Nencki Institute of Experimental Biology, Department of Neurophysiology, Warsaw, Poland.
Neuropsychologia. 2011 Oct;49(12):3327-37. doi: 10.1016/j.neuropsychologia.2011.08.006. Epub 2011 Aug 16.
Left unilateral spatial neglect resulting from right brain damage is characterized by loss of awareness for stimuli in the contralesional side of space, despite intact visual pathways. We examined using fMRI whether patients with neglect are more likely to consciously detect in the neglected hemifield, emotionally negative complex scenes rather than visually similar neutral pictures and if so, what neural mechanisms mediate this effect. Photographs of emotional and neutral scenes taken from the IAPS were presented in a divided visual field paradigm. As expected, the detection rate for emotional stimuli presented in the neglected field was higher than for neutral ones. Successful detection of emotional scenes as opposed to neutral stimuli in the left visual field (LVF) produced activations in the parahippocampal and anterior cingulate areas in the right hemisphere. Detection of emotional stimuli presented in the intact right visual field (RVF) activated a distributed network of structures in the left hemisphere, including anterior and posterior cingulate cortex, insula, as well as visual striate and extrastriate areas. LVF-RVF contrasts for emotional stimuli revealed activations in right and left attention related prefrontal areas whereas RVF-LVF comparison showed activations in the posterior cingulate and extrastriate visual cortex in the left hemisphere. An additional analysis contrasting detected vs. undetected emotional LVF stimuli showed involvement of left anterior cingulate, right frontal and extrastriate areas. We hypothesize that beneficial role of emotion in overcoming neglect is achieved by activation of frontal and limbic lobe networks, which provide a privileged access of emotional stimuli to attention by top-down modulation of processing in the higher-order extrastriate visual areas. Our results point to the importance of top-down regulatory role of the frontal attentional systems, which might enhance visual activations and lead to greater salience of emotional stimuli for perceptual awareness.
右脑损伤导致的左侧空间忽略症的特征是，尽管视觉通路完好，但对空间对侧的刺激失去意识。我们使用 fMRI 检查了忽略症患者是否更有可能在忽略的半视野中无意识地检测到情绪负面的复杂场景，而不是视觉上相似的中性图片，如果是这样，那么这种效应的神经机制是什么。从 IAPS 拍摄的情绪和中性场景的照片以分视场范式呈现。正如预期的那样，在忽略场中呈现的情绪刺激的检测率高于中性刺激。与左视野 (LVF) 中的中性刺激相比，成功检测到情绪场景会在右半球的海马旁回和前扣带区域产生激活。在完整的右视野 (RVF) 中检测到情绪刺激会激活左半球的分布式结构网络，包括前扣带和后扣带皮层、岛叶以及视觉纹状和纹外区域。情绪刺激的 LVF-RVF 对比显示，右和左与注意相关的前额叶区域有激活，而 RVF-LVF 比较显示左半球后扣带和纹外视觉皮层有激活。对检测到的与未检测到的情绪 LVF 刺激进行的额外分析显示，左前扣带、右额和纹外区域参与其中。我们假设，情绪在克服忽略方面的有益作用是通过激活额前叶和边缘叶网络来实现的，通过对更高阶的纹外视觉区域的处理进行自上而下的调制，为情绪刺激提供了优先进入注意力的途径。我们的研究结果表明，额前注意系统的自上而下的调节作用非常重要，这可能会增强视觉激活，并导致情绪刺激对感知意识的显著性增加。
