Scientists have discovered evidence of brain activity beyond a flat line EEG, opposing existing data that suggests there is no brain activity or possibility of life once a person enters the flat line stage.
Researchers from the University of Montreal say this major discovery suggests there is a “whole new frontier in animal and human brain functioning.”
For the study, published in the journal PLOS ONE, the research team observed a human patient who was in an “extreme deep hypoxic coma.” The patient was also under strong anti-epileptic medication that he was required to take for health issues.
From the analysis of the patient, the researchers say they observed unexplainable phenomena – the patient was showing cerebral activity in the brain.
The team decided to recreate the patient’s state in cats. They used an anesthetic called isoflurane to put the cats in a very deep – but reversible – coma.
The cats then passed the flat EEG line, the stage linked to silence in the governing area of the brain called the cortex.
During this flat line EEG, the researchers observed 100% cerebral brain activity in the cats through oscillations that were generated in the hippocampus – the part of the brain responsible for memory and learning. The oscillations were then transmitted to the cortex.
From this, the research team concluded that the EEG waves demonstrated in the cats, named “Nu-complexes,” were the same as those they observed in the brain of the human patient.
Daniel Kroeger of the Department of Stomatology at the University of Montreal and lead study author, says one implication of this finding is that there is now evidence that the brain is able to survive in an extremely deep coma if the integrity of the nervous structures is preserved.
“We also found that the hippocampus can send ‘orders’ to the brain’s commander in chief, the cortex.
The possibility of studying the learning and memory processes of the hippocampus during a state of coma will help further understanding of them. In short, all sorts of avenues for basic research are now open to us.”
Dr. Florin Amzica, professor of the School of Dentistry at the University of Montreal and director of the study, says that the most helpful aspect of this study is the potential for neuroprotection from the extreme deep coma.
After some patients have suffered a major injury, doctors place them in an artificial coma in order to protect their body and brain during recovery. But Dr. Amzica notes that the extreme deep coma used in the study could be more protective:
“Indeed, an organ or muscle that remains inactive for a long time eventually atrophies. It is plausible that the same applies to a brain kept for an extended period in a state corresponding to a flat EEG.”
“An inactive brain coming out of a prolonged coma may be in worse shape than a brain that has had minimal activity. Research on the effects of extreme deep coma during which the hippocampus is active, through Nu-complexes, is absolutely vital for the benefit of patients.”
However, Dr. Amzica warns of the importance of understanding exactly what these findings mean, particularly for patients and their relatives:
“Those who have decided to or have to ‘unplug’ a near-brain-dead relative needn’t worry or doubt their doctor. The current criteria for diagnosing brain death are extremely stringent. Our finding may perhaps in the long term lead to a redefinition of the criteria, but we are far from that. Moreover, this is not the most important or useful aspect of our study.”
Medical News Today recently reported on a study that revealed how sleep helps to boost reproduction of cells involved in brain repair.