Beyond the EEG: Life after ‘flat line’

Discovery of a new type of brain activity hints at just how much we have left to learn

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Beyond the “flat line,” there is no life—or so it was long believed. Florin Amzica at the Université de Montréal has detected a previously unknown type of brain activity in coma patients. It exists beyond a flat electroencephalogram (or EEG), which measures the electrical activity of the brain. “This finding came as a total surprise,” Amzica says.

Amzica’s study began after a colleague in Romania contacted him regarding a patient who’d suffered cardiorespiratory arrest, was revived, and brought to hospital. Doctors gave him anti-epileptic medication, which “deepened his coma,” Amzica says. An EEG specialist came to see the patient, and the electrical pattern being given off by the man’s brain “was completely unknown.” Amzica recreated the condition in the lab.

Amzica and his team gave anaesthesia to cats, putting them into an extremely deep, yet reversible, coma. The cats moved beyond the flat line on the EEG and into a new state, generating a previously unknown type of oscillation from the hippocampus, the part of the brain responsible for memory and learning. Amzica called these strange EEG waves, which were just like those observed in the human patient, “Nu-complexes.” When cats were brought out of the coma, they suffered no visible damage, although such studies haven’t been attempted in humans.

For family members who’ve had to grapple with end-of-life decisions for a loved one, Amzica offers reassurance. “Such a decision is taken under the guidance of physicians,” he notes. “They are obliged to do a battery of tests that establish without doubt that the brain is dead,” including examinations into whether blood is still reaching the brain. “In that case, there is no going into this deeper state.” The discovery of this Nu-complex state might be therapeutically useful: If we don’t use an organ, including the brain, it atrophies. This coma, in which neurons keep firing, could be protective. “It gives hope for a better outcome for these patients.”

The fact that Amzica’s discovered an entirely new type of brain activity hints at just how much we have left to learn. Despite decades of research, the human mind remains largely an undiscovered country.