decapitation in rats latency to unconsciousness and the ‘wave of death’斩首的老鼠延迟昏迷和死亡的波.pdf
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Decapitation in Rats: Latency to Unconsciousness and
the ‘Wave of Death’
Clementina M. van Rijn*, Hans Krijnen, Saskia Menting-Hermeling, Anton M. L. Coenen
Department of Biological Psychology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands
Abstract
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
wa
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