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Poststimulus response characteristics of the human cone flicker electroretinogram
Sowjanya Gowrisankaran1, J Jason McAnany, Kenneth R Alexander
1Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois.
Visual Neuroscience
|September 11, 2013
Summary
Post-stimulus responses in human cone flicker electroretinograms (ERG) suggest a resonant system. These findings may indicate oscillations in retinal ON bipolar cells, requiring further investigation.
Area of Science:
- Ophthalmology
- Neuroscience
- Physiology
Background:
- Human cone flicker electroretinograms (ERG) exhibit post-stimulus responses after flicker train termination at specific frequencies.
- The origin of these responses remains debated: a continuing stimulus effect or a resonant system oscillation.
Purpose of the Study:
- To investigate whether post-stimulus ERG responses are a continuation of the stimulus or indicative of a resonant system.
- To characterize the amplitude and timing properties of these post-stimulus responses.
Main Methods:
- ERG recordings from 10 visually normal adults.
- Stimulation using full-field sinusoidally modulated flicker trains.
- Presentation against a short-wavelength rod-saturating adapting field.
- Analysis of post-stimulus responses using a second-order resonant system model.
Main Results:
- At stimulus frequencies of 41.7–71.4 Hz, most subjects displayed at least three post-stimulus ERG responses.
- The interval between post-stimulus responses was consistent, averaging 14.4 ms (69.4 Hz).
- Response characteristics aligned with an underdamped second-order system with a resonance frequency of 70.3 Hz.
Conclusions:
- Post-stimulus ERG responses in humans exhibit characteristics of resonant oscillations.
- These oscillations may originate from retinal ON bipolar cells, similar to findings in retinal ganglion cells.
- Further research is needed to identify the specific retinal neurons responsible for these human flicker ERG responses.
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