Affective blindsight relies on low spatial frequencies
Affective blindsight relies on low spatial frequencies
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DOI：
10.1016/j.neuropsychologia.2017.10.009
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发表时间：
2019-05-01
期刊：
影响因子：
2.6
通讯作者：
Pegna, Alan J.
中科院分区：
文献类型：
--
作者：
Burra, Nicolas;Hervais-Adelman, Alexis;Pegna, Alan J.
人类的大脑可以在没有意识的情况下快速处理情绪的面部表情。对初级视觉皮层受损患者的几项研究表明，尽管他们的皮层失明，但他们可能能够猜测面部表情。这种无意识的处理过程被称为情感性盲视，它可能是通过一条完整的皮层下视觉通路产生的，这条通路从上级丘通向枕，然后到达杏仁核。该通路被认为是处理由低空间频率的刺激所传达的原始视觉信息的通路，为了研究是否是这种情况，我们研究了一名双侧皮质盲和情感盲的患者（TN）。一个功能性磁共振成像的范例中，恐惧和中性的表情，提出了使用的脸，无论是未经过滤，或过滤，以消除高或低的空间频率。未经过滤的恐惧面孔产生右侧杏仁核激活，尽管患者没有意识到刺激的存在。更重要的是，恐惧面孔的低空间频率成分继续产生右侧杏仁核活动，而高空间频率成分则没有。因此，我们的研究结果证实，在低空间频率的视觉信息是足以产生情感盲视，进一步表明，它的存在可能依赖于皮质下丘枕杏仁通路。
The human brain can process facial expressions of emotions rapidly and without awareness. Several studies in patients with damage to their primary visual cortices have shown that they may be able to guess the emotional expression on a face despite their cortical blindness. This non-conscious processing, called affective blindsight, may arise through an intact subcortical visual route that leads from the superior colliculus to the pulvinar, and thence to the amygdala. This pathway is thought to process the crude visual information conveyed by the low spatial frequencies of the stimuli.In order to investigate whether this is the case, we studied a patient (TN) with bilateral cortical blindness and affective blindsight. An fMRI paradigm was performed in which fearful and neutral expressions were presented using faces that were either unfiltered, or filtered to remove high or low spatial frequencies. Unfiltered fearful faces produced right amygdala activation although the patient was unaware of the presence of the stimuli. More importantly, the low spatial frequency components of fearful faces continued to produce right amygdala activity while the high spatial frequency components did not. Our findings thus confirm that the visual information present in the low spatial frequencies is sufficient to produce affective blindsight, further suggesting that its existence could rely on the subcortical colliculo-pulvino-amygdalar pathway.