Detección de novedad y codificación predictiva en el sistema auditivo: Impacto clínico en disfunciones auditivas y vestibulares. Revisión de la literatura / Deviance detection and predictive coding in the auditory system: Clinical impact in auditory and vestibular dysfunctions

Una propiedad fundamental de los sistemas sensoriales es su capacidad para detectar estímulos novedosos en el entorno. El sistema nervioso posee neuronas que disminuyen su respuesta a los estímulos sonoros que se repiten a lo largo del tiempo y otras neuronas que aumentan su frecuencia de disparo ante estímulos novedosos, siendo la diferencia entre ambas respuestas conocida como adaptación-específica a estímulos. En las últimas décadas, se ha propuesto que el cerebro establece, continuamente, predicciones de los estímulos novedosos y del entorno basándose en sus experiencias previas y en modelos de representación internos, teoría denominada codificación predictiva. En esta revisión, abordaremos algunos conceptos de la adaptación-específica a estímulos y codificación predictiva, centrándonos principalmente en el sistema auditivo. Por último, propondremos una explicación teórica basada en el marco de la codificación predictiva para algunas disfunciones neuropsiquiátricas, auditivas y vestibulares.

A fundamental property of sensory systems is their ability to detect novel stimuli in the environment. The nervous system possesses neurons that decrease their response to sound stimuli that are repeated over time and other neurons that increase their firing rate to novel stimuli, the difference between the two responses being known as stimulus-specific adaptation. In recent decades, it has been proposed that the brain continuously makes predictions of novel stimuli and the environment based on its previous experiences and internal representational models, a theory called predictive coding. In this review, we will address some concepts of stimulus-specific adaptation and predictive coding, focusing mainly on the auditory system. Finally, we will propose a theoretical explanation based on the predictive coding framework for some neuropsychiatric, auditory, and vestibular dysfunctions.

Entanglement Negativity and Concurrence in Some Low-Dimensional Spin Systems.

The influence of magnon bands on entanglement in the antiferromagnetic XXZ model on a triangular lattice, which models the bilayer structure consisting of an antiferromagnetic insulator and normal metal, is investigated. This effect was studied in ferromagnetic as well as antiferromagnetic triangular lattices. Quantum entanglement measures given by the entanglement negativity have been studied, where a magnon current is induced in the antiferromagnet due to interfacial exchange coupling between localized spins in the antiferromagnet and itinerant electrons in a normal metal. Moreover, quantum correlations in other frustrated models, namely the metal-insulation antiferromagnetic bilayer model and the Heisenberg model with biquadratic and bicubic interactions, are analyzed.

Mismatch Negativity is associated with affective social behavior in microcephaly.

Some children with severe microcephaly related to Zika virus infection show affective social-like behavior, such as smiling and rejection to a stranger's lap. Our objective was to check the association between this behavior and the occurrence of Mismatch Response (MMR) in event-related potentials. Twenty eight microcephalic children, aged 1-3 years, were divided in Affect(+) and Affect(-) groups, according to either the presence or absence of affective social-like behavior, respectively, and underwent the OddBall paradigm with vowels as auditory stimuli. MMR was statistically estimated comparing MMR sample means between both groups. The Affect(+) group significantly differed from the Affect(-) group and, as opposed to the latter, showed MMR as Mismatch Negativity (MMN) in the left occipital, left and right posterior temporal, and (especially) the right and median parietal leads. The relationship observed between MMN and affective social-like behavior suggests that these children may have cognitive mechanisms capable of providing some social interaction, despite their profound neurological dysfunction. MMN diagnostic techniques seem to be promising for the triage of microcephalic subjects regarding cognitive functions and for choosing a strategy for some social adaptation.

Pentapartite Entanglement Measures of GHZ and W-Class State in the Noninertial Frame.

We study both pentapartite GHZ and W-class states in the noninertial frame and explore their entanglement properties by carrying out the negativities including 1-4, 2-3, and 1-1 tangles, the whole entanglement measures such as algebraic and geometric averages π5 and Π5, and von Neumann entropy. We illustrate graphically the difference between the pentapartite GHZ and W-class states. We find that all 1-4, 2-3 tangles and the whole entanglements, which are observer dependent, degrade more quickly as the number of accelerated qubits increases. The entanglements of these quantities still exist even at the infinite acceleration limit. We also notice that all 1-1 tangles of pentapartite GHZ state Nαß=NαIß=NαIßI=0 where α,ß∈(A,B,C,D,E), whereas all 1-1 tangles of the W-class state Nαß,NαIß and NαIßI are unequal to zero, e.g., Nαß=0.12111 but NαIß and NαIßI disappear at r>0.61548 and r>0.38671, respectively. We notice that the entanglement of the pentapartite GHZ and W-class quantum systems decays faster as the number of accelerated particles increases. Moreover, we also illustrate the difference of von Neumann entropy between them and find that the entropy in the pentapartite W-class state is greater than that of GHZ state. The von Neumann entropy in the pentapartite case is more unstable than those of tripartite and tetrapartite subsystems in the noninertial frame.

Aversiveness of errors and the error-related negativity (ERN): A systematic review on the affective states' manipulations findings.

Error-related negativity (ERN) has been used to investigate neural mechanisms underlying error processing and conflict monitoring. Recent evidence highlights that affective and motivational states modulate the ERN and that aversiveness of errors plays a vital role in error monitoring. Therefore, our primary objective was to systematically evaluate and describe the influence of affect state-related manipulations on the ERN. A total of 51 publications identified from PsyInfo, PubMed, and PsyArticles databases were included following the Prisma procedures for systematic reviews. Papers were analyzed using sample attributes, psychological paradigms, and states manipulations. The present study shows that the ERN component has recurrently appeared to be sensitive to manipulations of affective states in the reviewed literature. However, conclusive findings concerning the affect state-dependent properties of the ERN remain elusive. Results are discussed considering heterogeneity in paradigms, variables, and the state-trait interactions. Furthermore, recommendations for future high-quality studies are provided along with the necessity of upcoming high-power replication attempts and more studies with positive affect manipulations.

Potencial de disparidad o Mismatch negativity y P3a en pacientes con esquizofrenia / Mismatch negativity and P3a in patients with Schizophrenia

Resumen Antecedentes: la esquizofrenia es una enfermedad crónica que genera gran discapacidad, para la cual se han reportado biomarcadores potenciales, pero sin suficiente validez clínica. El mismatch negativity (MMN) y el P3a son potenciales relacionados con eventos que han demostrado ser indicadores neurofisiológicos del procesamiento auditivo pre-atencional y potenciales biomarcadores. Objetivo: evaluar el MMN y P3a en pacientes con diagnóstico de esquizofrenia y su relación con variables sociodemográficas y clínicas. Método: estudio cuantitativo transversal de 23 sujetos con esquizofrenia (ESQ) y 22 controles sanos (SN). Las amplitudes promedio y latencias del MMN/P3a para la condición infrecuente en duración y frecuencia fueron obtenidas mediante un paradigma oddball auditivo en un EEG de 32 canales. Resultados: se encontraron diferencias para la condición frecuencia en la amplitud del MMN (p=0.046; CI 95% 0.009; 0.87) y la amplitud del P3a (p=0.042; CI 95% 0.025; 1.24) entre los grupos; la amplitud del MMN fue menor en el grupo ESQ (-0.36 DE 0.51 µV) en comparación con los participantes del grupo de SN (-0.81 DE 0.89 µV), mientras que la amplitud del P3a fue menor en el grupo SN (0.18 DE 0.97 µV) versus el grupo ESQ (0.82 DE 1.05 µV). En relación con las variables sociodemográficas y clínicas, las asociaciones con el P3a fueron moderadas y con el MMN débiles. Conclusiones: la reducción de la amplitud del MMN a la condición frecuencia exhibe mayor utilidad que el P3a como medida de alta estabilidad en pacientes con esquizofrenia, lo que reitera su posible uso como biomarcador.

Abstract Background: schizophrenia is a chronic disease that generates great disability, which currently has potential biomarkers but without sufficient clinical validity. Mismatch negativity (MMN) and P3a are event-related potentials that have been shown to be neurophysiological indicators of pre-attentional auditory processing and potential biomarkers. Objective: to evaluate MMN and P3a in patients with a diagnosis of schizophrenia and their relationship with sociodemographic and clinical variables. Method: a quantitative cross-sectional study of 23 subjects with schizophrenia and 22 healthy controls was performed. The average amplitudes and latencies of the MMN/P3a for the condition infrequent in duration and infrequent in frequency were obtained using an auditory oddball paradigm on a 32-channel EEG. Results: differences were found for the frequency condition in the amplitude of the MMN (p=0.046; 95% CI 0.009; 0.87) and the amplitude of the P3a (p=0.042; 95% CI 0.025; 1.24) between the groups; MMN amplitude was lower in schizophrenia (-0.36 SD 0.51 µV) compared to healthy controls (-0.81 SD 0.89 µV), while P3a amplitude was lower in healthy controls (0.18 SD 0.97 µV) versus the group with schizophrenia (0.82 SD 1.05 µV). In regard to sociodemographic and clinical variables, the associations with P3a were moderate, and showed weak MMN. Conclusions: MMN amplitude reduction to the frequency condition exhibits greater utility than P3a as a measure of high stability in schizophrenia, restating its potential use as a biomarker.

Does mismatch negativity have utility for NMDA receptor drug development in depression?

Rapid antidepressant effects associated with ketamine have shifted the landscape for the development of therapeutics to treat major depressive disorder (MDD) from a monoaminergic to glutamatergic model. Treatment with ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, may be effective, but has many non-glutamatergic targets, and clinical and logistical problems are potential challenges. These factors underscore the importance of manipulations of binding mechanics to produce antidepressant effects without concomitant clinical side effects. This will require identification of efficient biomarkers to monitor target engagement. The mismatch negativity (MMN) is a widely used electrophysiological signature linked to the activity of NMDA receptors (NMDAR) in humans and animals and validated in pre-clinical and clinical studies of ketamine. In this review, we explore the flexibility of the MMN and its capabilities for reliable use in drug development for NMDAR antagonists in MDD. We supplement this with findings from our own research with three distinct NMDAR antagonists. The research described illustrates that there are important distinctions between the mechanisms of NMDAR antagonism, which are further crystallized when considering the paradigm used to study the MMN. We conclude that the lack of standardized methodology currently prevents MMN from being ready for common use in drug discovery. Clinical trial registration: This manuscript describes data collected from the following National Institutes of Health (NIH) and Veterans Affairs (VA) studies: AV-101, NCT03583554; lanicemine, NCT03166501; ketamine, NCT02556606.

New insights into neural networks of error monitoring and clinical implications: a systematic review of ERP studies in neurological diseases.

Error monitoring allows for the efficient performance of goal-directed behaviors and successful learning. Furthermore, error monitoring as a metacognitive ability may play a crucial role for neuropsychological interventions, such as rehabilitation. In the past decades, research has suggested two electrophysiological markers for error monitoring: the error-related negativity (ERN) and the error positivity (Pe), thought to reflect, respectively, error detection and error awareness. Studies on several neurological diseases have investigated the alteration of the ERN and the Pe, but these findings have not been summarized. Accordingly, a systematic review was conducted to understand what neurological conditions present alterations of error monitoring event-related potentials and their relation with clinical measures. Overall, ERN tended to be reduced in most neurological conditions while results related to Pe integrity are less clear. ERN and Pe were found to be associated with several measures of clinical severity. Additionally, we explored the contribution of different brain structures to neural networks underlying error monitoring, further elaborating on the domain-specificity of error processing and clinical implications of findings. In conclusion, electrophysiological signatures of error monitoring could be reliable measures of neurological dysfunction and a robust tool in neuropsychological rehabilitation.

Pitch and Duration Mismatch Negativity are Associated With Distinct Auditory Cortex and Inferior Frontal Cortex Volumes in the First-Episode Schizophrenia Spectrum.

BACKGROUND: Pitch and duration mismatch negativity (pMMN/dMMN) are related to left Heschl's gyrus gray matter volumes in first-episode schizophrenia (FESz). Previous methods were unable to delineate functional subregions within and outside Heschl's gyrus. The Human Connectome Project multimodal parcellation (HCP-MMP) atlas overcomes this limitation by parcellating these functional subregions. Further, MMN has generators in inferior frontal cortex, and therefore, may be associated with inferior frontal cortex pathology. With the novel use of the HCP-MMP to precisely parcellate auditory and inferior frontal cortex, we investigated relationships between gray matter and pMMN and dMMN in FESz. METHODS: pMMN and dMMN were measured at Fz from 27 FESz and 27 matched healthy controls. T1-weighted MRI scans were acquired. The HCP-MMP atlas was applied to individuals, and gray matter volumes were calculated for bilateral auditory and inferior frontal cortex parcels and correlated with MMN. FDR correction was used for multiple comparisons. RESULTS: In FESz only, pMMN was negatively correlated with left medial belt in auditory cortex and area 47L in inferior frontal cortex. Duration MMN negatively correlated with the following auditory parcels: left medial belt, lateral belt, parabelt, TA2, and right A5. Further, dMMN was associated with left area 47L, right area 44, and right area 47L in inferior frontal cortex. CONCLUSIONS: The novel approach revealed overlapping and distinct gray matter associations for pMMN and dMMN in auditory and inferior frontal cortex in FESz. Thus, pMMN and dMMN may serve as biomarkers of underlying pathological deficits in both similar and slightly different cortical areas.

Pontes sobre o nada: narrativas do sofrimento e transformação existencial / Bridges over nothingness: narratives of suffering and existential transformation

O principal intuito do presente artigo é questionar uma tendência estrutural de nosso modo tradicional de compreensão do problema da negatividade. Se considerarmos a reação imediata à afirmação de que a existência se caracteriza exatamente como uma indeterminação ontológica radical, não é incomum perceber a dificuldade de assumir essa afirmação sem uma certa sensação de que inviabiliza por completo a própria existência, caso não seja contrabalanceada por alguma dimensão de soterramento da nadidade, de pavimentação da negatividade. Tal dificuldade repercute sobre os modos mais imediatos de lidar com o sofrimento existencial e mesmo de pensar o foco mais essencial das terapias em geral. Na medida em que questionamos esses modos e seus pressupostos mais imediatos, o que buscamos aqui é antes de tudo investigar até que ponto o problema mais intrínseco do sofrimento reside precisamente na carga imensa que provém justamente da tentativa de fugir dele. Heidegger é, nesse contexto, nosso parceiro mais próximo de diálogo, assim como a metáfora da ponte e do farol que nos guia incessantemente em nosso caminho.

The central aim of the present article is to put in question a structural tendency of our tradition of understanding the problem of negativity. If we consider the immediate reaction to the assertion that existence characterizes itself exactly through a very ontological indeterminacy, it is not uncommon to perceive how hard is to embrace this assertion without a sensation that it makes impossible the own existence, if it is not counterbalanced by any kind of attenuation to such a nothingness, of paving negativity. Such difficulty resonates over the main ways to cope with existential suffering and even of thinking the most essential focus of therapies in general. Putting in question these ways of thinking and their presupposes, we are trying over all to investigate if suffering itself has its basis in the extraordinary weight arousing from the proper attempt to avoid suffering. Heidegger is, in this context, our closer partner of dialog, such as the metaphors of the bridge and the lighthouse which guide us in our path.

Sartre por Barbaras: movimentos de uma leitura crítica / Sartre by Barbaras: movements of a critical reading / Sartre por Barbaras: movimientos de una lectura crítica

Neste trabalho nos propomos a apresentar alguns movimentos da leitura crítica que Renaud Barbaras realiza da filosofia de Sartre. Para tal, escolhemos como fio condutor a retomada que este autor faz do dualismo de base da filosofia sartriana, em continuidade com a crítica de Merleau-Ponty, porém de modo a abrir outros caminhos de reflexão. Gostaríamos de evidenciar nestes caminhos o quanto Barbaras não somente potencializa a crítica precedente, mas realiza aproximações e problematizações originais que, ao mesmo tempo em que tornam mais evidentes os impasses da filosofia sartriana, não deixam de abrir novas possibilidades de investigação. Estas últimas nuances serão apontadas através da crítica propriamente barbarasiana da questão do outro e do desejo em Sartre.

In this work we propose to present some movements of the critical reading that Renaud Barbaras performs of Sartre's philosophy. For this, we have chosen as the guiding thread the author's reiteration of the basic dualism of Sartre's philosophy, in alignment with Merleau-Ponty's critique, but seeking to open other paths of reflection. We would like to point out in these paths that not only does Barbaras enhance the preceding critiques, but makes original approaches and problematizations, which makes the impasses of Sartre's philosophy more evident while also opening new possibilities for investigation. These later nuances will be pointed out through a properly Barbarasian critique of the question of the other and the of the desire in Sartre.

En este trabajo nos proponemos presentar algunos movimientos de la lectura crítica que Renaud Barbaras realiza de la filosofía de Sartre. Para eso escogimos, como hilo conductor, la recuperación que este autor hace del dualismo de base de la filosofía sartriana, en continuidad con la crítica de Merleau-Ponty, como modo de abrir otros caminos de reflexión. En estos caminos nos gustaría evidenciar la manera en que Barbaras no solo potencializa la crítica precedente sino el modo en que realiza aproximaciones y problematizaciones originales, que al mismo tiempo en que tornan más evidentes los impases de la filosofía sartriana, no dejan de abrir nuevas posibilidades de investigación. Estos últimos matices son puntuados a través de la crítica propiamente barbarasiana de la cuestión del otro y el deseo en Sartre.

A dupla potencialidade do irrepresentável e a negatividade necessária: trauma e pulsão de morte / The double potentiality of the irrepresentable and the necessary negativity: trauma and death instinct / La doble potencialidad del irrepresentable y la negatividad necesaria: trauma y pulsión de muerte

Este artigo analisa, a partir de revisão da literatura e articulações teóricas, a dupla potencialidade do não representado, da negatividade e do vazio psíquico, os quais, ao mesmo tempo que apontam para um limite do aparelho psíquico, o lançam para o trabalho, contribuindo para a constituição e diferenciação da subjetividade. Entendemos que o que é tomado pelo psiquismo, em um primeiro momento, como um obstáculo, impassível de digestão mental, em um segundo momento, pode se tornar motor de criação que gerará um novo limite. Essa concepção pode ser deduzida do próprio modo de funcionamento do psiquismo: se, de um lado, pode haver um limite circunstancial de processamento da estimulação endógena e exógena que alcança o aparelho psíquico, de outro lado, através do mecanismo de compulsão à repetição, por exemplo, o esforço do processamento psíquico opera de forma interminável. Os diferentes modelos a partir dos quais o conceito de trauma pode ser pensado servirão de fio condutor para analisar os efeitos e os destinos psíquicos do irrepresentado, bem como para articular essas ideias com os conceitos de repetição e pulsão de morte.

This article analyses, from a literature review and theoretical articulations, the double potentiality of the unrepresented, of negativity and of emptiness over the psyche, that at the same time points out a limit of the psychic apparatus, lances it for work, contributing for subjective constitution and differentiation. The direction chosen here favors the idea that what is taken in the first place by the psyche as an obstacle, impassible of mental digestion, at a second moment can turn out to be a motor of surpassingness that will engender a new limit. This conception can be deducted from the own way that psyche functions, because if in one hand there can be a circumstantial limit of processing endogenous and exogenous stimulation that reaches the psychic apparatus, in the other hand, through compulsion repetition mechanism, for example, the effort of psychic processing operates in an interminable way. The different models that the concept of trauma can be thought through will serve as a conducting wire to analyze the effects and psychic destinies of the unrepresented, as well as to articulate these ideas with the concepts of repetition and death instinct.

Este artículo analiza, a partir de revisión de la literatura y articulaciones teóricas, la doble potencialidad del irrepresentado, de la negatividad y del vacío psíquico, los cuales, al mismo tiempo que apuntan hacia un límite del aparato psíquico, lo lanzan para el trabajo, contribuyendo a la constitución y diferenciación de la subjetividad. Entendemos que lo que es tomado por el psiquismo, en un primer momento, como un obstáculo, impasible de digestión mental, en un segundo momento, puede convertirse en motor de creación que generará un nuevo límite. Esta concepción puede ser deducida del propio modo de funcionamiento del psiquismo: si, por un lado, puede haber un límite circunstancial de procesamiento de la estimulación endógena y exógena que alcanza el aparato psíquico, por otro lado, a través del mecanismo de compulsión a la repetición, por ejemplo, el esfuerzo del procesamiento psíquico opera de forma interminable. Los diferentes modelos a partir de los cuales el concepto de trauma puede ser pensado servirán de hilo conductor para analizar los efectos y los destinos psíquicos del irrepresentado, así como para articular esas ideas con los conceptos de repetición y pulsión de muerte.

Altered auditory processing and effective connectivity in 22q11.2 deletion syndrome.

22q11.2 deletion syndrome (22q11.2DS) is one of the most common copy number variants and confers a markedly increased risk for schizophrenia. As such, 22q11.2DS is a homogeneous genetic liability model which enables studies to delineate functional abnormalities that may precede disease onset. Mismatch negativity (MMN), a brain marker of change detection, is reduced in people with schizophrenia compared to healthy controls. Using dynamic causal modelling (DCM), previous studies showed that top-down effective connectivity linking the frontal and temporal cortex is reduced in schizophrenia relative to healthy controls in MMN tasks. In the search for early risk-markers for schizophrenia we investigated the neural basis of change detection in a group with 22q11.2DS. We recorded high-density EEG from 19 young non-psychotic 22q11.2 deletion carriers, as well as from 27 healthy non-carriers with comparable age distribution and sex ratio, while they listened to a sequence of sounds arranged in a roving oddball paradigm. Despite finding no significant reduction in the MMN responses, whole-scalp spatiotemporal analysis of responses to the tones revealed a greater fronto-temporal N1 component in the 22q11.2 deletion carriers. DCM showed reduced intrinsic connection within right primary auditory cortex as well as in the top-down, connection from the right inferior frontal gyrus to right superior temporal gyrus for 22q11.2 deletion carriers although not surviving correction for multiple comparison. We discuss these findings in terms of reduced adaptation and a general increased sensitivity to tones in 22q11.2DS.

Psychoacoustics and Neurophysiological Alterations after 30-36 Hours of Sleep Deprivation.

BACKGROUND AND AIM: Sleep deprivation (SD) may result in perceptual and cognitive alterations in healthy subjects. Our objective was to compare whether psychoacoustics and neurophysiological variables in healthy subjects were altered after SD of 30-36 h. METHOD: We examined 22 subjects by means of several psychoacoustics tests, P300 and mismatch negativity (MMN) recordings, and brainstem auditory evoked potentials (BAEP) before and after 30-36 h of SD. RESULTS: In the psychoacoustics tests, we found that after SD, difficulties were experienced by the left ear in the discrimination of words in noise and by the right ear in music discrimination. In the neurophysiological tests, we found delayed latencies of P300 and MMN wave; there was a delay of wave I in both ears, and wave V in the right ear in BAEP. We found significant correlations with positive direction between P300 latency and words in noise and music discrimination in the right ear. CONCLUSIONS: SD results in alterations of central auditory processing perception and delays of brain neurophysiological responses, with some correlations between the psychoacoustics and neurophysiological tests. These alterations may relate to other cognitive alterations that deserve more research in future studies.

Uso del Análisis por Componentes Independientes en la extracción de artefactos de la respuesta Mismatch Negativity / Use of Independent Component Analysis in the extraction of Artifacts of the Mismatch Negativity Response

Resumen: El Potencial de disparidad es una respuesta cortical elicitada por la detección automática de estímulos con distintas características, permitiendo la exploración de procesos neuropsicológico. Sin embargo el análisis de esta señal se puede dificultar por una baja relación señal a ruido debida a los artefactos presentes en la adquisición de la misma. Diversas publicaciones proponen el uso de implementaciones de la técnica de Separación Ciega de fuentes, como el Análisis por Componentes Independientes (ACI), para preprocesar las señales y eliminar estos artefactos. Sin em bargo, no se ha estudiado cuál de los algoritmos ACI que se encuentran en la literatura será el óptimo para mejorar la calidad del MMN, por lo que en este estudio se propuso determinar si existen diferencias significativas en las respuestas obtenidas al utilizar los algoritmos de FastICA, Infomax y SOBI para eliminar los artefactos típicamente presentes en este tipo de señales. Adicionalmente se dan algunas características de estos artefactos a manera de sistematizar la identificación y eliminaciones de los mismos, además de comparar las respuestas obtenidas con y sin preprocesamiento, así como la distribución topográfica de este potencial antes y después de la eliminación de artefactos. Mediante el algoritmo Infomax se identifican mejor los Componentes Independientes asociados con artefactos, resultando en un MMN de mayor amplitud y distribución topográfica fronto-central con predominancia izquierda.

Abstract: Mismatch Negativity is a cortical response elicited by the automatic detection of stimuli which have different characteristics, allowing exploration of neuropsychological processes. However, the analysis of this signal can be di fficult by a low SNR due to artifacts present when the signal is recorded. Different publications propose to use the approach given by the Blind Source Separation Technique by means of the Independent Component Analysis (ICA) to preprocess and eliminate these artifacts. Nevertheless, it has not been studied which of the ICA algorithms found in the literature will be optimal for improving the quality of MMN. Therefore the aim of this study is to determine whether there are significant differences in the responses obtained by using FastICA, Infomax and SOBI to remove artifacts typically present in such signals. In addition, some features of the Independent Components related to artifacts are given in order to systematize the identification and elimination of those. In addition, MMN responses obtained with and without data preprocessing, as well as topographic maps before and after the elimination of artifacts were compared. Thus, Infomax is the best ICA algorithm to calculate Independent Components associated with artifacts, resulting in high amplitude MMN and a topographic map with a clear fronto-central distribution with left-hemisphere predominance.

Propiedades psicométricas de la escala de negatividad social de Newsom en universitarios chilenos / Psychometric properties of Newson´s social negativity exchange scale in a Chilean college age students

El objetivo de este estudio fue estimar las propiedades psicométricas de la Escala de Negatividad Social de Newsom, la cual mide el efecto negativo de las interacciones sociales en el bienestar individual. Para ello, se seleccionó a 526 universitarios, realizando análisis factorial exploratorio con 50% de la muestra y análisis factorial confirmatorio con el restante 50%. A diferencia de la estructura de cuatro factores sugerida por los autores, los resultados de este estudio indican que la escala tiene una estructura factorial de dos factores, agrupando el primer factor 4 ítems y el segundo 8. Las cargas factoriales fueron superiores a 0,3 y se obtuvieron buenos indicadores de bondad de ajuste. La consistencia interna de la escala, medida con Alfa de Cronbach fue 0,86. La evidencia sugiere que la Escala de Negatividad Social de Newsom es un instrumento válido y confiable que puede ser utilizado en población Chilena.

The purpose of this study was to determine the psychometric properties of the Social Negativity Exchange Scale developed by Newsom et al, which is defined as the negative effect that social interactions have on individual wellbeing. Thus, a sample of five hundred and twenty two (n= 526) college-age students was non-randomly selected. An exploratory factor analysis was conducted with 50% of them, and then a confirmatory factor analysis with the others. A two-factor solution was identified, with the first factor grouping four items and the second factor eight items. Fit indexes were good, with factorial loadings greater than .3. the total scale reliability was .86. The evidence obtained in this study suggests that the Newsom´s Social Negativity Exchange Scale is a valid and reliable scale to be used with Chilean population.

N1 response attenuation and the mismatch negativity (MMN) to within- and across-category phonetic contrasts.

According to the neural adaptation model of the mismatch negativity (MMN), the sensitivity of this event-related response to both acoustic and categorical information in speech sounds can be accounted for by assuming that (a) the degree of overlapping between neural representations of two sounds depends on both the acoustic difference between them and whether or not they belong to distinct phonetic categories, and (b) a release from stimulus-specific adaptation causes an enhanced N1 obligatory response to infrequent deviant stimuli. On the basis of this view, we tested in Experiment 1 whether the N1 response to the second sound of a pair (S2 ) would be more attenuated in pairs of identical vowels compared with pairs of different vowels, and in pairs of exemplars of the same vowel category compared with pairs of exemplars of different categories. The psychoacoustic distance between S1 and S2 was the same for all within-category and across-category pairs. While N1 amplitudes decreased markedly from S1 to S2 , responses to S2 were quite similar across pair types, indicating that the attenuation effect in such conditions is not stimulus specific. In Experiment 2, a pronounced MMN was elicited by a deviant vowel sound in an across-category oddball sequence, but not when the exact same deviant vowel was presented in a within-category oddball sequence. This adds evidence that MMN reflects categorical phonetic processing. Taken together, the results suggest that different neural processes underlie the attenuation of the N1 response to S2 and the MMN to vowels.

Electrophysiological correlates of decision making impairment in multiple sclerosis.

Although previous studies have shown that patients with multiple sclerosis (MS) may exhibit impaired decision making (DM), the specific neuro-cognitive processes that underlie this deficiency remain unknown. Inefficient DM may occur due to poor option assessment or a deficit in the evaluation of choice outcomes. This study uses, for the first time, the event-related potential (ERP) technique to analyze these DM subprocesses in patients with MS. Sixteen MS patients and nineteen control subjects performed a DM task based on the Iowa Gambling Task while a digital EEG was recorded. The P3b was analyzed as an index of option assessment, and both the feedback-related negativity (FRN) and P3b were considered markers for choice outcome evaluation. We found that MS patients made a larger number of unfavorable choices during the DM task (P = 0.02), with no differences between groups for reaction times. There were no significant differences in P3b for option assessment between the groups. In the control group, the type of feedback (gain, loss, or nothing) modified the FRN (F = 3.72, P = 0.033) and the P3b (F = 3.15, P = 0.059). This effect was not observed in the MS group. Also, FRN latencies were shorter in the MS group compared to controls (P = 0.047). Finally, lesions in temporal regions revealed by MRI were associated with DM both in behavioral and electrophysiological terms. We conclude that the DM impairment of patients with MS may be due to a deficit in their evaluation of choice outcomes or a general alteration in emotional reactivity.

Altruistic traits are predicted by neural responses to monetary outcomes for self vs charity.

Human altruism is often expressed through charitable donation-supporting a cause that benefits others in society, at cost to oneself. The underlying mechanisms of this other-regarding behavior remain imperfectly understood. By recording event-related-potential (ERP) measures of brain activity from human participants during a social gambling task, we identified markers of differential responses to receipt of monetary outcomes for oneself vs for a charitable cause. We focused our ERP analyses on the frontocentral feedback-related negativity (FRN) and three subcomponents of the attention-related P300 (P3) brain wave: the frontocentral P2 and P3a and the parietal P3b. The FRN distinguished between gains and losses for both self and charity outcomes. Importantly, this effect of outcome valence was greater for self than charity for both groups and was independent of two altruism-related measures: participants' pre-declared intended donations and the actual donations resulting from their choices. In contrast, differences in P3 subcomponents for outcomes for self vs charity strongly predicted both of our laboratory measures of altruism-as well as self-reported engagement in real-life altruistic behaviors. These results indicate that individual differences in altruism are linked to individual differences in the relative deployment of attention (as indexed by the P3) toward outcomes affecting other people.

Adult-like neuroelectrical response to inequity in children: Evidence from the ultimatum game.

People react aversely when faced with unfair situations, a phenomenon that has been related to an electroencephalographic (EEG) potential known as medial frontal negativity (MFN). To our knowledge, the existence of the MFN in children has not yet been demonstrated. Here, we recorded EEG activity from 15 children playing the ultimatum game (UG) and who afterward performed a recognition task, in order to assess whether they could recognize the unfair and fair (familiar) proposers among unfamiliar faces. During the recognition task, we also acquired pupil dilation data to investigate subconscious recognition processes. A typical (adult-like) MFN component was detected in reaction to unfair proposals. We found a positive correlation between reaction time and empathy, as well as a negative correlation between reaction time and systematic reasoning scores. Finally, we detected a significant difference in pupil dilation in response to unfamiliar faces versus UG proposers. Our data provide the first evidence of MFN in children, which appears to index similar neurophysiological phenomena as in adults. Also, reaction time to fair proposals seems to be related to individual traits, as represented by empathy and systematizing. Our pupil dilation data provide evidence that automatic responses to faces did not index fairness, but familiarity. These findings have implications for our understanding of social development in typically developing children.