Шестакова Анна Николаевна

Impact of induced moods, sensation seeking, and emotional contagion on economic decisions under risk

2022 · ARTICLE · en

In addition to probabilities of monetary gains and losses, personality traits, socio-economic factors, and specific contexts such as emotions and framing influence financial risk taking. Here, we investigated the effects of joyful, neutral, and sad mood states on participants’ risk-taking behaviour in a simple task with safe and risky options. We also analysed the effect of framing on risk taking. In different trials, a safe option was framed in terms of either financial gains or losses. Moreover, we investigated the effects of emotional contagion and sensation-seeking personality traits on risk taking in this task. We did not observe a significant effect of induced moods on risk taking. Sad mood resulted in a slight non-significant trend of risk aversion compared to a neutral mood. Our results partially replicate previous findings regarding the presence of the framing effect. As a novel finding, we observed that participants with a low emotional contagion score demonstrated increased risk aversion during a sad mood and a similar trend at the edge of significance was present in high sensation seekers. Overall, our results highlight the importance of taking into account personality traits of experimental participants in financial risk-taking studies.

Frequency tagging of syntactic structure or lexical properties; a registered MEG study

2022 · ARTICLE · en

A traditional view on sentence comprehension holds that the listener parses linguistic input using hierarchical syntactic rules. Recently, physiological evidence for such a claim has been provided by Ding et al.’s (2016) MEG study that demonstrated, using a frequency-tagging paradigm, that regularly occurring syntactic constituents were spontaneously tracked by listeners. Even more recently, this study's results have been challenged as artifactual by Frank and Yang (2018) who successfully re-created Ding's results using a distributional semantic vector model that relied exclusively on lexical information and did not appeal to any hierarchical syntactic representations. The current MEG study was designed to dissociate the two interpretations of Ding et al.’s results. Taking advantage of the morphological richness of Russian, we constructed two types of sentences of different syntactic structure; critically, this was achieved by manipulating a single affix on one of the words while all other lexical roots and affixes in the sentence were kept the same. In Experiment 1, we successfully verified the intuition that due to almost complete lexical overlap the two types of sentences should yield the same activity pattern according to Frank and Yang’s (2018) lexico-semantic model. In Experiment 2, we recorded Russian listeners' MEG activity while they listened to the two types of sentences. Contradicting the hierarchical syntactic account and consistent with the lexico-semantic one, we observed no difference across the conditions in the way participants tracked the stimuli properties. Corroborated by other recent evidence, our findings show that peaks interpreted by Ding et al. as reflecting higher-level syntactic constituency may stem from non-syntactic factors.

N400 correlate of brand associations

2022 · ARTICLE · en

A number of neuromarketing studies employed brain responses called event-related potentials or ERPs as neural markers of brand associations. The use of the N400 component of ERPs in particular appeared to be the promising to study typicality of product-brand associations and their role for brand extension (Wang et al., 2012). The question, however, remains whether the N400 observed in the product-brand associations and brand associations as such can be explained by the same neurobiological mechanisms as the classical N400 response which in the neuroscience of language reflects semantic associations. In this electroencephalographic study, we compared semantic N400 in response to incongruency of sentence endings with the neural response to the degree of incongruency of associations to brands. To test, whether in the same subjects, incongruent brand associations would elicit the N400 brain response resembling semantic N400 we constructed two-word phrases in which brand names were proceeded by congruent or incongruent adjectives that played the role of brand associations. Sentences lacking any marketing context served as control stimuli and evoked classical centro-parietally distributed N400 response. The sensitivity of the brain activity to the incongruent brand associations was manifested in the fronto-centrally distributed N400 response within the same time window as in the non-marketing context. However, the correlation analysis of the N400 amplitudes in the brand and non-brand conditions did not reveal significant association between them suggesting different neuronal networks subserving processing of pure semantic and brand-association incongruences. To conclude, further studies employing multichannel EEG or magnetoencephalographic imaging would be necessary to elucidate the brain origin of brand and marketing associations as compared to pure semantic associations.

Использование транскраниальной магнитной стимуляции в исследованиях когнитивного диссонанса при принятии решений

2022 · ARTICLE · ru

Теория когнитивного диссонанса тесно связана с исследованием процесса принятия сложных решений. Механизмы когнитивного диссонанса связывают с активностью задней медиальной и дорсолатеральной префронтальной коры, прилежащего ядра и задней поясной коры, взаимосвязь которых по-разному интерпретируют по результатам нейровизуализационных и стимуляционных исследований. Одним из ключевых вопросов понимания механизмов когнитивного диссонанса является нейрохронометрия его возникновения и редуцирования, раскрытие которой возможно с помощью методов ТМС и ТЭС. ТМС и ТЭС протоколы влияния на когнитивный диссонанс различаются такими параметрами, как мишень, момент, частота, сила стимуляции, контрольные условия, что не позволяет напрямую сравнивать результаты исследований. Однако анализ стимуляционных исследований когнитивного диссонанса показал, что как краткосрочная высокочастотная, так и длительная низкочастотная стимуляция медиальной префронтальной коры значительно снижают влияние когнитивного диссонанса на предпочтения.

"Expert persuasion" can decrease Willingness to Pay for sugar-containing food

2022 · ARTICLE · en

Recent studies have revealed types of eating nudges that can steer consumers towards choosing healthier options. However, most of the previously studied interventions target individual decisions and are not directed to changing consumers’ underlying perception of unhealthy food. Here, we investigate how a healthy eating call - first-person narrative by a health expert - affects individuals’ willingness to pay (WTP) for sugar-free and sugar-containing food products. Participants performed two blocks of a bidding task, in which they had to bid on sweets labeled either as “sugar-free” or as “sugar-containing”. In-between the two blocks, half of the participants listened to a narrative by a dietary specialist emphasizing the health risks of sugar consumption, whereas the remaining participants listened to a control narrative irrelevant to food choices. We demonstrate that the health expert’s narrative decreased individuals’ WTP for sugar-containing food, but did not modulate their WTP for sugar-free food. Overall, our findings confirm that consumers may conform to healthy eating calls by rather devaluating unhealthy food products than by increasing the value of healthy ones. This paves the way for an avenue of innovative marketing strategies to support individuals in their food choices.

MEG study of somatosensory MMN evoked by electrical stimulation

2022 в печати · ARTICLE · en

Компонент вызванных потенциалов негативности рассогласования (НР) является перспективным инструментом для изучения механизмов нейропластичности, сенсорной памяти и других аспектов функционирования сенсорных систем в норме и патологии. Несмотря на многочисленные НР исследования в слуховой модальности, механизмы соматосенсорной НР остаются недостаточно изученными. Мы использовали электростимуляцию в “oddball”-парадигме, состоящей из двух блоков со стандартными (80%) и девиантными (20%) стимулами во время просмотра видеофильмов. Пермутационные тесты выявили значимые различия между ответами на стандартные и девиантные стимулы в условии, связанном с восприятием стандартного стимула указательным пальцем кисти и девиантного стимула мизинцем во временном окне 90–170 мс. Мы наблюдали фронто-центральное распределение компонента НР, схожее по пространственно-временной картине с соматосенсорным НР, известным по литературным данным. Основываясь на результатах нашей работы, мы считаем нужным проводить дополнительные исследования для выявления условий, в которых выявление НР является надежным, а также максимально комфортным для участников.

Do sparse brain activity patterns underlie human cognition?

2022 · ARTICLE · en

Accumulating multivariate pattern analysis (MVPA) results from fMRI studies suggest that information is represented in fingerprint patterns of activations and deactivations during perception, emotions, and cognition. We postulate that these fingerprint patterns might reflect neuronal-population level sparse code documented in two-photon calcium imaging studies in animal models, i.e., information represented in specific and reproducible ensembles of a few percent of active neurons amidst widespread inhibition in neural populations. We suggest that such representations constitute a fundamental organizational principle via interacting across multiple levels of brain hierarchy, thus giving rise to perception, emotions, and cognition.

ТРАНСКРАНИАЛЬНАЯ ЭЛЕКТРОСТИМУЛЯЦИЯ ПОСТОЯННЫМ ТОКОМ МОДУЛИРУЕТ КОМПОНЕНТ НЕГАТИВНОСТИ РЕЗУЛЬТАТА ДЕЙСТВИЯ В МОНЕТАРНОЙ ИГРЕ

2022 · ARTICLE · ru

Настоящее исследование было направлено на изучение нейрофизиологических эффектов транскраниальной стимуляции постоянным электрическим током (tDCS) в отношении компонента вызванных потенциалов, называемого “негативность результата действия” (feedback-related negativity, FRN). Испытуемые выполняли задачу на отложенное денежное подкрепление, во время которой пытались избежать денежных потерь различной величи- ны. Мы сравнили амплитуду FRN в ответ на информацию о денежной потере в контроль- ной группе с группой, получавшей катодную стимуляцию вентромедиальной префрон- тальной коры. Основываясь на имеющихся в литературе данных, мы предположили, что катодная tDCS будет подавлять амплитуду компонента FRN. Вопреки нашей гипотезе, ве- личина компонента в группе стимуляции была значимо выше, чем в контрольной группе. Данные результаты могут служить как дополнительным свидетельством усиливающего действия катодной tDCS, так и привести к предположению о том, что нейросети, участву- ющие в генерации сигнала при обработке денежной потери, отличаются от таковых при игре, не связанной с денежным вознаграждением

Effects of transspinal electrical stimulation estimated by transcranial magnetic stimulation

2022 · CHAPTER · en

The current study aimed to demonstrate the specifics of the effect of anodal transspinal direct current stimulation (tsDCS) applied at the level of the cervical spinal cord thickening on the corticospinal system of a healthy person. The study involved 54 healthy adults aged 22+/-4 years. Our results showed that application of a 1l-minute anodal tsDCS at the level of the cervical spinal cord C7-Th1 with a current value of 1.5 mA has an effect on the muscles of the upper limbs. In particular, the effect of tsDCS is a decrease in motor evoked potentials (MEP) amplitude immediately after stimulation, and an increase in amplitude 15 minutes after stimulation. These results can be explained by the fact that tsDCS induces changes in the excitability of the corticospinal tract, thereby causing suprasegmental effects in the brain and brainstem. The statistical analysis demonstrated that the dynamics of MEP amplitudes differs between groups receiving anodal tsDCS and sham stimulation. Altogether, these findings point to the need for further research into the effects of tsDCS on the upper limbs, as the effects of tsDCS are often limited to studies of the lower limbs. The current study showed that the noninvasive cervical tsDCS can modulate the excitability of the corticospinal tract, and thus can probably have a positive effect on the production of motor skills.

Effects of noninvasive anodal transspinal direct current stimulation of the cervical segments on motor learning in healthy subjects

2022 · CHAPTER · en