Changes of threshold luminance for a test flash (Ft) were studied as a function of temporal displacement between two conditioning flashes (Fc1 and Fc2), viewed with either the tested eye (monocular stimulation) or the homologous retinal location in the opposite eye (interocular stimulation). Under both conditions, the threshold was elevated most near the beginning of Fc1, fell to a minimum between flashes, and rose again to a secondary maximum near the beginning of Fc2. The form of this function changed dramatically as the Fc1–Fc2 interval decreased, the greatest effect being obtained with interocular stimulation. When a train of conditioning flashes (Fc1–Fc5) at or near fusion frequency was utilized, temporal oscillations of threshold luminance were detectable with monocular but not with interocular stimulation.
WILLIAM S. BATTERSBY and JOSEPH F. STURR, "Neural Limitations of Visual Excitability. IX. Monocular and Interocular Changes of Sensitivity During Flicker Stimulation," J. Opt. Soc. Am. 60, 121-126 (1970)