INSERM U877, Faculty of Medicine, Domaine de La Merci, 38700 La Tronche, France.
Neuroscience. 2010 Nov 24;171(1):173-86. doi: 10.1016/j.neuroscience.2010.08.051. Epub 2010 Aug 27.
Previous electrophysiological studies revealed that human faces elicit an early visual event-related potential (ERP) within the occipito-temporal cortex, the N170 component. Although face perception has been proposed to rely on automatic processing, the impact of selective attention on N170 remains controversial both in young and elderly individuals. Using early visual ERP and alpha power analysis, we assessed the influence of aging on selective attention to faces during delayed-recognition tasks for face and letter stimuli, examining 36 elderly and 20 young adults with preserved cognition. Face recognition performance worsened with age. Aging induced a latency delay of the N1 component for faces and letters, as well as of the face N170 component. Contrasting with letters, ignored faces elicited larger N1 and N170 components than attended faces in both age groups. This counterintuitive attention effect on face processing persisted when scenes replaced letters. In contrast with young, elderly subjects failed to suppress irrelevant letters when attending faces. Whereas attended stimuli induced a parietal alpha band desynchronization within 300-1000 ms post-stimulus with bilateral-to-right distribution for faces and left lateralization for letters, ignored and passively viewed stimuli elicited a central alpha synchronization larger on the right hemisphere. Aging delayed the latency of this alpha synchronization for both face and letter stimuli, and reduced its amplitude for ignored letters. These results suggest that due to their social relevance, human faces may cause paradoxical attention effects on early visual ERP components, but they still undergo classical top-down control as a function of endogenous selective attention. Aging does not affect the face bottom-up alerting mechanism but reduces the top-down suppression of distracting letters, possibly impinging upon face recognition, and more generally delays the top-down suppression of task-irrelevant information.
先前的电生理研究表明，人类面孔会在枕颞叶皮层中引发一种早期视觉事件相关电位（ERP），即 N170 成分。尽管人们提出面孔感知依赖于自动加工，但选择性注意对 N170 的影响在年轻人和老年人中都存在争议。我们使用早期视觉 ERP 和 alpha 功率分析来评估衰老对面孔选择性注意的影响，在延迟识别任务中评估面孔和字母刺激，共纳入 36 名认知正常的老年人和 20 名年轻人。面孔识别成绩随年龄增长而下降。衰老导致面孔和字母的 N1 成分以及面孔的 N170 成分潜伏期延长。与字母不同的是，在两个年龄组中，被忽视的面孔比被注意的面孔诱发更大的 N1 和 N170 成分。这种对面孔加工的反直觉的注意效应在场景取代字母时仍然存在。与年轻人不同的是，老年人在注意面孔时无法抑制不相关的字母。当注意刺激时，在刺激后 300-1000ms 期间，双侧至右侧分布的顶叶 alpha 频段去同步化，而对字母则为左侧偏侧化；当忽略和被动观看刺激时，右侧半球的中央 alpha 同步化较大。衰老延迟了面孔和字母刺激的 alpha 同步化潜伏期，并降低了对忽略字母的振幅。这些结果表明，由于人类面孔的社交相关性，它们可能会对面孔的早期视觉 ERP 成分产生矛盾的注意效应，但它们仍然会根据内源性选择性注意进行经典的自上而下的控制。衰老不会影响面孔的下传警觉机制，但会降低对分心字母的自上而下抑制，这可能会干扰面孔识别，更广泛地说，会延迟对无关信息的自上而下抑制。
