Publications by authors named "Giannis Lois"

Susceptibility to misinformation and belief polarization often reflects people's tendency to incorporate information in a biased way. Despite the presence of competing theoretical models, the underlying neurocognitive mechanisms of motivated reasoning remain elusive as previous empirical work did not properly track the belief formation process. To address this problem, we employed a design that identifies motivated reasoning as directional deviations from a Bayesian benchmark of unbiased belief updating.

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The low public demand for redistribution despite growing economic inequality has been characterized as a paradox especially for disadvantaged individuals. One prominent explanation for people's tolerance to growing inequality posits that increased optimism about prospects of upward mobility undermines support for redistribution. A less explored explanation postulates that low political efficacy of disadvantaged individuals to enact meaningful change erodes collective demand for redistribution.

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Power imbalance often leads to unequal allocations. However, it remains largely unknown how different forms of power and meritocratic considerations interact to shape fairness perceptions. Using modified Ultimatum Games, we examined how two power forms-decision power and availability of attractive outside option-affect bargaining behavior and fairness perceptions, and how meritocratic considerations are incorporated into the fairness perceptions of powerful and powerless individuals.

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Cognitive emotion regulation is a key mechanism for the maintenance of mental health, but may fail, when individuals are exposed to acute stress. To date, it is not well understood whether and to what extent acute stress effects contribute to impairments in emotion regulation capacities as the sparse existing studies have yielded heterogeneous results, indicating that stress timing might be a crucial factor. In the present study, 81 healthy participants underwent either an acute stress task (ScanSTRESS-C; n = 40) or a control condition (n = 41) while lying in the MRI scanner.

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Bipolar Disorder (BD) has a debilitating impact on psychosocial functioning and social decision-making. Recent evidence using the Ultimatum Game (UG) has shown increased rejection of moderately unfair offers in BD, suggesting impaired processing of ambiguous social information related to fairness. The present study builds upon this finding to investigate the neural substrates of fairness processing in BD.

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Identifying individual differences in stress reactivity is of particular interest in the context of stress-related disorders and resilience. Previous studies already identified several factors mediating the individual stress response of the hypothalamus-pituitary-adrenal axis (HPA). However, the impact of long-term HPA axis activity on acute stress reactivity remains inconclusive.

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Previous studies reported poor to fair test-retest reliability of amygdala BOLD responses to emotional stimuli. However, these findings are very heterogeneous across and within studies. The present study sought to systematically examine experimental and methodological factors that contribute to this heterogeneity.

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Objectives: The human brain is organized into large-scale networks that dynamically interact with each other. Extensive evidence has shown characteristic changes in certain large-scale networks during transitions from internally directed to externally directed attention. The aim of the present study was to compare these context-dependent network interactions during emotion regulation and to examine potential alterations in remitted unipolar and bipolar disorder patients.

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Rumination is associated with increased default-mode network (DMN) activity and functional connectivity (FC) in depressed and healthy individuals. In this study, we sought to examine the relationship between self-reported rumination and resting-state FC in the DMN and cognitive control networks in 25 remitted depressed patients and 25 matched healthy controls using independent component and seed-based analyses. We also explored potential group differences in the global pattern of resting-state FC.

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In the last two decades, neuroimaging research has reached a much deeper understanding of the neurobiological underpinnings of major depression (MD) and has converged on functional alterations in limbic and prefrontal neural networks, which are mainly linked to altered emotional processing observed in MD patients. To date, a considerable number of studies have sought to investigate how these neural networks change with pharmacological antidepressant treatment. In the current review, we therefore discuss results from a) pharmacological functional magnetic resonance imaging (fMRI) studies investigating the effects of selective serotonin or noradrenalin reuptake inhibitors on neural activation patterns in relation to emotional processing in healthy individuals, b) treatment studies in patients with unipolar depression assessing changes in neural activation patterns before and after antidepressant pharmacotherapy, and c) predictive neural biomarkers of clinical response in depression.

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Bipolar disorder is characterized by a functional imbalance between hyperactive ventral/limbic areas and hypoactive dorsal/cognitive brain regions potentially contributing to affective and cognitive symptoms. Resting-state studies in bipolar disorder have identified abnormal functional connectivity between these brain regions. However, most of these studies used a seed-based approach, thus restricting the number of regions that were analyzed.

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G-protein coupled receptors may mediate their effects on neuronal growth and differentiation through activation of extracellular signal-regulated kinases 1/2 (ERK1/2), often elicited by transactivation of growth factor receptor tyrosine kinases. This elaborate signaling process includes inducible formation and trafficking of multiprotein signaling complexes and is facilitated by pre-ordained membrane microdomains, in particular lipid rafts. In this study, we have uncovered novel signaling interactions of cannabinoid receptors with fibroblast growth factor receptors, which depended on lipid rafts and led to ERK1/2 activation in primary neurons derived from chick embryo telencephalon.

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