The effect of acute anoxia on the cortical somatosensory evoked potential in the rabbit

In the course of this study it was found that the functional state of the cortex during anoxic anoxia could be more accurately monitored by the cortical somatosensory evoked potentials (EPs) than by the electrocorticogram (ECoG). Compared with the ECoG, the EPs yield more detailed information. Five different steps may be distinguished in the evolution of EPs; the ECoG, however, exhibits only two (almost trivial) abnormal patterns (epileptic pattern and flat response). Of particular practical interest are the two steps preceding the disappearance of the EPs: (1) a rounding of the P wave accompanied by an increased voltage, followed later by (2) a decrease of the latter. If, at this stage, anoxia is maintained for 20 seconds, then permanent dysfunction is observed, at least during the time interval of the experimentation.