Browsing by Author "Zamorano, Francisco"
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- ItemA real-time fMRI neurofeedback system for the clinical alleviation of depression with a subject-independent classification of brain states: A proof of principle study(2022) Pereira, Jaime A.; Ray, Andreas; Rana, Mohit; Silva, Claudio; Salinas, Cesar; Zamorano, Francisco; Irani, Martin; Opazo, Patricia; Sitaram, Ranganatha; Ruiz, SergioMost clinical neurofeedback studies based on functional magnetic resonance imaging use the patient's own neural activity as feedback. The objective of this study was to create a subject-independent brain state classifier as part of a real-time fMRI neurofeedback (rt-fMRI NF) system that can guide patients with depression in achieving a healthy brain state, and then to examine subsequent clinical changes. In a first step, a brain classifier based on a support vector machine (SVM) was trained from the neural information of happy autobiographical imagery and motor imagery blocks received from a healthy female participant during an MRI session. In the second step, 7 right-handed female patients with mild or moderate depressive symptoms were trained to match their own neural activity with the neural activity corresponding to the "happiness emotional brain state" of the healthy participant. The training (4 training sessions over 2 weeks) was carried out using the rt-fMRI NF system guided by the brain-state classifier we had created. Thus, the informative voxels previously obtained in the first step, using SVM classification and Effect Mapping, were used to classify the Blood-Oxygen-Level Dependent (BOLD) activity of the patients and converted into real-time visual feedback during the neurofeedback training runs. Improvements in the classifier accuracy toward the end of the training were observed in all the patients [Session 4-1 Median = 6.563%; Range = 4.10-27.34; Wilcoxon Test (0), 2-tailed p = 0.031]. Clinical improvement also was observed in a blind standardized clinical evaluation [HDRS CE2-1 Median = 7; Range 2 to 15; Wilcoxon Test (0), 2-tailed p = 0.016], and in self-report assessments [BDI-II CE2-1 Median = 8; Range 1-15; Wilcoxon Test (0), 2-tailed p = 0.031]. In addition, the clinical improvement was still present 10 days after the intervention [BDI-II CE3-2_Median = 0; Range -1 to 2; Wilcoxon Test (0), 2-tailed p = 0.50/ HDRS CE3-2 Median = 0; Range -1 to 2; Wilcoxon Test (0), 2-tailed p = 0.625]. Although the number of participants needs to be increased and a control group included to confirm these findings, the results suggest a novel option for neural modulation and clinical alleviation in depression using noninvasive stimulation technologies.
- ItemA 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
- ItemCountry-level gender inequality is associated with structural differences in the brains of women and men(National Academy of Sciences, 2023) Zugman, Andrés; Alliende, Luz María; Medel Sierralta, Vicente Nicolás; Bethlehem, Richard A. I.; Seidlitz, Jakob; Ringlein, Grace; Arango, Celso; Arnatkeviciutė, Aurina; Asmal, Laila; Bellgrove, Mark; Benegal, Vivek; Bernardo, Miquel; Billeke, Pablo; Bosch-Bayard, Jorge; Bressan, Rodrigo; Busatto, Geraldo F.; Castro, Mariana N.; Chaim-Avancini, Tiffany; Compte, Albert; Costanzi, Monise; Czepielewski, Leticia; Dazzan, Paola; Fuente-Sandoval, Camilo de la; Forti, Marta di; Díaz-Caneja, Covadonga M.; Díaz-Zuluaga, Ana María; Plessis, Stefan du; Duran, Fabio L. S.; Fittipaldi, Sol; Fornito, Alex; Freimer, Nelson B.; Gadelha, Ary; Gama, Clarissa S.; Garani, Ranjini; García-Rizo, Clemente; González Campo, Cecilia; González-Valderrama, Alfonso; Guinjoan, Salvador; Holla, Bharath; Ibáñez, Agustín; Jackowski, Andrea; Ivanovic, Daniza; León-Ortiz, Pablo; Lochner, Christine; López Jaramillo, Carlos; Luckhoff, Hilmar; Massuda, Raffael; McGuire, Philip; Miyata, Jun; Mizrahi, Romina; Murray, Robin; Ozerdem, Aysegul; Pan, Pedro M.; Parellada, Mara; Phahladira, Lebogan; Ramírez Mahaluf, Juan P.; Reckziegel, Ramiro; Marques Tiago Reis; Reyes-Madrigal, Francisco; Roos, Annerine; Rosa, Pedro; Salum, Giovanni; Scheffler, Freda; Schumann, Gunter; Serpa, Mauricio; Stein, Dan J.; Tepper, Angeles; Tiego, Jeggan; Ueno, Tsukasa; Undurraga, Juan; Undurraga, Eduardo A.; Valdés-Sosa, Pedro; Valli, Isabel; Villarreal, Mirta; Winton-Brown, Toby T.; Yalin, Nefize; Zamorano, Francisco; Zanetti, Marcus V.; Veda, C.; Winkler, Anderson M.; Pine, Daniel S.; Evans-Lacko, Sara; Crossley Karmelic, Nicolas AndrésGender inequality across the world has been associated with a higher risk to mental health problems and lower academic achievement in women compared to men. We also know that the brain is shaped by nurturing and adverse socio-environmental experiences. Therefore, unequal exposure to harsher conditions for women compared to men in gender-unequal countries might be reflected in differences in their brain structure, and this could be the neural mechanism partly explaining women’s worse outcomes in gender-unequal countries. We examined this through a random-effects meta-analysis on cortical thickness and surface area differences between adult healthy men and women, including a meta-regression in which country-level gender inequality acted as an explanatory variable for the observed differences. A total of 139 samples from 29 different countries, totaling 7,876 MRI scans, were included. Thickness of the right hemisphere, and particularly the right caudal anterior cingulate, right medial orbitofrontal, and left lateral occipital cortex, presented no differences or even thicker regional cortices in women compared to men in gender-equal countries, reversing to thinner cortices in countries with greater gender inequality. These results point to the potentially hazardous effect of gender inequality on women’s brains and provide initial evidence for neuroscience-informed policies for gender equality.
- ItemFrontoparietal connectivity correlates with working memory performance in multiple sclerosis(2020) Figueroa Vargas, Alejandra; Carcamo, Claudia; Henriquez Ch, Rodrigo; Zamorano, Francisco; Ciampi Diaz, Ethel Leslie; Uribe San Martín, Reinaldo; Vásquez, Macarena; Aboitiz, Francisco; Billeke, PabloWorking Memory (WM) impairment is the most common cognitive deficit of patients with Multiple Sclerosis (MS). However, evidence of its neurobiological mechanisms is scarce. Here we recorded electroencephalographic activity of twenty patients with relapsing-remitting MS and minimal cognitive deficit, and 20 healthy control (HC) subjects while they solved a WM task. In spite of similar performance, the HC group demonstrated both a correlation between temporoparietal theta activity and memory load, and a correlation between medial frontal theta activity and successful memory performances. MS patients did not show theses correlations leading significant differences between groups. Moreover, cortical connectivity analyses using granger causality and phase-amplitude coupling between theta and gamma revealed that HC group, but not MS group, presented a load-modulated progression of the frontal-to-parietal connectivity. This connectivity correlated with working memory capacity in MS groups. This early alterations in the oscillatory dynamics underlaying working memory could be useful for plan therapeutic interventions.
- ItemFunctional differences of low- and high-frequency oscillatory dynamics during illusory border perception(ELSEVIER, 2010) Bosman, Conrado A.; Zamorano, Francisco; Aboitiz, FranciscoNeuronal oscillations are an essential part of several brain processes like perception, memory and attention, but little is known about the simultaneous dynamics of different frequency bands in such processes. Here, we studied the low- and high-frequency dynamics of neuronal oscillations in a task that involves covert searching and visual perception of an illusory contour figure (Kanisza square). Subjects were cued to a particular region of the space, and then a matrix of illusory contour inductors appeared. Illusory contour could appear at the cued position, in a different position or not appear at all. We analyze the condition in which an illusory contour appears and those in which the illusory borders do not appear. During the visual perception of the illusory contour, we found a significant increase in a narrow and sustained gamma frequency band (55-65 Hz). We also found a transient increase in the theta band (4-10 Hz), 0.3 s after stimuli onset. This low-frequency power increase correlates strongly with the detection of the illusory contour and it is inversely correlated with the gamma-band response. When illusory contours were absent, a sustained low-frequency response in the same frequency range was present until appearance of the motor response. The intensity of this low-frequency power response was also related to the speed of the motor response. We hypothesize that theta and gamma interact to process different aspects of the task. Gamma would be related to perception of the stimuli, while theta would be involved in search mechanisms or the initiation of a motor response. (C) 2010 Elsevier B.V. All rights reserved.
- ItemIntratask Variability As a Correlate for DRD4 and SLC6A3 Variants : A Pilot Study in ADHD(2015) Henríquez Henríquez, Marcela Patricia; Villarroel del Pino, Luis A.; Henríquez, Hugo; Zamorano, Francisco; Rothhammer, Francisco; Aboitiz, Francisco
- ItemParadoxical Expectation : Oscillatory Brain Activity Reveals Social Interaction Impairment in Schizophrenia(2015) Billeke, Pablo; Armijo, Aalejandra; Castillo, Daniel; López, Tamara; Zamorano, Francisco; Cosmelli, Diego; Aboitiz, Francisco
- ItemPatients recovering from COVID-19 who presented with anosmia during their acute episode have behavioral, functional, and structural brain alterations(2024) Kausel, Leonie; Figueroa-Vargas, Alejandra; Zamorano, Francisco; Stecher, Ximena; Aspe-Sanchez, Mauricio; Carvajal-Paredes, Patricio; Marquez-Rodriguez, Victor; Martinez-Molina, Maria Paz; Roman, Claudio; Soto-Fernandez, Patricio; Valdebenito-Oyarzo, Gabriela; Manterola, Carla; Uribe-San-Martin, Reinaldo; Silva, Claudio; Henriquez-Ch, Rodrigo; Aboitiz, Francisco; Polania, Rafael; Guevara, Pamela; Munoz-Venturelli, Paula; Soto-Icaza, Patricia; Billeke, PabloPatients recovering from COVID-19 commonly exhibit cognitive and brain alterations, yet the specific neuropathological mechanisms and risk factors underlying these alterations remain elusive. Given the significant global incidence of COVID-19, identifying factors that can distinguish individuals at risk of developing brain alterations is crucial for prioritizing follow-up care. Here, we report findings from a sample of patients consisting of 73 adults with a mild to moderate SARS-CoV-2 infection without signs of respiratory failure and 27 with infections attributed to other agents and no history of COVID-19. The participants underwent cognitive screening, a decision-making task, and MRI evaluations. We assessed for the presence of anosmia and the requirement for hospitalization. Groups did not differ in age or cognitive performance. Patients who presented with anosmia exhibited more impulsive alternative changes after a shift in probabilities (r = - 0.26, p = 0.001), while patients who required hospitalization showed more perseverative choices (r = 0.25, p = 0.003). Anosmia correlated with brain measures, including decreased functional activity during the decision-making task, thinning of cortical thickness in parietal regions, and loss of white matter integrity. Hence, anosmia could be a factor to be considered when identifying at-risk populations for follow-up.
- ItemSomeone has to give in: theta oscillations correlate with adaptive behavior in social bargaining(2014) Billeke, Pablo; Zamorano, Francisco; Lopez, Tamara; Rodriguez, Carlos; Cosmelli, Diego; Aboitiz, FranciscoDuring social bargain, one has to both figure out the others' intentions and behave strategically in such a way that the others' behaviors will be consistent with one's expectations. To understand the neurobiological mechanisms underlying these behaviors, we used electroencephalography while subjects played as proposers in a repeated ultimatum game. We found that subjects adapted their offers to obtain more acceptances in the last round and that this adaptation correlated negatively with prefrontal theta oscillations. People with higher prefrontal theta activity related to a rejection did not adapt their offers along the game to maximize their earning. Moreover, between-subject variation in posterior theta oscillations correlated positively with how individual theta activity influenced the change of offer after a rejection, reflecting a process of behavioral adaptation to the others' demands. Interestingly, people adapted better their offers when they knew that they where playing against a computer, although the behavioral adaptation did not correlate with prefrontal theta oscillation. Behavioral changes between human and computer games correlated with prefrontal theta activity, suggesting that low adaptation in human games could be a strategy. Taken together, these results provide evidence for specific roles of prefrontal and posterior theta oscillations in social bargaining.
- ItemTheta and Alpha Oscillation Impairments in Autistic Spectrum Disorder Reflect Working Memory Deficit(2017) Larraín Valenzuela, Josefina; Zamorano, Francisco; Soto Icaza, Patricia; Carrasco, Ximena; Herrera, Claudia; Aboitiz, Francisco; Daiber, Francisca; Billeke, Pablo
- ItemUse of Real-Time Functional Magnetic Resonance Imaging-Based Neurofeedback to Downregulate Insular Cortex in Nicotine-Addicted Smokers(2020) Rana, Mohit; Ruiz, Sergio; Sanchez Corzo, Andrea; Muehleck, Axel; Eck, Sandra; Salinas, Cesar; Zamorano, Francisco; Silva, Claudio; Rea, Massimiliano; Batra, Anil; Birbaumer, Niels; Sitaram, RanganathaIt has been more than a decade since the first functional magnetic resonance imaging (fMRI)-based neurofeedback approach was successfully implemented. Since then, various studies have demonstrated that participants can learn to voluntarily control a circumscribed brain region. Consequently, real-time fMRI (rtfMRI) provided a novel opportunity to study modifications of behavior due to manipulation of brain activity. Hence, reports of rtfMRI applications to train self-regulation of brain activity and the concomitant modifications in behavioral and clinical conditions such as neurological and psychiatric disorders [e.g., schizophrenia, obsessive compulsive Disorder (OCD), stroke] have rapidly increased.