Researchers have just discovered the origin of the phenomenon of overthinking, literally “thinking too much”, which leads to ruminating on thoughts, negative feelings or even past events.
- The parts of the brain that support social interactions are connected and in constant communication with the amygdala.
- These exchanges between the two zones can help to understand the birth of ruminations.
- This discovery could help treat depression and anxiety.
As soon as you leave a party, a flood of questions torments you: “Did they think I talked too much?”, “Did my joke offend them?”, “Why did I say that?”… This mental rumination, sometimes very difficult to stop, is nicknamed overthinking, in English.
Scientists from Northwestern University have shed light on one of the mechanisms of this phenomenon which leads to imagining what is happening in the minds of others. Their discovery, presented in the journal Science Advances on November 22, 2024, could one day help treat psychiatric conditions like anxiety and depression.
Thinking too much: the amygdala and the social cognitive network connected
“We spend a lot of time wondering, ‘How is this person feeling?’, ‘Did I say something to upset them?’,” says lead author Rodrigo Braga. The parts of the brain that make us allow you to do this are in regions of the human brain that have developed recently in our evolution, and this implies that it is a recently developed process. In essence, you are putting yourself in someone’s mind. else and you make deductions about what that person is thinking when you can’t really know.”
Using functional magnetic resonance imaging (MRI), scientists have discovered that areas of the social cognitive network – which support social interactions – are in constant communication with the amygdala. This part of the brain is known to play a role in managing threats and fear. Analyzes of brain scans of six volunteers reveal that brain areas of the social cognitive network have an important connection with the medial nucleus of the amygdala.
“This connection to the amygdala helps shape the function of the social cognitive network by providing access to the amygdala’s role in processing emotionally important content”indicate the researchers in a press release. The latter leads to ruminations, according to them.
“One of the most exciting things is that we were able to identify network regions that we weren’t able to see before”adds co-corresponding author Donnisa Edmonds. “This is something that had been underestimated before our study, and we were able to do it because we had such high-resolution data.”
Depression, anxiety: towards a new therapeutic option?
Faced with this discovery, researchers saw enormous potential for the fight against anxiety and depression, two psychological pathologies associated with hyperactivity of the amygdala. For them, the connectivity discovered between this area of the brain and that of the social cognitive network is likely to explain the excessive emotional responses and altered emotional regulation observed in patients. Which would then open up a new possible therapeutic avenue, according to them.
Indeed, currently, an anxious or depressed patient may be offered deep brain stimulation for treatment, but as the amygdala is located deep in the brain – directly behind the eyes – this means having an invasive surgical procedure. “Now, with the results of this study, a much less invasive procedure, transcranial magnetic stimulation (TMS), may be able to use knowledge about this brain connection to improve treatment,” assure the authors.
“With this knowledge that the amygdala is connected to other regions of the brain – potentially some that are closer to the skull, which is an easier region to target – this means that people doing TMS could instead target the amygdala. ‘amygdala by targeting these other regions”, specifies Donna Edmonds.
