TMS study of the role of the medial and dorsolateral prefrontal cortex in the post-decisional spreading of alternatives

The theory of cognitive dissonance suggested by Leon Festinger (1957) relies on the psychological observations of the inconsistency between people's choice and actions and proposes that the conflict between choice and actions causes the internal conflict named cognitive dissonance, which leads to the potential modification of the behavior or attitudes to reduce or eliminate this aversive state. Neuroimaging and stimulation studies revealed different neural correlates of the cognitive dissonance, including the medial prefrontal cortex, which is associated with identifying the internal conflict during making a complex choice, and dorsolateral prefrontal cortex implemented into the cognitive control. However, the order and timing of stages of the internal conflict emergence and subsequent changes in behavior and attitudes, which can be revealed by stimulation methods, has never been properly studied. The sample size was defined based on the study of Izuma and colleagues (2015), but since we have only 1 group and the within-subject design, our sample consists of 30 participants. The behavioral task will be realized in the framework of the choice-blindness paradigm of studying the post-decisional spreading of alternatives. The online transcranial magnetic stimulation (TMS) will be performed during the choice task. The TMS timing will give the opportunity to measure the neurochronometry of cognitive dissonance not only after the decision-making process, but also during it. We are going to apply the high-frequency (20 Hz) stimulation to pMFC and DLPFC at the intensity of 90% from the passive motor threshold, while in control groups the vertex will be stimulated, and stimulation with 10% intensity will be applied. The exact stimulation points were adopted from previous fMRI studies (Izuma et al., 2010; Izuma & Adolphs, 2013; Voight et al., 2019).