Important and interesting study of rodent brain activity using an asphyxial cardiac arrest model published April 2017. It shows interesting neural correlates of consciousness at near electrocerebral silence.
In cases of abrupt loss of blood circulation from cardiac arrest, a silent scalp EEG is reported to occur within 30; conversely, in cases of a gradual loss of blood flow, such as hypoxic respiratory failure, the EEG has been found to become isoelectric before cardiac arrest.
This study was investigating the latter, and they found asphyxial cardiac arrest induced a period of near-electrocerebral silence that was marked by increased phase coherence in the frontal lobes (motor cortex) and increased power in the rear visual cortices, both of which look like potential markers of consciousness.