65ª Reunião Anual da SBPC

C. Ciências Biológicas - 12. Neurociências e Comportamento - 1. Neurociências e Comportamento

HEMISPHERIC SPECIALIZATION FOR MANUAL RESPONSES TO POSITIVE AND NEGATIVE FACIAL EXPRESSIONS

Larissa Verônica Kamarowski - Departamento de Neurobiologia - PPG em Neurociências - UFF Sarah Carvalho-Oliveira - Departamento de Neurobiologia - PPG em Neurociências - UFF Marcelo Rodrigues Coppo - Departamento de Neurobiologia - PPG em Neurociências - UFF Tito Ramos Neto - Departamento de Neurobiologia - PPG em Neurociências - UFF Elton Hiroshi Matsushima - Departamento de Psicologia - UFF Luiz G Gawryszewski - Departamento de Neurobiologia - PPG em Neurociências - UFF

INTRODUÇÃO:

The right hemisphere has been considered as the dominant one for processing emotion. However, there are several results indicating that for both normal people and brain-injured patients, there is a hemispheric specialization in which the left hemisphere is dominant for positive emotions and the right, for negative emotions. These results were observed for a variety of stimuli, including faces expressing positive (happiness) and negative emotions (fear, anger). However, there are contradictory results for the Reaction Times (RT) to happy and fearful faces. Some authors have found a faster response to a happy face as compared to a fearful face and others have obtained the reverse. The flanker paradigm has been extensively employed for studying how peripheral stimuli (distractors) interfere with the response to a central target. For instance, two arrows on each side of a central arrow facilitate the response if they pointed to the same direction, but inhibit it when they pointed to the opposite direction.

OBJETIVO DO TRABALHO:

The objectives of this work was to compare the RT to a central emotional (happy or fearful) face occurring alone or simultaneously to two peripheral faces with equal or opposite emotional valences. (Face com Medo).

MÉTODOS:

Nineteen volunteers were tested in a task in which they have to press the right ("6") key after the appearance of a central happy face and the left ("a") key after a central fearful face, in one block of 156 trials, and according to a reverse instruction in other block. The orders of the blocks were counterbalanced between subjects. The medians of RT for each condition were submitted to an ANOVA with factors: EMOTION (Happiness vs. Fear), KEY (Left vs. Right) and DISTRACTORS (Absent, Equal or Different). A previous exam of the results showed that the pattern of about half (11/19) of the volunteers conforms to the main trend described in literature, that is, the response for a happy face using a right hand was shorter than for a fearful face, but the other volunteers (8/11) behave in opposite way. Considering that the two groups have opposite patterns and that the results of each group would be cancelled by the results of the other group, we run two ANOVAs, one

RESULTADOS E DISCUSSÃO:

For the group having faster response to Happy face, we found that the RT to a Happy face is shorter for a Right Hand response as compared to a Left Hand response and the opposite pattern was observed for the response to a Fearful face. In contrast, for the other group, having faster response for a Fearful face, we found that the response to a Happy face is longer for a Right Hand response as compared to a Left Hand response and the opposite pattern was observed for the response to a Fearful face. There is no significant effect due to distractors.

CONCLUSÕES:

In conclusion, we observed that the hemispheric specialization for positive and negative facial emotions is related to the facilitatory or inhibitory effect of this emotion on the reaction time to the central facial stimulus.

Palavras-chave: Emotion, Hemispheric specialization, Manual reaction time.