1963 Volume 80 Issue 1 Pages 75-88
1. The octopus ERG was investigated with microelectrode inserted into the retina. A sustained negative and positive responses were recorded at the surface and deeper layer respectively.
2. Marked differences between these two responses were found in the experiments of area-dependence and of moving spot.
3. Based on these differences and the results obtained from the retina of which optic nerve had been sectioned, the two potential origins were suggested confirming the previous proposal.
4. It was found that the deep response showed lateral spreads of both negativity and positivity into surrounding unilluminated areas.
5. Spread of negativity of the deep response was found to be insensitive to a mechanical cut but much influenced by an adapting light. Opposite effects of a mechanical cut and an adapting light were observed for the deep response.
6. The axon collaterals of the receptor cells were tentatively considered to be the structures which mediate the spread of positivity of the deep response.
The authors express thanks to Prof. J. Z. Young, University College London, for his interest and encouragement during this experiment, especially for his suggestion concerning the operative procedure of optic nerve sectioning. The authors are also indebted to the Onagawa Fisheries Laboratory, Faculty of Agriculture, Tohoku University, for a generous supply of octopuses.