Institute of Gerontology, Wayne State University, Detroit, MI, USA.
Int J Psychophysiol. 2013 Jul;89(1):78-87. doi: 10.1016/j.ijpsycho.2013.05.012. Epub 2013 May 27.
Age-related declines in motion perception have been well documented. We investigated the impact of age on electrophysiological correlates of motion perception, namely the P1 and N2 components of motion onset visual evoked potentials (MO-VEPs). Additionally, we used a model of response times based on the diffusion model to pinpoint the cognitive processes affected by aging. Twelve healthy adults (age <55 years) and 19 elderly (age >55 years) performed a motion direction discrimination task during EEG recording. Behaviorally, younger and older participants had similar, high accuracy rates--98% correct, but older adults exhibited 85 ms longer response times. Fitting behavioral results with a diffusion model revealed differences between young adults and elderly in non-decision time, which we argue reflects an early perceptual stage. Electrophysiologically, aging effects were present at MO-VEPs P1 and N2 components at the posterior sites. For the P1 component, older as compared to younger adults showed greater topographical voltage distribution. For the N2 component of elderly as compared to young adults we found delayed onsets and diminished amplitudes. We did not find any significant correlations between behavioral and MO-VEP measures. However, regression analysis showed that N2 amplitude and latency were significant age predictors. Overall, our results indicate that in motion perception, age-related changes occur in early stages of visual processing, most likely in striate and extrastriate visual cortices.
年龄相关的运动感知能力下降已经得到了充分的证明。我们研究了年龄对运动感知的电生理相关性的影响，即运动起始视觉诱发电位（MO-VEPs）的 P1 和 N2 成分。此外，我们使用基于扩散模型的反应时间模型来确定受老化影响的认知过程。12 名健康成年人（年龄<55 岁）和 19 名老年人（年龄>55 岁）在进行脑电图记录的同时完成了运动方向辨别任务。行为上，年轻和年长的参与者具有相似的、高准确率——98%正确，但年长的参与者反应时间长 85 毫秒。用扩散模型拟合行为结果表明，年轻成年人和老年人在非决策时间上存在差异，我们认为这反映了一个早期的感知阶段。电生理上，老年人的 MO-VEPs P1 和 N2 成分在后部位置出现了年龄相关的影响。对于 P1 成分，与年轻成年人相比，老年人显示出更大的地形电压分布。对于老年人的 N2 成分，与年轻成年人相比，我们发现潜伏期延迟和振幅减小。我们没有发现行为和 MO-VEP 测量之间的任何显著相关性。然而，回归分析表明，N2 幅度和潜伏期是年龄的显著预测因素。总的来说，我们的结果表明，在运动感知中，与年龄相关的变化发生在视觉处理的早期阶段，很可能发生在纹状和纹外视觉皮层。
