植物人真的处于无意识状态吗?

1997年，一个十几岁的男孩子在与人斗殴中心脏受伤导致脑缺血，经三周的昏迷后最终诊断为植物人状态：虽然他偶尔睁眼睛，但很显然，他对周围环境毫无有意识性的反应。

神经科学家Lorina Naci使用最简单的方式——让病人看电视，通过收集脑反应波信号来研究人类的脑意识活动。Naci选择恐怖影片《断魂枪声》“Bang! You’re Dead.”，剪辑其中最惊险恐怖部分，制作成一个8分钟的片段，测试观众观赏影片过程中脑内功能性磁共振影像（functional magnetic resonance imaging，fMRI）反应。正常人在观看时，因紧张焦虑在相应脑区（颞和顶叶脑皮层）呈现强反应信号。经监护人同意后，Naci对两位植物人状态病人开展了相应实验。其中一位就是上文中提到的男孩，另外一位是个20岁的女性病人，她在2007年因不明原因出现脑损伤并陷入昏迷。这名女性病人在观看影片的整个过程中，相应脑区没有反应。而惊奇的是，那位男性病人呈现如健康人类似的强反应信号，他是不是真正观赏了这个电影片段？

在语言和肢体运动缺失的情况下，仅由脑活动来解释人是否处在意识状态是当代神经科学的挑战性前沿领域。作者的研究在意识的基础这一问题上做出了贡献。该研究发表在Proceedings of the National Academy of Sciences上（文题：A common neural code for similar conscious experiences in different individuals   http://www.pnas.org/content/early/2014/09/11/1407007111）。

这一研究可能给诊断植物人状态的病人的意识信号研究开启一扇通往新通道的大门。是不是这些刺激信号对明显无意识和无反应的脑损伤病人有帮助？是否这种方法可以区分植物状态病人脑损伤的程度？

Abstract：The interpretation of human consciousness from brain activity, without recourse to speech or action, is one of the most provoking and challenging frontiers of modern neuroscience. We asked whether there is a common neural code that underpins similar conscious experiences, which could be used to decode these experiences in the absence of behavior. To this end, we used richly evocative stimulation (an engaging movie) portraying real-world events to elicit a similar conscious experience in different people. Common neural correlates of conscious experience were quantified and related to measurable, quantitative and qualitative, executive components of the movie through two additional behavioral investigations. The movie’s executive demands drove synchronized brain activity across healthy participants’ frontal and parietal cortices in regions known to support executive function. Moreover, the timing of activity in these regions was predicted by participants’ highly similar qualitative experience of the movie’s moment-to-moment executive demands, suggesting that synchronization of activity across participants underpinned their similar experience. Thus we demonstrate, for the first time to our knowledge, that a neural index based on executive function reliably predicted every healthy individual’s similar conscious experience in response to real-world events unfolding over time. This approach provided strong evidence for the conscious experience of a brain-injured patient, who had remained entirely behaviorally nonresponsive for 16 y. The patient’s executive engagement and moment-to-moment perception of the movie content were highly similar to that of every healthy participant. These findings shed light on the common basis of human consciousness and enable the interpretation of conscious experience in the absence of behavior.

上文由群晓科苑翻译整理，科学推广，服务民众。他人或机构如需使用，请提供该原始链接地址。

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