Spatial frequency interference on grating-induction.

Spatial frequency interference and facilitation in suprathreshold vision were studied using the grating-induction effect [McCourt, Vision Res. 22, 119-134 (1982)] as a sensitive probe. The effects on grating-induction magnitude produced by variations in "interfering" and "inducing" grating spatial frequency, contrast and phase were examined in four experiments. A limited range of high spatial frequency interfering gratings reduced the contrast of gratings induced by spatially coextensive lower frequency inducing gratings. Both phase-dependent and phase-independent interference was observed. Facilitation of grating-induction was produced by interfering gratings of lower frequency than the inducing grating. It is hypothesized that the grating-induction interference effect is due to inhibition of the low spatial frequency selective mechanisms responsible for induction, by channels tuned to higher frequencies. The functional significance of induction and spatial frequency inhibition is discussed, and a mathematical description of the results is presented.