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I. Motoyoshi, S. Nishida; Spatiotempoal interaction in detection of texture orientation modulations. Journal of Vision 2001;1(3):150. doi: 10.1167/1.3.150.
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© ARVO (1962-2015); The Authors (2016-present)
Previous studies have revealed spatial (Kingdom et al., 1995, Vision Res) and temporal (Motoyoshi & Nishida, 2000, ARVO) tunings of detection sensitivity for texture orientation modulations. Here, we examined whether there are spatiotemporal interactions. The threshold orientation contrast was measured for detecting an orientation modulation in a texture pattern. The waveform of the modulation was either square-wave (broadband), sinusoidal (low-pass), and missing-fundamental (high-pass). We used dynamic texture displays, in which the arrangement and mean orientation of Gabor micropatterns were randomly updated at a given frame rate (0–60 Hz). The increase in the frame rate reduced the detection sensitivity for all types of modulation waveform, but the reduction rate was relatively higher for sinusoidal modulation, and lower for the missing fundamental modulation. We also measured the detection sensitivity for the square-wave orientation modulation while varying the average distance between adjacent texture elements (0.2–1.3 deg). The results indicate that the increase in inter-element distances profoundly degraded the detection performance for 30–60 Hz dynamic displays, while it had little influence on detection of static displays. These results indicate that rapid stimulus changes impair the detection of large-scale orientation modulations more than the detection of small-scale modulations. This may imply that second-order filters for detecting orientation modulation shrink their integration areas (receptive fields) as the temporal frequency increases. Alternatively, while the second-order filters have stable spatial tuning, the detection sensitivity for large-scale modulations is apparently elevated for static displays by the aid of attentive process (e.g., sequential scrutiny of local orientations).
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