Browsing by Author "López, V."

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    Immediate effects of psychosocial stress on attention depend on subjective experience and not directly on stress-related physiological changes
    (2017) Palacios García, I.; Villena González, Mario; Campos Arteaga, G.; Artigas Vergara, C.; Jaramillo, K.; López, V.; Rodríguez, E.; Silva, J. R.
    Acute psychosocial stress is associated with physiological, subjective and cognitive changes. In particular, attention, which is considered one of the main processes driving cognition, has beenrelated to different stress outcomes, such as anxiety, cortisol levels and autonomic responses,individually. Nonetheless, their specific contributions to and association with attention is still notfully understood. To study this association, 42 male participants were asked to perform an attentional task just before and immediately after being exposed to either an experimental treatment designed to induce psychosocial stress using the Trier Social Stress Test (TSST) or a matching stress-free control condition. The salivary cortisol concentration, heart rate, and selfreported anxiety were measured to assess the physiological response to stress and the subjective experience during the protocol. As expected, psychosocial stress induced increases in heart rate, salivary cortisol levels and anxiety. The behavioral analysis revealed that members of the control group performed better on the attentional task after the protocol, while members of the TSST group showed no changes. Moreover, after dividing the stress group into sub-groups of participants with high and low anxiety, we observed that participants in the high-anxiety group not only failed to perform better but also performed worse. Finally, after testing several single-level mediation models, we found that anxiety is sufficient to explain the changes in attention and that it mediates the effects between heart rate and cortisol levels on attention. Our results suggest that the immediate effects of acute psychosocial stress on attention are highly dependent on the participant’s subjective experience, which, in turn, is affected and can mediate stress-related physiological changes.
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    Impact of acute psychosocial stress on attentional control in humans. A study of evoked potentials and pupillary response
    (2023) Rojas Thomas, Felipe Eduardo; Artigas, C.; Wainstein, G.; Morales, Juan-Pablo; Arriagada, M.; Soto, D.; Dagnino-Subiabre, A.; Silva, J.; López, V.Rojas Thomas, Felipe Eduardo; Artigas, C.; Wainstein, G.; Morales, Juan-Pablo; Arriagada, M.; Soto, D.; Dagnino-Subiabre, A.; Silva, J.; López, V.
    Psychosocial stress has increased considerably in our modern lifestyle, affecting global mental health. Deficits in attentional control are cardinal features of stress disorders and pathological anxiety. Studies suggest that changes in the locus coeruleus-norepinephrine system could underlie the effects of stress on top-down attentional control. However, the impact of psychosocial stress on attentional processes and its underlying neural mechanisms are poorly understood. This study aims to investigate the effect of psychosocial stress on attentional processing and brain signatures. Evoked potentials and pupillary activity related to the oddball auditory paradigm were recorded before and after applying the Montreal Imaging Stress Task (MIST). Electrocardiogram (ECG), salivary cortisol, and subjective anxiety/stress levels were measured at different experimental periods. The control group experienced the same physical and cognitive effort but without the psychosocial stress component. The results showed that stressed subjects exhibited decreased P3a and P3b amplitude, pupil phasic response, and correct responses. On the other hand, they displayed an increase in Mismatch Negativity (MMN). N1 amplitude after MIST only decreased in the control group. We found that differences in P3b amplitude between the first and second oddball were significantly correlated with pupillary dilation and salivary cortisol levels. Our results suggest that under social-evaluative threat, basal activity of the coeruleus-norepinephrine system increases, enhancing alertness and decreasing voluntary attentional resources for the cognitive task. These findings contribute to understanding the neurobiological basis of attentional changes in pathologies associated with chronic psychosocial stress.
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    Postoperative adjuvant treatment for gastric cancer improves long-tenn survival after curative resection and D2 lymphadenectomy. Results from a Latin American Center
    (2016) Norero Muñoz, Enrique; Bustos Carrasco, Marisa Orietta; Herrera, M.; Cerda, Jaime; González, P.; Ceroni Villanelo, Marco; Martínez Belmar, Cristian Antonio; Briceño, Eduardo; Rojas Romero, Hernán Humberto; Cartes, R.; López, V.; Hidalgo, V.; Báez, S.; Caracci, M.; Viñuela, E.; Díaz, A.
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    There Is No Face Like Home: Ratings for Cultural Familiarity to Own and Other Facial Dialects of Emotion With and Without Conscious Awareness in a British Sample
    (2019) Tsikandilakis, M.; Kausel Kamp, Leonie Margarita; Boncompte, G.; Yu, Z. L.; Oxner, M.; Lanfranco, R.; Bali, P.; Urale, P.; Peirce, J.; López, V.; Tong, E. M. W.; William, H.; Carmel, D.; Derrfuss, J.; Chapman, P.