Keywords

ERG

Abstract

Purpose. Standard electroretinogram (ERG) protocols are largely designed to isolate the responses of the rod and cone retinal pathways, including the use of adapting backgrounds to suppress unwanted off-pathway responses. Here, we record spectral ERGs in the low-to-high mesopic sensitivity range in the absence of any adapting background in order to assess interactions between the pathways.

Methods. We have developed a comprehensive neuroanalytic model of the component structure of the ERG driven by knowledge of the underlying retinal physiology, to enhance its power as a critical diagnostic tool for a broad range of both retinal and systemic dysfunctions. The ERG is conceptualized as a highly diagnostic signal of the retinal subsystems, each consisting of: an a-wave (photoreceptor extracellular current flow), a b-wave (transient bipolar cells), an inner retinal photopic negative response (PhNR; ganglion cells), and a melanopsin response (intrinsic ganglion-cell light response). This model is applied to an array of full-field spectral ERGs over a range of colors and intensities.

Results and Conclusion. Most of these response components are driven by both the rod and cone photoreceptor types, thus constituting about a dozen distinct components of the ERG, differentiated according to post-stimulus time of expression and the light level. At every light level, rod-driven components are typically slower than cone-driven components, equated for quantum catch. This neuroanalytic approach has been applied to a variety of spectral ERG datasets to account for as much as 95% of the variance of the ERG.

Location

St Pete, FL

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Comprehensive analysis of the retinal cell contributions to the human ERG

St Pete, FL

Purpose. Standard electroretinogram (ERG) protocols are largely designed to isolate the responses of the rod and cone retinal pathways, including the use of adapting backgrounds to suppress unwanted off-pathway responses. Here, we record spectral ERGs in the low-to-high mesopic sensitivity range in the absence of any adapting background in order to assess interactions between the pathways.

Methods. We have developed a comprehensive neuroanalytic model of the component structure of the ERG driven by knowledge of the underlying retinal physiology, to enhance its power as a critical diagnostic tool for a broad range of both retinal and systemic dysfunctions. The ERG is conceptualized as a highly diagnostic signal of the retinal subsystems, each consisting of: an a-wave (photoreceptor extracellular current flow), a b-wave (transient bipolar cells), an inner retinal photopic negative response (PhNR; ganglion cells), and a melanopsin response (intrinsic ganglion-cell light response). This model is applied to an array of full-field spectral ERGs over a range of colors and intensities.

Results and Conclusion. Most of these response components are driven by both the rod and cone photoreceptor types, thus constituting about a dozen distinct components of the ERG, differentiated according to post-stimulus time of expression and the light level. At every light level, rod-driven components are typically slower than cone-driven components, equated for quantum catch. This neuroanalytic approach has been applied to a variety of spectral ERG datasets to account for as much as 95% of the variance of the ERG.