STECHER GUZMAN, XIMENA PATRICIA
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STECHER GUZMAN, XIMENA PATRICIA
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xstecher@udd.cl
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56394442700

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2024 2024 2023 2023 2022 2022 0.0 0.0 0.2 0.2 0.4 0.4 0.6 0.6 0.8 0.8 1.0 1.0

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Publication

The parietal cortex has a causal role in ambiguity computations in humans

2024 , Gabriela Valdebenito-Oyarzo , María Paz Martínez-Molina , SOTO ICAZA, PATRICIA , Francisco Zamorano , Alejandra Figueroa-vargas , Josefina Larraín-Valenzuela , Ximena Stecher , César Salinas , Julien Bastin , Antoni Valero-Cabré , Rafael Polania , BILLEKE BOBADILLA, PABLO ERNESTO , Matthew F. S. Rushworth

Humans often face the challenge of making decisions between ambiguous options. The level of ambiguity in decision-making has been linked to activity in the parietal cortex, but its exact computational role remains elusive. To test the hypothesis that the parietal cortex plays a causal role in computing ambiguous probabilities, we conducted consecutive fMRI and TMS-EEG studies. We found that participants assigned unknown probabilities to objective probabilities, elevating the uncertainty of their decisions. Parietal cortex activity correlated with the objective degree of ambiguity and with a process that underestimates the uncertainty during decision-making. Conversely, the midcingulate cortex (MCC) encodes prediction errors and increases its connectivity with the parietal cortex during outcome processing. Disruption of the parietal activity increased the uncertainty evaluation of the options, decreasing cingulate cortex oscillations during outcome evaluation and lateral frontal oscillations related to value ambiguous probability. These results provide evidence for a causal role of the parietal cortex in computing uncertainty during ambiguous decisions made by humans.

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Us versus them mentality in football fans: Significant social defeat engages the mentalization network and disengages cognitive control areas

2022 , ZAMORANO MENDIETA, FRANCISCO , CARVAJAL PAREDES, PATRICIO ALEJANDRO , SOTO ICAZA, PATRICIA , César Salinas , STECHER GUZMAN, XIMENA PATRICIA , MUÑOZ REYES, JOSÉ ANTONIO , Vladimir López , Waldemar Méndez , Joel Barrera , Gonzalo Aragón-Caqueo , BILLEKE BOBADILLA, PABLO ERNESTO

Social affiliation is one of the building blocks that shapes cultures and communities. This motivation contributes to the development of social bonding among individuals within a group, enjoying rights, assuming obligations, and strengthening its identity. Evidence has shown that social affiliation has inspired different social phenomena, such as wars, political movements, social struggles, among others, based on two human motivations: the ingroup love and the outgroup hate. One contemporary group to study as a proxy of social affiliation, and ingroup and outgroup motivations is the sports competition. However, this affiliation model has been poorly considered in social neuroscience research. This research aimed to shed light on the neurobiological networks that are related to social affiliation in football fans of two of the most popular Chilean football teams. Methods: To this end, 43 male fans of two football rival teams watched videos of winning and losing goals of their favorite team while their brain activity was measured with functional magnetic resonance imaging (fMRI). Results: The results showed that while the activation of the reward system was observed in fans when their team scores goals against the rival, both the activation of the mentalization network and the inhibition of the dorsal anterior cingulate cortex were associated with the emotional correlates of defeat in football fans. Conclusions: Taking these findings together could contribute to a deeper understanding of social affiliation, and more importantly, of extreme affiliation phenomena, and fanaticism.

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