Parallel processes may underly pattern motion perception

Local measurements by small receptive fields induce ambiguous and noisy one-dimensional motion estimation. This problem can be overcome by selective integration or pooling over time and space to reconstruct the global pattern (Adelson Movshon, 1982). However, it remains unclear if the local signals from intersections could influence the global pattern motion perception. Many studies used multiple apertures in order to investigate motion integration over space (Alais, Van der Smagt, Van den Berg, Van de Grind, 1998; Maruya, Amano, Nishida, 2010; Mingolla, Todd, Norman, 1992; Takahashi, 2004), but none took this issue into consideration. Here we developed a novel stimulus and try to answer this question. We used a mask with multiple transparent apertures over a moving plaid. The plaid consisted of two overlapping moving gratings with directions 135° apart. The apertures were small (0.4°) and were placed in locations that allowed either only single contours (AP1) or intersections (AP2) to pass through. We hypothesized that if motion integration takes place only at higher stages with larger receptive fields, the probability of coherent pattern motion perception would not be affected by the relative ratios of the aperture types. Our results indicate that motion perception is largely affected by the ratio of aperture types. We conjecture that parallel processes at different stages are involved in motion integration