Scientists discover brain region that enables people to interact socially

LEIPZIG, Germany — Different parts of the brain carry out distinct roles. From interpreting sounds and images to regulating subconscious motor functions like heartbeat, the brain is robust. Every region has a job and some regions overlap in function. Its complexity makes it challenging to map which regions control certain tasks, especially considering those that carry out a wide range of jobs, such as the inferior parietal lobe (IPL). However, a group of researchers have determined that specific areas within the IPL control our ability to interact with each other socially.

This study, carried out by scientists from the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) in Leipzig and McGill University in Montreal, offers insight into the way in which our brains perceive the world through the inferior parietal lobe.

In their research, they found that the various regions of the IPL are wired for specific mental processes. This includes the ability to focus, language processing, and social interaction — displayed by the capacity to take other people’s perspectives into account. In addition, these parts of the brain interact with a variety of other areas in the brain depending on the distinct process taking place.

Social interactions are ‘complex’ for the brain

Brain IPL
When it comes to language comprehension, the anterior IPL in the left hemisphere of the brain is of importance (green). For attention, it is the anterior IPL in the right side of the brain (pink). If, on the other hand, social skills are required, the posterior parts of the IPL in both hemispheres of the brain spring into action simultaneously (orange, purple). (Credit: eLife)

The front most portion of the IPL in the brain’s left hemisphere springs into action when someone speaks to enable comprehension. Conversely, the front most portion of the IPL in the brain’s right hemisphere is in charge of attention span and the ability to focus. The rear regions of the IPL in both sides of the brain activate concurrently when social interactions are necessary.

“Social cognition requires the most complex interpretation. Therefore, the IPLs on both sides of the brain probably work together here,” explains study first author Ole Numssen in a university release.

Furthermore, these smaller sections of the brain collaborate with other brain regions. Each IPL division typically corresponds to a single brain hemisphere when it comes to attentiveness and communication. It’s a two-way street when it comes to social capabilities. In this case, the more complicated the work, the more extensive the contact with other regions.

According to Numssen, even in large apes, brain areas that connect with the IPL handle more complicated information in addition to simple physical impulses. These sections appear to have consistently digested more and more sophisticated information as they evolved through time. As a matter of fact, the IPL in humans is distinct from that of higher primates, suggesting that it has developed through time to support human cognitive activities.

Our brains are always adapting

The team studied these brain connections using three activities that individuals had to complete during an MRI scan. As part of the first assignment, individuals demonstrated their ability to process and communicate language effectively. In order to achieve this, they had to look at both genuine words (like “pigeon”), and other words like “pulre” that have no true meaning. Scientists then asked the group to distinguish the real words from the fake.

In the second test, each individual had to focus on one particular screen while the other screen was more engaging. This tested the ability of each individual to focus and maintain their attention, regardless of other stimulating surroundings. The “Sally Anne” exam was used in the third test to assess their capacity to see things from another person’s viewpoint. It is a four-panel cartoon depicting two people’s interactions with one another. Only those who imagine themselves in someone else’s shoes would be capable of accurately responding to the final question.

“Our results provide insight into the basic functioning of the human brain. We show how our brains dynamically adapt to changing requirements. To do this, it links specialized individual areas, such as the IPL, with other more general regions. The more demanding the tasks, the more intensively the individual areas interact with each other. This makes highly complex functions such as language or social skills possible,” Numssen says. “The IPL may ultimately be considered as one of the areas with which we interpret the world.”

The findings appear in the journal eLife.