Browsing by Author "Figueroa-Vargas, Alejandra"
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Item Frontoparietal connectivity correlates with working memory performance in multiple sclerosis(2020) Figueroa-Vargas, Alejandra; Cárcamo, Claudia; Henríquez-Ch, Rodrigo; Zamorano, Francisco; Ciampi, Ethel; Uribe-San-Martin, 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.Item Lateral Prefrontal Theta Oscillations Reflect Proactive Cognitive Control Impairment in Males With Attention Deficit Hyperactivity Disorder(2020-06) Zamorano, Francisco; Kausel, Leonie; Albornoz, Carlos; Lavin, Claudio; Figueroa-Vargas, Alejandra; Stecher, Ximena; Aragón-Caqueo, Diego; Carrasco, Ximena; Aboitiz, Francisco; Billeke, Pablottention Deficit Hyperactivity Disorder (ADHD) is a common neuropsychiatric disorder in which children present prefrontal cortex (PFC) related functions deficit. Proactive cognitive control is a process that anticipates the requirement of cognitive control and crucially depends on the maturity of the PFC. Since this process is important to ADHD symptomatology, we here test the hypothesis that children with ADHD have proactive cognitive control impairments and that these impairments are reflected in the PFC oscillatory activity. We recorded EEG signals from 29 male children with ADHD and 25 typically developing (TD) male children while they performed a Go-Nogo task, where the likelihood of a Nogo stimulus increased while a sequence of consecutive Go stimuli elapsed. TD children showed proactive cognitive control by increasing their reaction time (RT) concerning the number of preceding Go stimuli, whereas children with ADHD did not. This adaptation was related to modulations in both P3a potential and lateral prefrontal theta oscillation for TD children. Children with ADHD as a group did not demonstrate either P3a or theta modulation. But, individual variation in theta activity was correlated with the ADHD symptomatology. The results depict a neurobiological mechanism of proactive cognitive control impairments in children with ADHD.Publication Oscillatory activity underlying cognitive performance in children and adolescents with autism: a systematic review(2024) Soto-Icaza, Patricia; Soto-Fernández, Patricio; Kausel, Leonie; Márquez-Rodríguez, Víctor; Carvajal-Paredes, Patricio; Martínez-Molina, María Paz; Figueroa-Vargas, Alejandra; Billeke, PabloAutism spectrum disorder (ASD) is a neurodevelopmental condition that exhibits a widely heterogeneous range of social and cognitive symptoms. This feature has challenged a broad comprehension of this neurodevelopmental disorder and therapeutic efforts to address its difficulties. Current therapeutic strategies have focused primarily on treating behavioral symptoms rather than on brain psychophysiology. During the past years, the emergence of non-invasive brain stimulation techniques (NIBS) has opened alternatives to the design of potential combined treatments focused on the NEurophysiopathology of neuropsychiatric disorders like ASD. Such interventions require identifying the key brain mechanisms underlying the symptomatology and cognitive features. Evidence has shown alterations in oscillatory features of the neural ensembles associated with cognitive functions in ASD. In this line, we elaborated a systematic revision of the evidence of alterations in brain oscillations that underlie key cognitive processes that have been shown to be affected in ASD during childhood and adolescence, namely, social cognition, attention, working memory, inhibitory control, and cognitive flexibility. This knowledge could contribute to developing therapies based on NIBS to improve these processes in populations with ASDPublication Patients 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; Aspé-Sánchez, Mauricio; Carvajal-Paredes, Patricio; Márquez-Rodríguez, Víctor; Martínez-Molina, María Paz; Román, Claudio; Soto-Fernández, Patricio; Valdebenito-Oyarzo, Gabriela; Manterola, Carla; Uribe-San-Martín, Reinaldo; Silva, Claudio; Henríquez-Ch, Rodrigo; Aboitiz, Francisco; Polania, Rafael; Guevara, Pamela; Muñoz-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-upPublication The parietal cortex has a causal role in ambiguity computations in humans(2024) Valdebenito-Oyarzo, Gabriela; Martínez-Molina, María Paz; Soto-Icaza, Patricia; Zamorano, Francisco; Figueroa-Vargas, Alejandra; Larraín-Valenzuela, Josefina; Stecher, Ximena; Salinas, César; Bastin, Julien; Valero-Cabré, Antoni; Polania, RafaelHumans often face the challenge of making decisions between ambiguous options. The level of ambiguity in decision-making has been linked to activity in the parietal cortex, but its exact computational role remains elusive. To test the hypothesis that the parietal cortex plays a causal role in computing ambiguous probabilities, we conducted consecutive fMRI and TMS-EEG studies. We found that participants assigned unknown probabilities to objective probabilities, elevating the uncertainty of their decisions. Parietal cortex activity correlated with the objective degree of ambiguity and with a process that underestimates the uncertainty during decision-making. Conversely, the midcingulate cortex (MCC) encodes prediction errors and increases its connectivity with the parietal cortex during outcome processing. Disruption of the parietal activity increased the uncertainty evaluation of the options, decreasing cingulate cortex oscillations during outcome evaluation and lateral frontal oscillations related to value ambiguous probability. These results provide evidence for a causal role of the parietal cortex in computing uncertainty during ambiguous decisions made by humans.