The effect of phase-reversed and flashed presentations upon the apparent contrast of sinusoidal gratings.

The effect of duration upon the apparent contrast of a 0.7- and 7.0-c/deg sinusoidal grating was determined for two modes of temporal presentation: phase reversals and on-off flashes. For both spatial frequencies at durations of less than 60 msec, the apparent contrast of phase-reversed presentations was less than that of on-off flashes. However, for the 0.7-c/deg target at durations of 100-300 msec, the apparent contrast of the phase-reversed presentations was significantly greater than that of on-off presentations. There was no difference in the effect of the two modes of temporal presentation upon apparent contrast at longer durations with the 7.0-c/deg grating. These results are discussed in terms of the role of response transients in the perceived contrast of suprathreshold gratings. [ABSTRACT FROM AUTHOR]