Dekker Tessa M, Ban Hiroshi, van der Velde Bauke, Sereno Martin I, Welchman Andrew E, Nardini Marko
Institute of Ophthalmology, University College London, 11-43 Bath Street, EC1V 9EL London, UK.
Center for Information and Neural Networks, National Institute of Information and Communications Technology, 1-4 Yamadaoka, Suita, Osaka 565-0871, Japan; Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan.
Curr Biol. 2015 Nov 2;25(21):2856-2861. doi: 10.1016/j.cub.2015.09.043. Epub 2015 Oct 17.
Adults optimize perceptual judgements by integrating different types of sensory information [1, 2]. This engages specialized neural circuits that fuse signals from the same [3-5] or different [6] modalities. Whereas young children can use sensory cues independently, adult-like precision gains from cue combination only emerge around ages 10 to 11 years [7-9]. Why does it take so long to make best use of sensory information? Existing data cannot distinguish whether this (1) reflects surprisingly late changes in sensory processing (sensory integration mechanisms in the brain are still developing) or (2) depends on post-perceptual changes (integration in sensory cortex is adult-like, but higher-level decision processes do not access the information) [10]. We tested visual depth cue integration in the developing brain to distinguish these possibilities. We presented children aged 6-12 years with displays depicting depth from binocular disparity and relative motion and made measurements using psychophysics, retinotopic mapping, and pattern classification fMRI. Older children (>10.5 years) showed clear evidence for sensory fusion in V3B, a visual area thought to integrate depth cues in the adult brain [3-5]. By contrast, in younger children (<10.5 years), there was no evidence for sensory fusion in any visual area. This significant age difference was paired with a shift in perceptual performance around ages 10 to 11 years and could not be explained by motion artifacts, visual attention, or signal quality differences. Thus, whereas many basic visual processes mature early in childhood [11, 12], the brain circuits that fuse cues take a very long time to develop.
成年人通过整合不同类型的感官信息来优化感知判断[1,2]。这涉及到专门的神经回路，这些回路融合来自相同[3-5]或不同[6]模态的信号。虽然幼儿可以独立使用感官线索，但只有在10至11岁左右才会出现类似成年人的线索组合精度提升[7-9]。为什么需要这么长时间才能充分利用感官信息呢？现有数据无法区分这是(1)反映了感官处理中惊人的后期变化（大脑中的感官整合机制仍在发育）还是(2)取决于感知后变化（感觉皮层中的整合类似于成年人，但更高层次的决策过程无法获取该信息）[10]。我们测试了发育中大脑的视觉深度线索整合，以区分这些可能性。我们向6至12岁的儿童展示了通过双眼视差和相对运动描绘深度的图像，并使用心理物理学、视网膜拓扑映射和模式分类功能磁共振成像进行测量。年龄较大的儿童（>10.5岁）在V3B区域显示出明显的感官融合证据，V3B是一个被认为在成人大脑中整合深度线索的视觉区域[3-5]。相比之下，在年龄较小的儿童（<10.5岁）中，没有任何视觉区域存在感官融合的证据。这种显著的年龄差异与10至11岁左右感知性能的转变相关，并且不能用运动伪影、视觉注意力或信号质量差异来解释。因此，虽然许多基本视觉过程在儿童早期就已成熟[11,12]，但融合线索的大脑回路却需要很长时间才能发育成熟。
