Facultad de Medicina

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Browsing Facultad de Medicina by Author "Aboitiz, Francisco"

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    Attentional bias for food cues after sleeve gastrectomy : a behavioral and electrophysiological study
    (2019) Zumaeta Valenzuela, Arturo Ulises; Aboitiz, Francisco; Pontificia Universidad Católica de Chile. Facultad de Medicina
    Attentional bias for food cues (ABFC) has been linked to food craving, the inability to lose weight, and obesity. For this study, we explored the presence of ABFC in a bariatric group, using a food-modified Stroop task and visual task, with EEG and eye-tracking recording, respectively. Our data showed an increased attentional bias for appetizing food, a decreased bias for diet food and a prolonged brain processing of food stimuli in the bariatric group.
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    Modulation of attention by motor interaction: A study in a visual discrimination task
    (2019) Arellano Roco, Cristian Andrés; Aboitiz, Francisco; Maldonado Arbogast, Pedro; Pontificia Universidad Católica de Chile. Facultad de Medicina
    Most of the traditional neuroscience research has considered attention as a superior cognitive function mainly oriented to perceptual processes and away from sensorimotor functions. Alternatively, the “Attention for Action” framework proposes a close relationship between cognitive and sensorimotor processes, where attention would act as an integrative mechanism. There is empirical evidence suggesting that the processes of preparation and motor execution have a positive impact on the attentional and perceptual processes, but there is no consensus if the interaction of these processes produces interference or improvement in them. The aim of this thesis is to contribute to a better understanding of the interactions between attentional and motor processes. In this thesis we propose that the functional coupling between attentional and motor processes positively modulates attention processes. To evaluate this proposition we designed an ocular pursuit dual task that required sustained attention and discrimination of a visual stimulus (visual condition). By adding a motor relevant act to the task (motor condition) we were able to evaluate if this produced a modulating effect on the attention and if differences were observed between both experimental conditions. Task performance was measured using behavioral, electro physiological (ERPs) and pupil diameter variation parameters in both, a group of healthy children (Control group) and another group of children with attentional deficit (ADHD group). Behavioral results showed that the Control group had a better overall performance in the task than the ADHD group, with better performance in visual condition than in motor condition, but that differentiating effect between groups disappeared when comparing them within motor condition, that means the motor effect favored the performance of the ADHD group. Electrophysiology showed that in motor condition a modulating effect was produced on CNV, P1 and N1 compared with the visual condition for both groups, it being larger in the Control group. Finally, Control group showed a progressive increase in pupillary diameter along the trial in the motor condition, while in the visual condition this increase was stabilized 400 ms. prior to the appearance of visual stimulus and remained so until the end of the trial. ADHD group, however, showed a progressive increase in pupillary diameter along the trial for both conditions, which could reflect a greater attentional load of these subjects in the task. These results suggest that in the analyzed task there would be a positive modulatory effect of the motor component on the attentional processes, which despite not being clear in behavioral performance, is consistent at electrophysiological level and in the pupil diameter variation, which would reflect positive interaction between these processes.
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    The role of sleep-oscillations in the emergence of hippocampal-dependent memory during postnatal development
    (2022) García Pérez, María Alexandra; Valdés Guerrero, José Luis; Maldonado Arbogast, Pedro; Aboitiz, Francisco; Pontificia Universidad Católica de Chile. Escuela de Medicina
    Las memorias dependientes del hipocampo surgen tardíamente en el desarrollo postnatal y en paralelo con la maduración del hipocampo. El modelo de formación de la memoria en dos etapas afirma que durante el sueño ocurre un diálogo entre el hipocampo y la neocorteza, donde las oscilaciones lentas corticales (SO), los Spindles talamocorticales y los Sharp-wave ripples del hipocampo (SWR) se sincronizan, permitiendo la consolidación de los recuerdos de tipo episódicos. Sin embargo, este modelo no ha sido validado en etapas tempranas del desarrollo. En esta tesis, se evaluó la aparición de la memoria dependiente de hipocampo mediante la exposición sucesiva a la prueba conductual de reconocimiento de objeto-lugar. Junto con esto, se registró la actividad in vivo de SO, Spindles y SWRs durante periodos de sueño inmediatamente posteriores a la evocación en la tarea de objeto-lugar, donde encontramos que la memoria dependiente del hipocampo aparece en el día postnatal 32, independientemente del sobre-entrenamiento previo de la tarea. Curiosamente, observamos que los animales con mejor rendimiento tenían una mayor densidad y duración de los Spindles y una menor densidad de SWRs. Además, observamos cambios en el acoplamiento temporal entre SO-Spindles y Spindles-SWRs durante esta ventana temporal. Nuestros resultados aportan nuevas evidencias sobre el inicio de la memoria dependiente del hipocampo y explican cómo se ajustan los modelos de consolidación adulta en las primeras etapas del desarrollo postnatal.