Have you ever come home after a party with spinning thoughts about what the other guests thought about you? Have you gone to bed worried that you talked too much or told a joke that offended someone?
Research published Friday in the journal Science Advances revealed the mechanisms in our brains responsible for these thoughts. It indicates that our overthinking about social interactions is part of a process that links the ancient “lizard brain” with more recently developed areas of our brains.
“We spend a lot of time wondering, ‘What is that person feeling, thinking? Did I say something to upset them?’” said Rodrigo Braga of Northwestern University, senior author of the research. “The parts of the brain that allow us to do this are in regions of the human brain that have expanded recently in our evolution, and that implies that it’s a recently developed process. 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.”
These more recently evolved and advanced parts of the brain are known as the social cognitive network. For the first time, authors of the recent study showed how these parts of the brain are in constant communication with the amygdala, an ancient part of our brain often referred to as the “lizard brain” that is associated with fear and emotions.
Functions linked to this part of the brain include the racing heartbeat and sweaty palms people experience when faced with a frightening situation. They also include “social behaviors like parenting, mating, aggression and the navigation of social-dominance hierarchies,” said Braga.
“Previous studies have found co-activation of the amygdala and social cognitive network, but our study is novel because it shows the communication is always happening,” he explained.
Specifically, the study was the first to show connection between the amygdala’s medial nucleus and our newly evolved social cognitive network region. According to Northwestern, this access to the amygdala’s emotional processing helps shape the social cognitive network.
Researchers used functional magnetic resonance imaging (fMRI), a noninvasive brain-imaging technique, to demonstrate the amygdala-social cognitive network region link. Findings were replicated twice in each patient through data from six patients in the Natural Scenes Dataset (NSD).
Going forward, the researchers believe their findings can inform new treatments for anxiety and depression, conditions that involve amygdala hyperactivity. Already, deep brain stimulation is offered as a treatment for the conditions, but it requires a surgical procedure due to the location of the amygdala.
“Now, with this study’s findings, a much less-invasive procedure, transcranial magnetic stimulation (TMS), might be able to use knowledge about this brain connection to improve treatment, the authors said,” per Northwestern.
During a TMS procedure for depression, an electromagnetic coil is placed against the scalp to deliver magnetic pulses intended to stimulate nerve cells, according to the Mayo Clinic. While TMS has been approved by the U.S. Food and Drug Administration, it is usually used to treat depression if other treatments are not effective.
“Although the biology of why TMS works isn’t completely understood, the stimulation appears to affect how the brain is working,” said the clinic. “It seems to ease depression symptoms and improve mood.”
TMS is not the same as electroconvulsive therapy (ECT), which the Mayo Clinic said has been known to cause seizures or memory loss. Additionally, it does not require the use of anesthesia and is generally considered both safe and well tolerated. Potential side effects associated with TMS include scalp discomfort and pain, headache, tingling, spasms, twitching of facial muscles and lightheadedness.