10 research outputs found
Polarity-Dependent Transcranial Direct Current Stimulation Effects on Central Auditory Processing
Given the polarity dependent effects of transcranial direct current stimulation (tDCS) in facilitating or inhibiting neuronal processing, and tDCS effects on pitch perception, we tested the effects of tDCS on temporal aspects of auditory processing. We aimed to change baseline activity of the auditory cortex using tDCS as to modulate temporal aspects of auditory processing in healthy subjects without hearing impairment. Eleven subjects received 2mA bilateral anodal, cathodal and sham tDCS over auditory cortex in a randomized and counterbalanced order. Subjects were evaluated by the Random Gap Detection Test (RGDT), a test measuring temporal processing abilities in the auditory domain, before and during the stimulation. Statistical analysis revealed a significant interaction effect of time vs. tDCS condition for 4000 Hz and for clicks. Post-hoc tests showed significant differences according to stimulation polarity on RGDT performance: anodal improved 22.5% and cathodal decreased 54.5% subjects' performance, as compared to baseline. For clicks, anodal also increased performance in 29.4% when compared to baseline. tDCS presented polarity-dependent effects on the activity of the auditory cortex, which results in a positive or negative impact in a temporal resolution task performance. These results encourage further studies exploring tDCS in central auditory processing disorders
Gênero e empatia como moduladores dos processos de decisão social no Ultimatum Game: um estudo comportamental e eletrofisiológico
Por vivermos em sociedade, constantes escolhas estão relacionadas não somente aos nossos interesses pessoais. A diferença na percepção de injustiça em função da Amizade em estudos utilizando o jogo Ultimatum Game (UG) introduz uma nova questão com relação ao conceito amplamente aceito de punição altruÃstica. Dessa forma, a punição altruÃsta e o impacto dos fatores gênero e nÃvel de empatia como moduladores da percepção de injustiça precisam ser investigadas nas relações interpessoais. Nesse sentido, o presente estudo teve como objetivo (i) investigar o impacto da empatia e do gênero como fatores moduladores do comportamento na tarefa Ultimatum Game (UG) na interação com uma pessoa de confiança (um amigo) e um desconhecido; (ii) investigar o comportamento caracterizado como punição altruÃsta no UG adaptado em dois contextos diferentes de interação (com ou sem custos pessoais envolvidos). Para isso, foi realizado 2 experimentos. O experimento 1, semelhante ao estudo anterior, os participantes jogaram o UG com o amigo e um desconhecido como os propositores. Mas com o controle de nÃvel de empatia (alto e baixo) e gênero. No experimento 2, além do controle do gênero e do nÃvel de empatia, os participantes tinham que decidir se aceitavam ou rejeitavam propostas de divisão de R120,00 reias between three persons: the proposer, the participant and a third person ( dummy ), that was a friend and a unknown in the first part of the game. In the second part of the game, the participants only decide whether accept or reject in the place of the friend and an unknown and don´t had any earnings and any loss involved. As results, was observed large rate of rejection the unfair offers proposed by an unknown than by the friend. The friend was judged as more fair. Also, was observed that the men reject more offers made by an unknown. The participants with high level of empathy rejected more unfair offers that was made by an unknown and presented the MFN amplitude more negative for unknown proposer and more positive for friend proposer. The men with high level of empathy presented the MFN amplitude more negative for the unknown. In the second experiment, the participants rejected more unfair proposals for both kind of third part. The MFN amplitude was more negative when the proposals were unfair for both (the participant and the third part). As well as women and for high empathy level participants. In the second part of the experiment two, the participants benefited more the friend. The MFN amplitude was more negative for the men in the interaction unknown proposing to the friend. The women presented more large P3 amplitude in the interaction unknown proposing to the friend. Taken together, the results suggest that the empathy and gender impact when a friend is involved. Beside this, the personal gains and losses involvement also was an important factor in the fairness perception. The present study corroborates with preview studies that showed the fairness perception modulated the trust and that he empathy and gender are factors with more or less impact in different context.Fundo Mackenzie de Pesquis
Estudo preliminar sobre potenciais cognitivos em tarefa de tomada de decisão social
Decisões envolvem considerações cuidadosas sobre os riscos e benefÃcios envolvidos em uma determinada escolha. Por vivermos em sociedade, estas constantes escolhas estão relacionadas não só aos nossos interesses pessoais. Nesse sentido, a interação social tem um importante papel, pois o outro faz parte de um contexto no qual avaliamos possÃveis decisões. Estudos prévios mostram a importância da confiança e da empatia em processos de decisão. Nessa direção, Boudreau, McCubbins e Coulson (2009) mostraram que a confiança no outro interfere na resposta comportamental e também nos potenciais cognitivos registrados durante o teste. Entretanto, assim como em outros estudos, a confiança foi estudada pela orientação ao participante de que este estaria sendo orientado por outro ser - humano uma pessoa desconhecida). O uso de uma pessoa desconhecida limita a discussão a respeito do papel da confiança envolvida em processos decisórios. Dessa forma este estudo busca investigar os processos decisórios em uma tarefa na qual o participante levou ao laboratório uma pessoa (amigo de alta confiança) que funcionará como propositor. Além disso, ainda são poucos os estudos investigando potenciais relacionados a evento em tarefa de decisão social. Com isso, este estudo buscou compreender o papel da confiança em processos de decisão analisando o desempenho comportamental em tarefa adaptada do teste Ultimatum Game e também os potenciais cognitivos coletados simultaneamente. Entre os principais achados, encontrou-se uma alteração na percepção de justiça (o que na realidade não havia diferença) e, por conseqüência, uma alteração na tomada de decisão com maior aceite de propostas na condição de interação com a pessoa de confiança em comparação com os outros propositores. Além disso, os potenciais P3, FN e LPC foram modulados pelo impacto da confiança, pela interferência da internalização moral e apresentaram diferenças entre gênero. Este estudo pode aumentar o conhecimento sobre as bases neurobiológicas e comportamentais de processos decisórios envolvendo interação social, confiança e empatia.Decisions engage careful consideration of the risks and benefits involved in a particular choice. As we live in society, these choices are not only related to our personal interests. Therefore, social interaction has an important role, because the other is part of the context in which we evaluate decisions. Previous studies show the importance of trust and empathy in decision-making processes. In fact, Boudreau, McCubbins and Coulson (2009) showed that trust in another person interferes with behavioral response and also in event related potentials recorded during the test. However, as in other studies, trust was studied by the instruction given to participants that they will base their choices by reports made by another human being - unknown person. The use of an unknown person limits the interpretation of the role of trust involved in decision making processes. Thus this study aims to investigate the decision making processes in a task in which the participant brought to the lab a person (a trusted friend) that act as reporter. In addition, there are few studies investigating event-related potentials in tasks of social decision. Therefore, this study aim to understand the role of trust in decision-making by analysis of behavioral performance in an adapted version of the Ultimatum Game task and also investigate the event related potentials collected simultaneously. Among the main findings, we found a change in the perception of fairness (in fact there was no difference) and, consequently, a change in decision-making with more acceptance of proposals on the condition of interaction with the trusted person than other proposers. Moreover, the P3, FN and LPC potential were modulated by the impact of trust, and by moral internalization, and differed between genders. This study may increase knowledge about the neurobiological bases of behavior and decision making processes involving social interaction, trust and empathy
Mean RT for opposite trials (opposite/sad and opposite/happy) following tDCS and sham stimulation.
<p>Mean RT for opposite trials (opposite/sad and opposite/happy) following tDCS and sham stimulation.</p
Target locked grandmean waveforms at electrode FCz for the opposite trials(opposite/sad and opposite/happy) following tDCS and sham stimulation.
<p>Target locked grandmean waveforms at electrode FCz for the opposite trials(opposite/sad and opposite/happy) following tDCS and sham stimulation.</p
RGDT performance considering time and the type of stimulation (mean ±SEM).
<p>1A presents performance during 4000 Hz. * p = 0.04 for the comparison between performance during anodal tDCS and anodal baseline and between performance during cathodal tDCS and cathodal baseline. 1B presents performance during Clicks. * p = 0.015 for the comparison between performance during anodal tDCS and anodal baseline. ** p = 0.002 and p = 0.04 for performance during anodal tDCS in comparison to cathodal and sham tDCS, respectively.</p