THE LOCUS OF COLLINEAR FACILITATION IN TEXTURE PROCESSING: AN EARLY OR LATE CORTICAL SEAT?
This study addresses the issue of whether collinear facilitation in texture processing, an effect observed across different visual tasks, rests on centre-surround mechanisms or rather involves certain forms of top-down mediation. A group of nine subjects rated their confidence about the presence/absence of the target on a four-point scale. Backward-masking was used after several learning sessions. The detection performance --ms presentations. Improvement along sessions occurred in both target-present and target-absent trials. The target-present condition started by associating with higher confidence ratings and lower RTs, although performance was at a lower level than in the target-absent condition. Backward-masking did not disrupt the observed improvements, unlike what happens with non-collinear stimuli. Outcomes suggest that texture processing with collinear elements does depend on feed-forward processes mediating early-level interactions among VI cells.