The effects of peripheral movement and flicker on the detection thresholds of sinusoidal gratings

The effects of the contrast, spatial frequency, and temporal frequency of a surrounding field upon the detection thresholds of gratings

“…The pronounced reduction in sensitivity to low-spatial-frequency flickering or pulsed gratings thus supported the hypothesis. However, Bowling (1985) also observed a low-spatial-frequency sensitivity reduction when the test presentation was a f-sec cosine temporal envelope, indicating that the same mechanism is perhaps responsive to low spatial frequencies under both flickering and slow onset conditions.…”

“…The reduction in sensitivity is confined to test spatial frequencies lower than about 2 cycle/deg (cpd) (Bowling, 1985;Green, 1983). The effect occurs both with counterphase flickering test gratings and with briefly pulsed presentations of the test stimuli.…”

“…The experiments reported by Bowling (1985) were based on electrophysiological work by Kruger (1980Kruger ( , 1981, who demonstrated that the time-course of cat Y cells becomes more sustained in the presence of peripheral motion. It has been suggested that this effect may be due to nonlinear subunits which apparently influence the activity of Y cells, but not that of X cells (Derrington, Lennie, & Wright, 1979).…”

“…The apparatus and procedure were the same as those described by Bowling (1985). The stimuli were generated by means of a CRT image generator and displayed on an HP1310A VDU with an average luminance of 4.5 cd/m", The test stimulus was a .5-epd sinusoidal grating in each experiment, and occupied a central 6 0 diameter field.…”

“…The test field was surrounded by a B" square field, the characteristics of which varied according to the experimental condition. Thresholds of gratings presented within the test area were obtained by means of the modified staircase method described previously (Bowling, 1985).…”