目的:阅读障碍是影响全球数百万人的最常见的学习障碍之一。尽管阅读障碍的确切原因尚不清楚,大细胞通路的缺陷可能起作用。我们检查了可能的磁细胞缺乏,与通过测量亮度和颜色感知的细小细胞和koniocyell途径功能相比。
方法:视觉刺激由一系列自然图像组成,划分为亮度层,红色-绿色和蓝色-黄色,探测了大细胞,细小细胞,和声细胞通路,分别。13名患有阅读障碍的儿童和13名性别和年龄匹配的对照者进行了三项心理物理任务。在第一个任务中,指示受试者将亮度(magno)和红绿(parvo)图像的对比度与蓝黄(konio)图像的对比度相匹配。在第二个任务中,受试者检测红绿图像的隔离点,以探测细小细胞通路。在第三项任务中,通过使用四类图像测量识别任务中的反应时间和正确响应的百分比来评估时间处理,激活所有三个途径。
结果:与对照组相比,阅读障碍组的亮度和颜色对比度阈值显着升高,孤立点比率更高。此外,对于蓝黄图像,他们的正确反应明显低于对照组.
结论:我们可能认为,阅读障碍者可能患有大细胞和小细胞缺陷。此外,我们的结果显示koniacellular途径部分受损.因此,阅读障碍可能与所有三个视觉途径的缺陷有关。
OBJECTIVE: Dyslexia is one of the most common learning disabilities affecting millions of people worldwide. Although exact causes of dyslexia are not well-known, a deficit in the magnocellular pathway may play a role. We examined possible deficiency of magnocellular, as compared to parvocellular and
koniocellular pathway function by measuring luminance and color perception.
METHODS: Visual stimuli consisted of a series of natural images, divided into layers of luminance, red-green and blue-yellow, which probed magnocellular, parvocellular, and
koniocellular pathways, respectively. Thirteen children with dyslexia and 13 sex- and age- matched controls performed three psychophysical tasks. In the first task, subjects were instructed to match the contrast of luminance (magno) and red-green (parvo) images to that of the blue-yellow (konio) images. In the second task, subjects detected the isoluminant point of red-green images to probe parvocellular pathway. In the third task, temporal processing was assessed by measuring reaction time and percentage of correct responses in an identification task using four categories of images, activating all three pathways.
RESULTS: The dyslexic group had significantly elevated luminance and color contrast thresholds and higher isoluminant point ratio in comparison to the control group. Furthermore, they had significantly less correct responses than the control group for the blue-yellow images.
CONCLUSIONS: We may suggest that dyslexic subjects might suffer from both magnocellular and parvocellular deficits. Moreover, our results show partial impairment of the
koniocellular pathway. Thus, dyslexia might be associated with deficits in all three visual pathways.