but most of the analysis was performed for static images and static RGC responses, for simplicity.
1:Experimental Design and Method Selection:
The framework uses optimal linear reconstruction of the stimulus from retinal responses to infer the visual information available to the patient. A simulation of the physiological optics of the eye and light responses of the major retinal neurons was used to calculate the optimal linear transformation for reconstructing natural images from retinal activity.
2:Sample Selection and Data Sources:
The simulation focused on the four numerically dominant RGC types in macaque and human retinas: ON parasol, OFF parasol, ON midget, and OFF midget.
3:List of Experimental Equipment and Materials:
The ISETBio software was used to model transformation of a visual stimulus into RGC spikes in the healthy retina. Additions to software were used to simulate electrical activation of bipolar cells via a retinal prosthesis, in turn producing RGC spikes.
4:Experimental Procedures and Operational Workflow:
The stimulus image was modeled as an array of MxN pixels on a RGB computer display, and summarized by an MxNx3 matrix. The spectral power density of the display primaries was used to calculate a larger array (MxNxW) representing the display radiance, where each value of W indexes the radiance at a particular wavelength.
5:Data Analysis Methods:
Linear reconstruction was used to estimate the visual information available to a patient based on RGC activation. Reconstruction filters were calculated using linear regression.
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