Psicología

URI permanente para esta comunidad

https://repositorio.uft.cl/handle/20.500.12254/2380

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Examinando Psicología por Materia "3.1.4 - Neurociencias"

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    Ítem
    Impact of acute psychosocial stress on attentional control in humans: a study of evoked potentials and pupillary response
    (Elsevier, 2023-07-25) Rojas, Felipe
    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.
  • Miniatura
    Ítem
    Sequential dynamics of memory load: contralateral delay activity and behavioral evidence
    (Wolters Kluwer Health, 2026-04-14) Villena-González, Mario
    Background Working memory is a fundamental component of human cognition, essential for performing complex tasks that require holding and manipulating information. Visuospatial working memory (VSWM) enables the temporary retention of visual and spatial information, with its neural correlates, such as contralateral delay activity (CDA, a component of event-related potentials), providing insights into memory load dynamics. This study aimed to investigate how sequentially presented items are maintained and integrated into VSWM. Methods Twenty-three participants performed a task where three visual items were presented sequentially, followed by a retro-cue and a test array, while accuracy and CDA were measured. Results Behavioral results showed significant differences in accuracy across item positions, with the third item yielding the lowest accuracy. Electrophysiological findings revealed that CDA amplitude was more negative for the second item, suggesting greater cognitive resources were allocated to it compared to the first and third items. Correlations between working memory capacity, task performance, and CDA amplitudes suggest that individuals with higher working memory capacity can better adapt resource distribution to handle sequential information processing, particularly under conditions of increased cognitive load. Conclusion These results suggest that VSWM management involves dynamic, nonuniform allocation of cognitive resources influenced by the serial position of items. These insights expand our understanding of how VSWM processes sequential inputs and may inform future studies on optimizing cognitive strategies for tasks involving complex visual and spatial information.