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Visualization of Tangential Cell Migration in the Developing Chick Optic Tectum
Published on: October 24, 2018
The pattern ERG in chicks - Stimulus dependence and optic nerve section
Lisa A Ostrin1, Vivian Choh2, Christine F Wildsoet3
1University of Houston College of Optometry, 4901 Calhoun, Houston, TX 77004, USA.
Vision Research
|September 27, 2016
Summary
Pattern electroretinography (pERG) effectively assesses retinal function in chicks, showing robust responses sensitive to defocus and blur. Chick pERG is independent of retinal ganglion cells (RGCs), indicating their minimal contribution to this visual response.
Area of Science:
- Ophthalmology
- Neuroscience
- Animal Models
Background:
- Chicks are extensively utilized in research on eye growth regulation and myopia development.
- Assessing retinal function is crucial for understanding visual development and disease progression in avian models.
Purpose of the Study:
- To evaluate the efficacy of pattern electroretinography (pERG) as a tool for measuring retinal function in chick models.
- To investigate the impact of optical defocus and diffusing blur on pERG responses in chicks.
- To determine the contribution of retinal ganglion cells (RGCs) to chick pERG.
Main Methods:
- PERGs were recorded in White-Leghorn chickens across a range of spatial frequencies (0.05-2.2c/d), contrast levels (1-100%), and temporal reversal frequencies (0.5-20Hz).
- Acute effects of optical defocus and diffusing blur were assessed.
- Flash electroretinograms (ERGs) and pERGs were recorded post-monocular optic nerve section (ONS) up to 6 weeks, with complementary SD-OCT imaging.
Main Results:
- Normal chicks exhibited distinct positive (P1 at 43ms) and negative (N95 at 75ms) waveforms, with optimal P1 amplitudes at 0.06-0.1c/d SF.
- Measurable P1 responses were obtained with contrast levels above 5%.
- Defocus and diffusing blur significantly reduced pERG amplitudes across all spatial frequencies, while pERG responses remained unaffected after ONS.
Conclusions:
- Chicks demonstrate robust pERG responses that are sensitive to optical defocus and diffusing blur, validating its use in eye growth studies.
- The pERG response in chicks is not dependent on retinal ganglion cells, suggesting alternative neural pathways contribute to this signal.
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