Department of Psychology, Chuo University, Tokyo 192-0393, Japan; Japan Society for the Promotion of Science, Tokyo 102-0083, Japan.
Department of Psychology, Chuo University, Tokyo 192-0393, Japan.
Curr Biol. 2019 Sep 23;29(18):3059-3064.e2. doi: 10.1016/j.cub.2019.07.044. Epub 2019 Sep 5.
Motion direction of a large high-contrast pattern is more difficult to perceive than that of a small one [1]. This counterintuitive perceptual phenomenon is considered to reflect surround suppression, a receptive field property observed in the visual cortex [2-5]. Here, we demonstrate that this phenomenon can be observed in human infants. Infants at 7 to 8 months of age showed higher sensitivity for a small motion stimulus than for a large one. However, infants under 6 months showed the opposite result; motion sensitivity was higher for a large stimulus. These results suggest that suppressive surround regions beyond classical receptive fields develop in the second half of the first year. Moreover, we examined the size of spatial summation in infants and found that the spatial summation area shrinks from 3 to 8 months of age. Our findings suggest that the summation area for motion is broad with no surround suppression in early infancy and that it narrows and acquires suppressive surround regions in the first year of life, which might reflect the developmental changes in the receptive field structure.
大高对比度图案的运动方向比小图案更难感知[1]。这种违反直觉的感知现象被认为反映了周围抑制，这是在视觉皮层中观察到的一种感受野特性[2-5]。在这里，我们证明这种现象可以在人类婴儿中观察到。7 到 8 个月大的婴儿对小运动刺激的敏感性高于大运动刺激。然而，6 个月以下的婴儿则表现出相反的结果；大刺激的运动敏感性更高。这些结果表明，在第一年的下半年，经典感受野之外的抑制性周围区域会发展。此外，我们检查了婴儿的空间总和大小，发现空间总和区域从 3 个月到 8 个月逐渐缩小。我们的发现表明，在婴儿早期，运动的总和区域很宽，没有周围抑制，而在生命的第一年，它会变窄并获得抑制性的周围区域，这可能反映了感受野结构的发育变化。
