Be it feelings of pain or pain relief, new research has shown that mice can mirror those emotions in their brain and, as a result, feel the same way as their companions.
For example, if an injured mouse come across a healthy companion, the social contact is enough to pass on the pain to the fellow mouse. Soon, the bystander mouse will start behaving as though it is in pain. And this transfer of emotions isn’t just restricted to pain — it’s the same for fear and pain relief as well.
A study published in Science News, a magazine that publishes latest news of science, medicine and technology, found that mice can mirror each other’s feelings due to brain pathways linking empathy and social behaviour.
Monique Smith, a neuroscientist at Stanford University, who conducted the study on pain and relief along with her colleagues and published their findings in the magazine, said that it “can help researchers understand human empathy”, and the same can, perhaps, is applied one day to treat those with emotional and behavioural disorders.
In one of the experiments, the researchers injected a mouse with a substance causing an arthritis-like inflammation in one hind paw. They left another mouse unharmed. After about an hour, the mouse that was left untouched had worse pain than the one that was injected. While the injected mice felt pain in just one paw, the mouse that wasn’t touched showed heightened sensitivity in both hind paws, said Jeffrey Mogil, a neuroscientist at McGill University in Montreal, who was not part of the study.
In another experiment, two mice were injected with the inflammation-causing substance, and only got a dose of morphine too. A few hours later, the mouse that didn’t get the morphine injection, too, behaved as if it had got the drug.
Robert Malenka, a neuroscientist at Stanford University, said: “You’ve actually relieved pain in this animal simply by letting it hang out with another animal whose pain was relieved.”
To understand this behaviour, Smith, Malenka and another neuroscientist studied the brain regions that were responsible for such feelings when the mice spent time together. They figured it was nerve cells in an area of the brain concerning memory and cognition — the same area of the brain associated with human empathy.
Who knows, maybe in future this research can actually prompt further studies of how social interaction among humans may provide pain relief.