Chakraborty Arijit, Anstice Nicola S, Jacobs Robert J, Paudel Nabin, LaGasse Linda L, Lester Barry M, Wouldes Trecia A, Harding Jane E, Thompson Benjamin
School of Optometry and Vision Science, University of Auckland, New Zealand.
Brown Center for the Study of Children at Risk, Warren Alpert Medical School at Brown University, USA.
Vision Res. 2015 Oct;115(Pt A):83-91. doi: 10.1016/j.visres.2015.08.007. Epub 2015 Sep 2.
Global motion processing depends on a network of brain regions that includes extrastriate area V5 in the dorsal visual stream. For this reason, psychophysical measures of global motion perception have been used to provide a behavioral measure of dorsal stream function. This approach assumes that global motion is relatively independent of visual functions that arise earlier in the visual processing hierarchy such as contrast sensitivity and visual acuity. We tested this assumption by assessing the relationships between global motion perception, contrast sensitivity for coherent motion direction discrimination (henceforth referred to as contrast sensitivity) and habitual visual acuity in a large group of 4.5-year-old children (n=117). The children were born at risk of abnormal neurodevelopment because of prenatal drug exposure or risk factors for neonatal hypoglycemia. Motion coherence thresholds, a measure of global motion perception, were assessed using random dot kinematograms. The contrast of the stimuli was fixed at 100% and coherence was varied. Contrast sensitivity was measured using the same stimuli by fixing motion coherence at 100% and varying dot contrast. Stereoacuity was also measured. Motion coherence thresholds were not correlated with contrast sensitivity or visual acuity. However, lower (better) motion coherence thresholds were correlated with finer stereoacuity (ρ=0.38, p=0.004). Contrast sensitivity and visual acuity were also correlated (ρ=-0.26, p=0.004) with each other. These results indicate that global motion perception for high contrast stimuli is independent of contrast sensitivity and visual acuity and can be used to assess motion integration mechanisms in children.
全局运动处理依赖于一个脑区网络，该网络包括背侧视觉通路中的纹外区V5。因此，全局运动感知的心理物理学测量方法已被用于提供背侧通路功能的行为测量指标。这种方法假定全局运动相对独立于视觉处理层级中较早出现的视觉功能，如对比敏感度和视敏度。我们通过评估一大组4.5岁儿童（n = 117）的全局运动感知、连贯运动方向辨别对比敏感度（以下简称对比敏感度）和习惯性视敏度之间的关系，来检验这一假设。这些儿童因产前药物暴露或新生儿低血糖风险因素而出生时存在神经发育异常的风险。使用随机点运动图评估运动连贯阈值，这是一种全局运动感知的测量方法。刺激的对比度固定为100%，连贯性则有所变化。通过将运动连贯性固定为100%并改变点对比度，使用相同的刺激来测量对比敏感度。还测量了立体视敏度。运动连贯阈值与对比敏感度或视敏度均无相关性。然而，较低（较好）的运动连贯阈值与更精细的立体视敏度相关（ρ = 0.38，p = 0.004）。对比敏感度和视敏度之间也相互相关（ρ = -0.26，p = 0.004）。这些结果表明，高对比度刺激的全局运动感知独立于对比敏感度和视敏度，可用于评估儿童的运动整合机制。
