Scotopic Process and On-Elements in Human Retina
1951 年 54 巻 3 号 p. 215-221
詳細
1951 年 54 巻 3 号 p. 215-221
Percentage increases in electrical excitability of the eye after exposure to white light are denoted, by ζ.
1. At the fovea, ζ-time curves or excitability curves depend little on the duration of pre-illumination; the time interval. between the end of pre-illumination and the crest of the curve or crest time reamins constant irrespective of the intensity and duration of the light stimulus.
2. On the contrary, at the periphery of the retina and at a sufficiently low intensity of pre-illumination, the crest time generally depends on the duration of pre-illumination in such a manner that it is shorter with increasing duration. The crest time remains, however, independent. of the duration of pre-illumination when it is measured from the beginning of the light stimulus.
3. This finding suggests that the change in electrical excitability in the scotopic mechanism is caused by the on-effects of illumination, and this interpretation agrees with Grant's animal experiments suggesting that on-elements are characteristic for rods.
4. The true crest time of the scotopic process is longer than that of any photopic process. In other word, the scotopic process is the slowest one in the retina.
