Moradi Afsane, Mehrinejad Seyed Abolghasem, Ghadiri Mohammad, Rezaei Farzin
Department of Psychology, School of Education of Psychology, University of Alzahra, Tehran, Iran.
Department of Psychiatry, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
Basic Clin Neurosci. 2017 Jan;8(1):27-36. doi: 10.15412/J.BCN.03080104.
Emotional stimulus is processed automatically in a bottom-up way or can be processed voluntarily in a top-down way. Imaging studies have indicated that bottom-up and top-down processing are mediated through different neural systems. However, temporal differentiation of top-down versus bottom-up processing of facial emotional expressions has remained to be clarified. The present study aimed to explore the time course of these processes as indexed by the emotion-specific P100 and late positive potential (LPP) event-related potential (ERP) components in a group of healthy women.
Fourteen female students of Alzahra University, Tehran, Iran aged 18-30 years, voluntarily participated in the study. The subjects completed 2 overt and covert emotional tasks during ERP acquisition.
The results indicated that fearful expressions significantly produced greater P100 amplitude compared to other expressions. Moreover, the P100 findings showed an interaction between emotion and processing conditions. Further analysis indicated that within the overt condition, fearful expressions elicited more P100 amplitude compared to other emotional expressions. Also, overt conditions created significantly more LPP latencies and amplitudes compared to covert conditions.
Based on the results, early perceptual processing of fearful face expressions is enhanced in top-down way compared to bottom-up way. It also suggests that P100 may reflect an attentional bias toward fearful emotions. However, no such differentiation was observed within later processing stages of face expressions, as indexed by the ERP LPP component, in a top-down versus bottom-up way. Overall, this study provides a basis for further exploring of bottom-up and top-down processes underlying emotion and may be typically helpful for investigating the temporal characteristics associated with impaired emotional processing in psychiatric disorders.
情绪刺激可以通过自下而上的方式自动进行处理，也可以通过自上而下的方式进行自主处理。成像研究表明，自下而上和自上而下的处理是由不同的神经系统介导的。然而，面部情绪表达的自上而下与自下而上处理的时间差异仍有待阐明。本研究旨在通过一组健康女性中与情绪特异性P100和晚期正电位（LPP）事件相关电位（ERP）成分来探索这些过程的时间进程。
伊朗德黑兰阿尔扎赫拉大学的14名年龄在18至30岁之间的女学生自愿参与了该研究。受试者在ERP采集过程中完成了两项显性和隐性情绪任务。
结果表明，与其他表情相比，恐惧表情显著产生更大的P100波幅。此外，P100的研究结果显示了情绪与处理条件之间的相互作用。进一步分析表明，在显性条件下，与其他情绪表情相比，恐惧表情引发更多的P100波幅。而且，与隐性条件相比，显性条件产生的LPP潜伏期和波幅明显更多。
基于这些结果，与自下而上的方式相比，恐惧面部表情的早期感知处理在自上而下的方式中得到增强。这也表明P100可能反映了对恐惧情绪的注意力偏向。然而，在表情的后期处理阶段，以ERP的LPP成分为指标，未观察到自上而下与自下而上方式之间的这种差异。总体而言，本研究为进一步探索情绪背后的自下而上和自上而下过程提供了基础，并且可能对研究精神疾病中情绪处理受损相关的时间特征特别有帮助。
