FLICKR, EUSKALANATOOne criterion generally used to determine brain death is a flat or isoelectric electroencephalogram (EEG) trace. But new research published last week (September 18) in PLOS One showed that neuronal activity can be detected when the brain is in an extreme deep coma, even after an EEG has flatlined.
Researchers from the University of Montreal observed previously unreported spikes of neuronal activity, which they called Nu-complexes, in the EEG of one human patient in a deep coma. In order to see whether they could recreate the Nu-complexes in the lab, the researchers subjected cats to increasing amounts of anesthesia, putting each animal into a reversible, drug-induced coma. At a medium-high dose of anesthesia, the cats’ EEG traces flatlined, but when the scientists increased the dose of anesthesia even more, they saw Nu-complexes in each cat’s EEG. The researchers then pinpointed the origin of the Nu-complexes to the hippocampus.
Because a flat EEG is usually used in combination with other clinical indicators to confirm brain death, the discovery of Nu-complexes does not suggest that a ...
