Ключарёв Василий Андреевич

Modulation of choice-induced preference changes using tDCS

2017 · CHAPTER · en

The theory of cognitive dissonance suggests that individuals prefer new incoming information to be consistent with already existing knowledge. Conflicting or inconsistent information results in an emotionally uncomfortable state called cognitive dissonance. Cognitive dissonance theory suggests that a choice between two similarly valued alternatives creates psychological tension (cognitive dissonance) that is reduced by a post-decision re-evaluation of the alternatives. According to the action-based model of cognitive dissonance, activity in the posterior medial prefrontal cortex (pMFC) underlies the detection of cognitive conflicts and the reduction of the dissonance. Nevertheless, the neurocomputational foundation of cognitive dissonance remains unclear. In this study, for the first time we show that cathodal transcranial direct current stimulation (tDCS) of the pMFC significantly reduced post-decision re-evaluation of the alternatives. An ongoing follow-up study that applied anodal tDCS to the pMFC preliminarily showed a tendency to increase choice-induced preference changes. Our results suggest that cognitive dissonance, underlined by the activity of the prefrontal cortex, is a part of the performance-monitoring circuitry

Neurobiological mechanisms of social punishment

2016 · CHAPTER · en

Human societies crucially depend on social norms that specify appropriate actions in various situation. The effect of norms on collective behavior can break down if norm violations are not sanctioned. Social punishment is a form of behavior to enforce social norm compliance that relies on two key brain region: the “mentalizing network” (right temporo-parietal junction – rTPJ) evaluating individual responsibility and the “central-executive network” (right dorsolateral prefrontal cortex – rDLPFC) determining the final decision to punish norm violators. Here we further investigate the role of the brain network – rDLPFC-rTPJ – in third-party punishment. We used transcranial direct-current stimulation (tDCS) to disrupt the rDLPFC-rTPJ network of healthy subjects while they performed the Dictator Game. Our results suggests that the frequency of third-party punishment increased after the tDCS of the rDLPFC-rTPJ. To the best of our knowledge, this is the first study demonstrating the effect of simultaneous tDCS of the rDLPFC and rTPJ on the third-party punishment. We also show that personality traits modulate the effect of tDCS on the third-party punishment.

Neural correlates of informational cascades: brain mechanisms of social influence on belief updating

2015 · ARTICLE · en

Informational cascades can occur when rationally acting individuals decide independently of their private information and follow the decisions of preceding decision-makers. In the process of updating beliefs, differences in the weighting of private and publicly available social information may modulate the probability that a cascade starts in a decisive way. By using functional magnetic resonance imaging, we examined neural activity while participants updated their beliefs based on the decisions of two fictitious stock market traders and their own private information, which led to a final decision of buying one of two stocks. Computational modeling of the behavioral data showed that a majority of participants overweighted private information. Overweighting was negatively correlated with the probability of starting an informational cascade in trials especially prone to conformity. Belief updating by private information was related to activity in the inferior frontal gyrus/anterior insula, the dorsolateral prefrontal cortex and the parietal cortex; the more a participant overweighted private information, the higher the activity in the inferior frontal gyrus/anterior insula and the lower in the parietal-temporal cortex. This study explores the neural correlates of overweighting of private information, which underlies the tendency to start an informational cascade.

Social Influence and Persuasion and Message Propagation

2015 · CHAPTER · en

Our decisions are affected not only by objective information about the available options but also by other people. Recent brain imaging studies have adopted the cognitive neuroscience approach for studying the neural mechanisms of social influence. A number of studies have shown that social influence is associated with neural activity in the medial prefrontal cortex and ventral striatum, which are two brain areas involved in the fundamental and not exclusively social mechanisms of performance monitoring. Therefore, the neural mechanisms of social influence could be deeply integrated into our general neuronal performance-monitoring mechanisms.

Social Influence and Persuasion and Message Propagation. Brain Mapping: An Encyclopedic Reference. Academic Press, 2015.Academic Press: Elsevier, 2015; ISBN: 978-0-12-397025-1

2015 · CHAPTER · en

Brain Mapping: A Comprehensive Reference offers foundational information for students and researchers across neuroscience. With over 300 articles and a media rich environment, this resource provides exhaustive coverage of the methods and systems involved in brain mapping, fully links the data to disease (presenting side by side maps of healthy and diseased brains for direct comparisons), and offers data sets and fully annotated color images. Each entry is built on a layered approach of the content - basic information for those new to the area and more detailed material for experienced readers. Edited and authored by the leading experts in the field, this work offers the most reputable, easily searchable content with cross referencing across articles, a one-stop reference for students, researchers and teaching faculty. Broad overview of neuroimaging concepts with applications across the neurosciences and biomedical research Fully annotated color images and videos for best comprehension of concepts Layered content for readers of different levels of expertise Easily searchable entries for quick access of reputable information Live reference links to ScienceDirect, Scopus and PubMed

Path Dependence in Risky Choice: Affective and Deliberative Processes in Brain and Behavior

2014 · ARTICLE · en

tDecision-makers show an increased risk appetite when they gamble with previously wonmoney, the house money effect, and when they have a chance to make up for a prior loss,the break even effect. To explore the origins of these effects, we use functional magneticresonance imaging to record the brain activities of subjects while they make sequential riskychoices. The behavioral data from our experiment confirm the path dependence of choices,despite the short trial duration and the many task repetitions required for neuroimaging.The brain data yield evidence that the increased risk appetite after gains and losses is relatedto an increased activity of affective brain processes and a decreased activity of deliberativebrain processes.

MEG signature of social conformity: evidence from evoked and induced responses.

2014 · PREPRINT · en

Humans often adjust their behavior to match the group norms. In this study, we used magnetoencephalographic (MEG) source imaging to investigate the electromagnetic responses to the perceived mismatch between individual and group opinions. After participants were exposed to group opinion that conflicted with their own, we observed an evoked response in the posterior medial prefrontal cortex (pMPFC) occurring around 200 ms, corresponding to the feedback-related negativity (FRN) – a component of the evoked response associated with processing negative feedback and reinforcement learning. This response was accompanied by an increase in power of theta oscillations (4-8 Hz) over a number of frontal sites (including OFC and pMPFC). The magnitude of both evoked and induced responses to the perceived conflict with social norms was stronger in participants who showed relatively low conformity. Overall, our results suggest that the activation of the pMPFC following conflicts with group opinion, as recoded by MEG, may reflect an enhanced control state – a process complimentary to the reinforcement learning signal in the ventral striatum reported in previous studies of social conformity

Нейробиологические механизмы социального влияния

2014 · ARTICLE · ru

В последние годы развитие неинвазивных методов исследования активности головного мозга че- ловека позволило пролить свет на нейробиологические механизмы социального влияния на приня- тие решений. В данном обзоре представлены современные нейробиологические исследования соци- ального влияния и обсуждаются ключевые теоретические модели возможных нейробиологических механизмов, лежащих в основе социального влияния. Ряд исследований демонстрирует тесную связь социального влияния с нейрофизиологической системой обучения с подкреплением и контроля де- ятельности. Вероятно, отклонение от поведения (мнения) группы интерпретируется нервной систе- мой как поведенческая ошибка или «ошибка предсказания вознаграждения», что запускает процесс изменения поведения на основе дофаминергического механизма обучения с подкреплением.

Resting state brain activity predicts individuals’ conformity

2013 · CHAPTER · en

The modification of judgments in a group situation: MEG correlates of conformity

2013 · CHAPTER · en