Small social rodents can exhibit the kind of consoling behavior to others once thought to be strictly a human trait, researchers at Emory University’s Yerkes National Primate Research Center found.
The discovery could have important implications for patients with socially impaired disorders such as autism spectrum and schizophrenia, a co-author of the study said.
In a paper published this week in the journal Science, Yerkes researchers studied the prairie vole, a small rodent that mates for life and raises offspring together. The voles showed a consoling behavior to those they shared a cage with, even those who were not relatives, said Dr. Larry Young, a professor at Yerkes and in the Department of Psychiatry.
Once thought to be strictly human, consoling behavior has since been observed in chimpanzees, elephants and crows. But this is the first time it has been detected in rodents and animals of this size, Young said.
“What this study shows is you don’t need a big brain, you don’t need complex cognitive processes to be able to show this kind of response,” he said. The empathy the voles feel may not be the same as what humans feel, but they probably share a kind of “gut reaction we also have when you see someone in pain, a gut instinctive tendency to direct your attention to that person in pain and maybe try to help them,” Young said.
The same behavior was not observed in a similar animal, the meadow vole, that does not partner up so the behavior may have evolved from that social context, he said. Mothers have an instinctive drive to console offspring, and this may be similar to that for others, he said.
“If you live in a family unit, if anybody is stressed the whole family can be stressed,” Young said. “It seems that because they live in this social structure this capacity to detect the stress of another and then to act upon that to try to relieve that stress is an adaptive behavior.
It is also the first time it has been found in an important lab animal, he said.
“For the first time, we now have an animal model where we can go in and begin to look at the brain mechanisms,” Young said.
And there they found what appears to be another similarity. When they observed consoling animals, the part of the brain that lit up most significantly is the anterior cingulate cortex, the same part of the brain that lights up in humans when observing another in pain. The chemical messenger oxytocin, known to be involved in humans in a mother bonding to an infant, for instance, also seemed to be involved in the voles. The researchers confirmed that blocking the action of oxytocin in that part of the brain caused the voles not to console.
That could be important for human disorders where there is a similar disability, such as autism, Young said.
“Being able to show empathy requires that you can detect the distress of others and consoling requires that you act upon that,” he said. “What we think we are tapping into is a neural system that alerts the brain when another familiar individual is distressed and then to act upon that.”
While they are still working on exploring the new finding and better understanding the mechanisms involved, designing a therapy will probably be more complex than just giving patients an oxytocin supplement, Young said. It probably also needs to have some component of behavioral therapy, he said.
“It’s like teaching the brain how to be empathetic, how to detect the stress of others,” Young said.