Bogfjellmo Lotte-Guri, Bex Peter J, Falkenberg Helle K
Department of Optometry and Visual Science, Buskerud and Vestfold University College, Kongsberg, Norway.
J Vis. 2014 Feb 25;14(2):19. doi: 10.1167/14.2.19.
Global motion perception matures during childhood and involves the detection of local directional signals that are integrated across space. We examine the maturation of local directional selectivity and global motion integration with an equivalent noise paradigm applied to direction discrimination. One hundred and three observers (6-17 years) identified the global direction of motion in a 2AFC task. The 8° central stimuli consisted of 100 dots of 10% Michelson contrast moving 2.8°/s or 9.8°/s. Local directional selectivity and global sampling efficiency were estimated from direction discrimination thresholds as a function of external directional noise, speed, and age. Direction discrimination thresholds improved gradually until the age of 14 years (linear regression, p < 0.05) for both speeds. This improvement was associated with a gradual increase in sampling efficiency (linear regression, p < 0.05), with no significant change in internal noise. Direction sensitivity was lower for dots moving at 2.8°/s than at 9.8°/s for all ages (paired t test, p < 0.05) and is mainly due to lower sampling efficiency. Global motion perception improves gradually during development and matures by age 14. There was no change in internal noise after the age of 6, suggesting that local direction selectivity is mature by that age. The improvement in global motion perception is underpinned by a steady increase in the efficiency with which direction signals are pooled, suggesting that global motion pooling processes mature for longer and later than local motion processing.
全局运动感知在儿童期逐渐成熟，涉及对跨空间整合的局部方向信号的检测。我们使用应用于方向辨别的等效噪声范式来研究局部方向选择性和全局运动整合的成熟过程。103名观察者（6至17岁）在二选一迫选任务中识别全局运动方向。8°的中央刺激由100个对比度为10%的迈克尔逊条纹点组成，以2.8°/秒或9.8°/秒的速度移动。根据方向辨别阈值作为外部方向噪声、速度和年龄的函数来估计局部方向选择性和全局采样效率。两种速度下，方向辨别阈值在14岁之前逐渐改善（线性回归，p<0.05）。这种改善与采样效率的逐渐增加相关（线性回归，p<0.05），内部噪声无显著变化。所有年龄段中，点以2.8°/秒移动时的方向敏感性低于以9.8°/秒移动时（配对t检验，p<0.05），这主要是由于采样效率较低。全局运动感知在发育过程中逐渐改善，并在14岁时成熟。6岁以后内部噪声没有变化，表明局部方向选择性在该年龄已成熟。全局运动感知的改善是由方向信号汇集效率的稳步提高所支撑的，这表明全局运动汇集过程的成熟比局部运动处理更晚且持续时间更长。
