Browsing by Author "Pereira Quezada, Jaime Andrés"

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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