Bonneh Y, Sagi D, 1997, "Configuration saliency revealed by dichoptic masking" Perception 26 ECVP Abstract Supplement
Configuration saliency revealed by dichoptic masking
Y Bonneh, D Sagi
We studied suprathreshold spatial integration by testing the saliency of multi Gabor element configurations in dichoptic masking conditions. Dichoptic presentations allows for a competition between spatially overlapping suprathreshold stimuli that involve nonoverlapping receptive fields in the first stage of visual filtering.
Different spatial configurations of Gabor patches (sigma=lambda=0.12 deg) were presented to one eye (target) together with a bandpass noise presented to the other eye (mask). After a short rivalry period (128 ms) in which a dominance of one eye was established, a probe (a randomly positioned small rectangle of reduced contrast in the target) was presented for an additional detection period (80 ms). Probe detection performance was measured (2AFC) by finding the mask contrast leading to 75% correct response.
We find that textures of randomly oriented patches are more dominant than uniform textures where the effect decreases and even reverses with decreasing of contrast. For suprathreshold (1-D) contours, however, we find that smooth collinear contours are more dominant than `jagged' ones, regardless of contrast. These findings suggest principles underlying an early lateral integration mechanism based on contrast-dependent inhibitory and excitatory connections. This mechanism could be based on iso-orientation surround (2-D) inhibition and collinear (1-D) facilitation, with inhibition being more effective at high contrasts.