Research reveals how the brain links social thinking and emotional processing

We've all been there. Right after leaving the party, your brain is suddenly filled with intrusive thoughts of what other people were thinking. “Did they think I talked too much?” “Did my jokes offend them?” “Did they have a good time?”

In a new study from Northwestern Medicine, scientists seek to better understand how humans evolved to become skilled at considering what's going on in the minds of others. I tried. The findings could one day influence the treatment of mental illnesses such as anxiety and depression.

We spend a lot of time wondering, “What is that person feeling or thinking?” Did I say something that offended them? ’ The part of the brain that makes this possible is in an area of ​​the human brain that recently expanded during human evolution, meaning it is a recently developed process. Essentially, you're putting yourself in someone else's mind and guessing what they're thinking, even though you don't actually know it yourself. ”

Rodrigo Braga, senior author

The study discovered a more recently evolved and sophisticated part of the human brain that supports social interaction. It's called the social cognitive network – it's connected to an ancient part of the brain called the amygdala and is constantly communicating.

The amygdala, also known as the “lizard brain,” is typically associated with threat detection and fear processing. A classic example of the amygdala being activated is the physiological and emotional response to seeing a snake. That means your body freaks out, your heart races, your palms sweat, and so on. But the amygdala also does other things, Braga says.

“For example, the amygdala is responsible for social behaviors such as parenting, mating, aggression, and navigating social dominance hierarchies,” said Braga, assistant professor of neurology at Northwestern University Feinberg School of Medicine. “Previous studies have shown that the amygdala and social cognitive network are activated at the same time, but our study is novel because it shows that communication is happening all the time.”

The study was published in the journal Nov. 22. scientific progress.

High-resolution brain scans are key

There is a specific part of the amygdala called the medial nucleus that is very important for social behavior. This study shows for the first time that the medial nucleus of the amygdala is connected to newly evolved social cognitive network regions involved in thinking about others. This link to the amygdala helps shape the functioning of the social cognitive network by providing access to the amygdala's role in processing emotionally significant content.

This was only possible thanks to functional magnetic resonance imaging (fMRI). fMRI is a non-invasive brain imaging technique that measures brain activity by detecting changes in blood oxygen levels. Kendrick Kaye, a University of Minnesota collaborator and co-author of the study, has joined Braga and co-corresponding author Donisa Edmonds with six people as part of the Natural Scenery Dataset (NSD). provided fMRI data taken from the brains of study participants. These high-resolution scans have allowed scientists to see details of social cognitive networks that were never detected in lower-resolution brain scans. Moreover, they were able to reproduce this finding up to twice in each individual.

“One of the most exciting things was that we were able to identify areas of the network that we hadn't been able to see before,” said Edmonds, a neuroscience Ph.D. candidate in Braga's lab at Northwestern. “This was something that was underestimated before our study started, but because we had very high-resolution data, we were able to understand it.”

Possibility of treating anxiety and depression

Anxiety and depression are both associated with hyperactivity in the amygdala, which can contribute to exaggerated emotional responses and impaired emotional regulation, Edmonds said. Currently, people with either condition can undergo deep brain stimulation for treatment, but because the amygdala is located deep in the brain, just behind the eyes, it is difficult to undergo invasive surgical procedures. That's it. The authors said their findings could allow a much less invasive technique, transcranial magnetic stimulation (TMS), to use knowledge of this brain connectivity to improve treatment.

“Through this knowledge that the amygdala is connected to other brain regions, potentially some regions closer to the skull could be easier to target. This means that people doing TMS could instead use these “It means you can target the amygdala by targeting other areas,” Edmonds said.

The title of the study is “The human social cognitive network includes multiple regions within the amygdala.'' Other Northwestern co-authors include Christina Zelano, Joseph J. Salvo, Nathan Anderson, Maya Lakshman and Chaohan Yang.