Séverine MAHON

We are conducting translational research aimed at exploring the functional consequences of cerebral anoxia on neurons and neural networks. We recently developed an experimental model of transient asphyxia that enabled us to examine in real time, from EEG to individual neurons, the events occurring in the cerebral cortex during anoxia and resuscitation. We showed sequential changes in cerebral activity after oxygen deprivation: 1) a time interval during which no change in activity is observed, 2) a period of cortical activation (10-20 s after the onset of anoxia) during which EEG and neurons show rapid arousal-like activity patterns (15-40 Hz), 3) a period of slow oscillations in the delta range (1-5 Hz), 4) an isoelectric (flat) EEG on which arises, 5) a world called "death wave", which we have demonstrated to be due to the synchronization of anoxic depolarizations in cortical neurons. As our model allows cerebral oxygenation to be restored, we discovered a new cortical wave, the "wave of resuscitation", which we correlated with a recovery of electrical activities after oxygenation has been restored. This wave is currently the only real-time marker of successful resuscitation. We are currently looking for early, non-invasive and clinically easily recordable electrical markers that would be likely to predict the degree of impairment of brain function following anoxia.