Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, People's Republic of China.
PLoS One. 2011 Apr 6;6(4):e18262. doi: 10.1371/journal.pone.0018262.
Emotional stimuli have evolutionary significance for the survival of organisms; therefore, they are attention-grabbing and are processed preferentially. The neural underpinnings of two principle emotional dimensions in affective space, valence (degree of pleasantness) and arousal (intensity of evoked emotion), have been shown to be dissociable in the olfactory, gustatory and memory systems. However, the separable roles of valence and arousal in scene perception are poorly understood. In this study, we asked how these two emotional dimensions modulate overt visual attention. Twenty-two healthy volunteers freely viewed images from the International Affective Picture System (IAPS) that were graded for affective levels of valence and arousal (high, medium, and low). Subjects' heads were immobilized and eye movements were recorded by camera to track overt shifts of visual attention. Algebraic graph-based approaches were introduced to model scan paths as weighted undirected path graphs, generating global topology metrics that characterize the algebraic connectivity of scan paths. Our data suggest that human subjects show different scanning patterns to stimuli with different affective ratings. Valence salient stimuli (with neutral arousal) elicited faster and larger shifts of attention, while arousal salient stimuli (with neutral valence) elicited local scanning, dense attention allocation and deep processing. Furthermore, our model revealed that the modulatory effect of valence was linearly related to the valence level, whereas the relation between the modulatory effect and the level of arousal was nonlinear. Hence, visual attention seems to be modulated by mechanisms that are separate for valence and arousal.
情绪刺激对生物的生存具有进化意义；因此，它们引人注目，并优先处理。情感空间中两个主要情感维度的神经基础，效价（愉悦程度）和唤醒（唤起情绪的强度），已在嗅觉、味觉和记忆系统中被证明是可分离的。然而，场景感知中效价和唤醒的可分离作用知之甚少。在这项研究中，我们想知道这两个情绪维度如何调节显性视觉注意力。22 名健康志愿者自由观看了国际情感图片系统（IAPS）的图片，这些图片的效价和唤醒程度（高、中、低）进行了分级。受试者的头部被固定，通过摄像头记录眼动，以跟踪显性视觉注意力的转移。我们引入了基于代数图的方法将扫描路径建模为加权无向路径图，生成全局拓扑度量，用于描述扫描路径的代数连通性。我们的数据表明，人类受试者对具有不同情感评分的刺激表现出不同的扫描模式。效价显著的刺激（唤醒度为中性）引起更快和更大的注意力转移，而唤醒度显著的刺激（效价为中性）引起局部扫描、密集的注意力分配和深度处理。此外，我们的模型还揭示了效价的调制效应与效价水平呈线性关系，而调制效应与唤醒水平之间的关系是非线性的。因此，视觉注意力似乎是由分别针对效价和唤醒的机制来调节的。
