Monkeys might not be known for their generosity, but when they do seem to act selflessly, a specific area in their brains keeps track of these kindnesses.
The discovery of this neuronal tally chart may help scientists to understand the neural mechanisms underlying normal social behavior in primates and humans, and might even provide insight into disorders such as autism, in which social processing is disrupted.
Steve Chang and his colleagues from Duke University in Durham, North Carolina, used electrodes to directly record neuronal activity in three areas of the brain prefrontal cortex that are known to be involved in social decision-making, while monkeys performed reward-related tasks.
When given the option either to drink juice from a tube themselves or to give the juice away to a neighbor, the test monkeys would mostly keep the drink. But when the choice was between giving the juice to the neighbor or neither monkey receiving it, the choosing monkey would frequently opt to give the drink to the other monkey.
The researchers found that in two out of the three brain areas being recorded, neurons fired in the presence or absence of the juice reward only. By contrast, the third area — known as the anterior cingulate gyrus — responded only when the monkey allocated the juice to the neighbor and observed it being received. The authors suggest the neurons in the ACG respond to and record the act simultaneously. The study’s results are published today in Nature Neuroscience.
Written By: Becky Summerscontinue to source article at scientificamerican.com