The effects of early visual experience on cerebral RNA metabolism in the young chick.

Haywood, Jeff (1974). The effects of early visual experience on cerebral RNA metabolism in the young chick. PhD thesis The Open University.



1. A method for preparing nuclei in high yield from brain tissue of one-day old chicks was developed. These nuclei appeared to be essentially free from contamination by cytoplasm and endothelial cells. A further fractionation of nuclei according to size (i.e. of presumed neuronal arid glial origins) proved impractical.

2. The activity and some characteristics of the enzyme RNA polymerase in the nuclei were determined and compared to the data available on the same enzyme from other sources. The activity of the chick enzyme was higher than that from mammals but was basically similar in its response to ions in the assay medium.

3.The activity of RNA polymerase was measured in three brain regions of chicks either exposed for 30 minutes to an imprinting stimulus or kept in darkness. There was a 34% higher activity in the forebrain roof of the exposed than the dark-maintained birds.

4. A new set of equipment for exposing chicks to the imprinting stimulus or diffuse light was built and tested, both by the birds' behaviour after exposure and by their relative degrees of incorporation of 14c-uracil into brain RNA. These results were compared to those obtained previously on other equipment and found to be in general agreement.

5. Using the new equipment, the effects of different periods of exposure to the stimulus on the birds’ cerebral RNA polymerase activity were determined. These results were compared with those from the uracil incorporation experiments.

6. Possible extensions of the work are discussed in conjunction with other suggested directions in which such research could be pursued.

Viewing alternatives

Download history


Public Attention

Altmetrics from Altmetric

Number of Citations

Citations from Dimensions

Item Actions