Fabiani M, Friedman D
Cognitive Electrophysiology Laboratory, New York State Psychiatric Institute, NY 10032, USA.
Psychophysiology. 1995 Nov;32(6):579-94. doi: 10.1111/j.1469-8986.1995.tb01234.x.
A decrease in the frontal lobes' efficiency is supposed to play a role in age-related changes in cognitive function. If frontal lobes are involved in the maintenance of working memory, the elderly may require increased frontal activity because of more rapid memory decay. This is consistent with the fact that the P3 component of the event-related potential (ERP) has a more frontal orientation with increasing age. However, frontally distributed P3s are also observed in young people when novel stimuli are unexpectedly presented in an oddball paradigm. Young and old subjects were run in an auditory novelty oddball in which ERPs were recorded from 30 scalp sites. The young adults' P3s showed either a posterior (targets) or more frontally oriented (novels) scalp focus. The elderly were less accurate in their memory for the novel stimuli, and their P3s showed anterior and posterior foci to both targets and novels. The young adults' target P3s changed over time from a frontal to a posterior focus, whereas the old adults' did not. These results are consistent with decreased ability of the elderly to maintain the templates needed for stimulus categorization.
额叶效率的降低被认为在认知功能的年龄相关变化中起作用。如果额叶参与工作记忆的维持，由于记忆衰退更快，老年人可能需要增加额叶活动。这与事件相关电位（ERP）的P3成分随着年龄增长更偏向额叶的事实是一致的。然而，当新刺激在意料之外的奇偶数范式中呈现时，年轻人也会观察到额叶分布的P3。年轻和老年受试者参加了一个听觉新奇奇偶数实验，在该实验中从30个头皮部位记录ERP。年轻成年人的P3在头皮上要么表现为后部（目标）焦点，要么更偏向额叶（新奇刺激）焦点。老年人对新奇刺激的记忆准确性较低，他们的P3在目标和新奇刺激上都表现出前部和后部焦点。年轻成年人的目标P3随时间从额叶焦点变为后部焦点，而老年人则没有。这些结果与老年人维持刺激分类所需模板的能力下降是一致的。
