Holbrook Colin, Gordon Chelsea L, Iacoboni Marco
Department of Cognitive and Information Sciences, University of California, Merced;
Department of Cognitive and Information Sciences, University of California, Merced.
J Vis Exp. 2018 Sep 28(139):58204. doi: 10.3791/58204.
Decades of behavioral science research have documented functional shifts in attitudes and ideological adherence in response to various challenges, but little work to date has illuminated the neural mechanisms underlying these dynamics. This paper describes how continuous theta burst transcranial magnetic stimulation may be employed to experimentally assess the causal contribution of cortical regions to threat-related ideological shifts. In the example protocol provided here, participants are exposed to a threat prime-an explicit reminder of their own inevitable death and bodily decomposition-following a downregulation of the posterior medial frontal cortex (pMFC) or a sham stimulation. Next, disguised within a series of distracter tasks, participants' relative degree of ideological adherence is assessed-in the present example, with regard to coalitional prejudice and religious belief. Participants for whom the pMFC has been downregulated exhibit less coalitionally biased responses to an immigrant critical of the participants' national in-group, and less conviction in positive afterlife beliefs (i.e., God, angels, and heaven), despite having recently been reminded of death. These results complement prior findings that continuous theta burst stimulation of the pMFC influences social conformity and sharing and illustrate the feasibility of investigating the neural basis of high-level social cognitive shifts using transcranial magnetic stimulation.
数十年来，行为科学研究记录了人们在面对各种挑战时态度和意识形态依从性的功能转变，但迄今为止，几乎没有研究阐明这些动态变化背后的神经机制。本文描述了如何利用连续 theta 爆发式经颅磁刺激来通过实验评估皮质区域对与威胁相关的意识形态转变的因果贡献。在此提供的示例方案中，在对后内侧前额叶皮层（pMFC）进行下调或假刺激后，让参与者接触一个威胁启动刺激——明确提醒他们自己不可避免的死亡和身体腐烂。接下来，在一系列干扰任务中，评估参与者意识形态依从性的相对程度——在本示例中，涉及联盟偏见和宗教信仰。pMFC 被下调的参与者对批评其国家内群体的移民表现出较少的联盟偏见反应，并且对积极来世信仰（即上帝、天使和天堂）的信念也较弱，尽管他们最近被提醒过死亡。这些结果补充了先前的研究发现，即对 pMFC 进行连续 theta 爆发式刺激会影响社会从众性和分享行为，并说明了使用经颅磁刺激研究高级社会认知转变神经基础的可行性。
