Browsing by Author "Ruiz Poblete, Sergio Marcelo"

Now showing 1 - 18 of 18
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    A subject-independent pattern-based Brain-Computer Interface
    (2015) Ray, Andreas M.; Sitaram, Ranganatha; Rana, Mohit; Pasqualotto, Emanuele; Buyukturkoglu, Korhan; Guan, Cuntai; Ang, Kai-Keng; Tejos Núñez, Cristián Andrés; Zamorano, Francisco; Ruiz Poblete, Sergio Marcelo; Birbaumer, Niels; Aboitiz, Francisco
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    Acquired self-control of insula cortex modulates emotion recognition and brain network connectivity in schizophrenia
    (2013) Ruiz Poblete, Sergio Marcelo; Lee, Sangkyun; Soekadar, Surjo R.; Caria, Andrea; Veit, Ralf; Kircher, Tilo; Birbaumer, Niels; Sitaram, Ranganatha
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    Clinical research in Chile: do not block the way of inquiry
    (2020) Valera, Luca; Ramos Vergara, Paulina Cecilia; Barrientos Zamorano, Marcelo; Altermatt Couratier, Fernando René; Ruiz Poblete, Sergio Marcelo; Von Bernhardi Montgomery, Rommy Edth B.; Cuello Fredes, Mauricio Arturo
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    Domestic violence in Chile
    (2014) León, T.; Grez, Marcela; Prato Escarate, Juan Andrés; Torres Barrenechea, Rafael; Ruiz Poblete, Sergio Marcelo
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    How feedback, motor imagery and reward influence brain self-regulation using real-time FMRI.
    (2015) Sepúlveda Delgado, Pradyumna; Tejos Núñez, Cristián Andrés; Ruiz Poblete, Sergio Marcelo; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    El uso de Neurofeedback (NF) con resonancia magnética funcional en tiempo real (Real-time fMRI neurofeedback, rtfMRI) permite la auto-regulación de la actividad metabólica del cerebro. El control de la actividad cerebral puede generar cambios conductuales, lo cual abre nuevas oportunidades para potenciales aplicaciones tanto terapéuticas como de investigación en neurociencias. El proceso de aprendizaje involucrado en alcanzar auto-regulación de la actividad hemodinámica del cerebro se cree que está relacionado a factores como el tipo y contingencia del feedback, recompensa, el uso de imaginería mental, la duración del entrenamiento, entre otros. Instruir explícitamente a los participantes a usar imaginería mental es una práctica común en experimentos de rtfMRI-NF, bajo el supuesto de que esta estrategia mejorará y acelerará el proceso de aprendizaje. Del mismo modo, se asume que la entrega de recompensa monetaria según desempeño refuerza y mejora la auto-regulación cerebral. Sin embargo, la estrategia óptima para mejorar el control voluntario de la actividad cerebral aún no está clara.
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    How feedback, motor imagery, and reward influence brain self‐regulation using real‐time fMRI
    (2016) Sepulveda, P.; Sitaram, Ranganatha; Rana, M.; Montalba, C.; Tejos Núñez, Cristián Andrés; Ruiz Poblete, Sergio Marcelo
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    Learned Control of Inter-Hemispheric Connectivity: Effects on Bimanual Motor Performance
    (2017) Kajal, D.; Braun, C.; Mellinger, J.; Sacchet, M.; Ruiz Poblete, Sergio Marcelo; Fetz, E.; Birbaumer, N.; Sitaram, Ranganatha
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    P300 amplitude is insensitive to working memory load in schizophrenia
    (2011) Gaspar Ramos, Pablo Arturo; Ruiz Poblete, Sergio Marcelo; Zamorano Mendieta, Francisco Javier; Altayó, Marcela; Pérez Sangüesa, Carolina Alejandra; Bosman Vittini, Conrado Arturo; Aboitiz, Francisco
    Abstract Background Working memory (WM) tasks usually elicit a P300 ERP component, whose amplitude decreases with increasing WM load. So far, this effect has not been studied in schizophrenics (SZs), a group that is considered to have an aberrant brain connectivity and impairments in WM capacity. The aim of this study was to determine the dependency of the P300 component on WM load in a sample of SZ subjects. Methods We recorded 26 subjects (13 SZ patients and their matched controls) with an 80-channel electroencephalogram. Subjects performed an N-back task, a WM paradigm that manipulates the number of items to be stored in memory. Results In healthy subjects, P300 amplitude was highest in the low WM load condition, and lowest in both the attentional control condition and the high WM load condition. In contrast, SZs evidenced low P300 amplitude in all conditions. A significant between group difference in P300 amplitude was evidenced only at the low WM load condition (1 -back), being smaller in SZs. Conclusions SZ subjects display a lower than normal P300 amplitude, which does not vary as a function of memory load. These results are consistent with a general impairment in WM capacity in these patients.
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    Real-time fMRI brain computer interfaces : Self-regulation of single brain regions to networks
    (2014) Ruiz Poblete, Sergio Marcelo; Buyukturkoglu, Korhan; Rana, Mohit; Birbaumer, Niels; Sitaram, Ranganatha
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    Real-time neurofeedback based on functional magnetic resonance imaging as a new approach to study the face processing network in autism spectrum.
    (2019) Pereira Quezada, Jaime Andrés; Ruiz Poblete, Sergio Marcelo; Pontificia Universidad Católica de Chile. Facultad de Medicina
    One of the most important and early impairments in autism spectrum disorder (ASD) is the abnormal visual processing of human faces. This deficit has been associated with hypoactivation of the fusiform face area (FFA), one of the main hubs of the face-processing network. Neurofeedback based on real-time fMRI (rtfMRI-NF) is a technique that allows the self-regulation of circumscribed brain regions, leading to specific neural modulation and behavioral changes. The aim of the present study was to train participants with ASD to achieve up-regulation of the FFA using rtfMRI-NF, to investigate the neural effects of FFA up-regulation in ASD. For this purpose, three groups of volunteers with normal I.Q. and fluent language were recruited to participate in a rtfMRI-NF protocol of eight training runs in two days. Five subjects with ASD participated as part of the experimental group and received contingent feedback to self-regulate bilateral FFA. Two control groups, each one with three participants with typical development (TD), underwent the same protocol: one group with contingent feedback and the other with sham feedback. Whole-brain and functional connectivity analysis using each fusiform gyrus as independent seeds were carried out. The results show that individuals with TD and ASD can achieve FFA up-regulation with contingent feedback. RtfMRI-NF in ASD produced more numerous and stronger short-range connections among brain areas of the ventral visual stream and an absence of the long-range connections to insula an inferior frontal gyrus, as observed in TD subjects. Recruitment of inferior frontal gyrus was observed in both groups during FAA self-regulation. However, insula and caudate nucleus were only recruited in subjects with TD. These results could be explained from a neurodevelopment perspective as a lack of the normal specialization of visual processing areas, and a compensatory mechanism to process visual information of faces. RtfMRI-NF emerges as a potential tool to study visual processing in ASD, and to explore its clinical potential.
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    Self-Regulation of the Fusiform Face Area in Autism Spectrum: A Feasibility Study With Real-Time fMRI Neurofeedback
    (2019) Pereira Quezada, Jaime Andrés; Sepúlveda, P; Rana, M.; Montalba, C.; Tejos Núñez, Cristián Andrés; Torres Barrenechea, Rafael; Sitaram, Ranganatha; Ruiz Poblete, Sergio Marcelo
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    Sleep spindle activity in children with obstructive sleep apnea as a marker of neurocognitive performance : A pilot study
    (2018) Brockmann Veloso, Pablo Edmundo; Damiani Rebolledo, L. Felipe; Pincheira, E.; Daiber, F.; Ruiz Poblete, Sergio Marcelo; Aboitiz, Francisco; Ferri, R.; Bruni, O.
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    The Effect of Wealth Shocks on Loss Aversion: Behavior and Neural Correlates
    (2017) Chandrasekhar Pammi, V. S.; Ruiz Poblete, Sergio Marcelo; Lee, Sangkyun; Noussair, Charles N.; Sitaram, Ranganatha
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    Uso de benzodiazepinas en adultos mayores en América Latina
    (2017) Gómez, Saúl; León, Tomás; Macuer, Maximiliano; Alves, Mariana; Ruiz Poblete, Sergio Marcelo
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    Volitional control of the anterior insula in criminal psychopaths using real-time fMRI neurofeedback : A pilot study
    (2014) Sitaram, Ranganatha; Caria, Andrea; Ruiz Poblete, Sergio Marcelo; Veit, Ralf; Gaber, Tilman; Birbaumer, Niels
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    Volitional regulation of the supplementary motor area with fMRI-BCI neurofeedback in Parkinson's disease: A pilot study
    (IEEE, 2013) Buyukturkoglu, Korhan; Rana, Mohit; Ruiz Poblete, Sergio Marcelo; Hackley, Steven A.; Soekadar, Surjo R.; Birbaumer, Niels; Sitaram, Ranganatha
    It is hypothesized that a dysfunction of the supplementary motor area (SMA), secondary to a deficit of the nigrostriatal dopamine system, partially contributes to the symptomatology of Parkinson's disease (PD), i.e., akinesia. In this pilot study we investigated the effect of real-time fMRI neurofeedback based volitional up-regulation of the SMA on hand motor performance of one PD patient and 3 healthy volunteers. The effect of learned self-regulation was evaluated with speeded, bimanual, sequenced button-pressing trials, assessed immediately after each baseline and up-regulation block. Our pilot results indicate that volitional up-regulation of SMA is accompanied by slowing of sequenced button presses.