How your ‘lizard brain’ might help manage anxiety and depression

You had a blast at the party, telling funny stories and jokes, chatting with friends and strangers alike. But after you leave, you start to wonder: Did they really like me or did they think I talked too much? Was I actually funny or did the other guests find me obnoxious?
That’s your “lizard brain” whispering to you, according to a study from Northwestern Medicine. And the findings on our skills thinking about what others might be thinking could one day lead to treatments for psychiatric conditions like anxiety and depression.
The study was published Nov. 22 in the journal Science Advances.
In the first study of its kind to map with functional magnetic resonance imaging the details of the brain’s social cognitive network, researchers found that the amygdala — the ancient part of the brain often called the primitive “lizard brain”— is always talking to the part of the brain that supports social interaction. Tapping into that connection could be key to resolving some psychiatric issues that respond to treatment that stimulates parts of the brain.
The so-called lizard brain is the amygdala, which most people associate with its fight-or-flight warning system. But it’s also responsible for social behaviors including parenting, mating, aggression and navigating social hierarchies, said study senior author Rodrigo Braga. And it works very closely with the social cognitive network in the brain.
“We spend a lot of time wondering, “What is that person feeling, thinking? Did I say something to upset them?” Braga said. He added that “in essence, you’re putting yourself in someone else’s mind and making inferences about what that person is thinking when you cannot really know.”
According to a news release from Northwestern Medicine, this is the first study to show the amygdala’s medial nucleus connected to the social cognitive network regions, the part of the brain that thinks about other people. “This link to the amygdala helps shape the function of the social cognitive network by giving it access to the amygdala’s role in processing emotionally important content,” the release said.
The study team found this in collaboration with the University of Minnesota. A study co-author there, Donnisa Edmonds, provided high-resolution fMRI scans that measure brain activity. With the scans, the researchers could see details of the social cognitive network that had never been detected on lower-resolution brain scans. And they were able to replicate the findings once or twice in each individual to verify what they saw.
The researchers said that the amygdala is hyperactive with both anxiety and depression, so it can lead to excessive emotional response and poor emotional regulation, per Edmonds. Deep brain stimulation for either condition is an invasive, surgical procedure because of the amygdala’s location directly behind the eyes deep in the brain. But other connected parts of the brain are closer to the skull, they learned.
The researchers believe that transcranial magnetic stimulation (TMS) could use that to provide effective treatment.
“Through this knowledge that the amygdala is connected to other brain regions — potentially some that are closer to the skull, which is an easier region to target — that means people who do TMS could target the amygdala instead by targeting these other regions,” Edmonds said.