Gordon G E, McCulloch D L
Department of Psychology, Fylde College, Lancaster University, UK.
Doc Ophthalmol. 1999;99(1):1-10. doi: 10.1023/a:1002171011644.
Different features of visual function mature along unique timescales through infancy and early childhood. It is not clear which functions continue to mature in school age children. Functions believed to be mediated by the Magnocellular (M) and Parvocellular (P) pathways were compared in five- (n=25), eight- (n=21) and eleven-year-old children (n=21) and young adult controls (n=20). Steady-state visual evoked potentials were recorded from occipital electrodes in response to very low spatial frequency gratings, at a series of contrasts (M), and to high contrast gratings at a series of spatial frequencies (P). No evidence was found to indicate M pathway development across these age groups. However, the youngest children demonstrated elevated VEP thresholds to the high contrast gratings compared with either the adults or eleven-year-olds. This difference in threshold implies an immaturity of the high contrast, high spatial frequency stream, i.e. the putative P pathway.
视觉功能的不同特征在婴儿期和幼儿期沿着独特的时间尺度成熟。目前尚不清楚哪些功能在学龄儿童中继续成熟。对5岁（n = 25）、8岁（n = 21）和11岁儿童（n = 21）以及年轻成人对照组（n = 20）的大细胞（M）和小细胞（P）通路介导的功能进行了比较。从枕叶电极记录稳态视觉诱发电位，以响应一系列对比度下的极低空间频率光栅（M），以及一系列空间频率下的高对比度光栅（P）。未发现有证据表明这些年龄组之间存在M通路发育。然而，与成年人或11岁儿童相比，最年幼的儿童对高对比度光栅表现出更高的视觉诱发电位阈值。阈值的这种差异意味着高对比度、高空间频率信息流（即假定的P通路）不成熟。
