The activation of an empathy centre located between the two hemispheres of the brain is the driver for people to help others when they are feeling pain, suggests new research carried out under EU project SOCIORATS. Deactivating or reducing activity in the rostral cingulate cortex (rCC) alters behaviour, potentially offering a clue to why sociopaths and bullies, lacking empathy, behave badly with other humans. “This really points to the importance of this region of the brain,” says Dr Christian Keysers, co-head of the Social Brain Lab at the Netherlands Institute for Neuroscience in Amsterdam, which carried out the research. “We are getting closer to a true mechanistic understanding of what makes us social.” Supervised by Dr Keysers, with the support of the Marie Skłodowska-Curie programme, Dr Julen Hernandez-Lallement carried out experiments on 100 pairs of rats, discovering, like humans, rats will change their behaviour if they see it is hurting a fellow rat. He offered the rats a choice between two levers, one that provided a pellet of sugar with little effort and one that delivered the same amount of sugar with twice the effort due to a harder spring attached to it. Once the rats developed a strong preference for one of the levers, Dr Hernandez-Lallement then rigged them so the preferred lever not only delivered the sugar pellet but also delivered a little electric shock to a fellow rat next door.
They found half the rats switched to the other lever they liked less before. “Typically, that meant the rats are willing to work harder for sugar if the easy option is bad for another rat,” says Dr Keysers. They then took the experiment a stage further, deactivating the rCC, where they had found mirror neurons for pain. They found that without a fully functioning rCC the rats no longer avoided the shock lever that hurt the fellow rat. They showed no aversion towards actions that harm others. The research team noticed that not all the rats changed their behaviour in the first part of the experiment to help a fellow rat. “That’s interesting because it mirrors the individual differences we also find in humans and opens up avenues for further research on individual differences,” says Dr Keysers. As a result of the project’s insights, the researchers believe more neurologists will focus on the rCC in order to explain differences between individuals and to seek pharmacological interventions to treat criminal psychopathy. The laboratory is currently repeating the rat experiment on the anterior insula, another area of the brain linked to empathy. Dr Keysers is passionate about this kind of fundamental research at the border between social sciences and neuroscience because it has so much to teach us about human nature and that of other mammals: “Darwinian thinking suggests that animals evolved to win a race for the fittest, most selfish people. And yet our studies suggest that we (or at least many of us) are hard-wired to be empathic. That sheds a sweeter light on the world we live in.”
SOCIORATS, rats, empathy, rostral cingulate cortex (rCC), anterior insula, empathic, sociopaths, bullies