Section for Computational Sensomotorics, Dept. Cognitive Neurology, CIN & HIH, UKT, University of Tübingen, Otfried-Müller Strasse 25, 72076, Tübingen, Germany.
International Max Planck Research School for Cognitive and Systems Neuroscience, University of Tübingen, Spemannstrasse 38, 72076, Tübingen, Germany.
Sci Rep. 2018 Jan 24;8(1):1507. doi: 10.1038/s41598-018-19851-8.
The visual system is able to recognize body motion from impoverished stimuli. This requires combining stimulus information with visual priors. We present a new visual illusion showing that one of these priors is the assumption that bodies are typically illuminated from above. A change of illumination direction from above to below flips the perceived locomotion direction of a biological motion stimulus. Control experiments show that the underlying mechanism is different from shape-from-shading and directly combines information about body motion with a lighting-from-above prior. We further show that the illusion is critically dependent on the intrinsic luminance gradients of the most mobile parts of the moving body. We present a neural model with physiologically plausible mechanisms that accounts for the illusion and shows how the illumination prior might be encoded within the visual pathway. Our experiments demonstrate, for the first time, a direct influence of illumination priors in high-level motion vision.
视觉系统能够从贫乏的刺激中识别出身体运动。这需要将刺激信息与视觉先验相结合。我们提出了一种新的视觉错觉，表明其中一个先验是假设身体通常是从上方被照亮的。从上方到下方改变照明方向会翻转生物运动刺激的感知运动方向。控制实验表明，潜在的机制不同于阴影形状，而是直接将关于身体运动的信息与来自上方的照明先验相结合。我们进一步表明，这种错觉严重依赖于运动物体最活跃部分的固有亮度梯度。我们提出了一个具有生理上合理机制的神经模型，该模型解释了这种错觉，并展示了照明先验如何在视觉通路上进行编码。我们的实验首次证明了照明先验在高级运动视觉中具有直接影响。
