Miskovic Vladimir, Martinovic Jasna, Wieser Matthias J, Petro Nathan M, Bradley Margaret M, Keil Andreas
Department of Psychology, State University of New York at Binghamton, United States; Center for Affective Science, State University of New York at Binghamton, United States.
Department of Psychology, University of Aberdeen, United Kingdom.
Biol Psychol. 2015 Mar;106:11-7. doi: 10.1016/j.biopsycho.2015.01.012. Epub 2015 Jan 29.
Emotionally arousing scenes readily capture visual attention, prompting amplified neural activity in sensory regions of the brain. The physical stimulus features and related information channels in the human visual system that contribute to this modulation, however, are not known. Here, we manipulated low-level physical parameters of complex scenes varying in hedonic valence and emotional arousal in order to target the relative contributions of luminance based versus chromatic visual channels to emotional perception. Stimulus-evoked brain electrical activity was measured during picture viewing and used to quantify neural responses sensitive to lower-tier visual cortical involvement (steady-state visual evoked potentials) as well as the late positive potential, reflecting a more distributed cortical event. Results showed that the enhancement for emotional content was stimulus-selective when examining the steady-state segments of the evoked visual potentials. Response amplification was present only for low spatial frequency, grayscale stimuli, and not for high spatial frequency, red/green stimuli. In contrast, the late positive potential was modulated by emotion regardless of the scene's physical properties. Our findings are discussed in relation to neurophysiologically plausible constraints operating at distinct stages of the cortical processing stream.
引发情绪的场景很容易吸引视觉注意力，促使大脑感觉区域的神经活动增强。然而，人类视觉系统中导致这种调节的物理刺激特征和相关信息通道尚不清楚。在这里，我们操纵了具有不同享乐价和情绪唤起的复杂场景的低层次物理参数，以确定基于亮度的视觉通道与彩色视觉通道对情绪感知的相对贡献。在观看图片期间测量刺激诱发的脑电活动，并用于量化对较低层级视觉皮层参与敏感的神经反应（稳态视觉诱发电位）以及晚期正电位，反映更广泛分布的皮层事件。结果表明，在检查诱发视觉电位的稳态部分时，对情绪内容的增强是刺激选择性的。反应增强仅出现在低空间频率的灰度刺激中，而在高空间频率的红/绿刺激中则没有。相比之下，无论场景的物理属性如何，晚期正电位都受情绪调节。我们结合在皮层处理流不同阶段运行的神经生理学上合理的限制来讨论我们的发现。
