CRIS

Permanent URI for this communityhttps://investigadores.udd.cl/handle/123456789/1

Browse

Settings

Subject: search.filters.subject.electroencephalography

Search Results

Now showing 1 - 10 of 33
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Patterns of brain activity in choice or instructed go and no-go tasks
    (Springer Science and Business Media LLC, 2025-02-21)
    Sanaz Attaripour Isfahani
    ;
    Patrick McGurrin
    ;
    VIAL UNDURRAGA, FELIPE AGUSTIN  
    ;
    Mark Hallett
    The goal of this study was to investigate the decision making process for choosing what movements to make. We used electroencephalography (EEG) to investigate patterns of the contingent negative variation (CNV) associated with free-choice decisions to move or abstain, comparing them to conditions where actions were commanded. Our primary hypothesis was that choice tasks would differ significantly from each other and exhibit EEG patterns akin to their command-driven counterparts after the decisions were made, at least, in the 50 ms block of time prior to movement. A secondary analysis evaluated post hoc comparisons of time, in 50 ms blocks, to understand the temporal development of the CNV for each condition. We also conducted an exploratory analysis of EEG event-related desynchronization (ERD) to identify patterns of brain activity associated with the decision-making process. This approach was taken due to the exploratory nature of our hypotheses concerning the spatial and temporal characteristics of EEG activity during these free-choice versus commanded tasks. We studied 12 right-handed healthy volunteers (7 women, mean age 53 years, range 39–73 years) with no prior history of neurological or major psychiatric illness. A CNV paradigm encompassing commanded and choice tasks was devised, with a 2500 ms interval between S1 and S2, while recording EEG and electromyography (EMG). S1 provided full information about the upcoming task, which was to be executed at the time of S2. We assessed CNV and explored whole scalp EEG activity, including both voltage as well as power in the alpha and beta frequency ranges. Clear and similar CNVs were observed for command and choice go tasks prior to the movements, contrasting with near-zero CNVs for the command and choice no-go tasks. Separation of CNVs for command go and no-go tasks occurred around 1600 ms post-S1, and choice CNVs separated about 2150 ms post-S1. Exploratory analysis revealed that beta power provided information about decision and preparation processes much earlier. The left dorsolateral prefrontal cortex (DLPFC) exhibited the initial sign of decision approximately 500 ms post-S1 for all tasks, with subsequent preparation for movement or restraint involving distinct activity in various brain regions. The localization of effects in the left DLPFC was determined by visual analysis of the informative electrode sites. The CNVs separate about 2 s after S1, and it appears that this process represents preparation for movement (or no movement). Exploration of the beta activity suggests an earlier decision process which leads eventually to subsequent task preparation and activation. Choice decisions lag slightly behind command decisions, with the CNV apparently reflecting motor implementation rather than the decision-making process. In a simple motor task with an exploratory analysis, both commanded and choice-based decisions are rapidly initiated in the left DLPFC. While the CNV distinguishes between go and no-go conditions, it primarily appears to signify preparation for implementation of the task following the earlier decision. Further controlled studies will be needed to confirm these results.
    Scopus© Citations 3  1
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    The Power of Food Advertisements: A Brief Mindfulness Instruction Does Not Prevent Psychophysiological Responses Triggered by Food Ads
    (MDPI AG, 2025-02-25)
    Constanza Baquedano
    ;
    David Martinez-Pernia
    ;
    Vicente Soto
    ;
    Álvaro Rivera-Rei
    ;
    Antonia Zepeda
    Exposure to visually appealing food items can enhance their subjective realism, leading to increased cravings, salivation, and automatic approach tendencies. Prior research suggests that brief mindfulness instructions promoting dereification—recognizing stimuli as transient mental events—can mitigate these automatic reactions. Objectives: This study assesses whether brief mindfulness instruction can mitigate automatic consumption tendencies induced by food advertisements, exploring the corresponding behavioral, physiological, and neurophysiological mechanisms. Methods: Sixty participants were randomly assigned to two groups: one receiving brief mindfulness instruction and the other a non-dereifying control instruction while exposed to advertised foods. This was followed by an approach–avoidance task (AAT), during which behavioral data, salivary volume, event-related potentials (ERPs) from electroencephalogram recordings, and self-reports were collected. Results: The results showed no significant differences in approach behaviors between the groups. Hunger, food craving, and salivation levels increased uniformly in response to food cues for both groups. The N1, N2, P3, and late positive potential (LPP) ERPs remained unaltered by the instructions and consistent with the established AAT literature. Advertising heightened the appeal of neutral foods, as evidenced by increased N2, P3, and LPP responses. Conclusions: The brief mindfulness instruction failed to shield participants from the automatic responses elicited by food advertising, contrasting with the effects seen with non-advertised food.
      4
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Scopus© Citations 2  1
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Scopus© Citations 3  8
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Scopus© Citations 4  3
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Nistagmo secundario a albinismo con compromiso ocular en paciente femenina
    (2020)
    Luisa Schonhaut B.
    ;
    Joanna Britzmann L.
    ;
    Mario Zanolli S.
    ;
    Jovanka Pavlov N.
    ;
    Trinidad Hasbun Z.
    <jats:p>El nistagmo infantil es infrecuente y representa un desafío diagnóstico para el pediatra. El albinismo es una de sus principales causas, siendo difícil de sospechar en ausencia de compromiso cutáneo evidente, especialmente en pacientes femeninas, debido a que tipo de herencia del albinismo ocular.Objetivo: Describir un caso de nistagmo secundario a albinismo con compromiso ocular aislado en paciente femenina, para discutir el enfoque diagnóstico pediátrico.Caso Clínico: Paciente femenino de 3 semanas de vida, sin antecedentes mórbidos, derivada a neuropediatra y oftalmólogo por movimientos oculares paroxísticos desde las 2 semanas, con estudio con electroencefalograma e imágenes cerebrales normales. A los 3 meses se confirmó translucencia iridiana, nistagmo y astigmatismo hipermetrópico. La valuación dermatológica descartó compromiso cutáneo. Evolucionó con inclinación cefálica hacia abajo y retraso del desarrollo de la coordinación, fue manejada con lentes de corrección y kinesioterapia. A los 3 años, destacaba mejoría de la agudeza visual, disminución del nistagmo y neurodesarrollo normal. La evaluación oftalmológica de ambos padres fue normal y no había antecedentes de nistagmo o albinismo en la familia. Por decisión de los padres no se realizó estudio genético.Conclusión: El diagnóstico de nistagmo secundario a compromiso ocular del albinismo, aún en ausencia de afección cutánea, es clínico; el estudio genético permite confirmar la etiología, sin ser un examen imprescindible, a menos que se considere la planificación familiar. La pesquisa oportuna e intervención multidisciplinaria determinan un mejor pronóstico.</jats:p>
      1
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Multivariate word properties in fluency tasks reveal markers of Alzheimer's dementia
    (2023)
    Franco J. Ferrante
    ;
    Joaquín Migeot
    ;
    Agustina Birba
    ;
    Lucía Amoruso
    ;
    Gonzalo Pérez
    <jats:title>Abstract</jats:title><jats:sec><jats:title>INTRODUCTION</jats:title><jats:p>Verbal fluency tasks are common in Alzheimer's disease (AD) assessments. Yet, standard valid response counts fail to reveal disease‐specific semantic memory patterns. Here, we leveraged automated word‐property analysis to capture neurocognitive markers of AD vis‐à‐vis behavioral variant frontotemporal dementia (bvFTD).</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>Patients and healthy controls completed two fluency tasks. We counted valid responses and computed each word's frequency, granularity, neighborhood, length, familiarity, and imageability. These features were used for group‐level discrimination, patient‐level identification, and correlations with executive and neural (magnetic resonanance imaging [MRI], functional MRI [fMRI], electroencephalography [EEG]) patterns.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Valid responses revealed deficits in both disorders. Conversely, frequency, granularity, and neighborhood yielded robust group‐ and subject‐level discrimination only in AD, also predicting executive outcomes. Disease‐specific cortical thickness patterns were predicted by frequency in both disorders. Default‐mode and salience network hypoconnectivity, and EEG beta hypoconnectivity, were predicted by frequency and granularity only in AD.</jats:p></jats:sec><jats:sec><jats:title>DISCUSSION</jats:title><jats:p>Word‐property analysis of fluency can boost AD characterization and diagnosis.</jats:p></jats:sec><jats:sec><jats:title>Highlights</jats:title><jats:p><jats:list list-type="bullet"> <jats:list-item><jats:p>We report novel word‐property analyses of verbal fluency in AD and bvFTD.</jats:p></jats:list-item> <jats:list-item><jats:p>Standard valid response counts captured deficits and brain patterns in both groups.</jats:p></jats:list-item> <jats:list-item><jats:p>Specific word properties (e.g., frequency, granularity) were altered only in AD.</jats:p></jats:list-item> <jats:list-item><jats:p>Such properties predicted cognitive and neural (MRI, fMRI, EEG) patterns in AD.</jats:p></jats:list-item> <jats:list-item><jats:p>Word‐property analysis of fluency can boost AD characterization and diagnosis.</jats:p></jats:list-item> </jats:list></jats:p></jats:sec>
      3Scopus© Citations 10
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Another in need enhances prosociality and modulates frontal theta oscillations in young adults
    (2023)
    Claudio Lavín
    ;
    SOTO ICAZA, PATRICIA  
    ;
    Vladimir López
    ;
    BILLEKE BOBADILLA, PABLO ERNESTO  
    Decision-making is a process that can be strongly affected by social factors. Evidence has shown how people deviate from traditional rational-choice predictions under different levels of social interactions. The emergence of prosocial decision-making, defined as any action that is addressed to benefit another individual even at the expense of personal benefits, has been reported as an example of such social influence. Furthermore, brain evidence has shown the involvement of structures such as the prefrontal cortex, anterior insula, and midcingulate cortex during decision settings in which a decision maker interacts with others under physical pain or distress or while being observed by others.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Using a slightly modified version of the dictator game and EEG recordings, we tested the hypothesis that the inclusion of another person into the decision setting increases prosocial decisions in young adults and that this increase is higher when the other person is associated with others in need. At the brain level, we hypothesized that the increase in prosocial decisions correlates with frontal theta activity.</jats:p></jats:sec><jats:sec><jats:title>Results and Discussion</jats:title><jats:p>The results showed that including another person in the decision, setting increased prosocial behavior only when this presence was associated with someone in need. This effect was associated with an increase in frontocentral theta-oscillatory activity. These results suggest that the presence of someone in need enhances empathy concerns and norm compliance, raising the participants’ prosocial decision-making.
    Scopus© Citations 8  1
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Vestibular loss disrupts visual reactivity in the alpha EEG rhythm
    (2023)
    Richard T Ibitoye
    ;
    CASTRO ABARCA, PATRICIA BERNARDITA  
    ;
    Toby J. Ellmers
    ;
    Diego N. Kaski
    ;
    Adolfo M. Bronstein
    Scopus© Citations 4  1
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Systematic Review: Genetic, Neuroimaging, and Fluids Biomarkers for Frontotemporal Dementia Across Latin America Countries
    (2021)
    Claudia Duran-Aniotz
    ;
    Paulina Orellana  
    ;
    Tomas Leon Rodriguez
    ;
    Victoria Cabello
    ;
    Fernando Henriquez
    <jats:p>Frontotemporal dementia (FTD) includes a group of clinically, genetically, and pathologically heterogeneous neurodegenerative disorders, affecting the fronto-insular-temporal regions of the brain. Clinically, FTD is characterized by progressive deficits in behavior, executive function, and language and its diagnosis relies mainly on the clinical expertise of the physician/consensus group and the use of neuropsychological tests and/or structural/functional neuroimaging, depending on local availability. The modest correlation between clinical findings and FTD neuropathology makes the diagnosis difficult using clinical criteria and often leads to underdiagnosis or misdiagnosis, primarily due to lack of recognition or awareness of FTD as a disease and symptom overlap with psychiatric disorders. Despite advances in understanding the underlying neuropathology of FTD, accurate and sensitive diagnosis for this disease is still lacking. One of the major challenges is to improve diagnosis in FTD patients as early as possible. In this context, biomarkers have emerged as useful methods to provide and/or complement clinical diagnosis for this complex syndrome, although more evidence is needed to incorporate most of them into clinical practice. However, most biomarker studies have been performed using North American or European populations, with little representation of the Latin American and the Caribbean (LAC) region. In the LAC region, there are additional challenges, particularly the lack of awareness and knowledge about FTD, even in specialists. Also, LAC genetic heritage and cultures are complex, and both likely influence clinical presentations and may modify baseline biomarker levels. Even more, due to diagnostic delay, the clinical presentation might be further complicated by both neurological and psychiatric comorbidity, such as vascular brain damage, substance abuse, mood disorders, among others. This systematic review provides a brief update and an overview of the current knowledge on genetic, neuroimaging, and fluid biomarkers for FTD in LAC countries. Our review highlights the need for extensive research on biomarkers in FTD in LAC to contribute to a more comprehensive understanding of the disease and its associated biomarkers. Dementia research is certainly reduced in the LAC region, highlighting an urgent need for harmonized, innovative, and cross-regional studies with a global perspective across multiple areas of dementia knowledge.</jats:p>
      1  2Scopus© Citations 23