LONG-LASTING, LONG-RANGE DETECTION FACILITATION

We examined the time course of threshold reduction in the Gabor latera l masking paradigm. Contrast detection thresholds were measured (2AFC) for a briefly presented (36 ms) foveal Gabor signal (GS), preceded by a presentation (90 ms) of two high-contrast GS flanked masks, with st imulus onset asynchrony (SOA) Varying from 0 to 16290 ms. Using target -to-mask separations of 3 lambda, and 12 lambda (lambda = 0.15 degrees , GS wavelength), the 3 lambda separated GS masks enhanced target thre shold by 0.25 log units at SOA = 0 and by 0.17 log units at 2700 ms. A t 12 lambda separation, threshold was enhanced by 0.11 log units at SO A = 0 and by 0.14 log units at 2700 ms. Long-range (12 lambda) and sho rt-range (3 lambda) enhancements persisted for over 16 s. Delayed and simultaneous enhancement depended on the stimulus configuration (maxim al for collinear target and masks), local parameters (orientation, spa tial frequency and phase), and the presented eye (dichoptic versus mon optic). The results suggest that spatial filters in early vision retai n an input trace far beyond the perceptual integration range. This tra ce may subserve the consolidation of filter activity into long-term me mory. (C) 1998 Elsevier Science Ltd. All rights reserved.