Department of Biological Psychology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands.
PLoS One. 2011 Jan 27;6(1):e16514. doi: 10.1371/journal.pone.0016514.
The question whether decapitation is a humane method of euthanasia in awake animals is being debated. To gather arguments in this debate, obsolete rats were decapitated while recording the EEG, both of awake rats and of anesthetized rats. Following decapitation a fast and global loss of power of the EEG was observed; the power in the 13-100 Hz frequency band, expressing cognitive activity, decreased according to an exponential decay function to half the initial value within 4 seconds. Whereas the pre-decapitation EEG of the anesthetized animals showed a burst suppression pattern quite different from the awake animals, the power in the postdecapitation EEG did not differ between the two groups. This might indicate that either the power of the EEG does not correlate well with consciousness or that consciousness is briefly regained in the anesthetized group after decapitation. Remarkably, after 50 seconds (awake group) or 80 seconds (anesthetized group) following decapitation, a high amplitude slow wave was observed. The EEG before this wave had more power than the signal after the wave. This wave might be due to a simultaneous massive loss of membrane potentials of the neurons. Still functioning ion channels, which keep the membrane potential intact before the wave, might explain the observed power difference. Two conclusions were drawn from this experiment. It is likely that consciousness vanishes within seconds after decapitation, implying that decapitation is a quick and not an inhumane method of euthanasia. It seems that the massive wave which can be recorded approximately one minute after decapitation reflects the ultimate border between life and death. This observation might have implications in the discussions on the appropriate time for organ donation.
斩首是否是清醒动物安乐死的一种人道方法正在争论中。为了在这场辩论中收集论据，我们对已淘汰的大鼠进行了斩首实验，同时记录清醒大鼠和麻醉大鼠的脑电图。斩首后，观察到脑电图迅速而全面地丧失能量；表示认知活动的 13-100Hz 频段的功率按照指数衰减函数下降到初始值的一半，用时 4 秒。虽然麻醉动物的术前脑电图呈现出与清醒动物截然不同的爆发抑制模式，但术后脑电图的功率在两组之间没有差异。这可能表明脑电图的功率与意识状态没有很好的相关性，或者意识在麻醉组斩首后短暂恢复。值得注意的是，斩首后 50 秒（清醒组）或 80 秒（麻醉组）后，观察到一个高振幅慢波。在此波之前的脑电图的功率大于该波之后的信号。此波可能是由于神经元的膜电位同时大量丧失所致。在此波之前仍能正常工作的离子通道可能解释了观察到的功率差异。从这个实验中得出了两个结论。意识可能在斩首后几秒钟内消失，这意味着斩首是一种快速而不是不人道的安乐死方法。似乎可以在斩首后大约一分钟记录到的大规模波反映了生与死的最终界限。这一观察结果可能对关于器官捐献适当时间的讨论产生影响。
