Department of Psychology, University of Bologna, Viale Berti Pichat, 5, Bologna, Italy; CsrNC, Centre for Studies and Research in Cognitive Neuroscience, University of Bologna, Viale Europa, 980, Cesena, Italy.
Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow, 58 Hillhead Street, Glasgow G12 8QB, UK.
Neuropsychologia. 2019 May;128:58-64. doi: 10.1016/j.neuropsychologia.2017.07.029. Epub 2017 Jul 25.
Implicit visual processing of emotional stimuli has been widely investigated since the classical studies on affective blindsight, in which patients with primary visual cortex lesions showed discriminatory abilities for unseen emotional stimuli in the absence of awareness. In addition, more recent evidence from hemianopic patients showed response facilitation and enhanced early visual encoding of seen faces, only when fearful faces were presented concurrently in the blind field. However, it is still unclear whether unseen fearful faces specifically facilitate visual processing of facial stimuli, or whether the facilitatory effect constitutes an adaptive mechanism prioritizing the visual analysis of any stimulus. To test this question, we tested a group of hemianopic patients who perform at chance in forced-choice discrimination tasks of stimuli in the blind field. Patients performed a go/no-go task in which they were asked to discriminate simple visual stimuli (Gabor patches) presented in their intact field, while fearful, happy and neutral faces were concurrently presented in the blind field. The results showed a reduction in response times to the Gabor patches presented in the intact field, when fearful faces were concurrently presented in the blind field, but only in patients with left hemispheric lesions. No facilitatory effect was observed in patients with right hemispheric lesions. These results suggest that unseen fearful faces are implicitly processed and can facilitate the visual analysis of simple visual stimuli presented in the intact field. This effect might be subserved by activity in the spared colliculo-amygdala-extrastriate pathway that promotes efficient visual analysis of the environment and rapid execution of defensive responses. Such a facilitation is observed only in patients with left lesions, favouring the hypothesis that the right hemisphere mediates implicit visual processing of fear signals.
自经典的情感盲视研究以来，人们广泛研究了对情绪刺激的内隐视觉处理，在这些研究中，初级视皮层损伤的患者在没有意识的情况下对看不见的情绪刺激表现出辨别能力。此外，来自偏盲患者的最新证据表明，当恐惧面孔同时出现在盲区内时，可见面孔的反应会得到促进，并且早期视觉编码得到增强。然而，目前尚不清楚看不见的恐惧面孔是否专门促进了面部刺激的视觉处理，或者促进效应是否构成了一种优先分析任何刺激的视觉分析的自适应机制。为了检验这个问题，我们测试了一组在盲区内进行刺激的强制选择辨别任务中表现出机会水平的偏盲患者。患者进行了一个 Go/No-Go 任务，要求他们辨别呈现于其正常视野内的简单视觉刺激（Gabor 补丁），同时在盲区内同时呈现恐惧、快乐和中性面孔。结果表明，当恐惧面孔同时出现在盲区内时，呈现于正常视野内的 Gabor 补丁的反应时间会减少，但仅在左侧半球损伤的患者中观察到这种效应。在右侧半球损伤的患者中未观察到促进效应。这些结果表明，看不见的恐惧面孔被内隐地处理，并且可以促进呈现于正常视野内的简单视觉刺激的视觉分析。这种效应可能由活动在 spared colliculo-amygdala-extrastriate 通路中得到支持，该通路促进了对环境的有效视觉分析和快速执行防御反应。这种促进仅在左侧损伤的患者中观察到，这有利于右侧半球介导恐惧信号的内隐视觉处理的假说。
