The cerebral mechanisms of social interaction in a couple deciphered by an MRI

What happens in our brain when we have physical contact with a loved one? Researchers from Aalto University and the PET Center in Turku (Finland) studied the brain mechanisms of two individuals during social interactions. The results of their study were published in the journal Frontiers in Psychiatry.

The researchers performed simultaneous MRI scans of two people to study the perception of touch in the brain. According to them, the MRI of two individuals embracing in the arms of each other shows how physical contact drives the changes in the brains of couples. This new method, which simultaneously collects images of the brain activity of two people, has allowed researchers to study the influence of social interaction on their brains.

To carry out the experiment, the researchers studied ten couples. They asked them to spend 45 minutes inside the specially designed MRI scanner to obtain brain images of the two people during physical contact.

Mental imitation, a fundamental mechanism of social interaction

According to Riitta Hari, professor emeritus at Aalto University, “it is an excellent start for the study of natural interactions. People don’t just react to external stimuli, but adjust their actions moment by moment based on what they expect next..” According to her, while magnetic resonance has always been used to scan one person at a time, technology developed at Aalto University has split the head coil used for regular brain scans into two separate coils to achieve simultaneous brain images of two people placed close enough together inside the scanner.

During the scan, the participants were facing each other, almost hugging each other and, as instructed by the researchers, the subjects took turns slapping their lips. While the two people were inside the scanner, the researchers recorded alterations reflected in the motor and sensory areas of the couples’ brains, which helped them study the fundamentals of human interaction.

“During a social interaction, people’s brains are literally synchronizeddevelops Professor Lauri Nummenmaa, of the PET center in Turku. Mental imitation associated with the movements of other people is probably one of the fundamental mechanisms of social interaction. New technology being developed today will provide entirely new possibilities for studying brain mechanisms of social interaction.”

“For example, during a conversation or problem solving, people’s brain functions are flexibly linked together.adds Riitta Hari. However, we cannot understand the brain basis of real-time social interaction if we cannot simultaneously scan the brain functions of both people involved in the social interaction..”