The Processing Of Scene Gist And Fear Stimuli Inside Scene: Electrophysiological Evidence From ERP Studies

The relationship between cognition and emotion is an important issue in psychology. Recent evidence indicated that the cognition of scene could influence the processing of fear stimuli. Scene is a semantically coherent human-scaled view of a real-world environment comprising background elements and multiple discrete objects arranged in a spatially licensed manner. The gist of scene is the meaning information that an observer can identify and infer from the scene. The gist of scene includes perceptual, emotional and semantic properties. Researchers had studied the influence of the emotional context to the early processing of fear face. The relationship between semantic scene and the processing of fear stimuli is still not explored. When can the semantic scene be extracted by brain? How does it influence the processing of fear stimuli inside the scene and vice versa?Two ERP experiments in normal undergraduates were carried out to address these questions. The experiment material included the picture of snake in a door, door picture, and snake picture. Door was open or close, which was the function and the semantic property of door scene. Snake is the fear stimuli. Experiment 1 aimed to explore the brain mechanism of the processing of scene gist and the processing of fear stimuli in the picture of snake in a door, in which subjects should make button-press responses as soon as possible. Experiment 2 studied the brain mechanism of the processing in the picture of snake in a door, door picture, and snake picture, in which subjects should make button-press responses after the cue appeared.The results were as the following: (1) Indexed by P1 component, the study found that human brain could extract the semantic information of scene gist in 100-120ms. The P1 amplitudes were larger for snake in door-open scene than snake in door-close scene, which maybe indicated that the degree of fear of snake in door-open scene was larger than snake in door-close scene. The difference in P1 amplitudes between door-open scene and door-close scene only existed in fear material, not in neutral material. The early processing of scene gist was related to emotional property of material, and was independent to experimental task, which meant that fear scenario was the prerequisite conditions that brain quickly extracted the semantic information of scene gist. The P1 amplitudes were larger for fear materials than neutral materials, which indicated the negativity bias of fear in ERP could be firstly found on P1 component.(2) N2 component maybe indicated that brain inhibited the processing of fear stimuli. The N2 amplitudes were larger for snake in door-close scene than snake in door-open scene. This significant effect for scene in N2 amplitudes was only found in door task and snake task of fear material, not in passively watching task of fear material and in neutral material, which meant that N2 was related to both the emotional property of material and experiment task. The effect for scene in N2 amplitudes is more significant in door task than in snake task, which indicated that the explicit processing of scene gist facilitated inhibitive processing of the fear stimuli.(3) Right hemisphere seemed more active in the processing of the scene gist, especially in the early processing.