Browsing by Author "Aboitiz, Francisco"

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    A healthcare approach to mental integrity
    (2024) Wajnerman-Paz, Abel; Aboitiz, Francisco; Alamos, Florencia; Vergara, Paulina Ramos
    The current human rights framework can shield people from many of the risks associated with neurotechnological applications. However, it has been argued that we need either to articulate new rights or reconceptualise existing ones in order to prevent some of these risks. In this paper, we would like to address the recent discussion about whether current reconceptualisations of the right to mental integrity identify an ethical dimension that is not covered by existing moral and/or legal rights. The main challenge of these proposals is that they make mental integrity indistinguishable from autonomy. They define mental integrity in terms of the control we can have over our mental states, which seems to be part of the authenticity condition for autonomous action. Based on a fairly comprehensive notion of mental health (ie, a notion that is not limited to the mere absence of illness), we propose an alternative view according to which mental integrity can be characterised both as a positive right to (medical and non-medical) interventions that restore and sustain mental and neural function, and promote its development and a negative right protecting people from interventions that threaten or undermine these functions or their development. We will argue that this notion is dissociated from cognitive control and therefore can be adequately distinguished from autonomy.
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    A 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
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    Agency improves working memory and accelerates visual and attentional processing
    (2020) Loyola-Navarro, R.; Moenne Vargas, Cristóbal Matías; Vergara, R.C.; Hyafil, A.; Aboitiz, Francisco; Maldonado, P.E.
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    Anatomy of corpus callosum in prenatally malnourished rats
    (SOC BIOLGIA CHILE, 2012) Olivares, Ricardo; Morgan, Carlos; Perez, Hernan; Hernandez, Alejandro; Aboitiz, Francisco; Soto Moyano, Ruben; Gil, Julio; Ortiz, Alexis; Flores, Osvaldo; Gimeno, Miguel; Laborda, Jesus
    The effect of prenatal malnutrition on the anatomy of the corpus callosum was assessed in adult rats (45-52 days old). In the prenatally malnourished animals we observed a significant reduction of the corpus callosum total area, partial areas, and perimeter, as compared with normal animals. In addition, the splenium of corpus callosum (posterior fifth) showed a significant decrease of fiber diameters in the myelinated fibers without changing density. There was also a significant decrease in diameter and a significant increase in density of unmyelinated fibers. Measurements of perimeter's fractal dimensions from sagittal sections of the brain and corpus callosum did not show significant differences between malnourished and control animals. These findings indicate that cortico-cortical connections are vulnerable to the prenatal malnutrition, and suggest this may affect interhemispheric conduction velocity, particular), in visual connections (splenium).
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    Attending to the heart is associated with posterior alpha band increase and a reduction in sensitivity to concurrent visual stimuli
    (Society for Psychophysiological Research, 2017) Villena González, Mario; Moenne Vargas, Cristóbal Matías; Lagos, Rodrigo A.; Alliende Correa, Luz María; Billeke, Pablo; Aboitiz, Francisco; López Hernández, Vladimir; Cosmelli, Diego
    Attentional mechanisms have been studied mostly in specific sensory domains, such as auditory, visuospatial, or tactile modalities. In contrast, attention to internal interoceptive visceral targets has only recently begun to be studied, despite its potential importance in emotion, empathy, and self-awareness. Here, we studied the effects of shifting attention to the heart using a cue-target detection paradigm during continuous EEG recordings. Subjects were instructed to count either a series of visual stimuli (visual condition) or their own heartbeats (heart condition). Visual checkerboard stimuli were used as attentional probes throughout the task. Consistent with previous findings, attention modulated the amplitude of the heartbeat-evoked potentials. Directing attention to the heart significantly reduced the visual P1/N1 amplitude evoked by the attentional probe. ERPs locked to the attention-directing cue revealed a novel frontal positivity around 300 ms postcue. Finally, spectral power in the alpha band over parieto-occipital regions was higher while attending to the heart-when compared to the visual task-and correlated with subject's performance in the interoceptive task. These results are consistent with a shared, resource-based attentional mechanism whereby allocating attention to bodily signals can affect early responses to visual stimuli.
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    Attention deficit hyperactivity disorder in Aymara children
    (SOC MEDICA SANTIAGO, 2012) Carrasco, Ximena; Daiber, Francisca; Rothhammer, Paula; Huerta, Daniela; Andrade, Claudia; Opazo, Patricia; Paz Lagos, Liza; Rothhammer, Francisco; Aboitiz, Francisco
    Background: The assessment of Attentional Deficit Hyperactivity Disorder (ADHD) among ethnic groups may reveal environmental or cultural variables that influence the appearance of this disorder. Aim: To assess the presence and characteristics of ADHD in two communities of the inland Arica valleys (Azapa and Lluta), where the Aymara population predominates. Material and Methods: Starting from a screening based on the Conner's test, we evaluated 79 children aged 8 to 13 years. Sixty children were of Aymara origin and 19 children were of non-Aymara origin. Twenty Aymara and 9 non-Aymara children had ADHD. They were compared with a group of patients from Santiago, Chile (110 children) that were previously assessed. Results: Patients from Azapa/Lluta displayed similar characteristics to those from Santiago. However the former had significantly less psychiatric comorbidities than the latter. On the other hand, the non-Aymara subgroup of Azapa/Lluta displayed an increased rate of comorbidities and was exclusively of the combined subtype, although their sample size is too small to draw strong conclusions. Conclusions: Although we cannot dismiss biological variables, the importance of family values and the respect to authorities may be protective factors for ADHD, associated to Aymara culture. Our findings suggest that the clinical characteristics of ADHD are not uniform among ethnic groups and cultures. The relative contribution of environmental and genetic factors in this variability remain to be determined. (Rev Med Chile 2012; 140: 1409-1416).
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    Attentional bias for food cues after sleeve gastrectomy : a behavioral and electrophysiological study
    (2019) Zumaeta Valenzuela, Arturo Ulises; Aboitiz, Francisco; Pontificia Universidad Católica de Chile. Facultad de Medicina
    Attentional bias for food cues (ABFC) has been linked to food craving, the inability to lose weight, and obesity. For this study, we explored the presence of ABFC in a bariatric group, using a food-modified Stroop task and visual task, with EEG and eye-tracking recording, respectively. Our data showed an increased attentional bias for appetizing food, a decreased bias for diet food and a prolonged brain processing of food stimuli in the bariatric group.
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    Attentional networks in preschool children with and without early symptoms of attention deficit and hyperactivity disorder who participated in a working memory training program
    (2021) Oyarzún Gavilán, Felipe Andrés; Aboitiz, Francisco; Pontificia Universidad Católica de Chile. Facultad de Medicina
    Attention is an important cognitive process for daily life because it allows us to be expectant to situations in the environment and to select some information from many options that are presented simultaneously. It is a process that is affected in neurodevelopmental problems such as attention deficit and hyperactivity disorder (ADHD). There is a lot of knowledge about cognitive difficulties in children diagnosed with ADHD, but little is known about what happens during the development of this disorder, especially in the stages prior to being diagnosed or at preschool stages. For this reason, we decided to study the attention, based on the paradigm of attentional networks, in preschool children with both typical development and early symptoms of ADHD. As the brain regions that improve the activity after working memory training are similar to the regions that are activated in attentional tasks, we proposed that working memory training could improve attention. To achieve this objective we evaluate attention (Attentional network task, ANT) and working memory (verbal and visuospatial) before and after an intensive computer-based working memory training. The results of the study showed that children with early symptoms of attention deficit and hyperactivity disorder have a decrease in modulation of the orienting and executive attentional networks, but not the alerting network, in comparison with typical development children. Additionally, we found that working memory training can improve the modulation of executive attentional network in children with early symptoms of attention deficit and hyperactivity disorder, but not in typically developing children. These results show the importance of studying the course of abnormal development of attention, in stages prior to the diagnosis of ADHD. Additionally, we suggest working memory training as a method to improve some difficulties in modulating attention in children with early symptoms of ADHD.
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    Brain response to auditory deviance with and without conscious access
    (2022) Osorio Galeano, Sergio Andrés; Aboitiz, Francisco; Pontificia Universidad Católica de Chile. Facultad de Medicina
    La habilidad de extraer regularidades estadísticas presentes en estímulos sensoriales y detectar cuando se presentan violaciones a dichas regularidades es de vital importancia para los organismos biológicos, en tanto median respuestas autonómicas y dirigidas a metas que son cruciales para la supervivencia. Por un lado, la extracción de regularidades estadísticas presentes en la escena sensorial permite la consolidación de un modelo interno del mundo. Por otro, la detección de violaciones en estas regularidades permite la actualización de dicho modelo, mediando así procesos de adaptación conductual. En el campo de la neurociencia cognitiva, la respuesta del cerebro a la desviación sensorial en la modalidad auditiva ha sido estudiada de manera clásica por medio de los potenciales asociados a eventos (ERPs, por su sigla en inglés). Esta literatura ha mostrado que la respuesta del cerebro a la desviación auditiva se puede caracterizar por la secuencia de dos respuestas neurales en la señal electroencefalográfica: el potencial de disparidad (MMN, por su sigla en inglés) y la respuesta P3. El MMN es un evento neural automático que puede ser observado independientemente de los estados atencionales o de consciencia de los individuos, mientras que la respuesta P3 depende crucialmente del acceso consciente a la desviación sensorial. Otros dos potenciales marcadores de la desviación auditiva son los cambios fásicos en el tamaño de la pupila e incremento evocados en el poder oscilatorio de las bandas de frecuencia theta (4-7 Hz) y beta (15-30 Hz). Mientras la literatura muestra que la detección de la desviación está acompañada de incrementos en el tamaño de la pupila (un marcador de la alerta y del sistema norepinefrinérgico) y del poder de theta y beta, no se conoce muy bien como estas respuestas neurales estarían moduladas por el acceso consciente a la desviación auditiva. Entender cómo responde el cerebro a la desviación auditiva con y sin acceso consciente nos permitiría entender la interacción dinámica existente entre mecanismos de procesamiento bottom-up y de modulación top-down durante el comportamiento enfocado a metas. En este estudio, nos propusimos entender cómo responde el cerebro a la desviación auditiva con y sin acceso consciente. Para esto, diseñamos una versión modificada de la tarea clásica de tipo oddball auditivo que nos permitió separar el procesamiento consciente del procesamiento subconsciente de la desviación auditiva. Para esto, identificamos los umbrales de discriminación consciente de cada individuo, lo cual nos permitió presentar a nuestros sujetos secuencias de tonos donde el último estímulo (el estímulo objetivo), podía ser otro tono estándar, un estímulo subumbral o un estímulo supraumbral. Los participantes debían reportar si el último estímulo de cada secuencia había sido igual o distinto de los anteriores. Por medio de esta tarea, recogimos datos conductuales (índices de sensibilidad y tiempos de reacción), pupilométricos (respuestas evocadas) y electroencefalográficos (ERPs, transformaciones de tiempo frecuencia al nivel de los electrodos y de las fuentes corticales, así como datos de conectividad funcional). Nuestros resultados muestran que las desviaciones subumbrales fueron incorrecta y sistemáticamente juzgadas como tonos estándar, lo cual refleja el procesamiento subconsciente de la desviación. En cambio, las desviaciones supraumbrales fueron correcta y sistemáticamente reportadas como diferentes, lo cual da cuenta del acceso consciente a la desviación auditiva. Además, replicamos hallazgos sobre la secuencia de MMN y P3 como marcadores confiables del procesamiento consciente y subconsciente de la desviación. Los datos pupilométricos sugieren que todos los estímulos objetivos están asociados a una respuesta pupilar, pero que dicha respuesta es mayor durante el procesamiento subconsciente de la desviación auditiva, reflejando de esta manera el procesamiento de la incertidumbre perceptual inesperada. Incrementos en el poder de theta y beta fueron observados en regiones corticales previamente asociadas con los orígenes del MMN y P3, incluyendo regiones temporales, prefrontales y cinguladas. Mientras que el poder de theta en regiones temporales reflejaría predicciones auditivas y mantención de la información sobre la identidad de un estímulo auditivo novedoso, los incrementos en el poder de beta en regiones prefrontales y cinguladas reflejarían la detección de un error en la predicción y la incertidumbre sensorial. Finalmente, incrementos en la conectividad funcional dentro del rango de theta reflejarían intercambio de información entre procesadores corticales distribuidos globalmente, lo cual soportaría la percepción consciente y la toma de decisiones, mientras que incrementos de conectividad funcional dentro del rango de beta reflejarían procesos de modulación top-down señalando así la necesidad de adaptación de los niveles de alerta debido a una alta incertidumbre y mecanismos de detección de errores en la predicción que son sensibles a una mayor saliencia del evento sensorial. Nuestros resultados subrayan como el cerebro asigna pesos a los mecanismos bottom-up y top-down durante el comportamiento enfocado a metas en función de si los eventos sensoriales son percibidos conscientemente o no, así como la contribución de la adaptación de la alerta durante esta interacción entre mecanismos de procesamiento de la información sensorial. Eso ilustra además la relación dinámica y en constante adaptación entre percepción y cognición.
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    Chapter 13 : Origin and evolution of human speech : emergence from a trimodal auditory, visual and vocal network
    (2019) Michon Desbiey, Maëva; López Hernández, Vladimir; Aboitiz, Francisco
    In recent years, there have been important additions to the classical model of speech processing as originally depicted by the Broca–Wernicke model consisting of an anterior, productive region and a posterior, perceptive region, both connected via the arcuate fasciculus. The modern view implies a separation into a dorsal and a ventral pathway conveying different kinds of linguistic information, which parallels the organization of the visual system. Furthermore, this organization is highly conserved in evolution and can be seen as the neural scaffolding from which the speech networks originated. In this chapter we emphasize that the speech networks are embedded in a multimodal system encompassing audio-vocal and visuo-vocal connections, which can be referred to an ancestral audio-visuo-motor pathway present in nonhuman primates. Likewise, we propose a trimodal repertoire for speech processing and acquisition involving auditory, visual and motor representations of the basic elements of speech: phoneme, observation of mouth movements, and articulatory processes. Finally, we discuss this proposal in the context of a scenario for early speech acquisition in infants and in human evolution.
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    Chronic stress decreases the expression of sympathetic markers in the pineal gland and increases plasma melatonin concentration in rats
    (WILEY, 2006) Dagnino Subiabre, Alexies; Orellana, Juan A.; Carmona Fontaine, Carlos; Montiel, Juan; Diaz Veliz, Gabriela; Seron Ferre, Maria; Wyneken, Ursula; Concha, Miguel L.; Aboitiz, Francisco
    Chronic stress affects brain areas involved in learning and emotional responses. Although most studies have concentrated on the effect of stress on limbic-related brain structures, in this study we investigated whether chronic stress might induce impairments in diencephalic structures associated with limbic components of the stress response. Specifically, we analyzed the effect of chronic immobilization stress on the expression of sympathetic markers in the rat epithalamic pineal gland by immunohistochemistry and western blot, whereas the plasma melatonin concentration was determined by radioimmunoassay. We found that chronic stress decreased the expression of three sympathetic markers in the pineal gland, tyrosine hydroxylase, the p75 neurotrophin receptor and alpha-tubulin, while the same treatment did not affect the expression of the non-specific sympathetic markers Erk1 and Erk2, and glyceraldehyde-3-phosphate dehydrogenase. Furthermore, these results were correlated with a significant increase in plasma melatonin concentration in stressed rats when compared with control animals. Our findings indicate that stress may impair pineal sympathetic inputs, leading to an abnormal melatonin release that may contribute to environmental maladaptation. In addition, we propose that the pineal gland is a target of glucocorticoid damage during stress.
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    Chronic stress induces dendritic atrophy in the rat medial geniculate nucleus: Effects on auditory conditioning
    (ELSEVIER, 2009) Dagnino Subiabre, Alexies; Munoz Llancao, Pablo; Terreros, Gonzalo; Wyneken, Ursula; Diaz Veliz, Gabriela; Porter, Benjamin; Kilgard, Michael P.; Atzori, Marco; Aboitiz, Francisco
    Chronic stress induces dendritic atrophy in the inferior colliculus (IC, auditory mesencephalon) and impairs auditory avoidance conditioning. The aim of this study was to determine in Golgi preparations and in cued fear conditioning whether stress affects other auditory components, like the thalamic medial geniculate nucleus (MG) or the posterior thalamic nucleus (PO), in Sprague-Dawley rats. Chronic restraint stress produced a significant dendritic atrophy in the MG (stress: 407 +/- 55 mu m; control: 808 +/- 120 mu m; p < 0.01) but did not affect auditory fear conditioning. The last result was in apparent contrast with the fact that stress impairs both the acquisition of auditory avoidance conditioned responses and the dendritic structure in two major nuclei of the auditory system. In order to analyze this disagreement, we investigated whether the stress-related freezing to tone occurring in the fear conditioning protocol corresponded to a conditioned or an unconditioned fear response, using changes in tone instead of light throughout conditioning trials. Chronic stress significantly enhanced visual fear conditioning in stressed animals compared to controls (stress: 58.9 +/- 8.42%, control: 23.31 +/- 8.01%; p < 0.05), but this fear enhancement was related to unconditioned fear. Conversely, chronic stress did not affect the morphology of the PO (subserving both auditory and somatosensory information) or the corresponding auditory and somatosensory unconditioned responses (acoustic startle response and escape behavior). Our results suggest that the auditory conditioned stimulus can be processed in part independently of the IC and MG in the stressed animals, and sent to the amygdala via the PO inducing unconditioned fear. Comparable alterations could be produced in major depression. (C) 2009 Elsevier B.V. All rights reserved.
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    Chronic stress induces upregulation of brain-derived neurotrophic factor (BDNF) rnRNA and integrin alpha 5 expression in the rat pineal gland
    (ELSEVIER SCIENCE BV, 2006) Dagnino Subiabre, Alexies; Zepeda Carreno, Rodrigo; Diaz Veliz, Gabriela; Mora, Sergio; Aboitiz, Francisco
    Chronic stress affects brain areas involved in learning and emotional responses. These alterations have been related with the development of cognitive deficits in major depression. Moreover, stress induces deleterious actions on the epithalamic pineal organ, a gland involved in a wide range of physiological functions. The aim of this study was to investigate whether the stress effects on the pineal gland are related with changes in the expression of neurotrophic factors and cell adhesion molecules. Using reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, we analyzed the effect of chronic immobilization stress on the BDNF mRNA and integrin alpha 5 expression in the rat pineal gland. We found that BDNF is produced in situ in the pineal gland. Chronic immobilization stress induced upregulation of BDNF mRNA and integrin alpha 5 expression in the rat pineal gland but did not produce changes in beta-actin mRNA or in GAPDH expression. Stressed animals also evidenced an increase in anxiety-like behavior and acute gastric lesions. These results suggest that BDNF and integrin a5 may have a counteracting effect to the deleterious actions of immobilization stress on functionally stimulated pinealocytes. Furthermore, this study proposes that the pineal gland may be a target of glucocorticoid damage during stress. (c) 2006 Elsevier B.V. All rights reserved.
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    Contextual imitation of intransitive body actions in a Beluga whale (Delphinapterus leucas): a "do as other does" study
    (2017) Abramson, Jose Z.; Hernández-Lloreda, María Victoria; Esteban, José Antonio; Colmenares, Fernando; Aboitiz, Francisco; Call, Josep
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    Coordinated prefrontal-hippocampal activity and navigation strategy-related prefrontal firing during spatial memory formation
    (2018) Negron-Oyarzo, Ignacio; Espinosa, Nelson; Aguilar, Marcelo; Fuenzalida, Marco; Aboitiz, Francisco; Fuentealba, Pablo
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    Déficit atencional con hiperactividad: trastorno multicausal de la conducta, con heredabilidad y comorbilidad genética moderadas
    (2017) Puddu, G.; Rothhammer, P.; Carrasco, X.; Aboitiz, Francisco; Rothhammer, F.
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    DRD4 dopamine receptor alleles in Chilean students of different ethnic origin and its relation with the risk for attention deficit/hyperactivity disorder
    (SOC MEDICA SANTIAGO, 2012) Rothhammer, Paula; Paz Lagos, Liza; Espinosa Parrilla, Yolanda; Aboitiz, Francisco; Rothhammer, Francisco
    Background: Worldwide diversity of alleles of D4 receptor gene (DRD4), linked to attention deficit hyperactivity disorder (ADHD), is mostly the result of length and single nucleotide polymorphisms in a 48-bp tandem repeat (VNTR). Alleles containing from two (2R) to eleven (11R) repeats have been identified. The most common are 4R, 7R and 2R. Aim: To study the association of ADHD risk with DRD4 genotypes in Chilean students. Subjects and Methods: ADHD risk data were obtained through the abbreviated Conner's Scale for School Teachers in 66 Aymara children (11 cases and 55 controls), 91 Rapa-Nui children (60 cases ad 31 controls) and 96 children from a mixed urban population from Santiago (51 cases and 45 controls). DNA extracted from saliva was amplified by polymerase chain reaction (PCR) to genotype the DRD4 VNTR. Results: The distribution of DRD4 alleles reveals that, beneath the 4R allele, 7R exhibits the second highest frequencies in Aymara and Santiago children. In Polynesian children, 2R ranks after 4R. A statistically significant association between ADHD risk and 2R/4R genotype was identified in Polynesian children (p < 0.05; odds ratio = 3.7). Conclusions: Different DRD4 genotypes are associated with ADHD phenotype in Chilean populations, probably as a consequence of their initial colonization history. (Rev Med Chile 2012; 140: 1276-1281).