Exposure of albino rats to continuous, low-intensity illumination produces degeneration of photoreceptors. In this study adult albino rats that were housed in either cyclic light or constant light (440 lux) were tested on pattern discriminations, intensity discriminations, and color discriminations for at least 24 weeks. Rats showed a decreased ability to perform pattern discriminations after approximately 7 weeks in constant light and after 24 weeks in constant light their performance was near chance. However, intensity discriminations and color discriminations were not impaired during 24 weeks in constant light. The fact that the constant light-exposed rats could perform color discriminations suggests that at least two different visual pigments are transducing light in these animals, despite the fact that no intact photoreceptor cells were observed in the retinas of the constant light-exposed rats.
ASJC Scopus subject areas
- Developmental Neuroscience