Related Experiment Videos
Developmental variation in the structure of the retina
R H Masland1, J F Rizzo, J H Sandell
1Program in Neuroscience, Harvard Medical School, Boston, Massachusetts 02114.
Summary
Anomalous structures in rabbit retinas, including type 3 cells, are rare but consistently present, indicating precise developmental control. These "developmental errors" share features with normal amacrine cells, suggesting a programmed origin.
Area of Science:
- Neuroscience
- Developmental Biology
- Ophthalmology
Background:
- Developmental errors occur in nervous systems of various species.
- Understanding these events in the mammalian retina is crucial for developmental neuroscience.
Purpose of the Study:
- To investigate the frequency and generation of anomalous structures in the mammalian retina.
- To compare these anomalies with normal amacrine cell populations.
Main Methods:
- Studied three anomalous structures (type 3 cells, stray processes, displaced cells) in rabbit retinas.
- Used whole-mount preparations and topological mapping.
- Counted indoleamine-accumulating and tyrosine hydroxylase (TH)-positive amacrine cells for comparison.
Main Results:
- Anomalous structures were rare and variable between animals (varied >4-fold).
- However, their numbers showed low variation between the two eyes of the same animal (avg. 14% difference).
- Anomalous structures were present in all rabbits, with consistent morphology, suggesting precise developmental control.
Conclusions:
- The anomalous retinal structures studied are under precise control by the developmental program.
- These anomalies share phenotypic features with regular indoleamine-accumulating amacrine cells.