Voluntary control of a phantom limb.
Voluntary control of a phantom limb.
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自愿控制幻肢。
DOI：
10.1016/j.neuropsychologia.2015.06.032
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发表时间：
2015
期刊：
影响因子：
2.6
通讯作者：
Walsh E
中科院分区：
文献类型：
--
作者：
Walsh E
自愿行动常常伴随着有意识的意图体验。这种经历的内容及其神经基础仍然存在争议。一种观点认为，大脑只是回顾性地归因意图来解释缺乏明显触发刺激的行为的发生。在这里，我们使用感觉运动节律的脑电图频率分析来研究先天性缺乏左手和左臂的参与者（CL，本文的合著者）用右手或幻觉“左手”准备并做出自愿动作时的大脑活动。 CL 报告了她感受到按下按键的意图的那一刻。然后将该时间点用作对齐和平均脑电图的标记。在第二种情况下，CL 被要求在所有试验中准备行动，但随后在某些试验中，在最后一刻取消行动。对于右手，我们观察到移动前 β 波段光谱功率典型降低，然后移动后 β 波段反弹。当 CL 准备但随后取消运动时，我们发现了先前报告的特征脑电图模式，即接近感知到的运动意图的时间左额叶频谱功率增加。有趣的是，当 CL 用她的幻像左手准备和抑制运动时，也存在相同的积极和抑制意志的神经特征。这些脑电图信号与之前在 14 名健康志愿者组成的小组中报告的信号相似。我们的结果表明，有意识的意图可能取决于准备性的大脑活动，而不是取决于做出或曾经做出过相应的身体运动。将有意识的意志简化为纯粹的回顾性虚构的说法无法轻易解释我们的参与者的行动和抑制的神经现象学。相反，结果与运动前的特定神经事件可能产生积极和消极意志的意识体验的观点是一致的。
Voluntary actions are often accompanied by a conscious experience of intention. The content of this experience, and its neural basis, remain controversial. On one view, the mind just retrospectively ascribes intentions to explain the occurrence of actions that lack obvious triggering stimuli. Here, we use EEG frequency analysis of sensorimotor rhythms to investigate brain activity when a participant (CL, co-author of this paper) with congenital absence of the left hand and arm, prepared and made a voluntary action with the right or the phantom “left hand”. CL reported the moment she experienced the intention to press a key. This timepoint was then used as a marker for aligning and averaging EEG. In a second condition, CL was asked to prepare the action on all trials, but then, on some trials, to cancel the action at the last moment. For the right hand, we observed a typical reduction in beta-band spectral power prior to movement, followed by beta rebound after movement. When CL prepared but then cancelled a movement, we found a characteristic EEG pattern reported previously, namely a left frontal increase in spectral power close to the time of the perceived intention to move. Interestingly, the same neural signatures of positive and inhibitory volition were also present when CL prepared and inhibited movements with her phantom left hand. These EEG signals were all similar to those reported previously in a group of 14 healthy volunteers. Our results suggest that conscious intention may depend on preparatory brain activity, and not on making, or ever having made, the corresponding physical body movement. Accounts that reduce conscious volition to mere retrospective confabulation cannot easily explain our participant's neurophenomenology of action and inhibition. In contrast, the results are consistent with the view that specific neural events prior to movement may generate conscious experiences of positive and negative volition.