Insel Nathan, Ruiz-Luna María Luisa, Permenter Michelle, Vogt Julie, Erickson Cynthia A, Barnes Carol A
Evelyn F McKnight Brain Institute, University of Arizona, Tucson, AZ 85724, USA.
Behav Neurosci. 2008 Dec;122(6):1328-42. doi: 10.1037/a0012928.
Studies demonstrating recognition deficits with aging often use tasks in which subjects have an incentive to correctly encode or retrieve the experimental stimuli. In contrast to these tasks, which may engage strategic encoding and retrieval processes, the visual paired comparison (VPC) task measures spontaneous eye movements made toward a novel as compared with familiar stimulus. In the present study, seven rhesus macaques aged 6 to 30 years exhibited a dramatic age-dependent decline in preference for a novel image compared with one presented seconds earlier. The age effect could not be accounted for by memory deficits alone, because it was present even when familiarization preceded test by 1 second. It also could not be explained by an encoding deficit, because the effect persisted with increased familiarity of the sample stimulus. Reduced novelty preference did correlate with eye movement variables, including reaction time distributions and saccade frequency. At long delay intervals (24 or 48 hours) aging was paradoxically associated with increased novelty preference. Several explanations for the age effect are considered, including the possible role of dopamine.
表明衰老会导致认知缺陷的研究通常使用一些任务，在这些任务中，受试者有动力正确编码或检索实验刺激。与这些可能涉及策略性编码和检索过程的任务不同，视觉配对比较（VPC）任务测量的是与熟悉刺激相比，对新刺激产生的自发眼动。在本研究中，7只6至30岁的恒河猴表现出与年龄相关的显著下降，即与几秒前呈现的图像相比，对新图像的偏好降低。年龄效应不能仅由记忆缺陷来解释，因为即使在测试前1秒进行了熟悉化处理，这种效应仍然存在。它也不能用编码缺陷来解释，因为随着样本刺激熟悉度的增加，这种效应仍然持续。新奇偏好的降低确实与眼动变量相关，包括反应时间分布和扫视频率。在长延迟间隔（24或48小时）时，衰老与新奇偏好增加存在矛盾的关联。研究考虑了对年龄效应的几种解释，包括多巴胺可能发挥的作用。
