Browsing by Author "Rojas Thomas, Felipe"

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    Altered Sensory and Stress Responses in Atopic Dermatitis: Effects of Acute Stress on Lesional and Non-Lesional Skin
    (WILEY, 2025) Tejos Bravo, Macarena; Cid, Dixon; Espinoza, Fernanda; Rojas Thomas, Felipe; Torres, Gustavo; Cossio, Maria Laura; Borzutzky, Arturo; Calvo, Margarita
    Itch and pain are both mediated by small sensory fibres. Atopic dermatitis (AD) patients usually report stress-induced flares, but the impact of stress on sensory fibres in lesional and non-lesional skin remains inconclusive. This observational study assessed the effect of acute stress on sensory profiles in subjects with AD (n = 18) and healthy controls (HC, n = 21). Participants completed clinical and psychological questionnaires, and quantitative sensory testing was performed on lesional and non-lesional skin in AD and healthy skin in HC. Assessments were done before and after the Montreal Imaging Stress Task, an acute stress protocol. Stress responses were evaluated by anxiety ratings, heart rate (HR) and salivary cortisol (CORT). Cortisol binding globulin (CBG) was quantified as an indirect measure for circulating CORT. AD participants reported higher anxiety, depression and stress perception than HC. HR was similar between groups, but AD participants showed a blunted CORT response post-stress and lower CBG levels, suggesting altered stress regulation. Acute stress reduced cold sensitivity in HC and non-lesional AD skin but had no effect on lesions. These findings indicate that the effects of stress on small fibres depend on the condition of the skin and emphasise the sensory alterations experienced by AD patients.
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    Altered Sensory and Stress Responses in Atopic Dermatitis: Effects of Acute Stress on Lesional and Non-Lesional Skin
    (HUMANA PRESS INC, 2025) Tejos Bravo, Macarena; Cid, Dixon; Espinoza, Fernanda; Rojas Thomas, Felipe; Torres, Gustavo; Cossio, Maria Laura; Borzutzky, Arturo; Calvo, Margarita
    Itch and pain are both mediated by small sensory fibres. Atopic dermatitis (AD) patients usually report stress-induced flares, but the impact of stress on sensory fibres in lesional and non-lesional skin remains inconclusive. This observational study assessed the effect of acute stress on sensory profiles in subjects with AD (n = 18) and healthy controls (HC, n = 21). Participants completed clinical and psychological questionnaires, and quantitative sensory testing was performed on lesional and non-lesional skin in AD and healthy skin in HC. Assessments were done before and after the Montreal Imaging Stress Task, an acute stress protocol. Stress responses were evaluated by anxiety ratings, heart rate (HR) and salivary cortisol (CORT). Cortisol binding globulin (CBG) was quantified as an indirect measure for circulating CORT. AD participants reported higher anxiety, depression and stress perception than HC. HR was similar between groups, but AD participants showed a blunted CORT response post-stress and lower CBG levels, suggesting altered stress regulation. Acute stress reduced cold sensitivity in HC and non-lesional AD skin but had no effect on lesions. These findings indicate that the effects of stress on small fibres depend on the condition of the skin and emphasise the sensory alterations experienced by AD patients.
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    When alertness fades: Drowsiness-induced visual dominance and oscillatory recalibration in audiovisual integration
    (2025) Artigas, Claudio; Morales Torres, Ricardo; Rojas Thomas, Felipe; Villena González, Mario; Rubio, Iván; Ramírez Benavides, Daniela; Bekinschtein, Tristán; Campos Arteaga, Germán; Rodríguez B., Eugenio
    Multisensory integration allows the brain to align inputs from different sensory modalities, enhancing perception and behavior. However, transitioning into drowsiness, a state marked by decreased attentional control and altered cortical dynamics, offers a unique opportunity to examine adaptations in these multisensory processes. In this study, we investigated how drowsiness influences reaction times (RTs) and neural oscillations during audiovisual multisensory integration. Participants performed a task where auditory and visual stimuli were presented either in a coordinated manner or with temporal misalignment (visual-first or auditory-first uncoordinated conditions). Behavioral results showed that drowsiness slowed RTs overall but revealed a clear sensory dominance effect: visual-first uncoordination facilitated RTs compared to auditory-first uncoordination, reflecting vision's dominant role in recalibrating sensory conflicts. In contrast, RTs in coordinated conditions remained stable across alert and drowsy states, suggesting that multisensory redundancy compensates for reduced cortical integration during drowsiness. At the neural level, distinct patterns of oscillatory activity emerged. Alpha oscillations supported attentional realignment and temporal alignment in visual-first conditions, while Gamma oscillations were recruited during auditory-first uncoordination, reflecting heightened sensory-specific processing demands. These effects were state-dependent, becoming more pronounced during drowsiness. Our findings demonstrate that drowsiness fundamentally reshapes multisensory integration by amplifying sensory dominance mechanisms, particularly vision. Compensatory neural mechanisms involving Alpha and Gamma oscillations maintain perceptual coherence under conditions of reduced cortical interaction. These results provide critical insights into how the brain adapts to sensory conflicts during states of diminished awareness, with broader implications for performance and decision-making in real-world drowsy states.