| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 857.92 KB | Adobe PDF |
Authors
Abstract(s)
Introdução: Emoções específicas produzem alterações cerebrais passíveis de ser detetadas
por eletroencefalografia. No presente trabalho objetivou-se analisar o registo
eletroencefalográfico associado a respostas emocionais, desencadeadas após visualização
de imagens padronizadas, bem como comparar essas mesmas respostas nas áreas
cerebrais analisadas – frontotemporais e occipitais.
Métodos: Doze jovens estudantes do Mestrado Integrado em Medicina na Faculdade de
Ciências da Saúde participaram no estudo. Após preenchimento do protocolo de
consentimento informado, de um questionário sociocomportamental e da Escala de
Alexitimia (TAS-20) os indivíduos foram divididos aleatoriamente em dois grupos: um
grupo foi submetido a imagens positivas e o outro a imagens negativas, com registo
eletroencefalográfico simultâneo. Cada participante assistiu a um conjunto de 20 imagens
da mesma categoria (positiva ou negativa), retiradas da base de dados Nencki Affective
Picture System, cada uma apresentada durante 8 segundos, com 2 segundos de intervalo.
Obteve-se o registo da atividade eletroencefalográfica, pré e pós imagens, de todo o córtex
através de um sistema de 128 elétrodos, tendo-se analisado as áreas corticais
frontotemporais e occipitais. Finalizado o registo, o participante preencheu um
questionário de avaliação emocional: o Self Assessment Manikin (SAM).
Resultados: Verificou-se uma diferença significativa na comparação das respostas
emocionais obtidas na região occipital direita (O2) entre os dois grupos (o que visualizou
imagens positivas versus o que foi submetido a imagens negativas), mediante aumento de
amplitude da banda alfa nesta região após apresentação de estímulos positivos; na
comparação das respostas obtidas na região frontal esquerda (F7) entre os dois grupos,
com aumento da frequência da banda gama no grupo que visualizou imagens negativas; e
na comparação das respostas obtidas na região frontal direita (F8) entre os dois grupos,
registando-se diminuição da frequência da banda gama após visualização de imagens
positivas.
Conclusão: Emoções específicas podem ser detetadas de forma distinta mediante registo
EEG. As respostas obtidas quer na banda alfa quer na banda gama no lobo occipital direito
após visualização de imagens positivas podem fazer denotar uma associação a um estado
de maior relaxamento (e, portanto, menor atividade cortical) neste grupo; já o aumento da frequência da banda gama no lobo frontal esquerdo após visualização de imagens
negativas pode refletir a mudança na atividade cortico-subcortical e o seu importante
papel no processamento de estímulos emocionais (particularmente de cariz negativo).
Introduction: Specific emotions can trigger brain changes that are likely to be detected by an electroencephalogram (EEG). In the present work we aim to analyze the electroencephalographic recording associated with emotional responses, elicited after the visualization of standardized images, as well as to compare those responses in the cerebral areas that we analyzed – frontotemporal and occipital. Methods: Twelve young Integrated Master’s Degree medical students of the Faculty of Health Sciences participated in the study. After filling out an informed consent protocol, a socio-behavioral survey and the Toronto Alexithymic Scale (TAS-20), the volunteers were randomly divided into two subgroups: one of them was subjected to viewing positive images, and the other one to negative images, while an electroencephalographic record was simultaneously done. Each participant watched a set of 20 pictures of the same category (positive versus negative), selected from the Nencki Affective Picture System database. Each of them was presented for 8 seconds, with a 2-second interval between them. We recorded whole brain electroencephalographic activity before and after the stimulus with a system of 128 electrodes, which enabled us to analyze the frontotemporal and occipital regions. After that, the volunteer filled out an emotional evaluation questionnaire: the Self Assessment Manikin (SAM). Results: We found a significant difference by comparing the emotional responses from the right occipital region (O2) between the two groups (the one who watched positive pictures versus the one who was subjected to negative ones), through an increase in the alpha band amplitude, after a positive stimulus was induced in that area of the brain; by comparing the emotional responses in the left frontal region (F7) between the two groups, with an increase in the gamma band frequency in the group that had been subjected to positive stimuli; and by comparing the emotional responses in the right frontal region (F8) between the two groups, which allowed us to observe a decrease in the frequency of gamma band after the viewing of positive images. Conclusion: Specific emotions can be detected and identified through an EEG recording. The responses we obtained after a positive stimulus, either in the alpha band or in the gamma band at the right occipital lobe, may be associated with a more relaxed state (thus, with less cortical activity) in this group; on the other hand, the increase in the frequency of gamma band after a negative stimulus at the left frontal lobe may reflect a change in the cortico-subcortical activity and its important role in processing emotional stimuli (mainly those with a negative component).
Introduction: Specific emotions can trigger brain changes that are likely to be detected by an electroencephalogram (EEG). In the present work we aim to analyze the electroencephalographic recording associated with emotional responses, elicited after the visualization of standardized images, as well as to compare those responses in the cerebral areas that we analyzed – frontotemporal and occipital. Methods: Twelve young Integrated Master’s Degree medical students of the Faculty of Health Sciences participated in the study. After filling out an informed consent protocol, a socio-behavioral survey and the Toronto Alexithymic Scale (TAS-20), the volunteers were randomly divided into two subgroups: one of them was subjected to viewing positive images, and the other one to negative images, while an electroencephalographic record was simultaneously done. Each participant watched a set of 20 pictures of the same category (positive versus negative), selected from the Nencki Affective Picture System database. Each of them was presented for 8 seconds, with a 2-second interval between them. We recorded whole brain electroencephalographic activity before and after the stimulus with a system of 128 electrodes, which enabled us to analyze the frontotemporal and occipital regions. After that, the volunteer filled out an emotional evaluation questionnaire: the Self Assessment Manikin (SAM). Results: We found a significant difference by comparing the emotional responses from the right occipital region (O2) between the two groups (the one who watched positive pictures versus the one who was subjected to negative ones), through an increase in the alpha band amplitude, after a positive stimulus was induced in that area of the brain; by comparing the emotional responses in the left frontal region (F7) between the two groups, with an increase in the gamma band frequency in the group that had been subjected to positive stimuli; and by comparing the emotional responses in the right frontal region (F8) between the two groups, which allowed us to observe a decrease in the frequency of gamma band after the viewing of positive images. Conclusion: Specific emotions can be detected and identified through an EEG recording. The responses we obtained after a positive stimulus, either in the alpha band or in the gamma band at the right occipital lobe, may be associated with a more relaxed state (thus, with less cortical activity) in this group; on the other hand, the increase in the frequency of gamma band after a negative stimulus at the left frontal lobe may reflect a change in the cortico-subcortical activity and its important role in processing emotional stimuli (mainly those with a negative component).
Description
Keywords
Atividade Cerebral Banda Alfa Banda Gama Eletroencefalograma Emoções Imagem