老年人整体运动知觉衰退的视觉机制——基于知觉模板模型

The Visual Mechanism Underlying the Healthy Aging of Global Motion Perception in the Elderly——Based on the Perceptual Template Model

整体运动知觉存在年龄相关的衰退,然其老化的视觉机制仍不清楚。本研究分别招募34名青年人和老年人为研究对象,采用随机点阵范式,首次以动态速度为外部噪声考察了这一问题。结果发现,老年组整体运动一致性阈值显著高于青年组,且中等速度下的差异较小,证明整体运动知觉存在老化效应,且老化程度受到速度的影响。对两组数据进行知觉模板拟合发现,以青年组为基准,老年组表征内部加法噪声和排除外部噪声能力的A_(a)和A_(f)均大于1,且A_(a)>>A_(f),提示老年人整体运动知觉的衰退可能源于其内部加法噪声的增强和排除外部噪声能力的减弱,其中内部加法噪声的增强更为显著。

Studies showed that global motion perception(GMP)declines with aging.However,the visual mechanism underlying the healthy aging of GMP in the older adults is still unclear.The present study,for the first time,taking dynamic speed as external noise,addressed this issue.In this study,34 younger and 34 older adults were recruited to perform a random dot kinematograms(RDK)task.Results showed that the older adults had significantly higher GMP threshold than the younger,indicating that there was significantly healthy aging in GMP.And the smaller difference between the two groups at moderate speed suggested that the aging effect of GMP was affected by speed.More importantly,Perceptual Template Model(PTM)fitting found that compared to the younger adults,older adults’A_(a)>1,A_(f)>1 and A_(a)>>A_(f),demonstrating that the decline in their GMP sensitivity might be due to the enhanced additive internal noise combined with the weakened ability to exclude external noise,especially the enhanced additive internal noise.