The effects of aging on motion detection and direction identification
The effects of aging on motion detection and direction identification
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DOI：
10.1016/j.visres.2007.01.001
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发表时间：
2007-03-01
期刊：
影响因子：
1.8
通讯作者：
Sekuler, Allison B.
中科院分区：
文献类型：
--
作者：
Bennett, Patrick J.;Sekuler, Robert;Sekuler, Allison B.
随机点电影照片被用来探测23岁到81岁的人类观察者的运动知觉。刺激要么是宽带方向噪声，它不会产生全局运动流动的体验，要么是较窄的方向信号，它倾向于产生连贯的、全局方向流动的体验。在每一次试验中，受试者评估他们是否确信信号已经出现，并使用计算机鼠标来指示感知到的全球流动的方向。在所有年龄段，当刺激持续时间从75毫秒增加到470毫秒时，对运动的敏感度和感知方向的准确性显著提高。然而，年龄较大的受试者(70岁)对运动的敏感度显著降低，在识别运动方向方面的准确性也明显降低。一项对照实验发现，年长的受试者能够准确地感知并记住一条线的方向，这排除了观察到的运动知觉缺陷是由于年长受试者无法操纵电脑鼠标的可能性。这些控制结果还表明，年轻的和年长的观察者都在0.24到6.0%的S持续时间内保持了稳健的视觉表征。70岁以下的受试者获得的运动检测和识别结果符合简单的多通道运动模型，尽管需要不同水平的加性内部噪声来拟合检测数据和方向识别数据，这表明运动方向和识别受到不同机制的制约。然而，为了符合来自最老受试者的数据，模型参数值必须显著改变，要么大幅增加加性内部噪声的水平，要么通过较小的噪声增加加上模型方向选择性通道带宽的增加。这些结果与最近的神经生理学研究结果定性一致，这些研究表明，在衰老的猴子和猫的视神经元中，方向选择性较弱，自发噪声较高。(C)2007爱思唯尔有限公司。保留所有权利。
Random dot cinematograms were used to probe motion perception in human observers ranging from 23 to 81 years of age. Stimuli were either broadband directional Noise, which produces no experience of global motion flow, or a narrower band directional Signal, which tended to produce experiences of coherent, global direction flow. On each trial, subjects rated their certainty that a Signal had been presented, and used a computer mouse to indicate the direction of perceived global flow. At all ages, sensitivity to motion and accuracy of perceived direction improved significantly as stimulus duration increased from 75 to 470 ms. However, older subjects (> 70 years of age) were significantly less sensitive to motion, and were significantly less accurate at identifying the direction of movement. A control experiment, which found that older subjects accurately perceived and remembered the orientation of a line, ruled out the possibility that the observed deficits in motion perception were due to an inability on the part of older subjects to manipulate the computer mouse. Those control results also showed that both younger and older observers maintained robust visual representations over durations ranging from .24 to 6.0 s. The motion detection and identification results obtained from subjects less than 70 years of age were well fit by a simple multichannel model of motion, although different levels of additive internal noise were needed to fit detection data and direction-identification data, suggesting that motion direction and identification are constrained by different mechanisms. To fit the data from the oldest subjects, however, the values of model parameters had to be significantly altered, either by increasing the level of additive internal noise substantially, or by a smaller increase in noise coupled with an increase in the bandwidth of the model's directionally selective channels. These results are qualitatively consistent with recent neuropbysiological studies showing weaker directional selectivity and higher spontaneous noise in visual neurons of senescent monkeys and cats. (c) 2007 Elsevier Ltd. All rights reserved.