Conscious awareness of flicker in humans involves frontal and parietal cortex
Conscious awareness of flicker in humans involves frontal and parietal cortex
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DOI：
10.1016/j.cub.2006.03.055
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发表时间：
2006-05-09
期刊：
影响因子：
9.2
通讯作者：
Rees, Geraint
中科院分区：
文献类型：
--
作者：
Carmel, David;Lavie, Nilli;Rees, Geraint
即使局限于同一空间位置，闪烁和稳定的光也会因其不同的时间模式而引起截然不同的意识体验。这种主观体验差异的神经基础仍然不确定[1]。在这里，我们使用人体功能性 MRI 来检查与闪烁意识有关的神经结构。参与者观察在临界闪烁融合 (CFF) 阈值下闪烁的单点光源，其中相同的刺激有时被视为闪烁，有时被视为稳定（融合）[1-3]。因此，我们能够比较大脑活动，以获得质量不同（闪烁或融合）但由相同的物理刺激引起的意识感知。在之前与不需要检测时间模式的任务中的视觉意识相关的额叶和顶叶皮层区域的闪烁（相对于融合）试验中观察到更大的大脑激活[4-14]。相比之下，在枕叶纹外皮层的融合（相对于闪烁）试验中观察到更大的激活。我们的研究结果表明，高层皮质区域的活动对于非空间任务背景下时间上不同的视觉事件的意识非常重要，因此他们表明额叶和顶叶区域可能在视觉意识中发挥一般作用。
Even when confined to the same spatial location, flickering and steady light evoke very different conscious experiences because of their distinct temporal patterns. The neural basis of such differences in subjective experience remains uncertain [1]. Here, we used functional MRI in humans to examine the neural structures involved in awareness of flicker. Participants viewed a single point source of light that flickered at the critical flicker fusion (CFF) threshold, where the same stimulus is sometimes perceived as flickering and sometimes as steady (fused) [1-3]. We were thus able to compare brain activity for conscious percepts that differed qualitatively (flickering or fused) but were evoked by identical physical stimuli. Greater brain activation was observed on flicker (versus fused) trials in regions of frontal and parietal cortex previously associated with visual awareness in tasks that did not require detection of temporal patterns [4-14]. In contrast, greater activation was observed on fused (versus flicker) trials in occipital extrastriate cortex. Our findings indicate that activity of higher-level cortical areas is important for awareness of temporally distinct visual events in the context of a nonspatial task, and they thus suggest that frontal and parietal regions may play a general role in visual awareness.