Weschke Sarah, Niedeggen Michael
Department of Education and Psychology, Freie Universität Berlin, Berlin, Germany.
PLoS One. 2016 Apr 21;11(4):e0153941. doi: 10.1371/journal.pone.0153941. eCollection 2016.
The phenomenon of social exclusion can be investigated by using a virtual ball-tossing game called Cyberball. In neuroimaging studies, structures have been identified which are activated during social exclusion. But to date the underlying mechanisms are not fully disclosed. In previous electrophysiological studies it was shown that the P3 complex is sensitive to exclusion manipulations in the Cyberball paradigm and that there is a correlation between P3 amplitude and self-reported social pain. Since this posterior event-related potential (ERP) was widely investigated using the oddball paradigm, we directly compared the ERP effects elicited by the target (Cyberball: "ball possession") and non-target (Cyberball: "ball possession of a co-player) events in both paradigms. Analyses mainly focused on the effect of altered stimulus probabilities of the target and non-target events between two consecutive blocks of the tasks. In the first block, the probability of the target and non-target event was 33% (Cyberball: inclusion), in the second block target probability was reduced to 17%, and accordingly, non-target probability was increased to 66% (Cyberball: exclusion). Our results indicate that ERP amplitude differences between inclusion and exclusion are comparable to ERP amplitude effects in a visual oddball task. We therefore suggest that ERP effects--especially in the P3 range--in the Oddball and Cyberball paradigm rely on similar mechanisms, namely the probability of target and non-target events. Since the simulation of social exclusion (Cyberball) did not trigger a unique ERP response, the idea of an exclusion-specific neural alarm system is not supported. The limitations of an ERP-based approach will be discussed.
社会排斥现象可以通过一种名为“赛博球”的虚拟抛球游戏来进行研究。在神经影像学研究中，已经确定了在社会排斥过程中被激活的结构。但迄今为止，其潜在机制尚未完全揭示。在以往的电生理研究中发现，P3复合体对赛博球范式中的排斥操作敏感，并且P3波幅与自我报告的社交痛苦之间存在相关性。由于这种后部事件相关电位（ERP）在oddball范式中得到了广泛研究，我们直接比较了两种范式中目标事件（赛博球：“持球”）和非目标事件（赛博球：“同组玩家持球”）所引发的ERP效应。分析主要集中在任务的两个连续块之间目标和非目标事件刺激概率变化的影响上。在第一个块中，目标和非目标事件的概率均为33%（赛博球：包含），在第二个块中，目标概率降至17%，相应地，非目标概率增至66%（赛博球：排斥）。我们的结果表明，包含和排斥之间的ERP波幅差异与视觉oddball任务中的ERP波幅效应相当。因此，我们认为oddball和赛博球范式中的ERP效应——尤其是在P3范围内——依赖于相似的机制，即目标和非目标事件的概率。由于社会排斥模拟（赛博球）并未引发独特的ERP反应，因此不支持存在特定于排斥的神经警报系统这一观点。我们将讨论基于ERP方法的局限性。
