Abstract

The summation index for double flashes was psychophysically obtained as a function of interflash interval t for five different adapting levels. Clear inhibition was found at about t = 50 and at t = 70 msec for the two brightest adapting fields. Inhibition was also observed at very large intervals, including t = 300 msec. To explain the curve, a temporal response with a positive component and a negative component (type-B response) was hypothesized for the human visual system, whose physiological correlates are discussed. For relatively low adapting levels, including dark adaptation, the summation-index curves showed a somewhat different shape. They did not show strong inhibition, but rather weak and long-continued inhibition, ranging from about t = 100 through 300 msec. Therefore, the temporal response for those conditions may be composed of a small but long-continued negative component (type-A response). The transfer from type-A response to type-B response is rather abrupt; it occurs at the adapting level where the increment threshold begins to increase from the value that corresponds to the absolute threshold.

© 1970 Optical Society of America

Temporal Summation of Positive and Negative Flashes in the Visual System*

Mitsuo Ikeda
J. Opt. Soc. Am. 55(11) 1527-1534 (1965)

Diphasic Nature of the Visual Response as Inferred from the Summation Index of n Flashes

Mitsuo Ikeda and Tohru Fujii
J. Opt. Soc. Am. 56(8) 1129-1131 (1966)

Temporal Summation During Backward Visual Masking*

Robert T. Kintz and Robert M. Boynton
J. Opt. Soc. Am. 59(2) 212-216 (1969)

Further Use of the Summation Index for the Study of Color Vision*

Mitsuo Ikeda
J. Opt. Soc. Am. 54(1) 89-94 (1964)

Neural Limitations of Visual Excitability. IX. Monocular and Interocular Changes of Sensitivity During Flicker Stimulation

WILLIAM S. BATTERSBY and JOSEPH F. STURR
J. Opt. Soc. Am. 60(1) 121-126 (1970)