Alperin Brittany R, Mott Katherine K, Rentz Dorene M, Holcomb Phillip J, Daffner Kirk R
Center for Brain/Mind Medicine, Division of Cognitive and Behavioral Neurology, Department of Neurology, Brigham, Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Psychophysiology. 2014 Jul;51(7):620-33. doi: 10.1111/psyp.12206. Epub 2014 Mar 24.
An age-related "anterior shift" in the distribution of the P3b is often reported. Temporospatial principal component analysis (PCA) was used to investigate the basis of this observation. ERPs were measured in young and old adults during a visual oddball task. PCA revealed two spatially distinct factors in both age groups, identified as the posterior P3b and anterior P3a. Young subjects generated a smaller P3a than P3b, while old subjects generated a P3a that did not differ in amplitude from their P3b. Rather than having a more anteriorly distributed P3b, old subjects produced a large, temporally overlapping P3a. The pattern of the age-related "anterior shift" in the P3 was similar for target and standard stimuli. The increase in the P3a in elderly adults may not represent a failure to habituate the novelty response, but may reflect greater reliance on executive control operations (P3a) to carry out the categorization/updating process (P3b).
经常有报道称，P3b分布存在与年龄相关的“前移”现象。采用颞空间主成分分析（PCA）来探究这一观察结果的依据。在年轻和老年成年人进行视觉Oddball任务期间测量了事件相关电位（ERP）。PCA在两个年龄组中均揭示了两个空间上不同的因素，分别确定为后部P3b和前部P3a。年轻受试者产生的P3a比P3b小，而老年受试者产生的P3a在幅度上与其P3b没有差异。老年受试者并非具有更靠前分布的P3b，而是产生了一个大的、时间上重叠的P3a。对于目标刺激和标准刺激，P3中与年龄相关的“前移”模式是相似的。老年人P3a的增加可能并不代表对新奇反应的习惯化失败，而是可能反映出在执行分类/更新过程（P3b）时对执行控制操作（P3a）的更大依赖。
