Codispoti Maurizio, Ferrari Vera, De Cesarei Andrea, Cardinale Rossella
Department of Psychology, University of Bologna, Viale Berti Pichat, 5-40127 Bologna, Italy.
Prog Brain Res. 2006;156:53-65. doi: 10.1016/S0079-6123(06)56003-0.
Event-related potential (ERP) studies have consistently found that emotionally arousing (pleasant and unpleasant) pictures elicit a larger late positive potential (LPP) than neutral pictures in a window from 400 to 800 ms after picture onset. In addition, an early ERP component has been reported to vary with emotional arousal in a window from about 150 to 300 ms with affective, compared to neutral stimuli, prompting significantly less positivity over occipito-temporal sites. Similar early and late ERP components have been found in explicit categorization tasks, suggesting that selective attention to target features results in similar cortical changes. Several studies have shown that the affective modulation of the LPP persisted even when the same pictures are repeated several times, when they are presented as distractors, or when participants are engaged in a competing task. These results indicate that categorization of affective stimuli is an obligatory process. On the other hand, perceptual factors (e.g., stimulus size) seem to affect the early ERP component but not the affective modulation of the LPP. Although early and late ERP components vary with stimulus relevance, given that they are differentially affected by stimulus and task manipulations, they appear to index different facets of picture processing.
事件相关电位（ERP）研究一致发现，在图片呈现后400至800毫秒的时间段内，情绪唤起（愉快和不愉快）的图片比中性图片诱发更大的晚期正电位（LPP）。此外，据报道，与中性刺激相比，在大约150至300毫秒的时间段内，一种早期ERP成分会随着情感唤起而变化，在枕颞部位引发的正性明显较少。在明确的分类任务中也发现了类似的早期和晚期ERP成分，这表明对目标特征的选择性注意会导致类似的皮层变化。几项研究表明，即使相同的图片重复多次、作为干扰物呈现或参与者进行竞争任务时，LPP的情感调制仍然存在。这些结果表明，情感刺激的分类是一个必然过程。另一方面，感知因素（如刺激大小）似乎会影响早期ERP成分，但不会影响LPP的情感调制。尽管早期和晚期ERP成分会随着刺激相关性而变化，但鉴于它们受到刺激和任务操作的不同影响，它们似乎反映了图片处理的不同方面。
