Browsing by Author "Fuentealba, Pablo"

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    Brain state-dependent recruitment of high-frequency oscillations in the human hippocampus
    (01/09/2017) Billeke, Pablo; Ossandón, Tomás; Stockle, Marcelo; Perrone-Bertolotti, Marcela; Kahane, Philippe; Lachaux, Jean-Philippe; Fuentealba, Pablo
    Ripples are high-frequency bouts of coordinated hippocampal activity believed to be crucial for information transfer and memory formation. We used intracortical macro electrodes to record neural activity in the human hippocampus of awake subjects undergoing surgical treatment for refractory epilepsy and distinguished two populations of ripple episodes based on their frequency spectrum. The phase-coupling of one population, slow ripples (90-110 Hz), to cortical delta oscillations was differentially modulated by cognitive task; whereas the second population, fast ripples (130-170 Hz), was not seemingly correlated to local neural activity. Furthermore, as cognitive tasks changed, the ongoing coordination of neural activity associated to slow ripples progressively augmented along the parahippocampal axis. Thus, during resting states, slow ripples were coordinated in restricted hippocampal territories; whereas during active states, such as attentionally-demanding tasks, high frequency activity emerged across the hippocampus and parehippocampal cortex, that was synchronized with slow ripples, consistent with ripples supporting information transfer and coupling anatomically distant regions. Hence, our results provide further evidence of neural diversity in hippocampal high-frequency oscillations and their association to cognitive processing in humans. (C) 2017 Elsevier Ltd. All rights reserved.
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    Diferencias en la percepción de inseguridad a nivel cognitivo y emocional de acuerdo al perfil socio demográfico y político. Estudio del gran Concepción, Chile
    (2016) Fuentealba, Pablo; Rojas, Juan Sebastián; Barriga, Omar
    El presente estudio evalúa la percepción de inseguridad en el conurbano del Gran Concepción, el segundo centro urbano más poblado de Chile. Se evaluó la probabilidad estimada de ser víctima de delito (dimensión cognitiva) y preocupación por ser víctima de delito (dimensión emocional). Para esto, se construyó y aplicó un "Cuestionario de Percepción de Inseguridad (CPI)", tipo Likert de 18 reactivos a una muestra consecutiva de 369 casos. Se realizó un análisis descriptivo de los resultados del CPI (porcentajes, media y DE) y se realizaron comparaciones según el perfil sociodemográfico y político mediante análisis bi-variados (ANOVA y t-Student) y pruebas post hoc (HSD de Tukey), con el propósito de identificar aquellos grupos que poseen mayores o menores niveles de inseguridad percibida. Se identificaron diferencias significativas según tramo etario, sexo y nivel educacional, pero no de acuerdo a la tendencia política.
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    Human Anterior Insula Encodes Performance Feedback and Relays Prediction Error to the Medial Prefrontal Cortex
    (2020) Billeke, Pablo; Ossandon, Tomas; Perrone-Bertolotti, Marcela; Kahane, Philippe; Bastin, Julien; Jerbi, Karim; Lachaux, Jean-Philippe; Fuentealba, Pablo
    Adaptive behavior requires the comparison of outcome predictions with actual outcomes (e.g., performance feedback). This process of performance monitoring is computed by a distributed brain network comprising the medial prefrontal cortex (mPFC) and the anterior insular cortex (AIC). Despite being consistently co-activated during different tasks, the precise neuronal computations of each region and their interactions remain elusive. In order to assess the neural mechanism by which the AIC processes performance feedback, we recorded AIC electrophysiological activity in humans. We found that the AIC beta oscillations amplitude is modulated by the probability of performance feedback valence (positive or negative) given the context (task and condition difficulty). Furthermore, the valence of feedback was encoded by delta waves phase-modulating the power of beta oscillations. Finally, connectivity and causal analysis showed that beta oscillations relay feedback information signals to the mPFC. These results reveal that structured oscillatory activity in the anterior insula encodes performance feedback information, thus coordinating brain circuits related to reward-based learning.

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