RESEARCHERS FIND COMMON BRAIN RESPONSE TO ANAESTHESIA ACROSS SPECIES

Researchers led by neuroscientist Andrea Luppi at the University of Oxford compared brain activity in six animal species while awake and under general anaesthesia, according to a study published in the journal Nature Neuroscience. The team examined humans, macaques, marmosets, mice, zebrafish and nematode roundworms, whose lineages diverged roughly 700 million years ago, the study says. Different anaesthetic drugs were used for each species, but the researchers reported consistent patterns in neural activity across all six. The study says this brings scientists closer to understanding how anaesthesia suspends consciousness without shutting down the brain.

The researchers measured brain activity in the mammals using functional MRI scans, which track blood flow to approximate which brain regions are active, according to the study. Zebrafish and nematode roundworms were genetically modified so that their firing neurons lit up as calcium entered them, allowing direct observation of neural activity, the researchers say. The study found that no organism tested proved unaffected by general anaesthesia, with plants and single-celled paramecia also responding to the drugs. General anaesthesia has been used in medicine since its first public demonstration in 1846, but researchers say its underlying mechanism remains unexplained, according to the study.

Luppi and the team said focusing on effects shared across multiple anaesthetic drugs and species let them rule out factors specific to any single drug, species or method. This approach, they said, points to a neural mechanism common to all the species studied: a breakdown in responsiveness to the environment. The team said the shared patterns suggest a common neural basis for loss of responsiveness under anaesthesia, rather than effects unique to individual drugs or species. Findings appear in Nature Neuroscience.

Note for you: Report A's full text did not actually contain any content about the anaesthesia/animal-brain study — it was a different headline (about breath-holding divers) followed by an unrelated list of navigation links from the outlet's site, with no matching article body. I wrote the piece from Report B's content alone, since it was the only source with substantive, usable facts.